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Subject: Re: [PATCH] MIPS: Fix IRQ tracing when call handle_fpe()
To:     YuanJunQing <yuanjunqing66@163.com>, tsbogend@alpha.franken.de
Cc:     paulburton@kernel.org, chenhc@lemote.com,
        linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        liulichao@loongson.cn
References: <20200525033123.13114-1-yuanjunqing66@163.com>
From:   Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Message-ID: <0cb09824-73c3-d0d0-3bfe-b94e382536d9@cogentembedded.com>
Date:   Mon, 25 May 2020 11:34:40 +0300
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Hello!

On 25.05.2020 6:31, YuanJunQing wrote:

>   Register "a1" is unsaved in this function,
>   when CONFIG_TRACE_IRQFLAGS is enabled,
>   the TRACE_IRQS_OFF macro will call trace_hardirqs_off(),
>   and this may change register "a1".
>   The variment of register "a1" may send SIGFPE signal

    Variment?

>   to task when call do_fpe(),and this may kill the task.

    Need space after comma.

> Signed-off-by: YuanJunQing <yuanjunqing66@163.com>
> ---
>   arch/mips/kernel/genex.S | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
> index 8236fb291e3f..956a76429773 100644
> --- a/arch/mips/kernel/genex.S
> +++ b/arch/mips/kernel/genex.S
> @@ -480,16 +480,18 @@ NESTED(nmi_handler, PT_SIZE, sp)
>   	/* gas fails to assemble cfc1 for some archs (octeon).*/ \
>   	.set	mips1
>   	SET_HARDFLOAT
> -	cfc1	a1, fcr31
> +	cfc1	s0, fcr31
>   	.set	pop
>   	CLI
>   	TRACE_IRQS_OFF
> +	move    a1,s0

    Need space after comma.

>   	.endm
>   
>   	.macro	__build_clear_msa_fpe
> -	_cfcmsa	a1, MSA_CSR
> +	_cfcmsa	s0, MSA_CSR
>   	CLI
>   	TRACE_IRQS_OFF
> +	move    a1,s0

    Ditto.

[...]

MBR, Sergei