lkml.org 
[lkml]   [2021]   [Feb]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v5 18/22] powerpc/syscall: Remove FULL_REGS verification in system_call_exception
Excerpts from Christophe Leroy's message of February 10, 2021 12:31 am:
>
>
> Le 09/02/2021 à 03:02, Nicholas Piggin a écrit :
>> Excerpts from Christophe Leroy's message of February 9, 2021 1:10 am:
>>> For book3s/64, FULL_REGS() is 'true' at all time, so the test voids.
>>> For others, non volatile registers are saved inconditionally.
>>>
>>> So the verification is pointless.
>>>
>>> Should one fail to do it, it would anyway be caught by the
>>> CHECK_FULL_REGS() in copy_thread() as we have removed the
>>> special versions ppc_fork() and friends.
>>>
>>> null_syscall benchmark reduction 4 cycles (332 => 328 cycles)
>>
>> I wonder if we rather make a CONFIG option for a bunch of these simpler
>> debug checks here (and also in interrupt exit, wrappers, etc) rather
>> than remove them entirely.
>
> We can drop this patch if you prefer. Anyway, like book3s/64, once ppc32 also do interrupt
> entry/exit in C, FULL_REGS() will already return true.

Sure let's do that.

Thanks,
Nick

\
 
 \ /
  Last update: 2021-02-10 03:30    [W:0.127 / U:0.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site