On 8xx, breakpoints stop after executing the instruction, so
stepping/emulation is not needed. Move it into a sub-function and
remove the #ifdefs.
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/kernel/hw_breakpoint.c | 60 ++++++++++++++++++++-----------------
1 file changed, 33 insertions(+), 27 deletions(-)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index a293a53b4365..a94142e729bf 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -198,15 +198,43 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs)
/*
* Handle debug exception notifications.
*/
+static bool stepping_handler(struct pt_regs *regs, struct perf_event *bp,
+ unsigned long addr)
+{
+ int stepped;
+ unsigned int instr;
+
+ /* Do not emulate user-space instructions, instead single-step them */
+ if (user_mode(regs)) {
+ current->thread.last_hit_ubp = bp;
+ regs->msr |= MSR_SE;
+ return false;
+ }
+
+ stepped = 0;
+ instr = 0;
+ if (!__get_user_inatomic(instr, (unsigned int *)regs->nip))
+ stepped = emulate_step(regs, instr);
+
+ /*
+ * 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.
+ */
+ 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;
+}
+
int hw_breakpoint_handler(struct die_args *args)
{
int rc = NOTIFY_STOP;
struct perf_event *bp;
struct pt_regs *regs = args->regs;
-#ifndef CONFIG_PPC_8xx
- int stepped = 1;
- unsigned int instr;
-#endif
struct arch_hw_breakpoint *info;
unsigned long dar = regs->dar;
@@ -251,32 +279,10 @@ int hw_breakpoint_handler(struct die_args *args)
(dar - bp->attr.bp_addr < bp->attr.bp_len)))
info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
-#ifndef CONFIG_PPC_8xx
- /* Do not emulate user-space instructions, instead single-step them */
- if (user_mode(regs)) {
- current->thread.last_hit_ubp = bp;
- regs->msr |= MSR_SE;
+ if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))
goto out;
- }
-
- stepped = 0;
- instr = 0;
- if (!__get_user_inatomic(instr, (unsigned int *) regs->nip))
- stepped = emulate_step(regs, instr);
/*
- * 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.
- */
- if (!stepped) {
- WARN(1, "Unable to handle hardware breakpoint. Breakpoint at "
- "0x%lx will be disabled.", info->address);
- perf_event_disable_inatomic(bp);
- goto out;
- }
-#endif
- /*
* As a policy, the callback is invoked in a 'trigger-after-execute'
* fashion
*/
--
2.13.3
On 6/28/19 9:25 PM, Christophe Leroy wrote:
> On 8xx, breakpoints stop after executing the instruction, so
> stepping/emulation is not needed. Move it into a sub-function and
> remove the #ifdefs.
>
> Signed-off-by: Christophe Leroy <[email protected]>
> ---
Reviewed-by: Ravi Bangoria <[email protected]>
Just one neat below...
[...]
> -#ifndef CONFIG_PPC_8xx
> - /* Do not emulate user-space instructions, instead single-step them */
> - if (user_mode(regs)) {
> - current->thread.last_hit_ubp = bp;
> - regs->msr |= MSR_SE;
> + if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))
May be split this line. It's 86 chars long and checkpatch.pl is warning
about this:
WARNING: line over 80 characters
#257: FILE: arch/powerpc/kernel/hw_breakpoint.c:282:
+ if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))
Le 03/07/2019 à 08:20, Ravi Bangoria a écrit :
>
>
> On 6/28/19 9:25 PM, Christophe Leroy wrote:
>> On 8xx, breakpoints stop after executing the instruction, so
>> stepping/emulation is not needed. Move it into a sub-function and
>> remove the #ifdefs.
>>
>> Signed-off-by: Christophe Leroy <[email protected]>
>> ---
>
> Reviewed-by: Ravi Bangoria <[email protected]>
>
> Just one neat below...
Thanks for the review.
>
> [...]
>
>> -#ifndef CONFIG_PPC_8xx
>> - /* Do not emulate user-space instructions, instead single-step them */
>> - if (user_mode(regs)) {
>> - current->thread.last_hit_ubp = bp;
>> - regs->msr |= MSR_SE;
>> + if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))
>
> May be split this line. It's 86 chars long and checkpatch.pl is warning
> about this:
Didn't you use arch/powerpc/tools/checkpatch.sh ?
powerpc accepts 90 chars per line.
Christophe
>
> WARNING: line over 80 characters
> #257: FILE: arch/powerpc/kernel/hw_breakpoint.c:282:
> + if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))
>
On 7/6/19 1:56 PM, Christophe Leroy wrote:
>
>
> Le 03/07/2019 à 08:20, Ravi Bangoria a écrit :
>>
>>
>> On 6/28/19 9:25 PM, Christophe Leroy wrote:
>>> On 8xx, breakpoints stop after executing the instruction, so
>>> stepping/emulation is not needed. Move it into a sub-function and
>>> remove the #ifdefs.
>>>
>>> Signed-off-by: Christophe Leroy <[email protected]>
>>> ---
>>
>> Reviewed-by: Ravi Bangoria <[email protected]>
>>
>> Just one neat below...
>
> Thanks for the review.
>
>>
>> [...]
>>
>>> -#ifndef CONFIG_PPC_8xx
>>> - /* Do not emulate user-space instructions, instead single-step them */
>>> - if (user_mode(regs)) {
>>> - current->thread.last_hit_ubp = bp;
>>> - regs->msr |= MSR_SE;
>>> + if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))
>>
>> May be split this line. It's 86 chars long and checkpatch.pl is warning
>> about this:
>
> Didn't you use arch/powerpc/tools/checkpatch.sh ?
>
> powerpc accepts 90 chars per line.
Hmm.. wasn't aware of it. Thanks!
On Fri, 2019-06-28 at 15:55:52 UTC, Christophe Leroy wrote:
> On 8xx, breakpoints stop after executing the instruction, so
> stepping/emulation is not needed. Move it into a sub-function and
> remove the #ifdefs.
>
> Signed-off-by: Christophe Leroy <[email protected]>
> Reviewed-by: Ravi Bangoria <[email protected]>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/658d029df0bce6472c94b724ca54d74bc6659c2e
cheers