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cortex_a: add 'dacrfixup' to cortex-a command group

work around issues with software breakpoints when the text segment
is mapped read-only by the OS. Set DACR to "all-manager" to bypass
TLB permission checks on memory access.

Change-Id: I79fd9b32b04a4d538d489896470ee30b26b72b30
Signed-off-by: Matthias Welwarsky <matthias@welwarsky.de>
Reviewed-on: http://openocd.zylin.com/3107
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>
tags/v0.10.0-rc1
Matthias Welwarsky 6 years ago
committed by Andreas Fritiofson
parent
commit
5bee7f5b2c
3 changed files with 76 additions and 2 deletions
  1. +7
    -0
      doc/openocd.texi
  2. +59
    -1
      src/target/cortex_a.c
  3. +10
    -1
      src/target/cortex_a.h

+ 7
- 0
doc/openocd.texi View File

@@ -7678,6 +7678,13 @@ Disabled by default
display information about target caches
@end deffn

@deffn Command {cortex_a dacrfixup [@option{on}|@option{off}]}
Work around issues with software breakpoints when the program text is
mapped read-only by the operating system. This option sets the CP15 DACR
to "all-manager" to bypass MMU permission checks on memory access.
Defaults to 'off'.
@end deffn

@deffn Command {cortex_a dbginit}
Initialize core debug
Enables debug by unlocking the Software Lock and clearing sticky powerdown indications


+ 59
- 1
src/target/cortex_a.c View File

@@ -106,6 +106,7 @@ static int cortex_a_restore_cp15_control_reg(struct target *target)
static int cortex_a_prep_memaccess(struct target *target, int phys_access)
{
struct armv7a_common *armv7a = target_to_armv7a(target);
struct cortex_a_common *cortex_a = target_to_cortex_a(target);
int mmu_enabled = 0;

if (phys_access == 0) {
@@ -113,6 +114,12 @@ static int cortex_a_prep_memaccess(struct target *target, int phys_access)
cortex_a_mmu(target, &mmu_enabled);
if (mmu_enabled)
cortex_a_mmu_modify(target, 1);
if (cortex_a->dacrfixup_mode == CORTEX_A_DACRFIXUP_ON) {
/* overwrite DACR to all-manager */
armv7a->arm.mcr(target, 15,
0, 0, 3, 0,
0xFFFFFFFF);
}
} else {
cortex_a_mmu(target, &mmu_enabled);
if (mmu_enabled)
@@ -129,8 +136,15 @@ static int cortex_a_prep_memaccess(struct target *target, int phys_access)
static int cortex_a_post_memaccess(struct target *target, int phys_access)
{
struct armv7a_common *armv7a = target_to_armv7a(target);
struct cortex_a_common *cortex_a = target_to_cortex_a(target);

if (phys_access == 0) {
if (cortex_a->dacrfixup_mode == CORTEX_A_DACRFIXUP_ON) {
/* restore */
armv7a->arm.mcr(target, 15,
0, 0, 3, 0,
cortex_a->cp15_dacr_reg);
}
dpm_modeswitch(&armv7a->dpm, ARM_MODE_ANY);
} else {
int mmu_enabled = 0;
@@ -1040,6 +1054,7 @@ static int cortex_a_internal_restore(struct target *target, int current,
buf_set_u32(arm->pc->value, 0, 32, resume_pc);
arm->pc->dirty = 1;
arm->pc->valid = 1;

/* restore dpm_mode at system halt */
dpm_modeswitch(&armv7a->dpm, ARM_MODE_ANY);
/* called it now before restoring context because it uses cpu
@@ -1336,6 +1351,16 @@ static int cortex_a_post_debug_entry(struct target *target)
(cortex_a->cp15_control_reg & 0x1000U) ? 1 : 0;
cortex_a->curr_mode = armv7a->arm.core_mode;

/* switch to SVC mode to read DACR */
dpm_modeswitch(&armv7a->dpm, ARM_MODE_SVC);
armv7a->arm.mrc(target, 15,
0, 0, 3, 0,
&cortex_a->cp15_dacr_reg);

LOG_DEBUG("cp15_dacr_reg: %8.8" PRIx32,
cortex_a->cp15_dacr_reg);

dpm_modeswitch(&armv7a->dpm, ARM_MODE_ANY);
return ERROR_OK;
}

@@ -3325,6 +3350,32 @@ COMMAND_HANDLER(handle_cortex_a_mask_interrupts_command)
return ERROR_OK;
}

COMMAND_HANDLER(handle_cortex_a_dacrfixup_command)
{
struct target *target = get_current_target(CMD_CTX);
struct cortex_a_common *cortex_a = target_to_cortex_a(target);

static const Jim_Nvp nvp_dacrfixup_modes[] = {
{ .name = "off", .value = CORTEX_A_DACRFIXUP_OFF },
{ .name = "on", .value = CORTEX_A_DACRFIXUP_ON },
{ .name = NULL, .value = -1 },
};
const Jim_Nvp *n;

if (CMD_ARGC > 0) {
n = Jim_Nvp_name2value_simple(nvp_dacrfixup_modes, CMD_ARGV[0]);
if (n->name == NULL)
return ERROR_COMMAND_SYNTAX_ERROR;
cortex_a->dacrfixup_mode = n->value;

}

n = Jim_Nvp_value2name_simple(nvp_dacrfixup_modes, cortex_a->dacrfixup_mode);
command_print(CMD_CTX, "cortex_a domain access control fixup %s", n->name);

return ERROR_OK;
}

static const struct command_registration cortex_a_exec_command_handlers[] = {
{
.name = "cache_info",
@@ -3366,7 +3417,14 @@ static const struct command_registration cortex_a_exec_command_handlers[] = {
.help = "mask cortex_a interrupts",
.usage = "['on'|'off']",
},

{
.name = "dacrfixup",
.handler = handle_cortex_a_dacrfixup_command,
.mode = COMMAND_EXEC,
.help = "set domain access control (DACR) to all-manager "
"on memory access",
.usage = "['on'|'off']",
},

COMMAND_REGISTRATION_DONE
};


+ 10
- 1
src/target/cortex_a.h View File

@@ -60,6 +60,11 @@ enum cortex_a_isrmasking_mode {
CORTEX_A_ISRMASK_ON,
};

enum cortex_a_dacrfixup_mode {
CORTEX_A_DACRFIXUP_OFF,
CORTEX_A_DACRFIXUP_ON
};

struct cortex_a_brp {
int used;
int type;
@@ -78,9 +83,12 @@ struct cortex_a_common {
uint32_t cp15_control_reg;
/* latest cp15 register value written and cpsr processor mode */
uint32_t cp15_control_reg_curr;
/* auxiliary control reg */
uint32_t cp15_aux_control_reg;
/* DACR */
uint32_t cp15_dacr_reg;
enum arm_mode curr_mode;


/* Breakpoint register pairs */
int brp_num_context;
int brp_num;
@@ -96,6 +104,7 @@ struct cortex_a_common {
uint32_t didr;

enum cortex_a_isrmasking_mode isrmasking_mode;
enum cortex_a_dacrfixup_mode dacrfixup_mode;

struct armv7a_common armv7a_common;



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