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target/cortex_a: enable DSCR_HALT_DBG_MODE during examine

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Arm architecture reference manual DDI0406C reports at page 2024 in
table C3-1 the processor behaviour on debug events depending on
the debug-mode (none, monitor or halt), mode selected through the
bits MDBGen and HDBGen in DSCR register.

The halt request is served independently from the debug-mode. Thus
it's useless to enable the halt debug-mode in cortex_a_halt() by
setting the bit HDBGen (macro DSCR_HALT_DBG_MODE).

On the other side, halting for a breakpoint, a watchpoint or a
vector catch requires being in halt debug-mode.
Today HDBGen is set only in cortex_a_halt(), so we are forced to
halt the core at least once before it can be halted for hitting a
breakpoint/watchpoint/vector-catch. This is annoying since there
is no need to halt the target to set a HW breakpoint.

Move in cortex_a_init_debug_access() the selection of the halt
debug-mode, so the mode is set during examine.
To prevent a misconfigured hardware breakpoint/watchpoint/vector
catch to halt the target when OpenOCD has already quit, return to
debug-mode none at OpenOCD exit.

Change-Id: I68a1c51de3572ca1b89e90caf7eb20374268e926
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/4783
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>
This commit is contained in:
Antonio Borneo 2018-12-03 18:50:43 +01:00 committed by Matthias Welwarsky
parent 322d2fa12c
commit bff87a7f28
1 changed files with 25 additions and 14 deletions
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39
src/target/cortex_a.c
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@ -202,6 +202,7 @@ static int cortex_a_mmu_modify(struct target *target, int enable)
static int cortex_a_init_debug_access(struct target *target)
{
struct armv7a_common *armv7a = target_to_armv7a(target);
uint32_t dscr;
int retval;
/* lock memory-mapped access to debug registers to prevent
@ -231,6 +232,16 @@ static int cortex_a_init_debug_access(struct target *target)
/* Resync breakpoint registers */
/* Enable halt for breakpoint, watchpoint and vector catch */
retval = mem_ap_read_atomic_u32(armv7a->debug_ap,
armv7a->debug_base + CPUDBG_DSCR, &dscr);
if (retval != ERROR_OK)
return retval;
retval = mem_ap_write_atomic_u32(armv7a->debug_ap,
armv7a->debug_base + CPUDBG_DSCR, dscr | DSCR_HALT_DBG_MODE);
if (retval != ERROR_OK)
return retval;
/* Since this is likely called from init or reset, update target state information*/
return cortex_a_poll(target);
}
@ -769,19 +780,6 @@ static int cortex_a_halt(struct target *target)
if (retval != ERROR_OK)
return retval;
/*
* enter halting debug mode
*/
retval = mem_ap_read_atomic_u32(armv7a->debug_ap,
armv7a->debug_base + CPUDBG_DSCR, &dscr);
if (retval != ERROR_OK)
return retval;
retval = mem_ap_write_atomic_u32(armv7a->debug_ap,
armv7a->debug_base + CPUDBG_DSCR, dscr | DSCR_HALT_DBG_MODE);
if (retval != ERROR_OK)
return retval;
int64_t then = timeval_ms();
for (;; ) {
retval = mem_ap_read_atomic_u32(armv7a->debug_ap,
@ -2889,7 +2887,20 @@ static int cortex_r4_target_create(struct target *target, Jim_Interp *interp)
static void cortex_a_deinit_target(struct target *target)
{
struct cortex_a_common *cortex_a = target_to_cortex_a(target);
struct arm_dpm *dpm = &cortex_a->armv7a_common.dpm;
struct armv7a_common *armv7a = &cortex_a->armv7a_common;
struct arm_dpm *dpm = &armv7a->dpm;
uint32_t dscr;
int retval;
if (target_was_examined(target)) {
/* Disable halt for breakpoint, watchpoint and vector catch */
retval = mem_ap_read_atomic_u32(armv7a->debug_ap,
armv7a->debug_base + CPUDBG_DSCR, &dscr);
if (retval == ERROR_OK)
mem_ap_write_atomic_u32(armv7a->debug_ap,
armv7a->debug_base + CPUDBG_DSCR,
dscr & ~DSCR_HALT_DBG_MODE);
}
free(cortex_a->brp_list);
free(dpm->dbp);