1 files changed, 57 insertions, 0 deletions
diff --git a/utils/hwstub/stub/asm/arm/system.S b/utils/hwstub/stub/asm/arm/system.S
new file mode 100644
index 0000000000..df6b5a2e81
--- /dev/null
+++ b/utils/hwstub/stub/asm/arm/system.S
@@ -0,0 +1,57 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2014 by Amaury Pouly
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+/* Handling of data abort:
+ * the code can register a "longjmp" buffer to restore the context in case of
+ * fault */
+.data
+data_abort_jmp_ctx_ptr:
+/* buffer contains in order: cpsr,r4-r11,sp,lr,pc */
+.skip   48 /* = 4 * (cpsr +  11 registers) */
+
+.text
+/* Prototype: int set_data_abort_jmp()
+ * Return: 1 in case of data abort, 0 otherwise */
+.global set_data_abort_jmp
+set_data_abort_jmp:
+    mrs     r2, cpsr
+    ldr     r1, =data_abort_jmp_ctx_ptr
+    mov     r0, #0
+    stmia   r1, {r2,r4-r11,sp,lr,pc} /* see PC note below */
+    bx      lr
+    mov     r0, #1 /* <-- PC points here in stmia */
+    bx      lr
+
+.global data_abort_handler
+data_abort_handler:
+    /* restore everything from context */
+    ldr     r1, =data_abort_jmp_ctx_ptr
+    /* NOTE: we need to restore sp_sys and lr_sys, for this we need the
+     * LDM  Rn, {}^
+     * variant, but we cannot restore PC from it because ^ has a different
+     * meaning and won't restore user/sys registers. On top of that, the
+     * non-PC ^ variant cannot do the register writeback, so on the PC restore,
+     * we reload all registers once again to avoid manually offseting the base
+     * register, it will trash sp_abt and lr_abr but those are unused anyway
+     * because we do not save the abort address and we don't use an abort stack */
+    ldmia   r1, {r0,r4-r11,sp,lr}^  /* this variant cannot have writeback (r1!) */
+    msr     spsr, r0
+    ldmia   r1, {r0,r4-r11,sp,lr,pc}^ /* reload some registers but we don't care */