/**
* Checks for and processes an ARM semihosting request. This is meant
* to be called when the target is stopped due to a debug mode entry.
* If the value 0 is returned then there was nothing to process. A non-zero
* return value signifies that a request was processed and the target resumed,
* or an error was encountered, in which case the caller must return
* immediately.
*
* @param target Pointer to the ARM target to process. This target must
* not represent an ARMv6-M or ARMv7-M processor.
* @param retval Pointer to a location where the return code will be stored
* @return non-zero value if a request was processed or an error encountered
*/
int arm_semihosting(struct target *target, int *retval)
{
struct arm *arm = target_to_arm(target);
uint32_t pc, lr, spsr;
struct reg *r;
if (!arm->is_semihosting)
return 0;
if (is_arm7_9(target_to_arm7_9(target))) {
if (arm->core_mode != ARM_MODE_SVC)
return 0;
/* Check for PC == 0x00000008 or 0xffff0008: Supervisor Call vector. */
r = arm->pc;
pc = buf_get_u32(r->value, 0, 32);
if (pc != 0x00000008 && pc != 0xffff0008)
return 0;
r = arm_reg_current(arm, 14);
lr = buf_get_u32(r->value, 0, 32);
/* Core-specific code should make sure SPSR is retrieved
* when the above checks pass...
*/
if (!arm->spsr->valid) {
LOG_ERROR("SPSR not valid!");
*retval = ERROR_FAIL;
return 1;
}
spsr = buf_get_u32(arm->spsr->value, 0, 32);
/* check instruction that triggered this trap */
if (spsr & (1 << 5)) {
/* was in Thumb (or ThumbEE) mode */
uint8_t insn_buf[2];
uint16_t insn;
*retval = target_read_memory(target, lr-2, 2, 1, insn_buf);
if (*retval != ERROR_OK)
return 1;
insn = target_buffer_get_u16(target, insn_buf);
/* SVC 0xab */
if (insn != 0xDFAB)
return 0;
} else if (spsr & (1 << 24)) {
/* was in Jazelle mode */
return 0;
} else {
/* was in ARM mode */
uint8_t insn_buf[4];
uint32_t insn;
*retval = target_read_memory(target, lr-4, 4, 1, insn_buf);
if (*retval != ERROR_OK)
return 1;
insn = target_buffer_get_u32(target, insn_buf);
/* SVC 0x123456 */
if (insn != 0xEF123456)
return 0;
}
} else if (is_armv7m(target_to_armv7m(target))) {
uint16_t insn;
if (target->debug_reason != DBG_REASON_BREAKPOINT)
return 0;
r = arm->pc;
pc = buf_get_u32(r->value, 0, 32);
pc &= ~1;
*retval = target_read_u16(target, pc, &insn);
if (*retval != ERROR_OK)
return 1;
/* bkpt 0xAB */
if (insn != 0xBEAB)
return 0;
} else {
LOG_ERROR("Unsupported semi-hosting Target");
return 0;
}
*retval = do_semihosting(target);
return 1;
}
/**
* Checks for and processes an ARM semihosting request. This is meant
* to be called when the target is stopped due to a debug mode entry.
* If the value 0 is returned then there was nothing to process. A non-zero
* return value signifies that a request was processed and the target resumed,
* or an error was encountered, in which case the caller must return
* immediately.
*
* @param target Pointer to the ARM target to process. This target must
* not represent an ARMv6-M or ARMv7-M processor.
* @param retval Pointer to a location where the return code will be stored
* @return non-zero value if a request was processed or an error encountered
*/
int arm_semihosting(struct target *target, int *retval)
{
struct arm *arm = target_to_arm(target);
struct armv7a_common *armv7a = target_to_armv7a(target);
uint32_t pc, lr, spsr;
struct reg *r;
if (!arm->is_semihosting)
return 0;
if (is_arm7_9(target_to_arm7_9(target)) ||
is_armv7a(armv7a)) {
uint32_t vbar = 0x00000000;
if (arm->core_mode != ARM_MODE_SVC)
return 0;
if (is_armv7a(armv7a)) {
struct arm_dpm *dpm = armv7a->arm.dpm;
*retval = dpm->prepare(dpm);
if (*retval == ERROR_OK) {
*retval = dpm->instr_read_data_r0(dpm,
ARMV4_5_MRC(15, 0, 0, 12, 0, 0),
&vbar);
dpm->finish(dpm);
if (*retval != ERROR_OK)
return 1;
} else {
return 1;
}
}
/* Check for PC == 0x00000008 or 0xffff0008: Supervisor Call vector. */
r = arm->pc;
pc = buf_get_u32(r->value, 0, 32);
if (pc != (vbar + 0x00000008) && pc != 0xffff0008)
return 0;
r = arm_reg_current(arm, 14);
lr = buf_get_u32(r->value, 0, 32);
/* Core-specific code should make sure SPSR is retrieved
* when the above checks pass...
*/
if (!arm->spsr->valid) {
LOG_ERROR("SPSR not valid!");
*retval = ERROR_FAIL;
return 1;
}
spsr = buf_get_u32(arm->spsr->value, 0, 32);
/* check instruction that triggered this trap */
if (spsr & (1 << 5)) {
/* was in Thumb (or ThumbEE) mode */
uint8_t insn_buf[2];
uint16_t insn;
*retval = target_read_memory(target, lr-2, 2, 1, insn_buf);
if (*retval != ERROR_OK)
return 1;
insn = target_buffer_get_u16(target, insn_buf);
/* SVC 0xab */
if (insn != 0xDFAB)
return 0;
} else if (spsr & (1 << 24)) {
/* was in Jazelle mode */
return 0;
} else {
/* was in ARM mode */
uint8_t insn_buf[4];
uint32_t insn;
*retval = target_read_memory(target, lr-4, 4, 1, insn_buf);
if (*retval != ERROR_OK)
return 1;
insn = target_buffer_get_u32(target, insn_buf);
/* SVC 0x123456 */
if (insn != 0xEF123456)
return 0;
}
} else if (is_armv7m(target_to_armv7m(target))) {
uint16_t insn;
if (target->debug_reason != DBG_REASON_BREAKPOINT)
return 0;
r = arm->pc;
pc = buf_get_u32(r->value, 0, 32);
pc &= ~1;
*retval = target_read_u16(target, pc, &insn);
if (*retval != ERROR_OK)
return 1;
/* bkpt 0xAB */
if (insn != 0xBEAB)
return 0;
} else {
LOG_ERROR("Unsupported semi-hosting Target");
return 0;
}
/* Perform semihosting if we are not waiting on a fileio
* operation to complete.
*/
if (!arm->semihosting_hit_fileio) {
*retval = do_semihosting(target);
if (*retval != ERROR_OK) {
LOG_ERROR("Failed semihosting operation");
return 0;
}
}
/* Post result to target if we are not waiting on a fileio
* operation to complete:
*/
if (!arm->semihosting_hit_fileio) {
*retval = post_result(target);
if (*retval != ERROR_OK) {
LOG_ERROR("Failed to post semihosting result");
return 0;
}
*retval = target_resume(target, 1, 0, 0, 0);
if (*retval != ERROR_OK) {
LOG_ERROR("Failed to resume target");
return 0;
}
return 1;
}
return 0;
}
