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

On 09/09/2012 05:05 PM, Benjamin Herrenschmidt wrote:

On Sun, 2012-09-09 at 04:36 -0700, Haren Myneni wrote:

quoted

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.

quoted

Signed-off-by: Haren Myneni <haren@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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