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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>
This commit is contained in:
David Brownell 2009-11-19 19:03:12 -08:00
parent d7760352e8
commit a1777fc649
1 changed files with 67 additions and 13 deletions
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80
src/target/cortex_a8.c
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@ -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);