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SubjectRe: [PATCH] MIPS: Fix IRQ tracing when call handle_fpe()
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yes, I will re-send email for this patch.

在 2020/5/26 下午9:04, Thomas Bogendoerfer 写道:
> On Tue, May 26, 2020 at 03:07:16PM +0800, yuanjunqing wrote:
>> 在 2020/5/25 下午4:42, Thomas Bogendoerfer 写道:
>>> On Mon, May 25, 2020 at 11:31:23AM +0800, 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
>>>> to task when call do_fpe(),and this may kill the task.
>>>>
>>>> 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
>>>> .endm
>>> do we realy need to read fcr31 that early ? Wouldn't it work to
>>> just move the cfc1 below TRACE_IRQS_OFF ?
>>>
>> yes, it can work when we just move the cfc1 below TRACE_IRQS_OFF,
>>  and the code is written as follows.
>>
>> CLI
>> TRACE_IRQS_OFF
>> .set mips1
>> SET_HARDFLOAT
>> cfc1 a1, fcr31
>> .set pop
>>   .endm
> good, could we do the same with _cfcmsa a1, MSA_CSR in the msa case ?
>
> Thomas.
>

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