[PATCH 2/2] riscv: tracing: Improve hardirq tracing message

[Guo Ren]

Add Fixes tag, and the upstream should go to generic entry.

Just for stable branches fixup:
Acked-by: Guo Ren <guoren at kernel.org>

On Wed, Sep 14, 2022 at 3:29 PM Yipeng Zou <zouyipeng at huawei.com> wrote:
>
> Loop in guoren at kernel.org,
>
> Please help review on this patch, thanks very much.
>
> 在 2022/9/9 17:40, Yipeng Zou 写道:
> > Ping.
> >
> > 在 2022/9/1 18:45, Yipeng Zou 写道:
> >> Use trace_hardirqs_on_caller to improve irq_tracing message.
> >>
> >> lockdep log in riscv showing the last {enabled,disabled} at
> >> __trace_hardirqs_{on,off} all the time(if called by).
> >> But that's not what we want to see, the caller is what we want.
> >>
> >> Before this commit:
> >> [   57.853175] hardirqs last  enabled at (2519):
> >> __trace_hardirqs_on+0xc/0x14
> >> [   57.853848] hardirqs last disabled at (2520):
> >> __trace_hardirqs_off+0xc/0x14
> >>
> >> After this commit
> >> [   53.781428] hardirqs last  enabled at (2595): restore_all+0xe/0x66
> >> [   53.782185] hardirqs last disabled at (2596):
> >> ret_from_exception+0xa/0x10
> >>
> >> Signed-off-by: Yipeng Zou <zouyipeng at huawei.com>
> >> ---
> >>   arch/riscv/kernel/trace_irq.c | 4 ++--
> >>   include/linux/irqflags.h      | 2 ++
> >>   2 files changed, 4 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/arch/riscv/kernel/trace_irq.c
> >> b/arch/riscv/kernel/trace_irq.c
> >> index 095ac976d7da..7ca24b26e19f 100644
> >> --- a/arch/riscv/kernel/trace_irq.c
> >> +++ b/arch/riscv/kernel/trace_irq.c
> >> @@ -16,12 +16,12 @@
> >>     void __trace_hardirqs_on(void)
> >>   {
> >> -    trace_hardirqs_on();
> >> +    trace_hardirqs_on_caller(CALLER_ADDR0);
> >>   }
> >>   NOKPROBE_SYMBOL(__trace_hardirqs_on);
> >>     void __trace_hardirqs_off(void)
> >>   {
> >> -    trace_hardirqs_off();
> >> +    trace_hardirqs_off_caller(CALLER_ADDR0);
> >>   }
> >>   NOKPROBE_SYMBOL(__trace_hardirqs_off);
> >> diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
> >> index 5ec0fa71399e..46774fa85cde 100644
> >> --- a/include/linux/irqflags.h
> >> +++ b/include/linux/irqflags.h
> >> @@ -53,6 +53,8 @@ extern void trace_hardirqs_on_prepare(void);
> >>   extern void trace_hardirqs_off_finish(void);
> >>   extern void trace_hardirqs_on(void);
> >>   extern void trace_hardirqs_off(void);
> >> +extern void trace_hardirqs_on_caller(unsigned long caller_addr);
> >> +extern void trace_hardirqs_off_caller(unsigned long caller_addr);
> >>     # define lockdep_hardirq_context() (raw_cpu_read(hardirq_context))
> >>   # define lockdep_softirq_context(p) ((p)->softirq_context)
> >
> --
> Regards,
> Yipeng Zou
>


-- 
Best Regards
 Guo Ren