/**
* 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;
}
/**
* ARM-specific bulk write from buffer to address of 8-bit wide NAND.
* For now this supports ARMv4,ARMv5 and ARMv7-M cores.
*
* Enhancements to target_run_algorithm() could enable:
* - ARMv6 and ARMv7 cores in ARM mode
*
* Different code fragments could handle:
* - 16-bit wide data (needs different setup)
*
* @param nand Pointer to the arm_nand_data struct that defines the I/O
* @param data Pointer to the data to be copied to flash
* @param size Size of the data being copied
* @return Success or failure of the operation
*/
int arm_nandwrite(struct arm_nand_data *nand, uint8_t *data, int size)
{
struct target *target = nand->target;
struct arm_algorithm armv4_5_algo;
struct armv7m_algorithm armv7m_algo;
void *arm_algo;
struct arm *arm = target->arch_info;
struct reg_param reg_params[3];
uint32_t target_buf;
uint32_t exit_var = 0;
int retval;
/* Inputs:
* r0 NAND data address (byte wide)
* r1 buffer address
* r2 buffer length
*/
static const uint32_t code_armv4_5[] = {
0xe4d13001, /* s: ldrb r3, [r1], #1 */
0xe5c03000, /* strb r3, [r0] */
0xe2522001, /* subs r2, r2, #1 */
0x1afffffb, /* bne s */
/* exit: ARMv4 needs hardware breakpoint */
0xe1200070, /* e: bkpt #0 */
};
/* Inputs:
* r0 NAND data address (byte wide)
* r1 buffer address
* r2 buffer length
*
* see contrib/loaders/flash/armv7m_io.s for src
*/
static const uint32_t code_armv7m[] = {
0x3b01f811,
0x3a017003,
0xaffaf47f,
0xbf00be00,
};
int target_code_size = 0;
const uint32_t *target_code_src = NULL;
/* set up algorithm */
if (is_armv7m(target_to_armv7m(target))) { /* armv7m target */
armv7m_algo.common_magic = ARMV7M_COMMON_MAGIC;
armv7m_algo.core_mode = ARM_MODE_THREAD;
arm_algo = &armv7m_algo;
target_code_size = sizeof(code_armv7m);
target_code_src = code_armv7m;
} else {
armv4_5_algo.common_magic = ARM_COMMON_MAGIC;
armv4_5_algo.core_mode = ARM_MODE_SVC;
armv4_5_algo.core_state = ARM_STATE_ARM;
arm_algo = &armv4_5_algo;
target_code_size = sizeof(code_armv4_5);
target_code_src = code_armv4_5;
}
if (nand->op != ARM_NAND_WRITE || !nand->copy_area) {
retval = arm_code_to_working_area(target, target_code_src, target_code_size,
nand->chunk_size, &nand->copy_area);
if (retval != ERROR_OK)
return retval;
}
nand->op = ARM_NAND_WRITE;
/* copy data to work area */
target_buf = nand->copy_area->address + target_code_size;
retval = target_write_buffer(target, target_buf, size, data);
if (retval != ERROR_OK)
return retval;
/* set up parameters */
init_reg_param(®_params[0], "r0", 32, PARAM_IN);
init_reg_param(®_params[1], "r1", 32, PARAM_IN);
init_reg_param(®_params[2], "r2", 32, PARAM_IN);
buf_set_u32(reg_params[0].value, 0, 32, nand->data);
buf_set_u32(reg_params[1].value, 0, 32, target_buf);
buf_set_u32(reg_params[2].value, 0, 32, size);
/* armv4 must exit using a hardware breakpoint */
if (arm->is_armv4)
exit_var = nand->copy_area->address + target_code_size - 4;
/* use alg to write data from work area to NAND chip */
retval = target_run_algorithm(target, 0, NULL, 3, reg_params,
nand->copy_area->address, exit_var, 1000, arm_algo);
if (retval != ERROR_OK)
LOG_ERROR("error executing hosted NAND write");
destroy_reg_param(®_params[0]);
destroy_reg_param(®_params[1]);
destroy_reg_param(®_params[2]);
return retval;
}
/**
* 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;
}
