[POWERPC] powerpc: Instrument Hypervisor Calls

Add instrumentation for hypervisor calls on pseries.  Call statistics
include number of calls, wall time and cpu cycles (if available) and
are made available via debugfs.  Instrumentation code is behind the
HCALL_STATS config option and has no impact if not enabled.

Signed-off-by: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S
index 9a99b056bd2..c00cfed7af2 100644
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S
@@ -10,9 +10,69 @@
 #include <asm/hvcall.h>
 #include <asm/processor.h>
 #include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
 	
 #define STK_PARM(i)     (48 + ((i)-3)*8)
 
+#ifdef CONFIG_HCALL_STATS
+/*
+ * precall must preserve all registers.  use unused STK_PARM()
+ * areas to save snapshots and opcode.
+ */
+#define HCALL_INST_PRECALL					\
+	std	r3,STK_PARM(r3)(r1);	/* save opcode */	\
+	mftb	r0;			/* get timebase and */	\
+	std     r0,STK_PARM(r5)(r1);	/* save for later */	\
+BEGIN_FTR_SECTION;						\
+	mfspr	r0,SPRN_PURR;		/* get PURR and */	\
+	std	r0,STK_PARM(r6)(r1);	/* save for later */	\
+END_FTR_SECTION_IFCLR(CPU_FTR_PURR);
+	
+/*
+ * postcall is performed immediately before function return which
+ * allows liberal use of volatile registers.
+ */
+#define HCALL_INST_POSTCALL					\
+	ld	r4,STK_PARM(r3)(r1);	/* validate opcode */	\
+	cmpldi	cr7,r4,MAX_HCALL_OPCODE;			\
+	bgt-	cr7,1f;						\
+								\
+	/* get time and PURR snapshots after hcall */		\
+	mftb	r7;			/* timebase after */	\
+BEGIN_FTR_SECTION;						\
+	mfspr	r8,SPRN_PURR;		/* PURR after */	\
+	ld	r6,STK_PARM(r6)(r1);	/* PURR before */	\
+	subf	r6,r6,r8;		/* delta */		\
+END_FTR_SECTION_IFCLR(CPU_FTR_PURR);				\
+	ld	r5,STK_PARM(r5)(r1);	/* timebase before */	\
+	subf	r5,r5,r7;		/* time delta */	\
+								\
+	/* calculate address of stat structure r4 = opcode */	\
+	srdi	r4,r4,2;		/* index into array */	\
+	mulli	r4,r4,HCALL_STAT_SIZE;				\
+	LOAD_REG_ADDR(r7, per_cpu__hcall_stats);		\
+	add	r4,r4,r7;					\
+	ld	r7,PACA_DATA_OFFSET(r13); /* per cpu offset */	\
+	add	r4,r4,r7;					\
+								\
+	/* update stats	*/					\
+	ld	r7,HCALL_STAT_CALLS(r4); /* count */		\
+	addi	r7,r7,1;					\
+	std	r7,HCALL_STAT_CALLS(r4);			\
+	ld      r7,HCALL_STAT_TB(r4);	/* timebase */		\
+	add	r7,r7,r5;					\
+	std	r7,HCALL_STAT_TB(r4);				\
+BEGIN_FTR_SECTION;						\
+	ld	r7,HCALL_STAT_PURR(r4);	/* PURR */		\
+	add	r7,r7,r6;					\
+	std	r7,HCALL_STAT_PURR(r4);				\
+END_FTR_SECTION_IFCLR(CPU_FTR_PURR);				\
+1:
+#else
+#define HCALL_INST_PRECALL
+#define HCALL_INST_POSTCALL
+#endif
+
 	.text
 
 _GLOBAL(plpar_hcall_norets)
@@ -21,8 +81,12 @@ _GLOBAL(plpar_hcall_norets)
 	mfcr	r0
 	stw	r0,8(r1)
 
+	HCALL_INST_PRECALL
+
 	HVSC				/* invoke the hypervisor */
 
+	HCALL_INST_POSTCALL
+
 	lwz	r0,8(r1)
 	mtcrf	0xff,r0
 	blr				/* return r3 = status */
@@ -33,6 +97,8 @@ _GLOBAL(plpar_hcall)
 	mfcr	r0
 	stw	r0,8(r1)
 
+	HCALL_INST_PRECALL
+
 	std     r4,STK_PARM(r4)(r1)     /* Save ret buffer */
 
 	mr	r4,r5
@@ -50,6 +116,8 @@ _GLOBAL(plpar_hcall)
 	std	r6, 16(r12)
 	std	r7, 24(r12)
 
+	HCALL_INST_POSTCALL
+
 	lwz	r0,8(r1)
 	mtcrf	0xff,r0
 
@@ -61,6 +129,8 @@ _GLOBAL(plpar_hcall9)
 	mfcr	r0
 	stw	r0,8(r1)
 
+	HCALL_INST_PRECALL
+
 	std     r4,STK_PARM(r4)(r1)     /* Save ret buffer */
 
 	mr	r4,r5
@@ -86,6 +156,8 @@ _GLOBAL(plpar_hcall9)
 	std	r11,56(r12)
 	std	r12,64(r12)
 
+	HCALL_INST_POSTCALL
+
 	lwz	r0,8(r1)
 	mtcrf	0xff,r0