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arm64: debug: consolidate software breakpoint handlers

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The software breakpoint handlers are hooked in directly from ptrace,
which makes it difficult to add additional handlers for things like
kprobes and kgdb.

This patch moves the handling code into debug-monitors.c, where we can
dispatch to different debug subsystems more easily.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Will Deacon
2013-03-16 08:48:13 +00:00
committed by Catalin Marinas
parent adace89562
commit 1442b6ed24
5 changed files with 75 additions and 66 deletions
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66
arch/arm64/kernel/debug-monitors.c
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@@ -24,6 +24,7 @@
#include <linux/init.h>
#include <linux/ptrace.h>
#include <linux/stat.h>
#include <linux/uaccess.h>
#include <asm/debug-monitors.h>
#include <asm/local.h>
@@ -226,13 +227,74 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
return 0;
}
static int __init single_step_init(void)
static int brk_handler(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
siginfo_t info;
if (!user_mode(regs))
return -EFAULT;
info = (siginfo_t) {
.si_signo = SIGTRAP,
.si_errno = 0,
.si_code = TRAP_BRKPT,
.si_addr = (void __user *)instruction_pointer(regs),
};
force_sig_info(SIGTRAP, &info, current);
return 0;
}
int aarch32_break_handler(struct pt_regs *regs)
{
siginfo_t info;
unsigned int instr;
bool bp = false;
void __user *pc = (void __user *)instruction_pointer(regs);
if (!compat_user_mode(regs))
return -EFAULT;
if (compat_thumb_mode(regs)) {
/* get 16-bit Thumb instruction */
get_user(instr, (u16 __user *)pc);
if (instr == AARCH32_BREAK_THUMB2_LO) {
/* get second half of 32-bit Thumb-2 instruction */
get_user(instr, (u16 __user *)(pc + 2));
bp = instr == AARCH32_BREAK_THUMB2_HI;
} else {
bp = instr == AARCH32_BREAK_THUMB;
}
} else {
/* 32-bit ARM instruction */
get_user(instr, (u32 __user *)pc);
bp = (instr & ~0xf0000000) == AARCH32_BREAK_ARM;
}
if (!bp)
return -EFAULT;
info = (siginfo_t) {
.si_signo = SIGTRAP,
.si_errno = 0,
.si_code = TRAP_BRKPT,
.si_addr = pc,
};
force_sig_info(SIGTRAP, &info, current);
return 0;
}
static int __init debug_traps_init(void)
{
hook_debug_fault_code(DBG_ESR_EVT_HWSS, single_step_handler, SIGTRAP,
TRAP_HWBKPT, "single-step handler");
hook_debug_fault_code(DBG_ESR_EVT_BRK, brk_handler, SIGTRAP,
TRAP_BRKPT, "ptrace BRK handler");
return 0;
}
arch_initcall(single_step_init);
arch_initcall(debug_traps_init);
/* Re-enable single step for syscall restarting. */
void user_rewind_single_step(struct task_struct *task)