diff options
Diffstat (limited to 'arch/powerpc/kernel/hw_breakpoint.c')
| -rw-r--r-- | arch/powerpc/kernel/hw_breakpoint.c | 49 |
1 files changed, 33 insertions, 16 deletions
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index 28ad3171bb82..1007ec36b4cb 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -195,14 +195,32 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs) tsk->thread.last_hit_ubp = NULL; } +static bool is_larx_stcx_instr(struct pt_regs *regs, unsigned int instr) +{ + int ret, type; + struct instruction_op op; + + ret = analyse_instr(&op, regs, instr); + type = GETTYPE(op.type); + return (!ret && (type == LARX || type == STCX)); +} + /* * Handle debug exception notifications. */ static bool stepping_handler(struct pt_regs *regs, struct perf_event *bp, unsigned long addr) { - int stepped; - unsigned int instr; + unsigned int instr = 0; + + if (__get_user_inatomic(instr, (unsigned int *)regs->nip)) + goto fail; + + if (is_larx_stcx_instr(regs, instr)) { + printk_ratelimited("Breakpoint hit on instruction that can't be emulated." + " Breakpoint at 0x%lx will be disabled.\n", addr); + goto disable; + } /* Do not emulate user-space instructions, instead single-step them */ if (user_mode(regs)) { @@ -211,23 +229,22 @@ static bool stepping_handler(struct pt_regs *regs, struct perf_event *bp, return false; } - stepped = 0; - instr = 0; - if (!__get_user_inatomic(instr, (unsigned int *)regs->nip)) - stepped = emulate_step(regs, instr); + if (!emulate_step(regs, instr)) + goto fail; + return true; + +fail: /* - * emulate_step() could not execute it. We've failed in reliably - * handling the hw-breakpoint. Unregister it and throw a warning - * message to let the user know about it. + * We've failed in reliably handling the hw-breakpoint. Unregister + * it and throw a warning message to let the user know about it. */ - if (!stepped) { - WARN(1, "Unable to handle hardware breakpoint. Breakpoint at " - "0x%lx will be disabled.", addr); - perf_event_disable_inatomic(bp); - return false; - } - return true; + WARN(1, "Unable to handle hardware breakpoint. Breakpoint at " + "0x%lx will be disabled.", addr); + +disable: + perf_event_disable_inatomic(bp); + return false; } int hw_breakpoint_handler(struct die_args *args) |