DAR is set to the first byte of overlap between actual access and
watched range at DSI on Book3S processor. But actual access range
might or might not be within user asked range. So for Book3S, it
must not call dar_within_range().
This revert portion of commit 39413ae00967 ("powerpc/hw_breakpoints:
Rewrite 8xx breakpoints to allow any address range size.").
Before patch:
# ./tools/testing/selftests/powerpc/ptrace/perf-hwbreak
...
TESTED: No overlap
FAILED: Partial overlap: 0 != 2
TESTED: Partial overlap
TESTED: No overlap
FAILED: Full overlap: 0 != 2
failure: perf_hwbreak
After patch:
TESTED: No overlap
TESTED: Partial overlap
TESTED: Partial overlap
TESTED: No overlap
TESTED: Full overlap
success: perf_hwbreak
Fixes: 39413ae00967 ("powerpc/hw_breakpoints: Rewrite 8xx breakpoints to allow any address range size.")
Reported-by: Michael Ellerman <[email protected]>
Signed-off-by: Ravi Bangoria <[email protected]>
---
arch/powerpc/kernel/hw_breakpoint.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 2462cd7c565c..d0854320bb50 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -331,11 +331,13 @@ int hw_breakpoint_handler(struct die_args *args)
}
info->type &= ~HW_BRK_TYPE_EXTRANEOUS_IRQ;
- if (!dar_within_range(regs->dar, info))
- info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
-
- if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info))
- goto out;
+ if (IS_ENABLED(CONFIG_PPC_8xx)) {
+ if (!dar_within_range(regs->dar, info))
+ info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
+ } else {
+ if (!stepping_handler(regs, bp, info))
+ goto out;
+ }
/*
* As a policy, the callback is invoked in a 'trigger-after-execute'
--
2.21.1
On 02/22/2020 08:20 AM, Ravi Bangoria wrote:
> DAR is set to the first byte of overlap between actual access and
> watched range at DSI on Book3S processor. But actual access range
> might or might not be within user asked range. So for Book3S, it
> must not call dar_within_range().
>
> This revert portion of commit 39413ae00967 ("powerpc/hw_breakpoints:
> Rewrite 8xx breakpoints to allow any address range size.").
>
> Before patch:
> # ./tools/testing/selftests/powerpc/ptrace/perf-hwbreak
> ...
> TESTED: No overlap
> FAILED: Partial overlap: 0 != 2
> TESTED: Partial overlap
> TESTED: No overlap
> FAILED: Full overlap: 0 != 2
> failure: perf_hwbreak
>
> After patch:
> TESTED: No overlap
> TESTED: Partial overlap
> TESTED: Partial overlap
> TESTED: No overlap
> TESTED: Full overlap
> success: perf_hwbreak
>
> Fixes: 39413ae00967 ("powerpc/hw_breakpoints: Rewrite 8xx breakpoints to allow any address range size.")
Oh, this seems to have been introduced by 27985b2a640e
("powerpc/watchpoint: Don't ignore extraneous exceptions blindly").
I must have lost it through a rebase as we were doing our series
approximately at the same time, sorry for that.
Reviewed-by: Christophe Leroy <[email protected]>
> Reported-by: Michael Ellerman <[email protected]>
> Signed-off-by: Ravi Bangoria <[email protected]>
> ---
> arch/powerpc/kernel/hw_breakpoint.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
> index 2462cd7c565c..d0854320bb50 100644
> --- a/arch/powerpc/kernel/hw_breakpoint.c
> +++ b/arch/powerpc/kernel/hw_breakpoint.c
> @@ -331,11 +331,13 @@ int hw_breakpoint_handler(struct die_args *args)
> }
>
> info->type &= ~HW_BRK_TYPE_EXTRANEOUS_IRQ;
> - if (!dar_within_range(regs->dar, info))
> - info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
> -
> - if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info))
> - goto out;
> + if (IS_ENABLED(CONFIG_PPC_8xx)) {
> + if (!dar_within_range(regs->dar, info))
> + info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
> + } else {
> + if (!stepping_handler(regs, bp, info))
> + goto out;
> + }
>
> /*
> * As a policy, the callback is invoked in a 'trigger-after-execute'
>
On 2/22/20 4:56 PM, Christophe Leroy wrote:
>
>
> On 02/22/2020 08:20 AM, Ravi Bangoria wrote:
>> DAR is set to the first byte of overlap between actual access and
>> watched range at DSI on Book3S processor. But actual access range
>> might or might not be within user asked range. So for Book3S, it
>> must not call dar_within_range().
>>
>> This revert portion of commit 39413ae00967 ("powerpc/hw_breakpoints:
>> Rewrite 8xx breakpoints to allow any address range size.").
>>
>> Before patch:
>> # ./tools/testing/selftests/powerpc/ptrace/perf-hwbreak
>> ...
>> TESTED: No overlap
>> FAILED: Partial overlap: 0 != 2
>> TESTED: Partial overlap
>> TESTED: No overlap
>> FAILED: Full overlap: 0 != 2
>> failure: perf_hwbreak
>>
>> After patch:
>> TESTED: No overlap
>> TESTED: Partial overlap
>> TESTED: Partial overlap
>> TESTED: No overlap
>> TESTED: Full overlap
>> success: perf_hwbreak
>>
>> Fixes: 39413ae00967 ("powerpc/hw_breakpoints: Rewrite 8xx breakpoints to allow any address range size.")
>
> Oh, this seems to have been introduced by 27985b2a640e ("powerpc/watchpoint: Don't ignore extraneous exceptions blindly").
>
> I must have lost it through a rebase as we were doing our series approximately at the same time, sorry for that.
>
> Reviewed-by: Christophe Leroy <[email protected]>
No worries. Thanks for the review :)
Ravi
On Sat, 2020-02-22 at 08:20:49 UTC, Ravi Bangoria wrote:
> DAR is set to the first byte of overlap between actual access and
> watched range at DSI on Book3S processor. But actual access range
> might or might not be within user asked range. So for Book3S, it
> must not call dar_within_range().
>
> This revert portion of commit 39413ae00967 ("powerpc/hw_breakpoints:
> Rewrite 8xx breakpoints to allow any address range size.").
>
> Before patch:
> # ./tools/testing/selftests/powerpc/ptrace/perf-hwbreak
> ...
> TESTED: No overlap
> FAILED: Partial overlap: 0 != 2
> TESTED: Partial overlap
> TESTED: No overlap
> FAILED: Full overlap: 0 != 2
> failure: perf_hwbreak
>
> After patch:
> TESTED: No overlap
> TESTED: Partial overlap
> TESTED: Partial overlap
> TESTED: No overlap
> TESTED: Full overlap
> success: perf_hwbreak
>
> Fixes: 39413ae00967 ("powerpc/hw_breakpoints: Rewrite 8xx breakpoints to allow any address range size.")
> Reported-by: Michael Ellerman <[email protected]>
> Signed-off-by: Ravi Bangoria <[email protected]>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/e08658a657f974590809290c62e889f0fd420200
cheers