[PATCH 1/6] powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller

[Haren Myneni]

On 09/09/2012 05:05 PM, Benjamin Herrenschmidt wrote:
> On Sun, 2012-09-09 at 04:36 -0700, Haren Myneni wrote:
>> The first instruction in ACCOUNT_CPU_USER_ENTRY is 'beq' which checkes for
>> exceptions coming from kernel mode. PPR value will be saved immediately after
>> ACCOUNT_CPU_USER_ENTRY and is also for user level exceptions. So moved this
>> branch instruction in the caller code.
> 
> grep fail ? ACCOUNT_CPU_USER_ENTRY is used in exception-64e.S as well,
> so that needs to be updated too.

Sorry, I will make this change.

> 
> Cheers,
> Ben.
> 
>> Signed-off-by: Haren Myneni <haren at us.ibm.com>
>>
>> ---
>>  arch/powerpc/include/asm/exception-64s.h |    3 ++-
>>  arch/powerpc/include/asm/ppc_asm.h       |    2 --
>>  arch/powerpc/kernel/entry_64.S           |    3 ++-
>>  3 files changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
>> index a43c147..45702e0 100644
>> --- a/arch/powerpc/include/asm/exception-64s.h
>> +++ b/arch/powerpc/include/asm/exception-64s.h
>> @@ -176,8 +176,9 @@ do_kvm_##n:								\
>>  	std	r10,0(r1);		/* make stack chain pointer	*/ \
>>  	std	r0,GPR0(r1);		/* save r0 in stackframe	*/ \
>>  	std	r10,GPR1(r1);		/* save r1 in stackframe	*/ \
>> +	beq	4f;			/* if from kernel mode		*/ \
>>  	ACCOUNT_CPU_USER_ENTRY(r9, r10);				   \
>> -	std	r2,GPR2(r1);		/* save r2 in stackframe	*/ \
>> +4:	std	r2,GPR2(r1);		/* save r2 in stackframe	*/ \
>>  	SAVE_4GPRS(3, r1);		/* save r3 - r6 in stackframe	*/ \
>>  	SAVE_2GPRS(7, r1);		/* save r7, r8 in stackframe	*/ \
>>  	ld	r9,area+EX_R9(r13);	/* move r9, r10 to stackframe	*/ \
>> diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
>> index ea2a86e..376e36d 100644
>> --- a/arch/powerpc/include/asm/ppc_asm.h
>> +++ b/arch/powerpc/include/asm/ppc_asm.h
>> @@ -30,7 +30,6 @@
>>  #define ACCOUNT_STOLEN_TIME
>>  #else
>>  #define ACCOUNT_CPU_USER_ENTRY(ra, rb)					\
>> -	beq	2f;			/* if from kernel mode */	\
>>  	MFTB(ra);			/* get timebase */		\
>>  	ld	rb,PACA_STARTTIME_USER(r13);				\
>>  	std	ra,PACA_STARTTIME(r13);					\
>> @@ -38,7 +37,6 @@
>>  	ld	ra,PACA_USER_TIME(r13);					\
>>  	add	ra,ra,rb;		/* add on to user time */	\
>>  	std	ra,PACA_USER_TIME(r13);					\
>> -2:
>>  
>>  #define ACCOUNT_CPU_USER_EXIT(ra, rb)					\
>>  	MFTB(ra);			/* get timebase */		\
>> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
>> index b40e0b4..8d21cc4 100644
>> --- a/arch/powerpc/kernel/entry_64.S
>> +++ b/arch/powerpc/kernel/entry_64.S
>> @@ -62,8 +62,9 @@ system_call_common:
>>  	std	r12,_MSR(r1)
>>  	std	r0,GPR0(r1)
>>  	std	r10,GPR1(r1)
>> +	beq	2f			/* if from kernel mode */
>>  	ACCOUNT_CPU_USER_ENTRY(r10, r11)
>> -	std	r2,GPR2(r1)
>> +2:	std	r2,GPR2(r1)
>>  	std	r3,GPR3(r1)
>>  	mfcr	r2
>>  	std	r4,GPR4(r1)
> 
> 
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