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

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Submitter Haren Myneni
Date Oct. 31, 2012, 6:51 a.m.
Message ID <1351666269.32304.12.camel@hbabu-laptop>
Download mbox | patch
Permalink /patch/195748/
State Changes Requested
Delegated to: Benjamin Herrenschmidt
Headers show

Comments

Haren Myneni - Oct. 31, 2012, 6:51 a.m.
[PATCH 1/6] powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller

The first instruction in ACCOUNT_CPU_USER_ENTRY is 'beq' which checks 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.

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 ++-
 arch/powerpc/kernel/exceptions-64e.S     |    3 ++-
 4 files changed, 6 insertions(+), 5 deletions(-)

Patch

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 56e0ff0..72c40dd 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)
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index 4684e33..709c06b 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -159,8 +159,9 @@  exc_##n##_common:							    \
 	std	r9,GPR9(r1);		/* save r9 in stackframe */	    \
 	std	r10,_NIP(r1);		/* save SRR0 to stackframe */	    \
 	std	r11,_MSR(r1);		/* save SRR1 to stackframe */	    \
+	beq	1f			/* if from kernel mode */
 	ACCOUNT_CPU_USER_ENTRY(r10,r11);/* accounting (uses cr0+eq) */	    \
-	ld	r3,excf+EX_R10(r13);	/* get back r10 */		    \
+1:	ld	r3,excf+EX_R10(r13);	/* get back r10 */		    \
 	ld	r4,excf+EX_R11(r13);	/* get back r11 */		    \
 	mfspr	r5,SPRN_SPRG_GEN_SCRATCH;/* get back r13 */		    \
 	std	r12,GPR12(r1);		/* save r12 in stackframe */	    \