From 5bee7f5b2c13b02f2d6ad98de6a826279777c8a9 Mon Sep 17 00:00:00 2001 From: Matthias Welwarsky Date: Tue, 24 Nov 2015 22:11:56 +0100 Subject: [PATCH] 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 Reviewed-on: http://openocd.zylin.com/3107 Tested-by: jenkins Reviewed-by: Paul Fertser --- doc/openocd.texi | 7 +++++ src/target/cortex_a.c | 60 ++++++++++++++++++++++++++++++++++++++++++- src/target/cortex_a.h | 11 +++++++- 3 files changed, 76 insertions(+), 2 deletions(-) diff --git a/doc/openocd.texi b/doc/openocd.texi index 86415319..78298b86 100644 --- a/doc/openocd.texi +++ b/doc/openocd.texi @@ -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 diff --git a/src/target/cortex_a.c b/src/target/cortex_a.c index 78ce33df..8a0d38bc 100644 --- a/src/target/cortex_a.c +++ b/src/target/cortex_a.c @@ -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 }; diff --git a/src/target/cortex_a.h b/src/target/cortex_a.h index d33188ff..1c63588e 100644 --- a/src/target/cortex_a.h +++ b/src/target/cortex_a.h @@ -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; -- 2.39.5