ARC: kgdb support

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
This commit is contained in:
Mischa Jonker 2013-01-18 15:12:24 +05:30 committed by Vineet Gupta
parent 2e651ea159
commit f46121bd26
5 changed files with 275 additions and 1 deletions

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@ -22,6 +22,7 @@ config ARC
select GENERIC_PENDING_IRQ if SMP
select GENERIC_SIGALTSTACK
select GENERIC_SMP_IDLE_THREAD
select HAVE_ARCH_KGDB
select HAVE_ARCH_TRACEHOOK
select HAVE_GENERIC_HARDIRQS
select HAVE_KPROBES
@ -378,7 +379,7 @@ config ARC_DW2_UNWIND
config ARC_DBG_TLB_PARANOIA
bool "Paranoia Checks in Low Level TLB Handlers"
depends on ARC_DBG && !SMP
depends on ARC_DBG
default n
config ARC_DBG_TLB_MISS_COUNT

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@ -0,0 +1,61 @@
/*
* 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.
*/
#ifndef __ARC_KGDB_H__
#define __ARC_KGDB_H__
#ifdef CONFIG_KGDB
#include <asm/user.h>
/* to ensure compatibility with Linux 2.6.35, we don't implement the get/set
* register API yet */
#undef DBG_MAX_REG_NUM
#define GDB_MAX_REGS 39
#define BREAK_INSTR_SIZE 2
#define CACHE_FLUSH_IS_SAFE 1
#define NUMREGBYTES (GDB_MAX_REGS * 4)
#define BUFMAX 2048
static inline void arch_kgdb_breakpoint(void)
{
__asm__ __volatile__ ("trap_s 0x4\n");
}
extern void kgdb_trap(struct pt_regs *regs, int param);
enum arc700_linux_regnums {
_R0 = 0,
_R1, _R2, _R3, _R4, _R5, _R6, _R7, _R8, _R9, _R10, _R11, _R12, _R13,
_R14, _R15, _R16, _R17, _R18, _R19, _R20, _R21, _R22, _R23, _R24,
_R25, _R26,
_BTA = 27,
_LP_START = 28,
_LP_END = 29,
_LP_COUNT = 30,
_STATUS32 = 31,
_BLINK = 32,
_FP = 33,
__SP = 34,
_EFA = 35,
_RET = 36,
_ORIG_R8 = 37,
_STOP_PC = 38
};
#else
static inline void kgdb_trap(struct pt_regs *regs, int param)
{
}
#endif
#endif /* __ARC_KGDB_H__ */

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@ -17,6 +17,7 @@ obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_ARC_DW2_UNWIND) += unwind.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_ARC_MISALIGN_ACCESS) += unaligned.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_ARC_FPU_SAVE_RESTORE) += fpu.o
CFLAGS_fpu.o += -mdpfp

205
arch/arc/kernel/kgdb.c Normal file
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@ -0,0 +1,205 @@
/*
* 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 <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;
}
unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
{
return instruction_pointer(regs);
}
int kgdb_arch_init(void)
{
single_step_data.armed = 0;
return 0;
}
void kgdb_trap(struct pt_regs *regs, int param)
{
/* 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 (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;
}
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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@ -20,6 +20,7 @@
#include <asm/setup.h>
#include <asm/kprobes.h>
#include <asm/unaligned.h>
#include <asm/kgdb.h>
void __init trap_init(void)
{
@ -141,6 +142,11 @@ void do_non_swi_trap(unsigned long cause, unsigned long address,
trap_is_kprobe(param, address, regs);
break;
case 3:
case 4:
kgdb_trap(regs, param);
break;
default:
break;
}