diff options
| -rw-r--r-- | arch/powerpc/include/asm/hw_breakpoint.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/kernel/hw_breakpoint.c | 23 |
2 files changed, 22 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h index 6576bad..ea87f8a 100644 --- a/arch/powerpc/include/asm/hw_breakpoint.h +++ b/arch/powerpc/include/asm/hw_breakpoint.h @@ -27,6 +27,7 @@ #ifdef CONFIG_HAVE_HW_BREAKPOINT struct arch_hw_breakpoint { + bool extraneous_interrupt; u8 len; /* length of the target data symbol */ int type; unsigned long address; diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index 7bd01a5..ed39805 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -204,6 +204,7 @@ int __kprobes hw_breakpoint_handler(struct die_args *args) int stepped = 1; struct arch_hw_breakpoint *info; unsigned int instr; + unsigned long dar = regs->dar; /* Disable breakpoints during exception handling */ set_dabr(0); @@ -234,6 +235,22 @@ int __kprobes hw_breakpoint_handler(struct die_args *args) goto out; } + /* + * Verify if dar lies within the address range occupied by the symbol + * being watched to filter extraneous exceptions. + */ + if (!((bp->attr.bp_addr <= dar) && + (dar <= (bp->attr.bp_addr + bp->attr.bp_len)))) { + /* + * This exception is triggered not because of a memory access + * on the monitored variable but in the double-word address + * range in which it is contained. We will consume this + * exception, considering it as 'noise'. + */ + info->extraneous_interrupt = true; + } else + info->extraneous_interrupt = false; + /* Do not emulate user-space instructions, instead single-step them */ if (user_mode(regs)) { bp->ctx->task->thread.last_hit_ubp = bp; @@ -261,7 +278,8 @@ int __kprobes hw_breakpoint_handler(struct die_args *args) * As a policy, the callback is invoked in a 'trigger-after-execute' * fashion */ - perf_bp_event(bp, regs); + if (!info->extraneous_interrupt) + perf_bp_event(bp, regs); set_dabr(info->address | info->type | DABR_TRANSLATION); out: @@ -292,7 +310,8 @@ int __kprobes single_step_dabr_instruction(struct die_args *args) * We shall invoke the user-defined callback function in the single * stepping handler to confirm to 'trigger-after-execute' semantics */ - perf_bp_event(bp, regs); + if (!bp_info->extraneous_interrupt) + perf_bp_event(bp, regs); /* * Do not disable MSR_SE if the process was already in |