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/*
* kgdb support for ARC
*
* Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kgdb.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <asm/disasm.h>
#include <asm/cacheflush.h>
static void to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs,
struct callee_regs *cregs)
{
int regno;
for (regno = 0; regno <= 26; regno++)
gdb_regs[_R0 + regno] = get_reg(regno, kernel_regs, cregs);
for (regno = 27; regno < GDB_MAX_REGS; regno++)
gdb_regs[regno] = 0;
gdb_regs[_FP] = kernel_regs->fp;
gdb_regs[__SP] = kernel_regs->sp;
gdb_regs[_BLINK] = kernel_regs->blink;
gdb_regs[_RET] = kernel_regs->ret;
gdb_regs[_STATUS32] = kernel_regs->status32;
gdb_regs[_LP_COUNT] = kernel_regs->lp_count;
gdb_regs[_LP_END] = kernel_regs->lp_end;
gdb_regs[_LP_START] = kernel_regs->lp_start;
gdb_regs[_BTA] = kernel_regs->bta;
gdb_regs[_STOP_PC] = kernel_regs->ret;
}
static void from_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs,
struct callee_regs *cregs)
{
int regno;
for (regno = 0; regno <= 26; regno++)
set_reg(regno, gdb_regs[regno + _R0], kernel_regs, cregs);
kernel_regs->fp = gdb_regs[_FP];
kernel_regs->sp = gdb_regs[__SP];
kernel_regs->blink = gdb_regs[_BLINK];
kernel_regs->ret = gdb_regs[_RET];
kernel_regs->status32 = gdb_regs[_STATUS32];
kernel_regs->lp_count = gdb_regs[_LP_COUNT];
kernel_regs->lp_end = gdb_regs[_LP_END];
kernel_regs->lp_start = gdb_regs[_LP_START];
kernel_regs->bta = gdb_regs[_BTA];
}
void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
{
to_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *)
current->thread.callee_reg);
}
void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
{
from_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *)
current->thread.callee_reg);
}
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
struct task_struct *task)
{
if (task)
to_gdb_regs(gdb_regs, task_pt_regs(task),
(struct callee_regs *) task->thread.callee_reg);
}
struct single_step_data_t {
uint16_t opcode[2];
unsigned long address[2];
int is_branch;
int armed;
} single_step_data;
static void undo_single_step(struct pt_regs *regs)
{
if (single_step_data.armed) {
int i;
for (i = 0; i < (single_step_data.is_branch ? 2 : 1); i++) {
memcpy((void *) single_step_data.address[i],
&single_step_data.opcode[i],
BREAK_INSTR_SIZE);
flush_icache_range(single_step_data.address[i],
single_step_data.address[i] +
BREAK_INSTR_SIZE);
}
single_step_data.armed = 0;
}
}
static void place_trap(unsigned long address, void *save)
{
memcpy(save, (void *) address, BREAK_INSTR_SIZE);
memcpy((void *) address, &arch_kgdb_ops.gdb_bpt_instr,
BREAK_INSTR_SIZE);
flush_icache_range(address, address + BREAK_INSTR_SIZE);
}
static void do_single_step(struct pt_regs *regs)
{
single_step_data.is_branch = disasm_next_pc((unsigned long)
regs->ret, regs, (struct callee_regs *)
current->thread.callee_reg,
&single_step_data.address[0],
&single_step_data.address[1]);
place_trap(single_step_data.address[0], &single_step_data.opcode[0]);
if (single_step_data.is_branch) {
place_trap(single_step_data.address[1],
&single_step_data.opcode[1]);
}
single_step_data.armed++;
}
int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
char *remcomInBuffer, char *remcomOutBuffer,
struct pt_regs *regs)
{
unsigned long addr;
char *ptr;
undo_single_step(regs);
switch (remcomInBuffer[0]) {
case 's':
case 'c':
ptr = &remcomInBuffer[1];
if (kgdb_hex2long(&ptr, &addr))
regs->ret = addr;
case 'D':
case 'k':
atomic_set(&kgdb_cpu_doing_single_step, -1);
if (remcomInBuffer[0] == 's') {
do_single_step(regs);
atomic_set(&kgdb_cpu_doing_single_step,
smp_processor_id());
}
return 0;
}
return -1;
}
int kgdb_arch_init(void)
{
single_step_data.armed = 0;
return 0;
}
void kgdb_trap(struct pt_regs *regs)
{
/* trap_s 3 is used for breakpoints that overwrite existing
* instructions, while trap_s 4 is used for compiled breakpoints.
*
* with trap_s 3 breakpoints the original instruction needs to be
* restored and continuation needs to start at the location of the
* breakpoint.
*
* with trap_s 4 (compiled) breakpoints, continuation needs to
* start after the breakpoint.
*/
if (regs->ecr_param == 3)
instruction_pointer(regs) -= BREAK_INSTR_SIZE;
kgdb_handle_exception(1, SIGTRAP, 0, regs);
}
void kgdb_arch_exit(void)
{
}
void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
instruction_pointer(regs) = ip;
}
void kgdb_call_nmi_hook(void *ignored)
{
/* Default implementation passes get_irq_regs() but we don't */
kgdb_nmicallback(raw_smp_processor_id(), NULL);
}
const struct kgdb_arch arch_kgdb_ops = {
/* breakpoint instruction: TRAP_S 0x3 */
#ifdef CONFIG_CPU_BIG_ENDIAN
.gdb_bpt_instr = {0x78, 0x7e},
#else
.gdb_bpt_instr = {0x7e, 0x78},
#endif
};
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