diff options
Diffstat (limited to 'firmware/thread.c')
| -rw-r--r-- | firmware/thread.c | 2535 |
1 files changed, 1436 insertions, 1099 deletions
diff --git a/firmware/thread.c b/firmware/thread.c index 8bebfedbf5..259a66a652 100644 --- a/firmware/thread.c +++ b/firmware/thread.c @@ -28,6 +28,10 @@ #ifdef RB_PROFILE #include <profile.h> #endif +/**************************************************************************** + * ATTENTION!! * + * See notes below on implementing processor-specific portions! * + ***************************************************************************/ /* Define THREAD_EXTRA_CHECKS as 1 to enable additional state checks */ #ifdef DEBUG @@ -59,9 +63,7 @@ * event queues. The kernel object must have a scheme to protect itself from * access by another processor and is responsible for serializing the calls * to block_thread(_w_tmo) and wakeup_thread both to themselves and to each - * other. If a thread blocks on an object it must fill-in the blk_ops members - * for its core to unlock _after_ the thread's context has been saved and the - * unlocking will be done in reverse from this heirarchy. + * other. Objects' queues are also protected here. * * 3) Thread Slot * This locks access to the thread's slot such that its state cannot be @@ -70,70 +72,66 @@ * a thread while it is still blocking will likely desync its state with * the other resources used for that state. * - * 4) Lists - * Usually referring to a list (aka. queue) that a thread will be blocking - * on that belongs to some object and is shareable amongst multiple - * processors. Parts of the scheduler may have access to them without actually - * locking the kernel object such as when a thread is blocked with a timeout - * (such as calling queue_wait_w_tmo). Of course the kernel object also gets - * it lists locked when the thread blocks so that all object list access is - * synchronized. Failure to do so would corrupt the list links. - * - * 5) Core Lists + * 4) Core Lists * These lists are specific to a particular processor core and are accessible - * by all processor cores and interrupt handlers. They are used when an - * operation may only be performed by the thread's own core in a normal - * execution context. The wakeup list is the prime example where a thread - * may be added by any means and the thread's own core will remove it from - * the wakeup list and put it on the running list (which is only ever - * accessible by its own processor). - */ -#define DEADBEEF ((unsigned int)0xdeadbeef) -/* Cast to the the machine int type, whose size could be < 4. */ -struct core_entry cores[NUM_CORES] IBSS_ATTR; -struct thread_entry threads[MAXTHREADS] IBSS_ATTR; - -static const char main_thread_name[] = "main"; -extern int stackbegin[]; -extern int stackend[]; + * by all processor cores and interrupt handlers. The running (rtr) list is + * the prime example where a thread may be added by any means. + */ -/* core_sleep procedure to implement for any CPU to ensure an asychronous wakup - * never results in requiring a wait until the next tick (up to 10000uS!). May - * require assembly and careful instruction ordering. +/*--------------------------------------------------------------------------- + * Processor specific: core_sleep/core_wake/misc. notes + * + * ARM notes: + * FIQ is not dealt with by the scheduler code and is simply restored if it + * must by masked for some reason - because threading modifies a register + * that FIQ may also modify and there's no way to accomplish it atomically. + * s3c2440 is such a case. + * + * Audio interrupts are generally treated at a higher priority than others + * usage of scheduler code with interrupts higher than HIGHEST_IRQ_LEVEL + * are not in general safe. Special cases may be constructed on a per- + * source basis and blocking operations are not available. + * + * core_sleep procedure to implement for any CPU to ensure an asychronous + * wakup never results in requiring a wait until the next tick (up to + * 10000uS!). May require assembly and careful instruction ordering. * - * 1) On multicore, stay awake if directed to do so by another. If so, goto step 4. - * 2) If processor requires, atomically reenable interrupts and perform step 3. - * 3) Sleep the CPU core. If wakeup itself enables interrupts (stop #0x2000 on Coldfire) - * goto step 5. + * 1) On multicore, stay awake if directed to do so by another. If so, goto + * step 4. + * 2) If processor requires, atomically reenable interrupts and perform step + * 3. + * 3) Sleep the CPU core. If wakeup itself enables interrupts (stop #0x2000 + * on Coldfire) goto step 5. * 4) Enable interrupts. * 5) Exit procedure. + * + * core_wake and multprocessor notes for sleep/wake coordination: + * If possible, to wake up another processor, the forcing of an interrupt on + * the woken core by the waker core is the easiest way to ensure a non- + * delayed wake and immediate execution of any woken threads. If that isn't + * available then some careful non-blocking synchonization is needed (as on + * PP targets at the moment). + *--------------------------------------------------------------------------- */ -static inline void core_sleep(IF_COP_VOID(unsigned int core)) - __attribute__((always_inline)); - -static void check_tmo_threads(void) - __attribute__((noinline)); -static inline void block_thread_on_l( - struct thread_queue *list, struct thread_entry *thread, unsigned state) - __attribute__((always_inline)); +/* Cast to the the machine pointer size, whose size could be < 4 or > 32 + * (someday :). */ +#define DEADBEEF ((uintptr_t)0xdeadbeefdeadbeefull) +struct core_entry cores[NUM_CORES] IBSS_ATTR; +struct thread_entry threads[MAXTHREADS] IBSS_ATTR; -static inline void block_thread_on_l_no_listlock( - struct thread_entry **list, struct thread_entry *thread, unsigned state) - __attribute__((always_inline)); +static const char main_thread_name[] = "main"; +extern uintptr_t stackbegin[]; +extern uintptr_t stackend[]; -static inline void _block_thread_on_l( - struct thread_queue *list, struct thread_entry *thread, - unsigned state IF_SWCL(, const bool single)) +static inline void core_sleep(IF_COP_VOID(unsigned int core)) __attribute__((always_inline)); -IF_SWCL(static inline) struct thread_entry * _wakeup_thread( - struct thread_queue *list IF_SWCL(, const bool nolock)) - __attribute__((IFN_SWCL(noinline) IF_SWCL(always_inline))); +void check_tmo_threads(void) + __attribute__((noinline)); -IF_SWCL(static inline) void _block_thread( - struct thread_queue *list IF_SWCL(, const bool nolock)) - __attribute__((IFN_SWCL(noinline) IF_SWCL(always_inline))); +static inline void block_thread_on_l(struct thread_entry *thread, unsigned state) + __attribute__((always_inline)); static void add_to_list_tmo(struct thread_entry *thread) __attribute__((noinline)); @@ -141,9 +139,6 @@ static void add_to_list_tmo(struct thread_entry *thread) static void core_schedule_wakeup(struct thread_entry *thread) __attribute__((noinline)); -static inline void core_perform_wakeup(IF_COP_VOID(unsigned int core)) - __attribute__((always_inline)); - #if NUM_CORES > 1 static inline void run_blocking_ops( unsigned int core, struct thread_entry *thread) @@ -159,10 +154,9 @@ static inline void store_context(void* addr) static inline void load_context(const void* addr) __attribute__((always_inline)); -void switch_thread(struct thread_entry *old) +void switch_thread(void) __attribute__((noinline)); - /**************************************************************************** * Processor-specific section */ @@ -172,8 +166,7 @@ void switch_thread(struct thread_entry *old) * Start the thread running and terminate it if it returns *--------------------------------------------------------------------------- */ -static void start_thread(void) __attribute__((naked,used)); -static void start_thread(void) +static void __attribute__((naked,used)) start_thread(void) { /* r0 = context */ asm volatile ( @@ -188,19 +181,18 @@ static void start_thread(void) #endif "mov lr, pc \n" /* Call thread function */ "bx r4 \n" - "mov r0, #0 \n" /* remove_thread(NULL) */ - "ldr pc, =remove_thread \n" - ".ltorg \n" /* Dump constant pool */ ); /* No clobber list - new thread doesn't care */ + thread_exit(); + //asm volatile (".ltorg"); /* Dump constant pool */ } /* For startup, place context pointer in r4 slot, start_thread pointer in r5 * slot, and thread function pointer in context.start. See load_context for * what happens when thread is initially going to run. */ #define THREAD_STARTUP_INIT(core, thread, function) \ - ({ (thread)->context.r[0] = (unsigned int)&(thread)->context, \ - (thread)->context.r[1] = (unsigned int)start_thread, \ - (thread)->context.start = (void *)function; }) + ({ (thread)->context.r[0] = (uint32_t)&(thread)->context, \ + (thread)->context.r[1] = (uint32_t)start_thread, \ + (thread)->context.start = (uint32_t)function; }) /*--------------------------------------------------------------------------- * Store non-volatile context. @@ -232,11 +224,11 @@ static inline void load_context(const void* addr) #if defined (CPU_PP) #if NUM_CORES > 1 -extern int cpu_idlestackbegin[]; -extern int cpu_idlestackend[]; -extern int cop_idlestackbegin[]; -extern int cop_idlestackend[]; -static int * const idle_stacks[NUM_CORES] NOCACHEDATA_ATTR = +extern uintptr_t cpu_idlestackbegin[]; +extern uintptr_t cpu_idlestackend[]; +extern uintptr_t cop_idlestackbegin[]; +extern uintptr_t cop_idlestackend[]; +static uintptr_t * const idle_stacks[NUM_CORES] NOCACHEDATA_ATTR = { [CPU] = cpu_idlestackbegin, [COP] = cop_idlestackbegin @@ -253,7 +245,7 @@ struct core_semaphores }; static struct core_semaphores core_semaphores[NUM_CORES] NOCACHEBSS_ATTR; -#endif +#endif /* CONFIG_CPU == PP5002 */ #endif /* NUM_CORES */ @@ -401,15 +393,15 @@ void corelock_unlock(struct corelock *cl) * no other core requested a wakeup for it to perform a task. *--------------------------------------------------------------------------- */ +#ifdef CPU_PP502x #if NUM_CORES == 1 -/* Shared single-core build debugging version */ static inline void core_sleep(void) { PROC_CTL(CURRENT_CORE) = PROC_SLEEP; nop; nop; nop; - set_interrupt_status(IRQ_FIQ_ENABLED, IRQ_FIQ_STATUS); + set_irq_level(IRQ_ENABLED); } -#elif defined (CPU_PP502x) +#else static inline void core_sleep(unsigned int core) { #if 1 @@ -429,8 +421,8 @@ static inline void core_sleep(unsigned int core) "ldr r1, [%[mbx], #0] \n" "tst r1, r0, lsr #2 \n" "bne 1b \n" - "mrs r1, cpsr \n" /* Enable interrupts */ - "bic r1, r1, #0xc0 \n" + "mrs r1, cpsr \n" /* Enable IRQ */ + "bic r1, r1, #0x80 \n" "msr cpsr_c, r1 \n" : : [ctl]"r"(&PROC_CTL(CPU)), [mbx]"r"(MBX_BASE), [c]"r"(core) @@ -452,11 +444,36 @@ static inline void core_sleep(unsigned int core) /* Wait for other processor to finish wake procedure */ while (MBX_MSG_STAT & (0x1 << core)); - /* Enable IRQ, FIQ */ - set_interrupt_status(IRQ_FIQ_ENABLED, IRQ_FIQ_STATUS); + /* Enable IRQ */ + set_irq_level(IRQ_ENABLED); #endif /* ASM/C selection */ } +#endif /* NUM_CORES */ #elif CONFIG_CPU == PP5002 +#if NUM_CORES == 1 +static inline void core_sleep(void) +{ + asm volatile ( + /* Sleep: PP5002 crashes if the instruction that puts it to sleep is + * located at 0xNNNNNNN0. 4/8/C works. This sequence makes sure + * that the correct alternative is executed. Don't change the order + * of the next 4 instructions! */ + "tst pc, #0x0c \n" + "mov r0, #0xca \n" + "strne r0, [%[ctl]] \n" + "streq r0, [%[ctl]] \n" + "nop \n" /* nop's needed because of pipeline */ + "nop \n" + "nop \n" + "mrs r0, cpsr \n" /* Enable IRQ */ + "bic r0, r0, #0x80 \n" + "msr cpsr_c, r0 \n" + : + : [ctl]"r"(&PROC_CTL(CURRENT_CORE)) + : "r0" + ); +} +#else /* PP5002 has no mailboxes - emulate using bytes */ static inline void core_sleep(unsigned int core) { @@ -486,8 +503,8 @@ static inline void core_sleep(unsigned int core) "ldrb r0, [%[sem], #0] \n" "cmp r0, #0 \n" "bne 1b \n" - "mrs r0, cpsr \n" /* Enable interrupts */ - "bic r0, r0, #0xc0 \n" + "mrs r0, cpsr \n" /* Enable IRQ */ + "bic r0, r0, #0x80 \n" "msr cpsr_c, r0 \n" : : [sem]"r"(&core_semaphores[core]), [c]"r"(core), @@ -512,11 +529,12 @@ static inline void core_sleep(unsigned int core) /* Wait for other processor to finish wake procedure */ while (core_semaphores[core].intend_wake != 0); - /* Enable IRQ, FIQ */ - set_interrupt_status(IRQ_FIQ_ENABLED, IRQ_FIQ_STATUS); + /* Enable IRQ */ + set_irq_level(IRQ_ENABLED); #endif /* ASM/C selection */ } -#endif /* CPU type */ +#endif /* NUM_CORES */ +#endif /* PP CPU type */ /*--------------------------------------------------------------------------- * Wake another processor core that is sleeping or prevent it from doing so @@ -553,7 +571,7 @@ void core_wake(unsigned int othercore) "strne r1, [%[ctl], %[oc], lsl #2] \n" "mov r1, r2, lsr #4 \n" "str r1, [%[mbx], #8] \n" /* Done with wake procedure */ - "msr cpsr_c, r3 \n" /* Restore int status */ + "msr cpsr_c, r3 \n" /* Restore IRQ */ : : [ctl]"r"(&PROC_CTL(CPU)), [mbx]"r"(MBX_BASE), [oc]"r"(othercore) @@ -604,7 +622,7 @@ void core_wake(unsigned int othercore) "strne r1, [r2, %[oc], lsl #2] \n" "mov r1, #0 \n" /* Done with wake procedure */ "strb r1, [%[sem], #0] \n" - "msr cpsr_c, r3 \n" /* Restore int status */ + "msr cpsr_c, r3 \n" /* Restore IRQ */ : : [sem]"r"(&core_semaphores[othercore]), [st]"r"(&PROC_STAT), @@ -640,8 +658,8 @@ void core_wake(unsigned int othercore) * * Needed when a thread suicides on a core other than the main CPU since the * stack used when idling is the stack of the last thread to run. This stack - * may not reside in the core in which case the core will continue to use a - * stack from an unloaded module until another thread runs on it. + * may not reside in the core firmware in which case the core will continue + * to use a stack from an unloaded module until another thread runs on it. *--------------------------------------------------------------------------- */ static inline void switch_to_idle_stack(const unsigned int core) @@ -670,11 +688,11 @@ static void core_switch_blk_op(unsigned int core, struct thread_entry *thread) /* Flush our data to ram */ flush_icache(); /* Stash thread in r4 slot */ - thread->context.r[0] = (unsigned int)thread; + thread->context.r[0] = (uint32_t)thread; /* Stash restart address in r5 slot */ - thread->context.r[1] = (unsigned int)thread->context.start; + thread->context.r[1] = thread->context.start; /* Save sp in context.sp while still running on old core */ - thread->context.sp = (void*)idle_stacks[core][IDLE_STACK_WORDS-1]; + thread->context.sp = idle_stacks[core][IDLE_STACK_WORDS-1]; } /*--------------------------------------------------------------------------- @@ -689,9 +707,8 @@ static void core_switch_blk_op(unsigned int core, struct thread_entry *thread) /*--------------------------------------------------------------------------- * This actually performs the core switch. */ -static void switch_thread_core(unsigned int core, struct thread_entry *thread) - __attribute__((naked)); -static void switch_thread_core(unsigned int core, struct thread_entry *thread) +static void __attribute__((naked)) + switch_thread_core(unsigned int core, struct thread_entry *thread) { /* Pure asm for this because compiler behavior isn't sufficiently predictable. * Stack access also isn't permitted until restoring the original stack and @@ -705,7 +722,6 @@ static void switch_thread_core(unsigned int core, struct thread_entry *thread) "mov sp, r2 \n" /* switch stacks */ "adr r2, 1f \n" /* r2 = new core restart address */ "str r2, [r1, #40] \n" /* thread->context.start = r2 */ - "mov r0, r1 \n" /* switch_thread(thread) */ "ldr pc, =switch_thread \n" /* r0 = thread after call - see load_context */ "1: \n" "ldr sp, [r0, #32] \n" /* Reload original sp from context structure */ @@ -733,13 +749,15 @@ static inline void core_sleep(void) /* FIQ also changes the CLKCON register so FIQ must be disabled when changing it here */ asm volatile ( - "mrs r0, cpsr \n" /* Prepare IRQ, FIQ enable */ - "bic r0, r0, #0xc0 \n" + "mrs r0, cpsr \n" + "orr r2, r0, #0x40 \n" /* Disable FIQ */ + "bic r0, r0, #0x80 \n" /* Prepare IRQ enable */ + "msr cpsr_c, r2 \n" "mov r1, #0x4c000000 \n" /* CLKCON = 0x4c00000c */ "ldr r2, [r1, #0xc] \n" /* Set IDLE bit */ "orr r2, r2, #4 \n" "str r2, [r1, #0xc] \n" - "msr cpsr_c, r0 \n" /* Enable IRQ, FIQ */ + "msr cpsr_c, r0 \n" /* Enable IRQ, restore FIQ */ "mov r2, #0 \n" /* wait for IDLE */ "1: \n" "add r2, r2, #1 \n" @@ -750,13 +768,14 @@ static inline void core_sleep(void) "ldr r2, [r1, #0xc] \n" /* Reset IDLE bit */ "bic r2, r2, #4 \n" "str r2, [r1, #0xc] \n" - "msr cpsr_c, r0 \n" /* Enable IRQ, FIQ */ + "msr cpsr_c, r0 \n" /* Enable IRQ, restore FIQ */ : : : "r0", "r1", "r2"); } #elif defined(CPU_TCC77X) static inline void core_sleep(void) { #warning TODO: Implement core_sleep + set_irq_level(IRQ_ENABLED); } #elif defined(CPU_TCC780X) static inline void core_sleep(void) @@ -765,8 +784,8 @@ static inline void core_sleep(void) asm volatile ( "mov r0, #0 \n" "mcr p15, 0, r0, c7, c0, 4 \n" /* Wait for interrupt */ - "mrs r0, cpsr \n" /* Unmask IRQ/FIQ at core level */ - "bic r0, r0, #0xc0 \n" + "mrs r0, cpsr \n" /* Unmask IRQ at core level */ + "bic r0, r0, #0x80 \n" "msr cpsr_c, r0 \n" : : : "r0" ); @@ -777,8 +796,8 @@ static inline void core_sleep(void) asm volatile ( "mov r0, #0 \n" "mcr p15, 0, r0, c7, c0, 4 \n" /* Wait for interrupt */ - "mrs r0, cpsr \n" /* Unmask IRQ/FIQ at core level */ - "bic r0, r0, #0xc0 \n" + "mrs r0, cpsr \n" /* Unmask IRQ at core level */ + "bic r0, r0, #0x80 \n" "msr cpsr_c, r0 \n" : : : "r0" ); @@ -787,6 +806,7 @@ static inline void core_sleep(void) static inline void core_sleep(void) { #warning core_sleep not implemented, battery life will be decreased + set_irq_level(0); } #endif /* CONFIG_CPU == */ @@ -796,8 +816,7 @@ static inline void core_sleep(void) *--------------------------------------------------------------------------- */ void start_thread(void); /* Provide C access to ASM label */ -static void __start_thread(void) __attribute__((used)); -static void __start_thread(void) +static void __attribute__((used)) __start_thread(void) { /* a0=macsr, a1=context */ asm volatile ( @@ -808,9 +827,8 @@ static void __start_thread(void) "move.l (%a1), %a2 \n" /* Fetch thread function pointer */ "clr.l (%a1) \n" /* Mark thread running */ "jsr (%a2) \n" /* Call thread function */ - "clr.l -(%sp) \n" /* remove_thread(NULL) */ - "jsr remove_thread \n" ); + thread_exit(); } /* Set EMAC unit to fractional mode with saturation for each new thread, @@ -823,9 +841,9 @@ static void __start_thread(void) */ #define THREAD_STARTUP_INIT(core, thread, function) \ ({ (thread)->context.macsr = EMAC_FRACTIONAL | EMAC_SATURATE, \ - (thread)->context.d[0] = (unsigned int)&(thread)->context, \ - (thread)->context.d[1] = (unsigned int)start_thread, \ - (thread)->context.start = (void *)(function); }) + (thread)->context.d[0] = (uint32_t)&(thread)->context, \ + (thread)->context.d[1] = (uint32_t)start_thread, \ + (thread)->context.start = (uint32_t)(function); }) /*--------------------------------------------------------------------------- * Store non-volatile context. @@ -874,8 +892,7 @@ static inline void core_sleep(void) *--------------------------------------------------------------------------- */ void start_thread(void); /* Provide C access to ASM label */ -static void __start_thread(void) __attribute__((used)); -static void __start_thread(void) +static void __attribute__((used)) __start_thread(void) { /* r8 = context */ asm volatile ( @@ -885,20 +902,16 @@ static void __start_thread(void) "mov #0, r1 \n" /* Start the thread */ "jsr @r0 \n" "mov.l r1, @(36, r8) \n" /* Clear start address */ - "mov.l 1f, r0 \n" /* remove_thread(NULL) */ - "jmp @r0 \n" - "mov #0, r4 \n" - "1: \n" - ".long _remove_thread \n" ); + thread_exit(); } /* Place context pointer in r8 slot, function pointer in r9 slot, and * start_thread pointer in context_start */ #define THREAD_STARTUP_INIT(core, thread, function) \ - ({ (thread)->context.r[0] = (unsigned int)&(thread)->context, \ - (thread)->context.r[1] = (unsigned int)(function), \ - (thread)->context.start = (void*)start_thread; }) + ({ (thread)->context.r[0] = (uint32_t)&(thread)->context, \ + (thread)->context.r[1] = (uint32_t)(function), \ + (thread)->context.start = (uint32_t)start_thread; }) /*--------------------------------------------------------------------------- * Store non-volatile context. @@ -947,7 +960,7 @@ static inline void load_context(const void* addr) } /*--------------------------------------------------------------------------- - * Put core in a power-saving state if waking list wasn't repopulated. + * Put core in a power-saving state. *--------------------------------------------------------------------------- */ static inline void core_sleep(void) @@ -969,9 +982,7 @@ static inline void core_sleep(void) #if THREAD_EXTRA_CHECKS static void thread_panicf(const char *msg, struct thread_entry *thread) { -#if NUM_CORES > 1 - const unsigned int core = thread->core; -#endif + IF_COP( const unsigned int core = thread->core; ) static char name[32]; thread_get_name(name, 32, thread); panicf ("%s %s" IF_COP(" (%d)"), msg, name IF_COP(, core)); @@ -987,9 +998,7 @@ static void thread_stkov(struct thread_entry *thread) #else static void thread_stkov(struct thread_entry *thread) { -#if NUM_CORES > 1 - const unsigned int core = thread->core; -#endif + IF_COP( const unsigned int core = thread->core; ) static char name[32]; thread_get_name(name, 32, thread); panicf("Stkov %s" IF_COP(" (%d)"), name IF_COP(, core)); @@ -998,111 +1007,67 @@ static void thread_stkov(struct thread_entry *thread) #define THREAD_ASSERT(exp, msg, thread) #endif /* THREAD_EXTRA_CHECKS */ -/*--------------------------------------------------------------------------- - * Lock a list pointer and returns its value - *--------------------------------------------------------------------------- - */ -#if CONFIG_CORELOCK == SW_CORELOCK -/* Separate locking function versions */ - /* Thread locking */ -#define GET_THREAD_STATE(thread) \ - ({ corelock_lock(&(thread)->cl); (thread)->state; }) -#define TRY_GET_THREAD_STATE(thread) \ - ({ corelock_try_lock(&thread->cl) ? thread->state : STATE_BUSY; }) -#define UNLOCK_THREAD(thread, state) \ - ({ corelock_unlock(&(thread)->cl); }) -#define UNLOCK_THREAD_SET_STATE(thread, _state) \ - ({ (thread)->state = (_state); corelock_unlock(&(thread)->cl); }) - -/* List locking */ -#define LOCK_LIST(tqp) \ - ({ corelock_lock(&(tqp)->cl); (tqp)->queue; }) -#define UNLOCK_LIST(tqp, mod) \ - ({ corelock_unlock(&(tqp)->cl); }) -#define UNLOCK_LIST_SET_PTR(tqp, mod) \ - ({ (tqp)->queue = (mod); corelock_unlock(&(tqp)->cl); }) - -/* Select the queue pointer directly */ -#define ADD_TO_LIST_L_SELECT(tc, tqp, thread) \ - ({ add_to_list_l(&(tqp)->queue, (thread)); }) -#define REMOVE_FROM_LIST_L_SELECT(tc, tqp, thread) \ - ({ remove_from_list_l(&(tqp)->queue, (thread)); }) - -#elif CONFIG_CORELOCK == CORELOCK_SWAP -/* Native swap/exchange versions */ +#if NUM_CORES > 1 +#define LOCK_THREAD(thread) \ + ({ corelock_lock(&(thread)->slot_cl); }) +#define TRY_LOCK_THREAD(thread) \ + ({ corelock_try_lock(&thread->slot_cl); }) +#define UNLOCK_THREAD(thread) \ + ({ corelock_unlock(&(thread)->slot_cl); }) +#define UNLOCK_THREAD_AT_TASK_SWITCH(thread) \ + ({ unsigned int _core = (thread)->core; \ + cores[_core].blk_ops.flags |= TBOP_UNLOCK_CORELOCK; \ + cores[_core].blk_ops.cl_p = &(thread)->slot_cl; }) +#else +#define LOCK_THREAD(thread) \ + ({ }) +#define TRY_LOCK_THREAD(thread) \ + ({ }) +#define UNLOCK_THREAD(thread) \ + ({ }) +#define UNLOCK_THREAD_AT_TASK_SWITCH(thread) \ + ({ }) +#endif + +/* RTR list */ +#define RTR_LOCK(core) \ + ({ corelock_lock(&cores[core].rtr_cl); }) +#define RTR_UNLOCK(core) \ + ({ corelock_unlock(&cores[core].rtr_cl); }) -/* Thread locking */ -#define GET_THREAD_STATE(thread) \ - ({ unsigned _s; \ - while ((_s = xchg8(&(thread)->state, STATE_BUSY)) == STATE_BUSY); \ - _s; }) -#define TRY_GET_THREAD_STATE(thread) \ - ({ xchg8(&(thread)->state, STATE_BUSY); }) -#define UNLOCK_THREAD(thread, _state) \ - ({ (thread)->state = (_state); }) -#define UNLOCK_THREAD_SET_STATE(thread, _state) \ - ({ (thread)->state = (_state); }) - -/* List locking */ -#define LOCK_LIST(tqp) \ - ({ struct thread_entry *_l; \ - while((_l = xchgptr(&(tqp)->queue, STATE_BUSYuptr)) == STATE_BUSYuptr); \ - _l; }) -#define UNLOCK_LIST(tqp, mod) \ - ({ (tqp)->queue = (mod); }) -#define UNLOCK_LIST_SET_PTR(tqp, mod) \ - ({ (tqp)->queue = (mod); }) - -/* Select the local queue pointer copy returned from LOCK_LIST */ -#define ADD_TO_LIST_L_SELECT(tc, tqp, thread) \ - ({ add_to_list_l(&(tc), (thread)); }) -#define REMOVE_FROM_LIST_L_SELECT(tc, tqp, thread) \ - ({ remove_from_list_l(&(tc), (thread)); }) +#ifdef HAVE_PRIORITY_SCHEDULING +#define rtr_add_entry(core, priority) \ + prio_add_entry(&cores[core].rtr, (priority)) +#define rtr_subtract_entry(core, priority) \ + prio_subtract_entry(&cores[core].rtr, (priority)) + +#define rtr_move_entry(core, from, to) \ + prio_move_entry(&cores[core].rtr, (from), (to)) #else -/* Single-core/non-locked versions */ - -/* Threads */ -#define GET_THREAD_STATE(thread) \ - ({ (thread)->state; }) -#define UNLOCK_THREAD(thread, _state) -#define UNLOCK_THREAD_SET_STATE(thread, _state) \ - ({ (thread)->state = (_state); }) - -/* Lists */ -#define LOCK_LIST(tqp) \ - ({ (tqp)->queue; }) -#define UNLOCK_LIST(tqp, mod) -#define UNLOCK_LIST_SET_PTR(tqp, mod) \ - ({ (tqp)->queue = (mod); }) - -/* Select the queue pointer directly */ -#define ADD_TO_LIST_L_SELECT(tc, tqp, thread) \ - ({ add_to_list_l(&(tqp)->queue, (thread)); }) -#define REMOVE_FROM_LIST_L_SELECT(tc, tqp, thread) \ - ({ remove_from_list_l(&(tqp)->queue, (thread)); }) - -#endif /* locking selection */ +#define rtr_add_entry(core, priority) +#define rtr_add_entry_inl(core, priority) +#define rtr_subtract_entry(core, priority) +#define rtr_subtract_entry_inl(core, priotity) +#define rtr_move_entry(core, from, to) +#define rtr_move_entry_inl(core, from, to) +#endif -#if THREAD_EXTRA_CHECKS /*--------------------------------------------------------------------------- - * Lock the thread slot to obtain the state and then unlock it. Waits for - * it not to be busy. Used for debugging. + * Thread list structure - circular: + * +------------------------------+ + * | | + * +--+---+<-+---+<-+---+<-+---+<-+ + * Head->| T | | T | | T | | T | + * +->+---+->+---+->+---+->+---+--+ + * | | + * +------------------------------+ *--------------------------------------------------------------------------- */ -static unsigned peek_thread_state(struct thread_entry *thread) -{ - int oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); - unsigned state = GET_THREAD_STATE(thread); - UNLOCK_THREAD(thread, state); - set_irq_level(oldlevel); - return state; -} -#endif /* THREAD_EXTRA_CHECKS */ /*--------------------------------------------------------------------------- - * Adds a thread to a list of threads using "intert last". Uses the "l" + * Adds a thread to a list of threads using "insert last". Uses the "l" * links. *--------------------------------------------------------------------------- */ @@ -1114,44 +1079,18 @@ static void add_to_list_l(struct thread_entry **list, if (l == NULL) { /* Insert into unoccupied list */ - thread->l.next = thread; thread->l.prev = thread; + thread->l.next = thread; *list = thread; return; } /* Insert last */ - thread->l.next = l; thread->l.prev = l->l.prev; - thread->l.prev->l.next = thread; + thread->l.next = l; + l->l.prev->l.next = thread; l->l.prev = thread; - - /* Insert next - thread->l.next = l->l.next; - thread->l.prev = l; - thread->l.next->l.prev = thread; - l->l.next = thread; - */ -} - -/*--------------------------------------------------------------------------- - * Locks a list, adds the thread entry and unlocks the list on multicore. - * Defined as add_to_list_l on single-core. - *--------------------------------------------------------------------------- - */ -#if NUM_CORES > 1 -static void add_to_list_l_locked(struct thread_queue *tq, - struct thread_entry *thread) -{ - struct thread_entry *t = LOCK_LIST(tq); - ADD_TO_LIST_L_SELECT(t, tq, thread); - UNLOCK_LIST(tq, t); - (void)t; } -#else -#define add_to_list_l_locked(tq, thread) \ - add_to_list_l(&(tq)->queue, (thread)) -#endif /*--------------------------------------------------------------------------- * Removes a thread from a list of threads. Uses the "l" links. @@ -1180,28 +1119,20 @@ static void remove_from_list_l(struct thread_entry **list, prev = thread->l.prev; /* Fix links to jump over the removed entry. */ - prev->l.next = next; next->l.prev = prev; + prev->l.next = next; } /*--------------------------------------------------------------------------- - * Locks a list, removes the thread entry and unlocks the list on multicore. - * Defined as remove_from_list_l on single-core. + * Timeout list structure - circular reverse (to make "remove item" O(1)), + * NULL-terminated forward (to ease the far more common forward traversal): + * +------------------------------+ + * | | + * +--+---+<-+---+<-+---+<-+---+<-+ + * Head->| T | | T | | T | | T | + * +---+->+---+->+---+->+---+-X *--------------------------------------------------------------------------- */ -#if NUM_CORES > 1 -static void remove_from_list_l_locked(struct thread_queue *tq, - struct thread_entry *thread) -{ - struct thread_entry *t = LOCK_LIST(tq); - REMOVE_FROM_LIST_L_SELECT(t, tq, thread); - UNLOCK_LIST(tq, t); - (void)t; -} -#else -#define remove_from_list_l_locked(tq, thread) \ - remove_from_list_l(&(tq)->queue, (thread)) -#endif /*--------------------------------------------------------------------------- * Add a thread from the core's timout list by linking the pointers in its @@ -1210,19 +1141,24 @@ static void remove_from_list_l_locked(struct thread_queue *tq, */ static void add_to_list_tmo(struct thread_entry *thread) { - /* Insert first */ - struct thread_entry *t = cores[IF_COP_CORE(thread->core)].timeout; + struct thread_entry *tmo = cores[IF_COP_CORE(thread->core)].timeout; + THREAD_ASSERT(thread->tmo.prev == NULL, + "add_to_list_tmo->already listed", thread); - thread->tmo.prev = thread; - thread->tmo.next = t; + thread->tmo.next = NULL; - if (t != NULL) + if (tmo == NULL) { - /* Fix second item's prev pointer to point to this thread */ - t->tmo.prev = thread; + /* Insert into unoccupied list */ + thread->tmo.prev = thread; + cores[IF_COP_CORE(thread->core)].timeout = thread; + return; } - cores[IF_COP_CORE(thread->core)].timeout = thread; + /* Insert Last */ + thread->tmo.prev = tmo->tmo.prev; + tmo->tmo.prev->tmo.next = thread; + tmo->tmo.prev = thread; } /*--------------------------------------------------------------------------- @@ -1233,91 +1169,520 @@ static void add_to_list_tmo(struct thread_entry *thread) */ static void remove_from_list_tmo(struct thread_entry *thread) { + struct thread_entry **list = &cores[IF_COP_CORE(thread->core)].timeout; + struct thread_entry *prev = thread->tmo.prev; struct thread_entry *next = thread->tmo.next; - struct thread_entry *prev; - if (thread == cores[IF_COP_CORE(thread->core)].timeout) + THREAD_ASSERT(prev != NULL, "remove_from_list_tmo->not listed", thread); + + if (next != NULL) + next->tmo.prev = prev; + + if (thread == *list) + { + /* List becomes next item and empty if next == NULL */ + *list = next; + /* Mark as unlisted */ + thread->tmo.prev = NULL; + } + else + { + if (next == NULL) + (*list)->tmo.prev = prev; + prev->tmo.next = next; + /* Mark as unlisted */ + thread->tmo.prev = NULL; + } +} + + +#ifdef HAVE_PRIORITY_SCHEDULING +/*--------------------------------------------------------------------------- + * Priority distribution structure (one category for each possible priority): + * + * +----+----+----+ ... +-----+ + * hist: | F0 | F1 | F2 | | F31 | + * +----+----+----+ ... +-----+ + * mask: | b0 | b1 | b2 | | b31 | + * +----+----+----+ ... +-----+ + * + * F = count of threads at priority category n (frequency) + * b = bitmask of non-zero priority categories (occupancy) + * + * / if H[n] != 0 : 1 + * b[n] = | + * \ else : 0 + * + *--------------------------------------------------------------------------- + * Basic priority inheritance priotocol (PIP): + * + * Mn = mutex n, Tn = thread n + * + * A lower priority thread inherits the priority of the highest priority + * thread blocked waiting for it to complete an action (such as release a + * mutex or respond to a message via queue_send): + * + * 1) T2->M1->T1 + * + * T1 owns M1, T2 is waiting for M1 to realease M1. If T2 has a higher + * priority than T1 then T1 inherits the priority of T2. + * + * 2) T3 + * \/ + * T2->M1->T1 + * + * Situation is like 1) but T2 and T3 are both queued waiting for M1 and so + * T1 inherits the higher of T2 and T3. + * + * 3) T3->M2->T2->M1->T1 + * + * T1 owns M1, T2 owns M2. If T3 has a higher priority than both T1 and T2, + * then T1 inherits the priority of T3 through T2. + * + * Blocking chains can grow arbitrarily complex (though it's best that they + * not form at all very often :) and build-up from these units. + *--------------------------------------------------------------------------- + */ + +/*--------------------------------------------------------------------------- + * Increment frequency at category "priority" + *--------------------------------------------------------------------------- + */ +static inline unsigned int prio_add_entry( + struct priority_distribution *pd, int priority) +{ + unsigned int count; + /* Enough size/instruction count difference for ARM makes it worth it to + * use different code (192 bytes for ARM). Only thing better is ASM. */ +#ifdef CPU_ARM + count = pd->hist[priority]; + if (++count == 1) + pd->mask |= 1 << priority; + pd->hist[priority] = count; +#else /* This one's better for Coldfire */ + if ((count = ++pd->hist[priority]) == 1) + pd->mask |= 1 << priority; +#endif + + return count; +} + +/*--------------------------------------------------------------------------- + * Decrement frequency at category "priority" + *--------------------------------------------------------------------------- + */ +static inline unsigned int prio_subtract_entry( + struct priority_distribution *pd, int priority) +{ + unsigned int count; + +#ifdef CPU_ARM + count = pd->hist[priority]; + if (--count == 0) + pd->mask &= ~(1 << priority); + pd->hist[priority] = count; +#else + if ((count = --pd->hist[priority]) == 0) + pd->mask &= ~(1 << priority); +#endif + + return count; +} + +/*--------------------------------------------------------------------------- + * Remove from one category and add to another + *--------------------------------------------------------------------------- + */ +static inline void prio_move_entry( + struct priority_distribution *pd, int from, int to) +{ + uint32_t mask = pd->mask; + +#ifdef CPU_ARM + unsigned int count; + + count = pd->hist[from]; + if (--count == 0) + mask &= ~(1 << from); + pd->hist[from] = count; + + count = pd->hist[to]; + if (++count == 1) + mask |= 1 << to; + pd->hist[to] = count; +#else + if (--pd->hist[from] == 0) + mask &= ~(1 << from); + + if (++pd->hist[to] == 1) + mask |= 1 << to; +#endif + + pd->mask = mask; +} + +/*--------------------------------------------------------------------------- + * Change the priority and rtr entry for a running thread + *--------------------------------------------------------------------------- + */ +static inline void set_running_thread_priority( + struct thread_entry *thread, int priority) +{ + const unsigned int core = IF_COP_CORE(thread->core); + RTR_LOCK(core); + rtr_move_entry(core, thread->priority, priority); + thread->priority = priority; + RTR_UNLOCK(core); +} + +/*--------------------------------------------------------------------------- + * Finds the highest priority thread in a list of threads. If the list is + * empty, the PRIORITY_IDLE is returned. + * + * It is possible to use the struct priority_distribution within an object + * instead of scanning the remaining threads in the list but as a compromise, + * the resulting per-object memory overhead is saved at a slight speed + * penalty under high contention. + *--------------------------------------------------------------------------- + */ +static int find_highest_priority_in_list_l( + struct thread_entry * const thread) +{ + if (thread != NULL) { - /* Next item becomes list head */ - cores[IF_COP_CORE(thread->core)].timeout = next; + /* Go though list until the ending up at the initial thread */ + int highest_priority = thread->priority; + struct thread_entry *curr = thread; - if (next != NULL) + do { - /* Fix new list head's prev to point to itself. */ - next->tmo.prev = next; + int priority = curr->priority; + + if (priority < highest_priority) + highest_priority = priority; + + curr = curr->l.next; } + while (curr != thread); - thread->tmo.prev = NULL; - return; + return highest_priority; } - prev = thread->tmo.prev; + return PRIORITY_IDLE; +} - if (next != NULL) +/*--------------------------------------------------------------------------- + * Register priority with blocking system and bubble it down the chain if + * any until we reach the end or something is already equal or higher. + * + * NOTE: A simultaneous circular wait could spin deadlock on multiprocessor + * targets but that same action also guarantees a circular block anyway and + * those are prevented, right? :-) + *--------------------------------------------------------------------------- + */ +static struct thread_entry * + blocker_inherit_priority(struct thread_entry *current) +{ + const int priority = current->priority; + struct blocker *bl = current->blocker; + struct thread_entry * const tstart = current; + struct thread_entry *bl_t = bl->thread; + + /* Blocker cannot change since the object protection is held */ + LOCK_THREAD(bl_t); + + for (;;) { - next->tmo.prev = prev; + struct thread_entry *next; + int bl_pr = bl->priority; + + if (priority >= bl_pr) + break; /* Object priority already high enough */ + + bl->priority = priority; + + /* Add this one */ + prio_add_entry(&bl_t->pdist, priority); + + if (bl_pr < PRIORITY_IDLE) + { + /* Not first waiter - subtract old one */ + prio_subtract_entry(&bl_t->pdist, bl_pr); + } + + if (priority >= bl_t->priority) + break; /* Thread priority high enough */ + + if (bl_t->state == STATE_RUNNING) + { + /* Blocking thread is a running thread therefore there are no + * further blockers. Change the "run queue" on which it + * resides. */ + set_running_thread_priority(bl_t, priority); + break; + } + + bl_t->priority = priority; + + /* If blocking thread has a blocker, apply transitive inheritance */ + bl = bl_t->blocker; + + if (bl == NULL) + break; /* End of chain or object doesn't support inheritance */ + + next = bl->thread; + + if (next == tstart) + break; /* Full-circle - deadlock! */ + + UNLOCK_THREAD(current); + +#if NUM_CORES > 1 + for (;;) + { + LOCK_THREAD(next); + + /* Blocker could change - retest condition */ + if (bl->thread == next) + break; + + UNLOCK_THREAD(next); + next = bl->thread; + } +#endif + current = bl_t; + bl_t = next; } - prev->tmo.next = next; - thread->tmo.prev = NULL; + UNLOCK_THREAD(bl_t); + + return current; } /*--------------------------------------------------------------------------- - * Schedules a thread wakeup on the specified core. Threads will be made - * ready to run when the next task switch occurs. Note that this does not - * introduce an on-core delay since the soonest the next thread may run is - * no sooner than that. Other cores and on-core interrupts may only ever - * add to the list. + * Readjust priorities when waking a thread blocked waiting for another + * in essence "releasing" the thread's effect on the object owner. Can be + * performed from any context. *--------------------------------------------------------------------------- */ -static void core_schedule_wakeup(struct thread_entry *thread) +struct thread_entry * + wakeup_priority_protocol_release(struct thread_entry *thread) { - int oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); - const unsigned int core = IF_COP_CORE(thread->core); - add_to_list_l_locked(&cores[core].waking, thread); + const int priority = thread->priority; + struct blocker *bl = thread->blocker; + struct thread_entry * const tstart = thread; + struct thread_entry *bl_t = bl->thread; + + /* Blocker cannot change since object will be locked */ + LOCK_THREAD(bl_t); + + thread->blocker = NULL; /* Thread not blocked */ + + for (;;) + { + struct thread_entry *next; + int bl_pr = bl->priority; + + if (priority > bl_pr) + break; /* Object priority higher */ + + next = *thread->bqp; + + if (next == NULL) + { + /* No more threads in queue */ + prio_subtract_entry(&bl_t->pdist, bl_pr); + bl->priority = PRIORITY_IDLE; + } + else + { + /* Check list for highest remaining priority */ + int queue_pr = find_highest_priority_in_list_l(next); + + if (queue_pr == bl_pr) + break; /* Object priority not changing */ + + /* Change queue priority */ + prio_move_entry(&bl_t->pdist, bl_pr, queue_pr); + bl->priority = queue_pr; + } + + if (bl_pr > bl_t->priority) + break; /* thread priority is higher */ + + bl_pr = find_first_set_bit(bl_t->pdist.mask); + + if (bl_pr == bl_t->priority) + break; /* Thread priority not changing */ + + if (bl_t->state == STATE_RUNNING) + { + /* No further blockers */ + set_running_thread_priority(bl_t, bl_pr); + break; + } + + bl_t->priority = bl_pr; + + /* If blocking thread has a blocker, apply transitive inheritance */ + bl = bl_t->blocker; + + if (bl == NULL) + break; /* End of chain or object doesn't support inheritance */ + + next = bl->thread; + + if (next == tstart) + break; /* Full-circle - deadlock! */ + + UNLOCK_THREAD(thread); + #if NUM_CORES > 1 - if (core != CURRENT_CORE) + for (;;) + { + LOCK_THREAD(next); + + /* Blocker could change - retest condition */ + if (bl->thread == next) + break; + + UNLOCK_THREAD(next); + next = bl->thread; + } +#endif + thread = bl_t; + bl_t = next; + } + + UNLOCK_THREAD(bl_t); + +#if NUM_CORES > 1 + if (thread != tstart) { - core_wake(core); + /* Relock original if it changed */ + LOCK_THREAD(tstart); } #endif - set_irq_level(oldlevel); + + return cores[CURRENT_CORE].running; } /*--------------------------------------------------------------------------- - * If the waking list was populated, move all threads on it onto the running - * list so they may be run ASAP. + * Transfer ownership to a thread waiting for an objects and transfer + * inherited priority boost from other waiters. This algorithm knows that + * blocking chains may only unblock from the very end. + * + * Only the owning thread itself may call this and so the assumption that + * it is the running thread is made. *--------------------------------------------------------------------------- */ -static inline void core_perform_wakeup(IF_COP_VOID(unsigned int core)) +struct thread_entry * + wakeup_priority_protocol_transfer(struct thread_entry *thread) { - struct thread_entry *w = LOCK_LIST(&cores[IF_COP_CORE(core)].waking); - struct thread_entry *r = cores[IF_COP_CORE(core)].running; + /* Waking thread inherits priority boost from object owner */ + struct blocker *bl = thread->blocker; + struct thread_entry *bl_t = bl->thread; + struct thread_entry *next; + int bl_pr; - /* Tranfer all threads on waking list to running list in one - swoop */ - if (r != NULL) + THREAD_ASSERT(thread_get_current() == bl_t, + "UPPT->wrong thread", thread_get_current()); + + LOCK_THREAD(bl_t); + + bl_pr = bl->priority; + + /* Remove the object's boost from the owning thread */ + if (prio_subtract_entry(&bl_t->pdist, bl_pr) == 0 && + bl_pr <= bl_t->priority) { - /* Place waking threads at the end of the running list. */ - struct thread_entry *tmp; - w->l.prev->l.next = r; - r->l.prev->l.next = w; - tmp = r->l.prev; - r->l.prev = w->l.prev; - w->l.prev = tmp; + /* No more threads at this priority are waiting and the old level is + * at least the thread level */ + int priority = find_first_set_bit(bl_t->pdist.mask); + + if (priority != bl_t->priority) + { + /* Adjust this thread's priority */ + set_running_thread_priority(bl_t, priority); + } + } + + next = *thread->bqp; + + if (next == NULL) + { + /* Expected shortcut - no more waiters */ + bl_pr = PRIORITY_IDLE; } else { - /* Just transfer the list as-is */ - cores[IF_COP_CORE(core)].running = w; + if (thread->priority <= bl_pr) + { + /* Need to scan threads remaining in queue */ + bl_pr = find_highest_priority_in_list_l(next); + } + + if (prio_add_entry(&thread->pdist, bl_pr) == 1 && + bl_pr < thread->priority) + { + /* Thread priority must be raised */ + thread->priority = bl_pr; + } + } + + bl->thread = thread; /* This thread pwns */ + bl->priority = bl_pr; /* Save highest blocked priority */ + thread->blocker = NULL; /* Thread not blocked */ + + UNLOCK_THREAD(bl_t); + + return bl_t; +} + +/*--------------------------------------------------------------------------- + * No threads must be blocked waiting for this thread except for it to exit. + * The alternative is more elaborate cleanup and object registration code. + * Check this for risk of silent data corruption when objects with + * inheritable blocking are abandoned by the owner - not precise but may + * catch something. + *--------------------------------------------------------------------------- + */ +void check_for_obj_waiters(const char *function, struct thread_entry *thread) +{ + /* Only one bit in the mask should be set with a frequency on 1 which + * represents the thread's own base priority */ + uint32_t mask = thread->pdist.mask; + if ((mask & (mask - 1)) != 0 || + thread->pdist.hist[find_first_set_bit(mask)] > 1) + { + unsigned char name[32]; + thread_get_name(name, 32, thread); + panicf("%s->%s with obj. waiters", function, name); } - /* Just leave any timeout threads on the timeout list. If a timeout check - * is due, they will be removed there. If they do a timeout again before - * being removed, they will just stay on the list with a new expiration - * tick. */ +} +#endif /* HAVE_PRIORITY_SCHEDULING */ + +/*--------------------------------------------------------------------------- + * Move a thread back to a running state on its core. + *--------------------------------------------------------------------------- + */ +static void core_schedule_wakeup(struct thread_entry *thread) +{ + const unsigned int core = IF_COP_CORE(thread->core); + + RTR_LOCK(core); + + thread->state = STATE_RUNNING; + + add_to_list_l(&cores[core].running, thread); + rtr_add_entry(core, thread->priority); + + RTR_UNLOCK(core); - /* Waking list is clear - NULL and unlock it */ - UNLOCK_LIST_SET_PTR(&cores[IF_COP_CORE(core)].waking, NULL); +#if NUM_CORES > 1 + if (core != CURRENT_CORE) + core_wake(core); +#endif } /*--------------------------------------------------------------------------- @@ -1326,7 +1691,7 @@ static inline void core_perform_wakeup(IF_COP_VOID(unsigned int core)) * tick when the next check will occur. *--------------------------------------------------------------------------- */ -static void check_tmo_threads(void) +void check_tmo_threads(void) { const unsigned int core = CURRENT_CORE; const long tick = current_tick; /* snapshot the current tick */ @@ -1335,54 +1700,98 @@ static void check_tmo_threads(void) /* If there are no processes waiting for a timeout, just keep the check tick from falling into the past. */ - if (next != NULL) + + /* Break the loop once we have walked through the list of all + * sleeping processes or have removed them all. */ + while (next != NULL) { - /* Check sleeping threads. */ - do - { - /* Must make sure noone else is examining the state, wait until - slot is no longer busy */ - struct thread_entry *curr = next; - next = curr->tmo.next; + /* Check sleeping threads. Allow interrupts between checks. */ + set_irq_level(0); - unsigned state = GET_THREAD_STATE(curr); + struct thread_entry *curr = next; - if (state < TIMEOUT_STATE_FIRST) - { - /* Cleanup threads no longer on a timeout but still on the - * list. */ - remove_from_list_tmo(curr); - UNLOCK_THREAD(curr, state); /* Unlock thread slot */ - } - else if (TIME_BEFORE(tick, curr->tmo_tick)) + next = curr->tmo.next; + + /* Lock thread slot against explicit wakeup */ + set_irq_level(HIGHEST_IRQ_LEVEL); + LOCK_THREAD(curr); + + unsigned state = curr->state; + + if (state < TIMEOUT_STATE_FIRST) + { + /* Cleanup threads no longer on a timeout but still on the + * list. */ + remove_from_list_tmo(curr); + } + else if (TIME_BEFORE(tick, curr->tmo_tick)) + { + /* Timeout still pending - this will be the usual case */ + if (TIME_BEFORE(curr->tmo_tick, next_tmo_check)) { - /* Timeout still pending - this will be the usual case */ - if (TIME_BEFORE(curr->tmo_tick, next_tmo_check)) - { - /* Earliest timeout found so far - move the next check up - to its time */ - next_tmo_check = curr->tmo_tick; - } - UNLOCK_THREAD(curr, state); /* Unlock thread slot */ + /* Earliest timeout found so far - move the next check up + to its time */ + next_tmo_check = curr->tmo_tick; } - else + } + else + { + /* Sleep timeout has been reached so bring the thread back to + * life again. */ + if (state == STATE_BLOCKED_W_TMO) { - /* Sleep timeout has been reached so bring the thread back to - * life again. */ - if (state == STATE_BLOCKED_W_TMO) +#if NUM_CORES > 1 + /* Lock the waiting thread's kernel object */ + struct corelock *ocl = curr->obj_cl; + + if (corelock_try_lock(ocl) == 0) { - remove_from_list_l_locked(curr->bqp, curr); + /* Need to retry in the correct order though the need is + * unlikely */ + UNLOCK_THREAD(curr); + corelock_lock(ocl); + LOCK_THREAD(curr); + + if (curr->state != STATE_BLOCKED_W_TMO) + { + /* Thread was woken or removed explicitely while slot + * was unlocked */ + corelock_unlock(ocl); + remove_from_list_tmo(curr); + UNLOCK_THREAD(curr); + continue; + } } +#endif /* NUM_CORES */ + + remove_from_list_l(curr->bqp, curr); + +#ifdef HAVE_WAKEUP_EXT_CB + if (curr->wakeup_ext_cb != NULL) + curr->wakeup_ext_cb(curr); +#endif - remove_from_list_tmo(curr); - add_to_list_l(&cores[core].running, curr); - UNLOCK_THREAD_SET_STATE(curr, STATE_RUNNING); +#ifdef HAVE_PRIORITY_SCHEDULING + if (curr->blocker != NULL) + wakeup_priority_protocol_release(curr); +#endif + corelock_unlock(ocl); } + /* else state == STATE_SLEEPING */ + + remove_from_list_tmo(curr); + + RTR_LOCK(core); - /* Break the loop once we have walked through the list of all - * sleeping processes or have removed them all. */ + curr->state = STATE_RUNNING; + + add_to_list_l(&cores[core].running, curr); + rtr_add_entry(core, curr->priority); + + RTR_UNLOCK(core); } - while (next != NULL); + + UNLOCK_THREAD(curr); } cores[core].next_tmo_check = next_tmo_check; @@ -1390,109 +1799,33 @@ static void check_tmo_threads(void) /*--------------------------------------------------------------------------- * Performs operations that must be done before blocking a thread but after - * the state is saved - follows reverse of locking order. blk_ops.flags is - * assumed to be nonzero. + * the state is saved. *--------------------------------------------------------------------------- */ #if NUM_CORES > 1 static inline void run_blocking_ops( unsigned int core, struct thread_entry *thread) { - struct thread_blk_ops *ops = &cores[IF_COP_CORE(core)].blk_ops; + struct thread_blk_ops *ops = &cores[core].blk_ops; const unsigned flags = ops->flags; - if (flags == 0) + if (flags == TBOP_CLEAR) return; - if (flags & TBOP_SWITCH_CORE) + switch (flags) { + case TBOP_SWITCH_CORE: core_switch_blk_op(core, thread); - } - -#if CONFIG_CORELOCK == SW_CORELOCK - if (flags & TBOP_UNLOCK_LIST) - { - UNLOCK_LIST(ops->list_p, NULL); - } - - if (flags & TBOP_UNLOCK_CORELOCK) - { + /* Fall-through */ + case TBOP_UNLOCK_CORELOCK: corelock_unlock(ops->cl_p); - } - - if (flags & TBOP_UNLOCK_THREAD) - { - UNLOCK_THREAD(ops->thread, 0); - } -#elif CONFIG_CORELOCK == CORELOCK_SWAP - /* Write updated variable value into memory location */ - switch (flags & TBOP_VAR_TYPE_MASK) - { - case TBOP_UNLOCK_LIST: - UNLOCK_LIST(ops->list_p, ops->list_v); - break; - case TBOP_SET_VARi: - *ops->var_ip = ops->var_iv; - break; - case TBOP_SET_VARu8: - *ops->var_u8p = ops->var_u8v; break; } -#endif /* CONFIG_CORELOCK == */ - /* Unlock thread's slot */ - if (flags & TBOP_UNLOCK_CURRENT) - { - UNLOCK_THREAD(thread, ops->state); - } - - ops->flags = 0; + ops->flags = TBOP_CLEAR; } #endif /* NUM_CORES > 1 */ - -/*--------------------------------------------------------------------------- - * Runs any operations that may cause threads to be ready to run and then - * sleeps the processor core until the next interrupt if none are. - *--------------------------------------------------------------------------- - */ -static inline struct thread_entry * sleep_core(IF_COP_VOID(unsigned int core)) -{ - for (;;) - { - set_irq_level(HIGHEST_IRQ_LEVEL); - /* We want to do these ASAP as it may change the decision to sleep - * the core or a core has woken because an interrupt occurred - * and posted a message to a queue. */ - if (cores[IF_COP_CORE(core)].waking.queue != NULL) - { - core_perform_wakeup(IF_COP(core)); - } - - /* If there are threads on a timeout and the earliest wakeup is due, - * check the list and wake any threads that need to start running - * again. */ - if (!TIME_BEFORE(current_tick, cores[IF_COP_CORE(core)].next_tmo_check)) - { - check_tmo_threads(); - } - - /* If there is a ready to run task, return its ID and keep core - * awake. */ - if (cores[IF_COP_CORE(core)].running == NULL) - { - /* Enter sleep mode to reduce power usage - woken up on interrupt - * or wakeup request from another core - expected to enable all - * interrupts. */ - core_sleep(IF_COP(core)); - continue; - } - - set_irq_level(0); - return cores[IF_COP_CORE(core)].running; - } -} - #ifdef RB_PROFILE void profile_thread(void) { @@ -1502,55 +1835,34 @@ void profile_thread(void) /*--------------------------------------------------------------------------- * Prepares a thread to block on an object's list and/or for a specified - * duration - expects object and slot to be appropriately locked if needed. + * duration - expects object and slot to be appropriately locked if needed + * and interrupts to be masked. *--------------------------------------------------------------------------- */ -static inline void _block_thread_on_l(struct thread_queue *list, - struct thread_entry *thread, - unsigned state - IF_SWCL(, const bool nolock)) +static inline void block_thread_on_l(struct thread_entry *thread, + unsigned state) { /* If inlined, unreachable branches will be pruned with no size penalty - because constant params are used for state and nolock. */ + because state is passed as a constant parameter. */ const unsigned int core = IF_COP_CORE(thread->core); /* Remove the thread from the list of running threads. */ + RTR_LOCK(core); remove_from_list_l(&cores[core].running, thread); + rtr_subtract_entry(core, thread->priority); + RTR_UNLOCK(core); /* Add a timeout to the block if not infinite */ switch (state) { case STATE_BLOCKED: - /* Put the thread into a new list of inactive threads. */ -#if CONFIG_CORELOCK == SW_CORELOCK - if (nolock) - { - thread->bqp = NULL; /* Indicate nolock list */ - thread->bqnlp = (struct thread_entry **)list; - add_to_list_l((struct thread_entry **)list, thread); - } - else -#endif - { - thread->bqp = list; - add_to_list_l_locked(list, thread); - } - break; case STATE_BLOCKED_W_TMO: /* Put the thread into a new list of inactive threads. */ -#if CONFIG_CORELOCK == SW_CORELOCK - if (nolock) - { - thread->bqp = NULL; /* Indicate nolock list */ - thread->bqnlp = (struct thread_entry **)list; - add_to_list_l((struct thread_entry **)list, thread); - } - else -#endif - { - thread->bqp = list; - add_to_list_l_locked(list, thread); - } + add_to_list_l(thread->bqp, thread); + + if (state == STATE_BLOCKED) + break; + /* Fall-through */ case STATE_SLEEPING: /* If this thread times out sooner than any other thread, update @@ -1568,35 +1880,11 @@ static inline void _block_thread_on_l(struct thread_queue *list, break; } -#ifdef HAVE_PRIORITY_SCHEDULING - /* Reset priorities */ - if (thread->priority == cores[core].highest_priority) - cores[core].highest_priority = LOWEST_PRIORITY; -#endif + /* Remember the the next thread about to block. */ + cores[core].block_task = thread; -#if NUM_CORES == 1 || CONFIG_CORELOCK == SW_CORELOCK - /* Safe to set state now */ + /* Report new state. */ thread->state = state; -#elif CONFIG_CORELOCK == CORELOCK_SWAP - cores[core].blk_ops.state = state; -#endif - -#if NUM_CORES > 1 - /* Delay slot unlock until task switch */ - cores[core].blk_ops.flags |= TBOP_UNLOCK_CURRENT; -#endif -} - -static inline void block_thread_on_l( - struct thread_queue *list, struct thread_entry *thread, unsigned state) -{ - _block_thread_on_l(list, thread, state IF_SWCL(, false)); -} - -static inline void block_thread_on_l_no_listlock( - struct thread_entry **list, struct thread_entry *thread, unsigned state) -{ - _block_thread_on_l((struct thread_queue *)list, thread, state IF_SWCL(, true)); } /*--------------------------------------------------------------------------- @@ -1607,72 +1895,134 @@ static inline void block_thread_on_l_no_listlock( * INTERNAL: Intended for use by kernel and not for programs. *--------------------------------------------------------------------------- */ -void switch_thread(struct thread_entry *old) +void switch_thread(void) { const unsigned int core = CURRENT_CORE; + struct thread_entry *block = cores[core].block_task; struct thread_entry *thread = cores[core].running; - struct thread_entry *block = old; - if (block == NULL) - old = thread; + /* Get context to save - next thread to run is unknown until all wakeups + * are evaluated */ + if (block != NULL) + { + cores[core].block_task = NULL; + +#if NUM_CORES > 1 + if (thread == block) + { + /* This was the last thread running and another core woke us before + * reaching here. Force next thread selection to give tmo threads or + * other threads woken before this block a first chance. */ + block = NULL; + } + else +#endif + { + /* Blocking task is the old one */ + thread = block; + } + } #ifdef RB_PROFILE - profile_thread_stopped(old - threads); + profile_thread_stopped(thread - threads); #endif /* Begin task switching by saving our current context so that we can * restore the state of the current thread later to the point prior * to this call. */ - store_context(&old->context); + store_context(&thread->context); /* Check if the current thread stack is overflown */ - if(((unsigned int *)old->stack)[0] != DEADBEEF) - thread_stkov(old); + if (thread->stack[0] != DEADBEEF) + thread_stkov(thread); #if NUM_CORES > 1 /* Run any blocking operations requested before switching/sleeping */ - run_blocking_ops(core, old); + run_blocking_ops(core, thread); #endif - /* Go through the list of sleeping task to check if we need to wake up - * any of them due to timeout. Also puts core into sleep state until - * there is at least one running process again. */ - thread = sleep_core(IF_COP(core)); - #ifdef HAVE_PRIORITY_SCHEDULING - /* Select the new task based on priorities and the last time a process - * got CPU time. */ - if (block == NULL) - thread = thread->l.next; + /* Reset the value of thread's skip count */ + thread->skip_count = 0; +#endif for (;;) { - int priority = thread->priority; + /* If there are threads on a timeout and the earliest wakeup is due, + * check the list and wake any threads that need to start running + * again. */ + if (!TIME_BEFORE(current_tick, cores[core].next_tmo_check)) + { + check_tmo_threads(); + } + + set_irq_level(HIGHEST_IRQ_LEVEL); + RTR_LOCK(core); - if (priority < cores[core].highest_priority) - cores[core].highest_priority = priority; + thread = cores[core].running; - if (priority == cores[core].highest_priority || - thread->priority_x < cores[core].highest_priority || - (current_tick - thread->last_run > priority * 8)) + if (thread == NULL) { - cores[core].running = thread; - break; + /* Enter sleep mode to reduce power usage - woken up on interrupt + * or wakeup request from another core - expected to enable + * interrupts. */ + RTR_UNLOCK(core); + core_sleep(IF_COP(core)); } + else + { +#ifdef HAVE_PRIORITY_SCHEDULING + /* Select the new task based on priorities and the last time a + * process got CPU time relative to the highest priority runnable + * task. */ + struct priority_distribution *pd = &cores[core].rtr; + int max = find_first_set_bit(pd->mask); - thread = thread->l.next; - } - - /* Reset the value of thread's last running time to the current time. */ - thread->last_run = current_tick; + if (block == NULL) + { + /* Not switching on a block, tentatively select next thread */ + thread = thread->l.next; + } + + for (;;) + { + int priority = thread->priority; + int diff; + + /* This ridiculously simple method of aging seems to work + * suspiciously well. It does tend to reward CPU hogs (under + * yielding) but that's generally not desirable at all. On the + * plus side, it, relatively to other threads, penalizes excess + * yielding which is good if some high priority thread is + * performing no useful work such as polling for a device to be + * ready. Of course, aging is only employed when higher and lower + * priority threads are runnable. The highest priority runnable + * thread(s) are never skipped. */ + if (priority <= max || + (diff = priority - max, ++thread->skip_count > diff*diff)) + { + cores[core].running = thread; + break; + } + + thread = thread->l.next; + } #else - if (block == NULL) - { - thread = thread->l.next; - cores[core].running = thread; - } + /* Without priority use a simple FCFS algorithm */ + if (block == NULL) + { + /* Not switching on a block, select next thread */ + thread = thread->l.next; + cores[core].running = thread; + } #endif /* HAVE_PRIORITY_SCHEDULING */ + RTR_UNLOCK(core); + set_irq_level(0); + break; + } + } + /* And finally give control to the next thread. */ load_context(&thread->context); @@ -1682,314 +2032,210 @@ void switch_thread(struct thread_entry *old) } /*--------------------------------------------------------------------------- - * Change the boost state of a thread boosting or unboosting the CPU - * as required. Require thread slot to be locked first. - *--------------------------------------------------------------------------- - */ -static inline void boost_thread(struct thread_entry *thread, bool boost) -{ -#ifdef HAVE_SCHEDULER_BOOSTCTRL - if ((thread->boosted != 0) != boost) - { - thread->boosted = boost; - cpu_boost(boost); - } -#endif - (void)thread; (void)boost; -} - -/*--------------------------------------------------------------------------- - * Sleeps a thread for a specified number of ticks and unboost the thread if - * if it is boosted. If ticks is zero, it does not delay but instead switches - * tasks. + * Sleeps a thread for at least a specified number of ticks with zero being + * a wait until the next tick. * * INTERNAL: Intended for use by kernel and not for programs. *--------------------------------------------------------------------------- */ void sleep_thread(int ticks) { - /* Get the entry for the current running thread. */ struct thread_entry *current = cores[CURRENT_CORE].running; -#if NUM_CORES > 1 - /* Lock thread slot */ - GET_THREAD_STATE(current); -#endif + LOCK_THREAD(current); - /* Set our timeout, change lists, and finally switch threads. - * Unlock during switch on mulicore. */ + /* Set our timeout, remove from run list and join timeout list. */ current->tmo_tick = current_tick + ticks + 1; - block_thread_on_l(NULL, current, STATE_SLEEPING); - switch_thread(current); + block_thread_on_l(current, STATE_SLEEPING); - /* Our status should be STATE_RUNNING */ - THREAD_ASSERT(peek_thread_state(current) == STATE_RUNNING, - "S:R->!*R", current); + UNLOCK_THREAD(current); } /*--------------------------------------------------------------------------- * Indefinitely block a thread on a blocking queue for explicit wakeup. - * Caller with interrupt-accessible lists should disable interrupts first - * and request a BOP_IRQ_LEVEL blocking operation to reset it. * * INTERNAL: Intended for use by kernel objects and not for programs. *--------------------------------------------------------------------------- */ -IF_SWCL(static inline) void _block_thread(struct thread_queue *list - IF_SWCL(, const bool nolock)) +void block_thread(struct thread_entry *current) { - /* Get the entry for the current running thread. */ - struct thread_entry *current = cores[CURRENT_CORE].running; - - /* Set the state to blocked and ask the scheduler to switch tasks, - * this takes us off of the run queue until we are explicitly woken */ + /* Set the state to blocked and take us off of the run queue until we + * are explicitly woken */ + LOCK_THREAD(current); -#if NUM_CORES > 1 - /* Lock thread slot */ - GET_THREAD_STATE(current); -#endif + /* Set the list for explicit wakeup */ + block_thread_on_l(current, STATE_BLOCKED); -#if CONFIG_CORELOCK == SW_CORELOCK - /* One branch optimized away during inlining */ - if (nolock) +#ifdef HAVE_PRIORITY_SCHEDULING + if (current->blocker != NULL) { - block_thread_on_l_no_listlock((struct thread_entry **)list, - current, STATE_BLOCKED); + /* Object supports PIP */ + current = blocker_inherit_priority(current); } - else #endif - { - block_thread_on_l(list, current, STATE_BLOCKED); - } - - switch_thread(current); - - /* Our status should be STATE_RUNNING */ - THREAD_ASSERT(peek_thread_state(current) == STATE_RUNNING, - "B:R->!*R", current); -} - -#if CONFIG_CORELOCK == SW_CORELOCK -/* Inline lock/nolock version of _block_thread into these functions */ -void block_thread(struct thread_queue *tq) -{ - _block_thread(tq, false); -} -void block_thread_no_listlock(struct thread_entry **list) -{ - _block_thread((struct thread_queue *)list, true); + UNLOCK_THREAD(current); } -#endif /* CONFIG_CORELOCK */ /*--------------------------------------------------------------------------- * Block a thread on a blocking queue for a specified time interval or until * explicitly woken - whichever happens first. - * Caller with interrupt-accessible lists should disable interrupts first - * and request that interrupt level be restored after switching out the - * current thread. * * INTERNAL: Intended for use by kernel objects and not for programs. *--------------------------------------------------------------------------- */ -void block_thread_w_tmo(struct thread_queue *list, int timeout) +void block_thread_w_tmo(struct thread_entry *current, int timeout) { /* Get the entry for the current running thread. */ - struct thread_entry *current = cores[CURRENT_CORE].running; - -#if NUM_CORES > 1 - /* Lock thread slot */ - GET_THREAD_STATE(current); -#endif + LOCK_THREAD(current); /* Set the state to blocked with the specified timeout */ current->tmo_tick = current_tick + timeout; + /* Set the list for explicit wakeup */ - block_thread_on_l(list, current, STATE_BLOCKED_W_TMO); + block_thread_on_l(current, STATE_BLOCKED_W_TMO); - /* Now force a task switch and block until we have been woken up - * by another thread or timeout is reached - whichever happens first */ - switch_thread(current); +#ifdef HAVE_PRIORITY_SCHEDULING + if (current->blocker != NULL) + { + /* Object supports PIP */ + current = blocker_inherit_priority(current); + } +#endif - /* Our status should be STATE_RUNNING */ - THREAD_ASSERT(peek_thread_state(current) == STATE_RUNNING, - "T:R->!*R", current); + UNLOCK_THREAD(current); } /*--------------------------------------------------------------------------- - * Explicitly wakeup a thread on a blocking queue. Has no effect on threads - * that called sleep(). - * Caller with interrupt-accessible lists should disable interrupts first. - * This code should be considered a critical section by the caller. + * Explicitly wakeup a thread on a blocking queue. Only effects threads of + * STATE_BLOCKED and STATE_BLOCKED_W_TMO. + * + * This code should be considered a critical section by the caller meaning + * that the object's corelock should be held. * * INTERNAL: Intended for use by kernel objects and not for programs. *--------------------------------------------------------------------------- */ -IF_SWCL(static inline) struct thread_entry * _wakeup_thread( - struct thread_queue *list IF_SWCL(, const bool nolock)) +unsigned int wakeup_thread(struct thread_entry **list) { - struct thread_entry *t; - struct thread_entry *thread; - unsigned state; - - /* Wake up the last thread first. */ -#if CONFIG_CORELOCK == SW_CORELOCK - /* One branch optimized away during inlining */ - if (nolock) - { - t = list->queue; - } - else -#endif - { - t = LOCK_LIST(list); - } + struct thread_entry *thread = *list; + unsigned int result = THREAD_NONE; /* Check if there is a blocked thread at all. */ - if (t == NULL) - { -#if CONFIG_CORELOCK == SW_CORELOCK - if (!nolock) -#endif - { - UNLOCK_LIST(list, NULL); - } - return NULL; - } + if (thread == NULL) + return result; - thread = t; - -#if NUM_CORES > 1 -#if CONFIG_CORELOCK == SW_CORELOCK - if (nolock) - { - /* Lock thread only, not list */ - state = GET_THREAD_STATE(thread); - } - else -#endif - { - /* This locks in reverse order from other routines so a retry in the - correct order may be needed */ - state = TRY_GET_THREAD_STATE(thread); - if (state == STATE_BUSY) - { - /* Unlock list and retry slot, then list */ - UNLOCK_LIST(list, t); - state = GET_THREAD_STATE(thread); - t = LOCK_LIST(list); - /* Be sure thread still exists here - it couldn't have re-added - itself if it was woken elsewhere because this function is - serialized within the object that owns the list. */ - if (thread != t) - { - /* Thread disappeared :( */ - UNLOCK_LIST(list, t); - UNLOCK_THREAD(thread, state); - return THREAD_WAKEUP_MISSING; /* Indicate disappearance */ - } - } - } -#else /* NUM_CORES == 1 */ - state = GET_THREAD_STATE(thread); -#endif /* NUM_CORES */ + LOCK_THREAD(thread); /* Determine thread's current state. */ - switch (state) + switch (thread->state) { case STATE_BLOCKED: case STATE_BLOCKED_W_TMO: - /* Remove thread from object's blocked list - select t or list depending - on locking type at compile time */ - REMOVE_FROM_LIST_L_SELECT(t, list, thread); -#if CONFIG_CORELOCK == SW_CORELOCK - /* Statment optimized away during inlining if nolock != false */ - if (!nolock) -#endif + remove_from_list_l(list, thread); + + result = THREAD_OK; + +#ifdef HAVE_PRIORITY_SCHEDULING + struct thread_entry *current; + struct blocker *bl = thread->blocker; + + if (bl == NULL) { - UNLOCK_LIST(list, t); /* Unlock list - removal complete */ + /* No inheritance - just boost the thread by aging */ + thread->skip_count = thread->priority; + current = cores[CURRENT_CORE].running; + } + else + { + /* Call the specified unblocking PIP */ + current = bl->wakeup_protocol(thread); } -#ifdef HAVE_PRIORITY_SCHEDULING - /* Give the task a kick to avoid a stall after wakeup. - Not really proper treatment - TODO later. */ - thread->last_run = current_tick - 8*LOWEST_PRIORITY; -#endif + if (current != NULL && thread->priority < current->priority + IF_COP( && thread->core == current->core )) + { + /* Woken thread is higher priority and exists on the same CPU core; + * recommend a task switch. Knowing if this is an interrupt call + * would be helpful here. */ + result |= THREAD_SWITCH; + } +#endif /* HAVE_PRIORITY_SCHEDULING */ + core_schedule_wakeup(thread); - UNLOCK_THREAD_SET_STATE(thread, STATE_RUNNING); - return thread; - default: - /* Nothing to do. State is not blocked. */ + break; + + /* Nothing to do. State is not blocked. */ #if THREAD_EXTRA_CHECKS + default: THREAD_PANICF("wakeup_thread->block invalid", thread); case STATE_RUNNING: case STATE_KILLED: + break; #endif -#if CONFIG_CORELOCK == SW_CORELOCK - /* Statement optimized away during inlining if nolock != false */ - if (!nolock) -#endif - { - UNLOCK_LIST(list, t); /* Unlock the object's list */ - } - UNLOCK_THREAD(thread, state); /* Unlock thread slot */ - return NULL; } -} -#if CONFIG_CORELOCK == SW_CORELOCK -/* Inline lock/nolock version of _wakeup_thread into these functions */ -struct thread_entry * wakeup_thread(struct thread_queue *tq) -{ - return _wakeup_thread(tq, false); + UNLOCK_THREAD(thread); + return result; } -struct thread_entry * wakeup_thread_no_listlock(struct thread_entry **list) +/*--------------------------------------------------------------------------- + * Wakeup an entire queue of threads - returns bitwise-or of return bitmask + * from each operation or THREAD_NONE of nothing was awakened. Object owning + * the queue must be locked first. + * + * INTERNAL: Intended for use by kernel objects and not for programs. + *--------------------------------------------------------------------------- + */ +unsigned int thread_queue_wake(struct thread_entry **list) { - return _wakeup_thread((struct thread_queue *)list, true); + unsigned result = THREAD_NONE; + + for (;;) + { + unsigned int rc = wakeup_thread(list); + + if (rc == THREAD_NONE) + break; /* No more threads */ + + result |= rc; + } + + return result; } -#endif /* CONFIG_CORELOCK */ /*--------------------------------------------------------------------------- * Find an empty thread slot or MAXTHREADS if none found. The slot returned * will be locked on multicore. *--------------------------------------------------------------------------- */ -static int find_empty_thread_slot(void) +static struct thread_entry * find_empty_thread_slot(void) { -#if NUM_CORES > 1 - /* Any slot could be on an IRQ-accessible list */ - int oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); -#endif - /* Thread slots are not locked on single core */ - + /* Any slot could be on an interrupt-accessible list */ + IF_COP( int oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); ) + struct thread_entry *thread = NULL; int n; for (n = 0; n < MAXTHREADS; n++) { /* Obtain current slot state - lock it on multicore */ - unsigned state = GET_THREAD_STATE(&threads[n]); + struct thread_entry *t = &threads[n]; + LOCK_THREAD(t); - if (state == STATE_KILLED -#if NUM_CORES > 1 - && threads[n].name != THREAD_DESTRUCT -#endif - ) + if (t->state == STATE_KILLED IF_COP( && t->name != THREAD_DESTRUCT )) { /* Slot is empty - leave it locked and caller will unlock */ + thread = t; break; } /* Finished examining slot - no longer busy - unlock on multicore */ - UNLOCK_THREAD(&threads[n], state); + UNLOCK_THREAD(t); } -#if NUM_CORES > 1 - set_irq_level(oldlevel); /* Reenable interrups - this slot is - not accesible to them yet */ -#endif - - return n; + IF_COP( set_irq_level(oldlevel); ) /* Reenable interrups - this slot is + not accesible to them yet */ + return thread; } @@ -2000,65 +2246,68 @@ static int find_empty_thread_slot(void) */ void core_idle(void) { -#if NUM_CORES > 1 - const unsigned int core = CURRENT_CORE; -#endif + IF_COP( const unsigned int core = CURRENT_CORE; ) set_irq_level(HIGHEST_IRQ_LEVEL); core_sleep(IF_COP(core)); } /*--------------------------------------------------------------------------- - * Create a thread - * If using a dual core architecture, specify which core to start the thread - * on, and whether to fall back to the other core if it can't be created + * Create a thread. If using a dual core architecture, specify which core to + * start the thread on. + * * Return ID if context area could be allocated, else NULL. *--------------------------------------------------------------------------- */ struct thread_entry* - create_thread(void (*function)(void), void* stack, int stack_size, + create_thread(void (*function)(void), void* stack, size_t stack_size, unsigned flags, const char *name IF_PRIO(, int priority) IF_COP(, unsigned int core)) { unsigned int i; - unsigned int stacklen; - unsigned int *stackptr; - int slot; + unsigned int stack_words; + uintptr_t stackptr, stackend; struct thread_entry *thread; unsigned state; + int oldlevel; - slot = find_empty_thread_slot(); - if (slot >= MAXTHREADS) + thread = find_empty_thread_slot(); + if (thread == NULL) { return NULL; } + oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); + /* Munge the stack to make it easy to spot stack overflows */ - stacklen = stack_size / sizeof(int); - stackptr = stack; - for(i = 0;i < stacklen;i++) + stackptr = ALIGN_UP((uintptr_t)stack, sizeof (uintptr_t)); + stackend = ALIGN_DOWN((uintptr_t)stack + stack_size, sizeof (uintptr_t)); + stack_size = stackend - stackptr; + stack_words = stack_size / sizeof (uintptr_t); + + for (i = 0; i < stack_words; i++) { - stackptr[i] = DEADBEEF; + ((uintptr_t *)stackptr)[i] = DEADBEEF; } /* Store interesting information */ - thread = &threads[slot]; thread->name = name; - thread->stack = stack; + thread->stack = (uintptr_t *)stackptr; thread->stack_size = stack_size; - thread->bqp = NULL; -#if CONFIG_CORELOCK == SW_CORELOCK - thread->bqnlp = NULL; -#endif thread->queue = NULL; +#ifdef HAVE_WAKEUP_EXT_CB + thread->wakeup_ext_cb = NULL; +#endif #ifdef HAVE_SCHEDULER_BOOSTCTRL - thread->boosted = 0; + thread->cpu_boost = 0; #endif #ifdef HAVE_PRIORITY_SCHEDULING - thread->priority_x = LOWEST_PRIORITY; + memset(&thread->pdist, 0, sizeof(thread->pdist)); + thread->blocker = NULL; + thread->base_priority = priority; thread->priority = priority; - thread->last_run = current_tick - priority * 8; - cores[IF_COP_CORE(core)].highest_priority = LOWEST_PRIORITY; + thread->skip_count = priority; + prio_add_entry(&thread->pdist, priority); #endif #if NUM_CORES > 1 @@ -2077,70 +2326,160 @@ struct thread_entry* state = (flags & CREATE_THREAD_FROZEN) ? STATE_FROZEN : STATE_RUNNING; - /* Align stack to an even 32 bit boundary */ - thread->context.sp = (void*)(((unsigned int)stack + stack_size) & ~3); + thread->context.sp = (typeof (thread->context.sp))stackend; /* Load the thread's context structure with needed startup information */ THREAD_STARTUP_INIT(core, thread, function); + thread->state = state; + if (state == STATE_RUNNING) - { -#if NUM_CORES > 1 - if (core != CURRENT_CORE) - { - /* Next task switch on other core moves thread to running list */ - core_schedule_wakeup(thread); - } - else -#endif - { - /* Place on running list immediately */ - add_to_list_l(&cores[IF_COP_CORE(core)].running, thread); - } - } + core_schedule_wakeup(thread); + + UNLOCK_THREAD(thread); + + set_irq_level(oldlevel); - /* remove lock and set state */ - UNLOCK_THREAD_SET_STATE(thread, state); - return thread; } #ifdef HAVE_SCHEDULER_BOOSTCTRL +/*--------------------------------------------------------------------------- + * Change the boost state of a thread boosting or unboosting the CPU + * as required. + *--------------------------------------------------------------------------- + */ +static inline void boost_thread(struct thread_entry *thread, bool boost) +{ + if ((thread->cpu_boost != 0) != boost) + { + thread->cpu_boost = boost; + cpu_boost(boost); + } +} + void trigger_cpu_boost(void) { - /* No IRQ disable nescessary since the current thread cannot be blocked - on an IRQ-accessible list */ struct thread_entry *current = cores[CURRENT_CORE].running; - unsigned state; - - state = GET_THREAD_STATE(current); boost_thread(current, true); - UNLOCK_THREAD(current, state); - - (void)state; } void cancel_cpu_boost(void) { struct thread_entry *current = cores[CURRENT_CORE].running; - unsigned state; - - state = GET_THREAD_STATE(current); boost_thread(current, false); - UNLOCK_THREAD(current, state); - - (void)state; } #endif /* HAVE_SCHEDULER_BOOSTCTRL */ /*--------------------------------------------------------------------------- - * Remove a thread from the scheduler. + * Block the current thread until another thread terminates. A thread may + * wait on itself to terminate which prevents it from running again and it + * will need to be killed externally. + * Parameter is the ID as returned from create_thread(). + *--------------------------------------------------------------------------- + */ +void thread_wait(struct thread_entry *thread) +{ + struct thread_entry *current = cores[CURRENT_CORE].running; + + if (thread == NULL) + thread = current; + + /* Lock thread-as-waitable-object lock */ + corelock_lock(&thread->waiter_cl); + + /* Be sure it hasn't been killed yet */ + if (thread->state != STATE_KILLED) + { + IF_COP( current->obj_cl = &thread->waiter_cl; ) + current->bqp = &thread->queue; + + set_irq_level(HIGHEST_IRQ_LEVEL); + block_thread(current); + + corelock_unlock(&thread->waiter_cl); + + switch_thread(); + return; + } + + corelock_unlock(&thread->waiter_cl); +} + +/*--------------------------------------------------------------------------- + * Exit the current thread. The Right Way to Do Things (TM). + *--------------------------------------------------------------------------- + */ +void thread_exit(void) +{ + const unsigned int core = CURRENT_CORE; + struct thread_entry *current = cores[core].running; + + /* Cancel CPU boost if any */ + cancel_cpu_boost(); + + set_irq_level(HIGHEST_IRQ_LEVEL); + + corelock_lock(¤t->waiter_cl); + LOCK_THREAD(current); + +#if defined (ALLOW_REMOVE_THREAD) && NUM_CORES > 1 + if (current->name == THREAD_DESTRUCT) + { + /* Thread being killed - become a waiter */ + UNLOCK_THREAD(current); + corelock_unlock(¤t->waiter_cl); + thread_wait(current); + THREAD_PANICF("thread_exit->WK:*R", current); + } +#endif + +#ifdef HAVE_PRIORITY_SCHEDULING + check_for_obj_waiters("thread_exit", current); +#endif + + if (current->tmo.prev != NULL) + { + /* Cancel pending timeout list removal */ + remove_from_list_tmo(current); + } + + /* Switch tasks and never return */ + block_thread_on_l(current, STATE_KILLED); + +#if NUM_CORES > 1 + /* Switch to the idle stack if not on the main core (where "main" + * runs) - we can hope gcc doesn't need the old stack beyond this + * point. */ + if (core != CPU) + { + switch_to_idle_stack(core); + } + + flush_icache(); +#endif + current->name = NULL; + + /* Signal this thread */ + thread_queue_wake(¤t->queue); + corelock_unlock(¤t->waiter_cl); + /* Slot must be unusable until thread is really gone */ + UNLOCK_THREAD_AT_TASK_SWITCH(current); + switch_thread(); + /* This should never and must never be reached - if it is, the + * state is corrupted */ + THREAD_PANICF("thread_exit->K:*R", current); +} + +#ifdef ALLOW_REMOVE_THREAD +/*--------------------------------------------------------------------------- + * Remove a thread from the scheduler. Not The Right Way to Do Things in + * normal programs. + * * Parameter is the ID as returned from create_thread(). * * Use with care on threads that are not under careful control as this may - * leave various objects in an undefined state. When trying to kill a thread - * on another processor, be sure you know what it's doing and won't be - * switching around itself. + * leave various objects in an undefined state. *--------------------------------------------------------------------------- */ void remove_thread(struct thread_entry *thread) @@ -2149,17 +2488,27 @@ void remove_thread(struct thread_entry *thread) /* core is not constant here because of core switching */ unsigned int core = CURRENT_CORE; unsigned int old_core = NUM_CORES; + struct corelock *ocl = NULL; #else const unsigned int core = CURRENT_CORE; #endif + struct thread_entry *current = cores[core].running; + unsigned state; int oldlevel; if (thread == NULL) - thread = cores[core].running; + thread = current; + + if (thread == current) + thread_exit(); /* Current thread - do normal exit */ oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); - state = GET_THREAD_STATE(thread); + + corelock_lock(&thread->waiter_cl); + LOCK_THREAD(thread); + + state = thread->state; if (state == STATE_KILLED) { @@ -2167,50 +2516,49 @@ void remove_thread(struct thread_entry *thread) } #if NUM_CORES > 1 + if (thread->name == THREAD_DESTRUCT) + { + /* Thread being killed - become a waiter */ + UNLOCK_THREAD(thread); + corelock_unlock(&thread->waiter_cl); + set_irq_level(oldlevel); + thread_wait(thread); + return; + } + + thread->name = THREAD_DESTRUCT; /* Slot can't be used for now */ + +#ifdef HAVE_PRIORITY_SCHEDULING + check_for_obj_waiters("remove_thread", thread); +#endif + if (thread->core != core) { /* Switch cores and safely extract the thread there */ - /* Slot HAS to be unlocked or a deadlock could occur - potential livelock - condition if the thread runs away to another processor. */ + /* Slot HAS to be unlocked or a deadlock could occur which means other + * threads have to be guided into becoming thread waiters if they + * attempt to remove it. */ unsigned int new_core = thread->core; - const char *old_name = thread->name; - thread->name = THREAD_DESTRUCT; /* Slot can't be used for now */ - UNLOCK_THREAD(thread, state); + corelock_unlock(&thread->waiter_cl); + + UNLOCK_THREAD(thread); set_irq_level(oldlevel); old_core = switch_core(new_core); oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); - state = GET_THREAD_STATE(thread); - - core = new_core; - - if (state == STATE_KILLED) - { - /* Thread suicided before we could kill it */ - goto thread_killed; - } - - /* Reopen slot - it's locked again anyway */ - thread->name = old_name; - if (thread->core != core) - { - /* We won't play thread tag - just forget it */ - UNLOCK_THREAD(thread, state); - set_irq_level(oldlevel); - goto thread_kill_abort; - } + corelock_lock(&thread->waiter_cl); + LOCK_THREAD(thread); + state = thread->state; + core = new_core; /* Perform the extraction and switch ourselves back to the original processor */ } #endif /* NUM_CORES > 1 */ -#ifdef HAVE_PRIORITY_SCHEDULING - cores[IF_COP_CORE(core)].highest_priority = LOWEST_PRIORITY; -#endif if (thread->tmo.prev != NULL) { /* Clean thread off the timeout list if a timeout check hasn't @@ -2218,87 +2566,86 @@ void remove_thread(struct thread_entry *thread) remove_from_list_tmo(thread); } +#ifdef HAVE_SCHEDULER_BOOSTCTRL + /* Cancel CPU boost if any */ boost_thread(thread, false); - - if (thread == cores[core].running) - { - /* Suicide - thread has unconditional rights to do this */ - /* Maintain locks until switch-out */ - block_thread_on_l(NULL, thread, STATE_KILLED); - -#if NUM_CORES > 1 - /* Switch to the idle stack if not on the main core (where "main" - * runs) */ - if (core != CPU) - { - switch_to_idle_stack(core); - } - - flush_icache(); #endif - /* Signal this thread */ - thread_queue_wake_no_listlock(&thread->queue); - /* Switch tasks and never return */ - switch_thread(thread); - /* This should never and must never be reached - if it is, the - * state is corrupted */ - THREAD_PANICF("remove_thread->K:*R", thread); - } -#if NUM_CORES > 1 - if (thread->name == THREAD_DESTRUCT) - { - /* Another core is doing this operation already */ - UNLOCK_THREAD(thread, state); - set_irq_level(oldlevel); - return; - } -#endif - if (cores[core].waking.queue != NULL) - { - /* Get any threads off the waking list and onto the running - * list first - waking and running cannot be distinguished by - * state */ - core_perform_wakeup(IF_COP(core)); - } +IF_COP( retry_state: ) switch (state) { case STATE_RUNNING: + RTR_LOCK(core); /* Remove thread from ready to run tasks */ remove_from_list_l(&cores[core].running, thread); + rtr_subtract_entry(core, thread->priority); + RTR_UNLOCK(core); break; case STATE_BLOCKED: case STATE_BLOCKED_W_TMO: /* Remove thread from the queue it's blocked on - including its * own if waiting there */ -#if CONFIG_CORELOCK == SW_CORELOCK - /* One or the other will be valid */ - if (thread->bqp == NULL) +#if NUM_CORES > 1 + if (&thread->waiter_cl != thread->obj_cl) { - remove_from_list_l(thread->bqnlp, thread); + ocl = thread->obj_cl; + + if (corelock_try_lock(ocl) == 0) + { + UNLOCK_THREAD(thread); + corelock_lock(ocl); + LOCK_THREAD(thread); + + if (thread->state != state) + { + /* Something woke the thread */ + state = thread->state; + corelock_unlock(ocl); + goto retry_state; + } + } } - else -#endif /* CONFIG_CORELOCK */ +#endif + remove_from_list_l(thread->bqp, thread); + +#ifdef HAVE_WAKEUP_EXT_CB + if (thread->wakeup_ext_cb != NULL) + thread->wakeup_ext_cb(thread); +#endif + +#ifdef HAVE_PRIORITY_SCHEDULING + if (thread->blocker != NULL) { - remove_from_list_l_locked(thread->bqp, thread); + /* Remove thread's priority influence from its chain */ + wakeup_priority_protocol_release(thread); } +#endif + +#if NUM_CORES > 1 + if (ocl != NULL) + corelock_unlock(ocl); +#endif break; - /* Otherwise thread is killed or is frozen and hasn't run yet */ + /* Otherwise thread is frozen and hasn't run yet */ } + thread->state = STATE_KILLED; + /* If thread was waiting on itself, it will have been removed above. * The wrong order would result in waking the thread first and deadlocking * since the slot is already locked. */ - thread_queue_wake_no_listlock(&thread->queue); + thread_queue_wake(&thread->queue); + + thread->name = NULL; thread_killed: /* Thread was already killed */ - /* Removal complete - safe to unlock state and reenable interrupts */ - UNLOCK_THREAD_SET_STATE(thread, STATE_KILLED); + /* Removal complete - safe to unlock and reenable interrupts */ + corelock_unlock(&thread->waiter_cl); + UNLOCK_THREAD(thread); set_irq_level(oldlevel); #if NUM_CORES > 1 -thread_kill_abort: /* Something stopped us from killing the thread */ if (old_core < NUM_CORES) { /* Did a removal on another processor's thread - switch back to @@ -2307,114 +2654,147 @@ thread_kill_abort: /* Something stopped us from killing the thread */ } #endif } +#endif /* ALLOW_REMOVE_THREAD */ +#ifdef HAVE_PRIORITY_SCHEDULING /*--------------------------------------------------------------------------- - * Block the current thread until another thread terminates. A thread may - * wait on itself to terminate which prevents it from running again and it - * will need to be killed externally. - * Parameter is the ID as returned from create_thread(). + * Sets the thread's relative base priority for the core it runs on. Any + * needed inheritance changes also may happen. *--------------------------------------------------------------------------- */ -void thread_wait(struct thread_entry *thread) +int thread_set_priority(struct thread_entry *thread, int priority) { - const unsigned int core = CURRENT_CORE; - struct thread_entry *current = cores[core].running; - unsigned thread_state; -#if NUM_CORES > 1 - int oldlevel; - unsigned current_state; -#endif + int old_base_priority = -1; + + /* A little safety measure */ + if (priority < HIGHEST_PRIORITY || priority > LOWEST_PRIORITY) + return -1; if (thread == NULL) - thread = current; + thread = cores[CURRENT_CORE].running; -#if NUM_CORES > 1 - oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); -#endif + /* Thread could be on any list and therefore on an interrupt accessible + one - disable interrupts */ + int oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); - thread_state = GET_THREAD_STATE(thread); + LOCK_THREAD(thread); -#if NUM_CORES > 1 - /* We can't lock the same slot twice. The waitee will also lock itself - first then the thread slots that will be locked and woken in turn. - The same order must be observed here as well. */ - if (thread == current) - { - current_state = thread_state; - } - else + /* Make sure it's not killed */ + if (thread->state != STATE_KILLED) { - current_state = GET_THREAD_STATE(current); - } -#endif + int old_priority = thread->priority; - if (thread_state != STATE_KILLED) - { - /* Unlock the waitee state at task switch - not done for self-wait - because the would double-unlock the state and potentially - corrupt another's busy assert on the slot */ - if (thread != current) + old_base_priority = thread->base_priority; + thread->base_priority = priority; + + prio_move_entry(&thread->pdist, old_base_priority, priority); + priority = find_first_set_bit(thread->pdist.mask); + + if (old_priority == priority) { -#if CONFIG_CORELOCK == SW_CORELOCK - cores[core].blk_ops.flags |= TBOP_UNLOCK_THREAD; - cores[core].blk_ops.thread = thread; -#elif CONFIG_CORELOCK == CORELOCK_SWAP - cores[core].blk_ops.flags |= TBOP_SET_VARu8; - cores[core].blk_ops.var_u8p = &thread->state; - cores[core].blk_ops.var_u8v = thread_state; -#endif + /* No priority change - do nothing */ } - block_thread_on_l_no_listlock(&thread->queue, current, STATE_BLOCKED); - switch_thread(current); - return; - } + else if (thread->state == STATE_RUNNING) + { + /* This thread is running - change location on the run + * queue. No transitive inheritance needed. */ + set_running_thread_priority(thread, priority); + } + else + { + thread->priority = priority; + + if (thread->blocker != NULL) + { + /* Bubble new priority down the chain */ + struct blocker *bl = thread->blocker; /* Blocker struct */ + struct thread_entry *bl_t = bl->thread; /* Blocking thread */ + struct thread_entry * const tstart = thread; /* Initial thread */ + const int highest = MIN(priority, old_priority); /* Higher of new or old */ - /* Unlock both slots - obviously the current thread can't have - STATE_KILLED so the above if clause will always catch a thread - waiting on itself */ + for (;;) + { + struct thread_entry *next; /* Next thread to check */ + int bl_pr; /* Highest blocked thread */ + int queue_pr; /* New highest blocked thread */ #if NUM_CORES > 1 - UNLOCK_THREAD(current, current_state); - UNLOCK_THREAD(thread, thread_state); - set_irq_level(oldlevel); -#endif -} + /* Owner can change but thread cannot be dislodged - thread + * may not be the first in the queue which allows other + * threads ahead in the list to be given ownership during the + * operation. If thread is next then the waker will have to + * wait for us and the owner of the object will remain fixed. + * If we successfully grab the owner -- which at some point + * is guaranteed -- then the queue remains fixed until we + * pass by. */ + for (;;) + { + LOCK_THREAD(bl_t); -#ifdef HAVE_PRIORITY_SCHEDULING -/*--------------------------------------------------------------------------- - * Sets the thread's relative priority for the core it runs on. - *--------------------------------------------------------------------------- - */ -int thread_set_priority(struct thread_entry *thread, int priority) -{ - unsigned old_priority = (unsigned)-1; - - if (thread == NULL) - thread = cores[CURRENT_CORE].running; + /* Double-check the owner - retry if it changed */ + if (bl->thread == bl_t) + break; -#if NUM_CORES > 1 - /* Thread could be on any list and therefore on an interrupt accessible - one - disable interrupts */ - int oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); + UNLOCK_THREAD(bl_t); + bl_t = bl->thread; + } #endif - unsigned state = GET_THREAD_STATE(thread); + bl_pr = bl->priority; - /* Make sure it's not killed */ - if (state != STATE_KILLED) - { - old_priority = thread->priority; - thread->priority = priority; - cores[IF_COP_CORE(thread->core)].highest_priority = LOWEST_PRIORITY; + if (highest > bl_pr) + break; /* Object priority won't change */ + + /* This will include the thread being set */ + queue_pr = find_highest_priority_in_list_l(*thread->bqp); + + if (queue_pr == bl_pr) + break; /* Object priority not changing */ + + /* Update thread boost for this object */ + bl->priority = queue_pr; + prio_move_entry(&bl_t->pdist, bl_pr, queue_pr); + bl_pr = find_first_set_bit(bl_t->pdist.mask); + + if (bl_t->priority == bl_pr) + break; /* Blocking thread priority not changing */ + + if (bl_t->state == STATE_RUNNING) + { + /* Thread not blocked - we're done */ + set_running_thread_priority(bl_t, bl_pr); + break; + } + + bl_t->priority = bl_pr; + bl = bl_t->blocker; /* Blocking thread has a blocker? */ + + if (bl == NULL) + break; /* End of chain */ + + next = bl->thread; + + if (next == tstart) + break; /* Full-circle */ + + UNLOCK_THREAD(thread); + + thread = bl_t; + bl_t = next; + } /* for (;;) */ + + UNLOCK_THREAD(bl_t); + } + } } -#if NUM_CORES > 1 - UNLOCK_THREAD(thread, state); + UNLOCK_THREAD(thread); + set_irq_level(oldlevel); -#endif - return old_priority; + + return old_base_priority; } /*--------------------------------------------------------------------------- - * Returns the current priority for a thread. + * Returns the current base priority for a thread. *--------------------------------------------------------------------------- */ int thread_get_priority(struct thread_entry *thread) @@ -2423,64 +2803,26 @@ int thread_get_priority(struct thread_entry *thread) if (thread == NULL) thread = cores[CURRENT_CORE].running; - return (unsigned)thread->priority; + return thread->base_priority; } +#endif /* HAVE_PRIORITY_SCHEDULING */ /*--------------------------------------------------------------------------- - * Yield that guarantees thread execution once per round regardless of - * thread's scheduler priority - basically a transient realtime boost - * without altering the scheduler's thread precedence. - * - * HACK ALERT! Search for "priority inheritance" for proper treatment. + * Starts a frozen thread - similar semantics to wakeup_thread except that + * the thread is on no scheduler or wakeup queue at all. It exists simply by + * virtue of the slot having a state of STATE_FROZEN. *--------------------------------------------------------------------------- */ -void priority_yield(void) -{ - const unsigned int core = CURRENT_CORE; - struct thread_entry *thread = cores[core].running; - thread->priority_x = HIGHEST_PRIORITY; - switch_thread(NULL); - thread->priority_x = LOWEST_PRIORITY; -} -#endif /* HAVE_PRIORITY_SCHEDULING */ - -/* Resumes a frozen thread - similar logic to wakeup_thread except that - the thread is on no scheduler list at all. It exists simply by virtue of - the slot having a state of STATE_FROZEN. */ void thread_thaw(struct thread_entry *thread) { -#if NUM_CORES > 1 - /* Thread could be on any list and therefore on an interrupt accessible - one - disable interrupts */ int oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); -#endif - unsigned state = GET_THREAD_STATE(thread); + LOCK_THREAD(thread); - if (state == STATE_FROZEN) - { - const unsigned int core = CURRENT_CORE; -#if NUM_CORES > 1 - if (thread->core != core) - { - core_schedule_wakeup(thread); - } - else -#endif - { - add_to_list_l(&cores[core].running, thread); - } - - UNLOCK_THREAD_SET_STATE(thread, STATE_RUNNING); -#if NUM_CORES > 1 - set_irq_level(oldlevel); -#endif - return; - } + if (thread->state == STATE_FROZEN) + core_schedule_wakeup(thread); -#if NUM_CORES > 1 - UNLOCK_THREAD(thread, state); + UNLOCK_THREAD(thread); set_irq_level(oldlevel); -#endif } /*--------------------------------------------------------------------------- @@ -2501,21 +2843,31 @@ unsigned int switch_core(unsigned int new_core) { const unsigned int core = CURRENT_CORE; struct thread_entry *current = cores[core].running; - struct thread_entry *w; - int oldlevel; - - /* Interrupts can access the lists that will be used - disable them */ - unsigned state = GET_THREAD_STATE(current); if (core == new_core) { - /* No change - just unlock everything and return same core */ - UNLOCK_THREAD(current, state); + /* No change - just return same core */ return core; } + int oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); + LOCK_THREAD(current); + + if (current->name == THREAD_DESTRUCT) + { + /* Thread being killed - deactivate and let process complete */ + UNLOCK_THREAD(current); + set_irq_level(oldlevel); + thread_wait(current); + /* Should never be reached */ + THREAD_PANICF("switch_core->D:*R", current); + } + /* Get us off the running list for the current core */ + RTR_LOCK(core); remove_from_list_l(&cores[core].running, current); + rtr_subtract_entry(core, current->priority); + RTR_UNLOCK(core); /* Stash return value (old core) in a safe place */ current->retval = core; @@ -2532,39 +2884,31 @@ unsigned int switch_core(unsigned int new_core) /* Do not use core_schedule_wakeup here since this will result in * the thread starting to run on the other core before being finished on - * this one. Delay the wakeup list unlock to keep the other core stuck + * this one. Delay the list unlock to keep the other core stuck * until this thread is ready. */ - oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL); - w = LOCK_LIST(&cores[new_core].waking); - ADD_TO_LIST_L_SELECT(w, &cores[new_core].waking, current); + RTR_LOCK(new_core); + + rtr_add_entry(new_core, current->priority); + add_to_list_l(&cores[new_core].running, current); /* Make a callback into device-specific code, unlock the wakeup list so * that execution may resume on the new core, unlock our slot and finally * restore the interrupt level */ - cores[core].blk_ops.flags = TBOP_SWITCH_CORE | TBOP_UNLOCK_CURRENT | - TBOP_UNLOCK_LIST; - cores[core].blk_ops.list_p = &cores[new_core].waking; -#if CONFIG_CORELOCK == CORELOCK_SWAP - cores[core].blk_ops.state = STATE_RUNNING; - cores[core].blk_ops.list_v = w; -#endif + cores[core].blk_ops.flags = TBOP_SWITCH_CORE; + cores[core].blk_ops.cl_p = &cores[new_core].rtr_cl; + cores[core].block_task = current; + + UNLOCK_THREAD(current); + + /* Alert other core to activity */ + core_wake(new_core); -#ifdef HAVE_PRIORITY_SCHEDULING - current->priority_x = HIGHEST_PRIORITY; - cores[core].highest_priority = LOWEST_PRIORITY; -#endif /* Do the stack switching, cache_maintenence and switch_thread call - requires native code */ switch_thread_core(core, current); -#ifdef HAVE_PRIORITY_SCHEDULING - current->priority_x = LOWEST_PRIORITY; - cores[current->core].highest_priority = LOWEST_PRIORITY; -#endif - /* Finally return the old core to caller */ return current->retval; - (void)state; } #endif /* NUM_CORES > 1 */ @@ -2578,12 +2922,11 @@ void init_threads(void) { const unsigned int core = CURRENT_CORE; struct thread_entry *thread; - int slot; /* CPU will initialize first and then sleep */ - slot = find_empty_thread_slot(); + thread = find_empty_thread_slot(); - if (slot >= MAXTHREADS) + if (thread == NULL) { /* WTF? There really must be a slot available at this stage. * This can fail if, for example, .bss isn't zero'ed out by the loader @@ -2592,33 +2935,29 @@ void init_threads(void) } /* Initialize initially non-zero members of core */ - thread_queue_init(&cores[core].waking); cores[core].next_tmo_check = current_tick; /* Something not in the past */ -#ifdef HAVE_PRIORITY_SCHEDULING - cores[core].highest_priority = LOWEST_PRIORITY; -#endif /* Initialize initially non-zero members of slot */ - thread = &threads[slot]; + UNLOCK_THREAD(thread); /* No sync worries yet */ thread->name = main_thread_name; - UNLOCK_THREAD_SET_STATE(thread, STATE_RUNNING); /* No sync worries yet */ -#if NUM_CORES > 1 - thread->core = core; -#endif + thread->state = STATE_RUNNING; + IF_COP( thread->core = core; ) #ifdef HAVE_PRIORITY_SCHEDULING + corelock_init(&cores[core].rtr_cl); + thread->base_priority = PRIORITY_USER_INTERFACE; + prio_add_entry(&thread->pdist, PRIORITY_USER_INTERFACE); thread->priority = PRIORITY_USER_INTERFACE; - thread->priority_x = LOWEST_PRIORITY; -#endif -#if CONFIG_CORELOCK == SW_CORELOCK - corelock_init(&thread->cl); + rtr_add_entry(core, PRIORITY_USER_INTERFACE); #endif + corelock_init(&thread->waiter_cl); + corelock_init(&thread->slot_cl); add_to_list_l(&cores[core].running, thread); if (core == CPU) { thread->stack = stackbegin; - thread->stack_size = (int)stackend - (int)stackbegin; + thread->stack_size = (uintptr_t)stackend - (uintptr_t)stackbegin; #if NUM_CORES > 1 /* This code path will not be run on single core targets */ /* TODO: HAL interface for this */ /* Wake up coprocessor and let it initialize kernel and threads */ @@ -2638,22 +2977,21 @@ void init_threads(void) /* Get COP safely primed inside switch_thread where it will remain * until a thread actually exists on it */ CPU_CTL = PROC_WAKE; - remove_thread(NULL); + thread_exit(); #endif /* NUM_CORES */ } } -/*--------------------------------------------------------------------------- - * Returns the maximum percentage of stack a thread ever used while running. - * NOTE: Some large buffer allocations that don't use enough the buffer to - * overwrite stackptr[0] will not be seen. - *--------------------------------------------------------------------------- - */ -int thread_stack_usage(const struct thread_entry *thread) +/* Shared stack scan helper for thread_stack_usage and idle_stack_usage */ +#if NUM_CORES == 1 +static inline int stack_usage(uintptr_t *stackptr, size_t stack_size) +#else +static int stack_usage(uintptr_t *stackptr, size_t stack_size) +#endif { - unsigned int *stackptr = thread->stack; - int stack_words = thread->stack_size / sizeof (int); - int i, usage = 0; + unsigned int stack_words = stack_size / sizeof (uintptr_t); + unsigned int i; + int usage = 0; for (i = 0; i < stack_words; i++) { @@ -2667,6 +3005,17 @@ int thread_stack_usage(const struct thread_entry *thread) return usage; } +/*--------------------------------------------------------------------------- + * Returns the maximum percentage of stack a thread ever used while running. + * NOTE: Some large buffer allocations that don't use enough the buffer to + * overwrite stackptr[0] will not be seen. + *--------------------------------------------------------------------------- + */ +int thread_stack_usage(const struct thread_entry *thread) +{ + return stack_usage(thread->stack, thread->stack_size); +} + #if NUM_CORES > 1 /*--------------------------------------------------------------------------- * Returns the maximum percentage of the core's idle stack ever used during @@ -2675,19 +3024,7 @@ int thread_stack_usage(const struct thread_entry *thread) */ int idle_stack_usage(unsigned int core) { - unsigned int *stackptr = idle_stacks[core]; - int i, usage = 0; - - for (i = 0; i < IDLE_STACK_WORDS; i++) - { - if (stackptr[i] != DEADBEEF) - { - usage = ((IDLE_STACK_WORDS - i) * 100) / IDLE_STACK_WORDS; - break; - } - } - - return usage; + return stack_usage(idle_stacks[core], IDLE_STACK_SIZE); } #endif |