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authorDavid Brownell <dbrownell@users.sourceforge.net>2009-11-19 19:03:12 -0800
committerDavid Brownell <dbrownell@users.sourceforge.net>2009-11-19 19:03:12 -0800
commita1777fc6493b4c1879ef133c565327212859d37c (patch)
tree3843e13117c6b2192da535ba207ac33dd88123ea /src/target
parentd7760352e8044e8eb8cd9b381574e34093e1f26f (diff)
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Cortex-A8: better context restore
The previous version never wrote dirty registers for non-current CPU modes ... fix that. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Diffstat (limited to 'src/target')
-rw-r--r--src/target/cortex_a8.c80
1 files changed, 67 insertions, 13 deletions
diff --git a/src/target/cortex_a8.c b/src/target/cortex_a8.c
index 01b7aee8..168fe127 100644
--- a/src/target/cortex_a8.c
+++ b/src/target/cortex_a8.c
@@ -531,7 +531,7 @@ static int cortex_a8_resume(struct target *target, int current,
armv4_5->core_mode, 15).valid = 1;
cortex_a8_restore_context(target);
-// arm7_9_restore_context(target); TODO Context is currently NOT Properly restored
+
#if 0
/* the front-end may request us not to handle breakpoints */
if (handle_breakpoints)
@@ -850,30 +850,84 @@ static int cortex_a8_step(struct target *target, int current, uint32_t address,
static int cortex_a8_restore_context(struct target *target)
{
- int i;
uint32_t value;
struct armv7a_common *armv7a = target_to_armv7a(target);
- struct armv4_5_common_s *armv4_5 = &armv7a->armv4_5_common;
+ struct reg_cache *cache = armv7a->armv4_5_common.core_cache;
+ unsigned max = cache->num_regs;
+ struct reg *r;
+ bool flushed, flush_cpsr = false;
LOG_DEBUG(" ");
if (armv7a->pre_restore_context)
armv7a->pre_restore_context(target);
- for (i = 15; i >= 0; i--)
- {
- if (ARMV4_5_CORE_REG_MODE(armv4_5->core_cache,
- armv4_5->core_mode, i).dirty)
- {
- value = buf_get_u32(ARMV4_5_CORE_REG_MODE(
- armv4_5->core_cache,
- armv4_5->core_mode, i).value,
- 0, 32);
+ /* Flush all dirty registers from the cache, one mode at a time so
+ * that we write CPSR as little as possible. Save CPSR and R0 for
+ * last; they're used to change modes and write other registers.
+ *
+ * REVISIT be smarter: save eventual mode for last loop, don't
+ * need to write CPSR an extra time.
+ */
+ do {
+ enum armv4_5_mode mode = ARMV4_5_MODE_ANY;
+ unsigned i;
+
+ flushed = false;
+
+ /* write dirty non-{R0,CPSR} registers sharing the same mode */
+ for (i = max - 1, r = cache->reg_list + 1; i > 0; i--, r++) {
+ struct armv4_5_core_reg *reg;
+
+ if (!r->dirty || i == ARMV4_5_CPSR)
+ continue;
+ reg = r->arch_info;
+
/* TODO Check return values */
- cortex_a8_dap_write_coreregister_u32(target, value, i);
+
+ /* Pick a mode and update CPSR; else ignore this
+ * register if it's for a different mode than what
+ * we're handling on this pass.
+ *
+ * REVISIT don't distinguish SYS and USR modes.
+ *
+ * FIXME if we restore from FIQ mode, R8..R12 will
+ * get wrongly flushed onto FIQ shadows...
+ */
+ if (mode == ARMV4_5_MODE_ANY) {
+ mode = reg->mode;
+ if (mode != ARMV4_5_MODE_ANY) {
+ cortex_a8_dap_write_coreregister_u32(
+ target, mode, 16);
+ flush_cpsr = true;
+ }
+ } else if (mode != reg->mode)
+ continue;
+
+ /* Write this register */
+ value = buf_get_u32(r->value, 0, 32);
+ cortex_a8_dap_write_coreregister_u32(target, value,
+ (reg->num == 16) ? 17 : reg->num);
+ r->dirty = false;
+ flushed = true;
}
+
+ } while (flushed);
+
+ /* now flush CPSR if needed ... */
+ r = cache->reg_list + ARMV4_5_CPSR;
+ if (flush_cpsr || r->dirty) {
+ value = buf_get_u32(r->value, 0, 32);
+ cortex_a8_dap_write_coreregister_u32(target, value, 16);
+ r->dirty = false;
}
+ /* ... and R0 always (it was dirtied when we saved context) */
+ r = cache->reg_list + 0;
+ value = buf_get_u32(r->value, 0, 32);
+ cortex_a8_dap_write_coreregister_u32(target, value, 0);
+ r->dirty = false;
+
if (armv7a->post_restore_context)
armv7a->post_restore_context(target);