[PATCH v2] riscv: tracing: Improve hardirq tracing message

[Conor.Dooley at microchip.com]

On 15/09/2022 14:36, Yipeng Zou wrote:
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> 
> 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
> 
> Fixes: 22e2100b1b07 ("riscv: fix oops caused by irqsoff latency tracer")
> Signed-off-by: Yipeng Zou <zouyipeng at huawei.com>
> Acked-by: Guo Ren <guoren at kernel.org>
> ---
> v2: add tags
> 
>   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);

Out of curiosity, why does riscv need to use this when
other archs don;t?

>   }
>   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)
> --
> 2.17.1
> 
> 
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