Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-27 06:31:52 +00:00
Code Issues Packages Projects Releases Wiki Activity
09cda0a400
linux/arch/arm/kernel/kgdb.c
Russell King (Oracle) d920eaa4c4 ARM: Fix kgdb breakpoint for Thumb2 
The kgdb code needs to register an undef hook for the Thumb UDF
instruction that will fault in order to be functional on Thumb2
platforms.

Reported-by: Johannes Stezenbach <js@sig21.net>
Tested-by: Johannes Stezenbach <js@sig21.net>
Fixes: 5cbad0ebf4 ("kgdb: support for ARCH=arm")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-02-21 14:56:53 +00:00

292 lines
7.2 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0
/*
* arch/arm/kernel/kgdb.c
*
* ARM KGDB support
*
* Copyright (c) 2002-2004 MontaVista Software, Inc
* Copyright (c) 2008 Wind River Systems, Inc.
*
* Authors: George Davis <davis_g@mvista.com>
* Deepak Saxena <dsaxena@plexity.net>
*/
#include <linux/irq.h>
#include <linux/kdebug.h>
#include <linux/kgdb.h>
#include <linux/uaccess.h>
#include <asm/patch.h>
#include <asm/traps.h>
struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
{
{ "r0", 4, offsetof(struct pt_regs, ARM_r0)},
{ "r1", 4, offsetof(struct pt_regs, ARM_r1)},
{ "r2", 4, offsetof(struct pt_regs, ARM_r2)},
{ "r3", 4, offsetof(struct pt_regs, ARM_r3)},
{ "r4", 4, offsetof(struct pt_regs, ARM_r4)},
{ "r5", 4, offsetof(struct pt_regs, ARM_r5)},
{ "r6", 4, offsetof(struct pt_regs, ARM_r6)},
{ "r7", 4, offsetof(struct pt_regs, ARM_r7)},
{ "r8", 4, offsetof(struct pt_regs, ARM_r8)},
{ "r9", 4, offsetof(struct pt_regs, ARM_r9)},
{ "r10", 4, offsetof(struct pt_regs, ARM_r10)},
{ "fp", 4, offsetof(struct pt_regs, ARM_fp)},
{ "ip", 4, offsetof(struct pt_regs, ARM_ip)},
{ "sp", 4, offsetof(struct pt_regs, ARM_sp)},
{ "lr", 4, offsetof(struct pt_regs, ARM_lr)},
{ "pc", 4, offsetof(struct pt_regs, ARM_pc)},
{ "f0", 12, -1 },
{ "f1", 12, -1 },
{ "f2", 12, -1 },
{ "f3", 12, -1 },
{ "f4", 12, -1 },
{ "f5", 12, -1 },
{ "f6", 12, -1 },
{ "f7", 12, -1 },
{ "fps", 4, -1 },
{ "cpsr", 4, offsetof(struct pt_regs, ARM_cpsr)},
};
char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
{
if (regno >= DBG_MAX_REG_NUM || regno < 0)
return NULL;
if (dbg_reg_def[regno].offset != -1)
memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
dbg_reg_def[regno].size);
else
memset(mem, 0, dbg_reg_def[regno].size);
return dbg_reg_def[regno].name;
}
int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
{
if (regno >= DBG_MAX_REG_NUM || regno < 0)
return -EINVAL;
if (dbg_reg_def[regno].offset != -1)
memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
dbg_reg_def[regno].size);
return 0;
}
void
sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
{
struct thread_info *ti;
int regno;
/* Just making sure... */
if (task == NULL)
return;
/* Initialize to zero */
for (regno = 0; regno < GDB_MAX_REGS; regno++)
gdb_regs[regno] = 0;
/* Otherwise, we have only some registers from switch_to() */
ti = task_thread_info(task);
gdb_regs[_R4] = ti->cpu_context.r4;
gdb_regs[_R5] = ti->cpu_context.r5;
gdb_regs[_R6] = ti->cpu_context.r6;
gdb_regs[_R7] = ti->cpu_context.r7;
gdb_regs[_R8] = ti->cpu_context.r8;
gdb_regs[_R9] = ti->cpu_context.r9;
gdb_regs[_R10] = ti->cpu_context.sl;
gdb_regs[_FP] = ti->cpu_context.fp;
gdb_regs[_SPT] = ti->cpu_context.sp;
gdb_regs[_PC] = ti->cpu_context.pc;
}
void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
{
regs->ARM_pc = pc;
}
static int compiled_break;
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)
{
unsigned long addr;
char *ptr;
switch (remcom_in_buffer[0]) {
case 'D':
case 'k':
case 'c':
/*
* Try to read optional parameter, pc unchanged if no parm.
* If this was a compiled breakpoint, we need to move
* to the next instruction or we will just breakpoint
* over and over again.
*/
ptr = &remcom_in_buffer[1];
if (kgdb_hex2long(&ptr, &addr))
linux_regs->ARM_pc = addr;
else if (compiled_break == 1)
linux_regs->ARM_pc += 4;
compiled_break = 0;
return 0;
}
return -1;
}
static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
{
kgdb_handle_exception(1, SIGTRAP, 0, regs);
return 0;
}
static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
{
compiled_break = 1;
kgdb_handle_exception(1, SIGTRAP, 0, regs);
return 0;
}
static struct undef_hook kgdb_brkpt_arm_hook = {
.instr_mask = 0xffffffff,
.instr_val = KGDB_BREAKINST,
.cpsr_mask = PSR_T_BIT | MODE_MASK,
.cpsr_val = SVC_MODE,
.fn = kgdb_brk_fn
};
static struct undef_hook kgdb_brkpt_thumb_hook = {
.instr_mask = 0xffff,
.instr_val = KGDB_BREAKINST & 0xffff,
.cpsr_mask = PSR_T_BIT | MODE_MASK,
.cpsr_val = PSR_T_BIT | SVC_MODE,
.fn = kgdb_brk_fn
};
static struct undef_hook kgdb_compiled_brkpt_arm_hook = {
.instr_mask = 0xffffffff,
.instr_val = KGDB_COMPILED_BREAK,
.cpsr_mask = PSR_T_BIT | MODE_MASK,
.cpsr_val = SVC_MODE,
.fn = kgdb_compiled_brk_fn
};
static struct undef_hook kgdb_compiled_brkpt_thumb_hook = {
.instr_mask = 0xffff,
.instr_val = KGDB_COMPILED_BREAK & 0xffff,
.cpsr_mask = PSR_T_BIT | MODE_MASK,
.cpsr_val = PSR_T_BIT | SVC_MODE,
.fn = kgdb_compiled_brk_fn
};
static int __kgdb_notify(struct die_args *args, unsigned long cmd)
{
struct pt_regs *regs = args->regs;
if (kgdb_handle_exception(1, args->signr, cmd, regs))
return NOTIFY_DONE;
return NOTIFY_STOP;
}
static int
kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
{
unsigned long flags;
int ret;
local_irq_save(flags);
ret = __kgdb_notify(ptr, cmd);
local_irq_restore(flags);
return ret;
}
static struct notifier_block kgdb_notifier = {
.notifier_call = kgdb_notify,
.priority = -INT_MAX,
};
/**
* kgdb_arch_init - Perform any architecture specific initalization.
*
* This function will handle the initalization of any architecture
* specific callbacks.
*/
int kgdb_arch_init(void)
{
int ret = register_die_notifier(&kgdb_notifier);
if (ret != 0)
return ret;
register_undef_hook(&kgdb_brkpt_arm_hook);
register_undef_hook(&kgdb_brkpt_thumb_hook);
register_undef_hook(&kgdb_compiled_brkpt_arm_hook);
register_undef_hook(&kgdb_compiled_brkpt_thumb_hook);
return 0;
}
/**
* kgdb_arch_exit - Perform any architecture specific uninitalization.
*
* This function will handle the uninitalization of any architecture
* specific callbacks, for dynamic registration and unregistration.
*/
void kgdb_arch_exit(void)
{
unregister_undef_hook(&kgdb_brkpt_arm_hook);
unregister_undef_hook(&kgdb_brkpt_thumb_hook);
unregister_undef_hook(&kgdb_compiled_brkpt_arm_hook);
unregister_undef_hook(&kgdb_compiled_brkpt_thumb_hook);
unregister_die_notifier(&kgdb_notifier);
}
int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
{
int err;
/* patch_text() only supports int-sized breakpoints */
BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE);
err = copy_from_kernel_nofault(bpt->saved_instr, (char *)bpt->bpt_addr,
BREAK_INSTR_SIZE);
if (err)
return err;
/* Machine is already stopped, so we can use __patch_text() directly */
__patch_text((void *)bpt->bpt_addr,
*(unsigned int *)arch_kgdb_ops.gdb_bpt_instr);
return err;
}
int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
{
/* Machine is already stopped, so we can use __patch_text() directly */
__patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr);
return 0;
}
/*
* Register our undef instruction hooks with ARM undef core.
* We register a hook specifically looking for the KGB break inst
* and we handle the normal undef case within the do_undefinstr
* handler.
*/
const struct kgdb_arch arch_kgdb_ops = {
#ifndef __ARMEB__
.gdb_bpt_instr = {0xfe, 0xde, 0xff, 0xe7}
#else /* ! __ARMEB__ */
.gdb_bpt_instr = {0xe7, 0xff, 0xde, 0xfe}
#endif
};
Reference in New Issue View Git Blame Copy Permalink