int kgdb_arch_handle_exception(int exception_vector, int signo,
int err_code, char *remcom_in_buffer,
char *remcom_out_buffer,
struct pt_regs *linux_regs)
{
int err;
switch (remcom_in_buffer[0]) {
case 'D':
case 'k':
/*
* Packet D (Detach), k (kill). No special handling
* is required here. Handle same as c packet.
*/
case 'c':
/*
* Packet c (Continue) to continue executing.
* Set pc to required address.
* Try to read optional parameter and set pc.
* If this was a compiled breakpoint, we need to move
* to the next instruction else we will just breakpoint
* over and over again.
*/
kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
atomic_set(&kgdb_cpu_doing_single_step, -1);
kgdb_single_step = 0;
/*
* Received continue command, disable single step
*/
if (kernel_active_single_step())
kernel_disable_single_step();
err = 0;
break;
case 's':
/*
* Update step address value with address passed
* with step packet.
* On debug exception return PC is copied to ELR
* So just update PC.
* If no step address is passed, resume from the address
* pointed by PC. Do not update PC
*/
kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id());
kgdb_single_step = 1;
/*
* Enable single step handling
*/
if (!kernel_active_single_step())
kernel_enable_single_step(linux_regs);
err = 0;
break;
default:
err = -1;
}
return err;
}
/*
* Handle single-step exception.
*/
int reinstall_suspended_bps(struct pt_regs *regs)
{
struct debug_info *debug_info = ¤t->thread.debug;
int handled_exception = 0, *kernel_step;
kernel_step = this_cpu_ptr(&stepping_kernel_bp);
/*
* Called from single-step exception handler.
* Return 0 if execution can resume, 1 if a SIGTRAP should be
* reported.
*/
if (user_mode(regs)) {
if (debug_info->bps_disabled) {
debug_info->bps_disabled = 0;
toggle_bp_registers(AARCH64_DBG_REG_BCR, DBG_ACTIVE_EL0, 1);
handled_exception = 1;
}
if (debug_info->wps_disabled) {
debug_info->wps_disabled = 0;
toggle_bp_registers(AARCH64_DBG_REG_WCR, DBG_ACTIVE_EL0, 1);
handled_exception = 1;
}
if (handled_exception) {
if (debug_info->suspended_step) {
debug_info->suspended_step = 0;
/* Allow exception handling to fall-through. */
handled_exception = 0;
} else {
user_disable_single_step(current);
}
}
} else if (*kernel_step != ARM_KERNEL_STEP_NONE) {
toggle_bp_registers(AARCH64_DBG_REG_BCR, DBG_ACTIVE_EL1, 1);
toggle_bp_registers(AARCH64_DBG_REG_WCR, DBG_ACTIVE_EL1, 1);
if (!debug_info->wps_disabled)
toggle_bp_registers(AARCH64_DBG_REG_WCR, DBG_ACTIVE_EL0, 1);
if (*kernel_step != ARM_KERNEL_STEP_SUSPEND) {
kernel_disable_single_step();
handled_exception = 1;
} else {
handled_exception = 0;
}
*kernel_step = ARM_KERNEL_STEP_NONE;
}
return !handled_exception;
}
