[POWERPC] Fix bugs in the hypervisor call stats code

There were a few issues with the HCALL_STATS code:

- PURR cpu feature checks were backwards
- We iterated one entry off the end of the hcall_stats array
- Remove dead update_hcall_stats() function prototype

I noticed one thing while debugging, and that is we call H_ENTER (to set
up the MMU hashtable in early init) before we have done the cpu fixups.
This means we will execute the PURR SPR reads even on a CPU that isnt
capable of it. I wonder if we can move the CPU feature fixups earlier.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/pseries/hvCall.S

@@ -26,7 +26,7 @@
 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);
+END_FTR_SECTION_IFSET(CPU_FTR_PURR);
 
 /*
  * postcall is performed immediately before function return which
@@ -43,7 +43,7 @@ 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);				\
+END_FTR_SECTION_IFSET(CPU_FTR_PURR);				\
 	ld	r5,STK_PARM(r5)(r1);	/* timebase before */	\
 	subf	r5,r5,r7;		/* time delta */	\
 								\
@@ -66,7 +66,7 @@ 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);				\
+END_FTR_SECTION_IFSET(CPU_FTR_PURR);				\
 1:
 #else
 #define HCALL_INST_PRECALL

arch/powerpc/platforms/pseries/hvCall_inst.c

@@ -34,7 +34,7 @@ DEFINE_PER_CPU(struct hcall_stats[HCALL_STAT_ARRAY_SIZE], hcall_stats);
  */
 static void *hc_start(struct seq_file *m, loff_t *pos)
 {
-	if ((int)*pos < HCALL_STAT_ARRAY_SIZE)
+	if ((int)*pos < (HCALL_STAT_ARRAY_SIZE-1))
 		return (void *)(unsigned long)(*pos + 1);
 
 	return NULL;
@@ -57,7 +57,7 @@ static int hc_show(struct seq_file *m, void *p)
 	struct hcall_stats *hs = (struct hcall_stats *)m->private;
 
 	if (hs[h_num].num_calls) {
-		if (!cpu_has_feature(CPU_FTR_PURR))
+		if (cpu_has_feature(CPU_FTR_PURR))
 			seq_printf(m, "%lu %lu %lu %lu\n", h_num<<2,
 				   hs[h_num].num_calls,
 				   hs[h_num].tb_total,

include/asm-powerpc/hvcall.h

@@ -252,8 +252,6 @@ struct hcall_stats {
 	unsigned long	tb_total;	/* total wall time (mftb) of calls. */
 	unsigned long	purr_total;	/* total cpu time (PURR) of calls. */
 };
-void update_hcall_stats(unsigned long opcode, unsigned long tb_delta,
-			unsigned long purr_delta);
 #define HCALL_STAT_ARRAY_SIZE	((MAX_HCALL_OPCODE >> 2) + 1)
 
 #endif /* __ASSEMBLY__ */