[RFC PATCH 05/19] powerpc/32: Use load and store multiple in GPR save/restore macros

[Christophe Leroy]

Le 07/11/2022 à 13:45, Nicholas Piggin a écrit :
> On Thu Nov 3, 2022 at 6:26 PM AEST, Christophe Leroy wrote:
>> It contradicts commit a85c728cb5e1 ("powerpc/32: Don't use lmw/stmw for
>> saving/restoring non volatile regs")
> 
> Hmm okay. Do you want to keep the #ifdef case in ppc_save_regs for ppc32
> to save ~124 bytes of text? I don't mind either way.

I think you can make ppc_save_regs() generic.

I don't think the lmw/stmw is worth it in ppc_save_regs(), just drop it.

Christophe

> 
> Thanks,
> Nick
> 
>>
>> Le 31/10/2022 à 06:54, Nicholas Piggin a écrit :
>>> ---
>>>    arch/powerpc/include/asm/ppc_asm.h | 18 ++++++++++++++++--
>>>    1 file changed, 16 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
>>> index 753a2757bcd4..ac44383d350a 100644
>>> --- a/arch/powerpc/include/asm/ppc_asm.h
>>> +++ b/arch/powerpc/include/asm/ppc_asm.h
>>> @@ -57,8 +57,22 @@
>>>    #define SAVE_NVGPRS(base)		SAVE_GPRS(14, 31, base)
>>>    #define REST_NVGPRS(base)		REST_GPRS(14, 31, base)
>>>    #else
>>> -#define SAVE_GPRS(start, end, base)	OP_REGS stw, 4, start, end, base, GPR0
>>> -#define REST_GPRS(start, end, base)	OP_REGS lwz, 4, start, end, base, GPR0
>>> +.macro __SAVE_GPRS start, end, base, offset
>>> +	.if \end == 31
>>> +		stmw	\start,\offset(\base)
>>> +	.else
>>> +		OP_REGS stw, 4, \start, \end, \base, \offset
>>> +	.endif
>>> +.endm
>>> +.macro __REST_GPRS start, end, base, offset
>>> +	.if \end == 31
>>> +		lmw	\start,\offset(\base)
>>> +	.else
>>> +		OP_REGS lwz, 4, \start, \end, \base, \offset
>>> +	.endif
>>> +.endm
>>> +#define SAVE_GPRS(start, end, base)	__SAVE_GPRS start, end, base, GPR0
>>> +#define REST_GPRS(start, end, base)	__REST_GPRS start, end, base, GPR0
>>>    #define SAVE_NVGPRS(base)		SAVE_GPRS(13, 31, base)
>>>    #define REST_NVGPRS(base)		REST_GPRS(13, 31, base)
>>>    #endif
>