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Subject[PATCH 4/6] perf_counter: powerpc: Make powerpc perf_counter code safe for 32-bit kernels
This abstracts a few things in arch/powerpc/kernel/perf_counter.c
that are specific to 64-bit kernels, and provides definitions for
32-bit kernels. In particular,

* Only 64-bit has MMCRA and the bits in it that give information
about a PMU interrupt (sampled PR, HV, slot number etc.)
* Only 64-bit has the lppaca and the lppaca->pmcregs_in_use field
* Use of SDAR is confined to 64-bit for now
* Only 64-bit has soft/lazy interrupt disable and therefore
pseudo-NMIs (interrupts that occur while interrupts are soft-disabled)
* Only 64-bit has PMC7 and PMC8
* Only 64-bit has the MSR_HV bit.

This also fixes the types used in a couple of places, where we were
using long types for things that need to be 64-bit.

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
arch/powerpc/kernel/perf_counter.c | 193 +++++++++++++++++++++++++-----------
1 files changed, 133 insertions(+), 60 deletions(-)
diff --git a/arch/powerpc/kernel/perf_counter.c b/arch/powerpc/kernel/perf_counter.c
index 54e0489..809fdf9 100644
--- a/arch/powerpc/kernel/perf_counter.c
+++ b/arch/powerpc/kernel/perf_counter.c
@@ -46,6 +46,115 @@ struct power_pmu *ppmu;
*/
static unsigned int freeze_counters_kernel = MMCR0_FCS;

+/*
+ * 32-bit doesn't have MMCRA but does have an MMCR2,
+ * and a few other names are different.
+ */
+#ifdef CONFIG_PPC32
+
+#define MMCR0_FCHV 0
+#define MMCR0_PMCjCE MMCR0_PMCnCE
+
+#define SPRN_MMCRA SPRN_MMCR2
+#define MMCRA_SAMPLE_ENABLE 0
+
+static inline unsigned long perf_ip_adjust(struct pt_regs *regs)
+{
+ return 0;
+}
+static inline void perf_set_pmu_inuse(int inuse) { }
+static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp) { }
+static inline u32 perf_get_misc_flags(struct pt_regs *regs)
+{
+ return 0;
+}
+static inline void perf_read_regs(struct pt_regs *regs) { }
+static inline int perf_intr_is_nmi(struct pt_regs *regs)
+{
+ return 0;
+}
+
+#endif /* CONFIG_PPC32 */
+
+/*
+ * Things that are specific to 64-bit implementations.
+ */
+#ifdef CONFIG_PPC64
+
+static inline unsigned long perf_ip_adjust(struct pt_regs *regs)
+{
+ unsigned long mmcra = regs->dsisr;
+
+ if ((mmcra & MMCRA_SAMPLE_ENABLE) && !(ppmu->flags & PPMU_ALT_SIPR)) {
+ unsigned long slot = (mmcra & MMCRA_SLOT) >> MMCRA_SLOT_SHIFT;
+ if (slot > 1)
+ return 4 * (slot - 1);
+ }
+ return 0;
+}
+
+static inline void perf_set_pmu_inuse(int inuse)
+{
+ get_lppaca()->pmcregs_in_use = inuse;
+}
+
+/*
+ * The user wants a data address recorded.
+ * If we're not doing instruction sampling, give them the SDAR
+ * (sampled data address). If we are doing instruction sampling, then
+ * only give them the SDAR if it corresponds to the instruction
+ * pointed to by SIAR; this is indicated by the [POWER6_]MMCRA_SDSYNC
+ * bit in MMCRA.
+ */
+static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp)
+{
+ unsigned long mmcra = regs->dsisr;
+ unsigned long sdsync = (ppmu->flags & PPMU_ALT_SIPR) ?
+ POWER6_MMCRA_SDSYNC : MMCRA_SDSYNC;
+
+ if (!(mmcra & MMCRA_SAMPLE_ENABLE) || (mmcra & sdsync))
+ *addrp = mfspr(SPRN_SDAR);
+}
+
+static inline u32 perf_get_misc_flags(struct pt_regs *regs)
+{
+ unsigned long mmcra = regs->dsisr;
+
+ if (TRAP(regs) != 0xf00)
+ return 0; /* not a PMU interrupt */
+
+ if (ppmu->flags & PPMU_ALT_SIPR) {
+ if (mmcra & POWER6_MMCRA_SIHV)
+ return PERF_EVENT_MISC_HYPERVISOR;
+ return (mmcra & POWER6_MMCRA_SIPR) ?
+ PERF_EVENT_MISC_USER : PERF_EVENT_MISC_KERNEL;
+ }
+ if (mmcra & MMCRA_SIHV)
+ return PERF_EVENT_MISC_HYPERVISOR;
+ return (mmcra & MMCRA_SIPR) ? PERF_EVENT_MISC_USER :
+ PERF_EVENT_MISC_KERNEL;
+}
+
+/*
+ * Overload regs->dsisr to store MMCRA so we only need to read it once
+ * on each interrupt.
+ */
+static inline void perf_read_regs(struct pt_regs *regs)
+{
+ regs->dsisr = mfspr(SPRN_MMCRA);
+}
+
+/*
+ * If interrupts were soft-disabled when a PMU interrupt occurs, treat
+ * it as an NMI.
+ */
+static inline int perf_intr_is_nmi(struct pt_regs *regs)
+{
+ return !regs->softe;
+}
+
+#endif /* CONFIG_PPC64 */
+
static void perf_counter_interrupt(struct pt_regs *regs);

void perf_counter_print_debug(void)
@@ -78,12 +187,14 @@ static unsigned long read_pmc(int idx)
case 6:
val = mfspr(SPRN_PMC6);
break;
+#ifdef CONFIG_PPC64
case 7:
val = mfspr(SPRN_PMC7);
break;
case 8:
val = mfspr(SPRN_PMC8);
break;
+#endif /* CONFIG_PPC64 */
default:
printk(KERN_ERR "oops trying to read PMC%d\n", idx);
val = 0;
@@ -115,12 +226,14 @@ static void write_pmc(int idx, unsigned long val)
case 6:
mtspr(SPRN_PMC6, val);
break;
+#ifdef CONFIG_PPC64
case 7:
mtspr(SPRN_PMC7, val);
break;
case 8:
mtspr(SPRN_PMC8, val);
break;
+#endif /* CONFIG_PPC64 */
default:
printk(KERN_ERR "oops trying to write PMC%d\n", idx);
}
@@ -283,7 +396,7 @@ static int check_excludes(struct perf_counter **ctrs, unsigned int cflags[],

static void power_pmu_read(struct perf_counter *counter)
{
- long val, delta, prev;
+ s64 val, delta, prev;

if (!counter->hw.idx)
return;
@@ -477,7 +590,7 @@ void hw_perf_enable(void)
mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE);
mtspr(SPRN_MMCR1, cpuhw->mmcr[1]);
if (cpuhw->n_counters == 0)
- get_lppaca()->pmcregs_in_use = 0;
+ perf_set_pmu_inuse(0);
goto out_enable;
}

@@ -510,7 +623,7 @@ void hw_perf_enable(void)
* bit set and set the hardware counters to their initial values.
* Then unfreeze the counters.
*/
- get_lppaca()->pmcregs_in_use = 1;
+ perf_set_pmu_inuse(1);
mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE);
mtspr(SPRN_MMCR1, cpuhw->mmcr[1]);
mtspr(SPRN_MMCR0, (cpuhw->mmcr[0] & ~(MMCR0_PMC1CE | MMCR0_PMCjCE))
@@ -1007,13 +1120,12 @@ const struct pmu *hw_perf_counter_init(struct perf_counter *counter)
* things if requested. Note that interrupts are hard-disabled
* here so there is no possibility of being interrupted.
*/
-static void record_and_restart(struct perf_counter *counter, long val,
+static void record_and_restart(struct perf_counter *counter, unsigned long val,
struct pt_regs *regs, int nmi)
{
u64 period = counter->hw.sample_period;
s64 prev, delta, left;
int record = 0;
- unsigned long mmcra, sdsync;

/* we don't have to worry about interrupts here */
prev = atomic64_read(&counter->hw.prev_count);
@@ -1033,8 +1145,8 @@ static void record_and_restart(struct perf_counter *counter, long val,
left = period;
record = 1;
}
- if (left < 0x80000000L)
- val = 0x80000000L - left;
+ if (left < 0x80000000LL)
+ val = 0x80000000LL - left;
}

/*
@@ -1047,22 +1159,9 @@ static void record_and_restart(struct perf_counter *counter, long val,
.period = counter->hw.last_period,
};

- if (counter->attr.sample_type & PERF_SAMPLE_ADDR) {
- /*
- * The user wants a data address recorded.
- * If we're not doing instruction sampling,
- * give them the SDAR (sampled data address).
- * If we are doing instruction sampling, then only
- * give them the SDAR if it corresponds to the
- * instruction pointed to by SIAR; this is indicated
- * by the [POWER6_]MMCRA_SDSYNC bit in MMCRA.
- */
- mmcra = regs->dsisr;
- sdsync = (ppmu->flags & PPMU_ALT_SIPR) ?
- POWER6_MMCRA_SDSYNC : MMCRA_SDSYNC;
- if (!(mmcra & MMCRA_SAMPLE_ENABLE) || (mmcra & sdsync))
- data.addr = mfspr(SPRN_SDAR);
- }
+ if (counter->attr.sample_type & PERF_SAMPLE_ADDR)
+ perf_get_data_addr(regs, &data.addr);
+
if (perf_counter_overflow(counter, nmi, &data)) {
/*
* Interrupts are coming too fast - throttle them
@@ -1088,25 +1187,12 @@ static void record_and_restart(struct perf_counter *counter, long val,
*/
unsigned long perf_misc_flags(struct pt_regs *regs)
{
- unsigned long mmcra;
+ u32 flags = perf_get_misc_flags(regs);

- if (TRAP(regs) != 0xf00) {
- /* not a PMU interrupt */
- return user_mode(regs) ? PERF_EVENT_MISC_USER :
- PERF_EVENT_MISC_KERNEL;
- }
-
- mmcra = regs->dsisr;
- if (ppmu->flags & PPMU_ALT_SIPR) {
- if (mmcra & POWER6_MMCRA_SIHV)
- return PERF_EVENT_MISC_HYPERVISOR;
- return (mmcra & POWER6_MMCRA_SIPR) ? PERF_EVENT_MISC_USER :
- PERF_EVENT_MISC_KERNEL;
- }
- if (mmcra & MMCRA_SIHV)
- return PERF_EVENT_MISC_HYPERVISOR;
- return (mmcra & MMCRA_SIPR) ? PERF_EVENT_MISC_USER :
- PERF_EVENT_MISC_KERNEL;
+ if (flags)
+ return flags;
+ return user_mode(regs) ? PERF_EVENT_MISC_USER :
+ PERF_EVENT_MISC_KERNEL;
}

/*
@@ -1115,20 +1201,12 @@ unsigned long perf_misc_flags(struct pt_regs *regs)
*/
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
- unsigned long mmcra;
unsigned long ip;
- unsigned long slot;

if (TRAP(regs) != 0xf00)
return regs->nip; /* not a PMU interrupt */

- ip = mfspr(SPRN_SIAR);
- mmcra = regs->dsisr;
- if ((mmcra & MMCRA_SAMPLE_ENABLE) && !(ppmu->flags & PPMU_ALT_SIPR)) {
- slot = (mmcra & MMCRA_SLOT) >> MMCRA_SLOT_SHIFT;
- if (slot > 1)
- ip += 4 * (slot - 1);
- }
+ ip = mfspr(SPRN_SIAR) + perf_ip_adjust(regs);
return ip;
}

@@ -1140,7 +1218,7 @@ static void perf_counter_interrupt(struct pt_regs *regs)
int i;
struct cpu_hw_counters *cpuhw = &__get_cpu_var(cpu_hw_counters);
struct perf_counter *counter;
- long val;
+ unsigned long val;
int found = 0;
int nmi;

@@ -1148,16 +1226,9 @@ static void perf_counter_interrupt(struct pt_regs *regs)
freeze_limited_counters(cpuhw, mfspr(SPRN_PMC5),
mfspr(SPRN_PMC6));

- /*
- * Overload regs->dsisr to store MMCRA so we only need to read it once.
- */
- regs->dsisr = mfspr(SPRN_MMCRA);
+ perf_read_regs(regs);

- /*
- * If interrupts were soft-disabled when this PMU interrupt
- * occurred, treat it as an NMI.
- */
- nmi = !regs->softe;
+ nmi = perf_intr_is_nmi(regs);
if (nmi)
nmi_enter();
else
@@ -1223,11 +1294,13 @@ int register_power_pmu(struct power_pmu *pmu)
pr_info("%s performance monitor hardware support registered\n",
pmu->name);

+#ifdef MSR_HV
/*
* Use FCHV to ignore kernel events if MSR.HV is set.
*/
if (mfmsr() & MSR_HV)
freeze_counters_kernel = MMCR0_FCHV;
+#endif /* CONFIG_PPC64 */

return 0;
}
--
1.6.0.4


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