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powerpc/perf: Move BHRB code into CONFIG_PPC64 region
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The new Branch History Rolling buffer (BHRB) code is only useful on 64bit
processors, so move it into the #ifdef CONFIG_PPC64 region.

This avoids code bloat on 32bit systems.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Michael Neuling authored and Benjamin Herrenschmidt committed May 14, 2013
1 parent a1797b2 commit d52f2dc
Showing 1 changed file with 127 additions and 121 deletions.
248 changes: 127 additions & 121 deletions arch/powerpc/perf/core-book3s.c
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Original file line number Diff line number Diff line change
Expand Up @@ -100,6 +100,10 @@ static inline int siar_valid(struct pt_regs *regs)
return 1;
}

static inline void power_pmu_bhrb_enable(struct perf_event *event) {}
static inline void power_pmu_bhrb_disable(struct perf_event *event) {}
void power_pmu_flush_branch_stack(void) {}
static inline void power_pmu_bhrb_read(struct cpu_hw_events *cpuhw) {}
#endif /* CONFIG_PPC32 */

static bool regs_use_siar(struct pt_regs *regs)
Expand Down Expand Up @@ -308,6 +312,129 @@ static inline int siar_valid(struct pt_regs *regs)
return 1;
}


/* Reset all possible BHRB entries */
static void power_pmu_bhrb_reset(void)
{
asm volatile(PPC_CLRBHRB);
}

static void power_pmu_bhrb_enable(struct perf_event *event)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);

if (!ppmu->bhrb_nr)
return;

/* Clear BHRB if we changed task context to avoid data leaks */
if (event->ctx->task && cpuhw->bhrb_context != event->ctx) {
power_pmu_bhrb_reset();
cpuhw->bhrb_context = event->ctx;
}
cpuhw->bhrb_users++;
}

static void power_pmu_bhrb_disable(struct perf_event *event)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);

if (!ppmu->bhrb_nr)
return;

cpuhw->bhrb_users--;
WARN_ON_ONCE(cpuhw->bhrb_users < 0);

if (!cpuhw->disabled && !cpuhw->bhrb_users) {
/* BHRB cannot be turned off when other
* events are active on the PMU.
*/

/* avoid stale pointer */
cpuhw->bhrb_context = NULL;
}
}

/* Called from ctxsw to prevent one process's branch entries to
* mingle with the other process's entries during context switch.
*/
void power_pmu_flush_branch_stack(void)
{
if (ppmu->bhrb_nr)
power_pmu_bhrb_reset();
}


/* Processing BHRB entries */
static void power_pmu_bhrb_read(struct cpu_hw_events *cpuhw)
{
u64 val;
u64 addr;
int r_index, u_index, target, pred;

r_index = 0;
u_index = 0;
while (r_index < ppmu->bhrb_nr) {
/* Assembly read function */
val = read_bhrb(r_index);

/* Terminal marker: End of valid BHRB entries */
if (val == 0) {
break;
} else {
/* BHRB field break up */
addr = val & BHRB_EA;
pred = val & BHRB_PREDICTION;
target = val & BHRB_TARGET;

/* Probable Missed entry: Not applicable for POWER8 */
if ((addr == 0) && (target == 0) && (pred == 1)) {
r_index++;
continue;
}

/* Real Missed entry: Power8 based missed entry */
if ((addr == 0) && (target == 1) && (pred == 1)) {
r_index++;
continue;
}

/* Reserved condition: Not a valid entry */
if ((addr == 0) && (target == 1) && (pred == 0)) {
r_index++;
continue;
}

/* Is a target address */
if (val & BHRB_TARGET) {
/* First address cannot be a target address */
if (r_index == 0) {
r_index++;
continue;
}

/* Update target address for the previous entry */
cpuhw->bhrb_entries[u_index - 1].to = addr;
cpuhw->bhrb_entries[u_index - 1].mispred = pred;
cpuhw->bhrb_entries[u_index - 1].predicted = ~pred;

/* Dont increment u_index */
r_index++;
} else {
/* Update address, flags for current entry */
cpuhw->bhrb_entries[u_index].from = addr;
cpuhw->bhrb_entries[u_index].mispred = pred;
cpuhw->bhrb_entries[u_index].predicted = ~pred;

/* Successfully popullated one entry */
u_index++;
r_index++;
}
}
}
cpuhw->bhrb_stack.nr = u_index;
return;
}

#endif /* CONFIG_PPC64 */

static void perf_event_interrupt(struct pt_regs *regs);
Expand Down Expand Up @@ -904,47 +1031,6 @@ static int collect_events(struct perf_event *group, int max_count,
return n;
}

/* Reset all possible BHRB entries */
static void power_pmu_bhrb_reset(void)
{
asm volatile(PPC_CLRBHRB);
}

void power_pmu_bhrb_enable(struct perf_event *event)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);

if (!ppmu->bhrb_nr)
return;

/* Clear BHRB if we changed task context to avoid data leaks */
if (event->ctx->task && cpuhw->bhrb_context != event->ctx) {
power_pmu_bhrb_reset();
cpuhw->bhrb_context = event->ctx;
}
cpuhw->bhrb_users++;
}

void power_pmu_bhrb_disable(struct perf_event *event)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);

if (!ppmu->bhrb_nr)
return;

cpuhw->bhrb_users--;
WARN_ON_ONCE(cpuhw->bhrb_users < 0);

if (!cpuhw->disabled && !cpuhw->bhrb_users) {
/* BHRB cannot be turned off when other
* events are active on the PMU.
*/

/* avoid stale pointer */
cpuhw->bhrb_context = NULL;
}
}

/*
* Add a event to the PMU.
* If all events are not already frozen, then we disable and
Expand Down Expand Up @@ -1180,15 +1266,6 @@ int power_pmu_commit_txn(struct pmu *pmu)
return 0;
}

/* Called from ctxsw to prevent one process's branch entries to
* mingle with the other process's entries during context switch.
*/
void power_pmu_flush_branch_stack(void)
{
if (ppmu->bhrb_nr)
power_pmu_bhrb_reset();
}

/*
* Return 1 if we might be able to put event on a limited PMC,
* or 0 if not.
Expand Down Expand Up @@ -1458,77 +1535,6 @@ struct pmu power_pmu = {
.flush_branch_stack = power_pmu_flush_branch_stack,
};

/* Processing BHRB entries */
void power_pmu_bhrb_read(struct cpu_hw_events *cpuhw)
{
u64 val;
u64 addr;
int r_index, u_index, target, pred;

r_index = 0;
u_index = 0;
while (r_index < ppmu->bhrb_nr) {
/* Assembly read function */
val = read_bhrb(r_index);

/* Terminal marker: End of valid BHRB entries */
if (val == 0) {
break;
} else {
/* BHRB field break up */
addr = val & BHRB_EA;
pred = val & BHRB_PREDICTION;
target = val & BHRB_TARGET;

/* Probable Missed entry: Not applicable for POWER8 */
if ((addr == 0) && (target == 0) && (pred == 1)) {
r_index++;
continue;
}

/* Real Missed entry: Power8 based missed entry */
if ((addr == 0) && (target == 1) && (pred == 1)) {
r_index++;
continue;
}

/* Reserved condition: Not a valid entry */
if ((addr == 0) && (target == 1) && (pred == 0)) {
r_index++;
continue;
}

/* Is a target address */
if (val & BHRB_TARGET) {
/* First address cannot be a target address */
if (r_index == 0) {
r_index++;
continue;
}

/* Update target address for the previous entry */
cpuhw->bhrb_entries[u_index - 1].to = addr;
cpuhw->bhrb_entries[u_index - 1].mispred = pred;
cpuhw->bhrb_entries[u_index - 1].predicted = ~pred;

/* Dont increment u_index */
r_index++;
} else {
/* Update address, flags for current entry */
cpuhw->bhrb_entries[u_index].from = addr;
cpuhw->bhrb_entries[u_index].mispred = pred;
cpuhw->bhrb_entries[u_index].predicted = ~pred;

/* Successfully popullated one entry */
u_index++;
r_index++;
}
}
}
cpuhw->bhrb_stack.nr = u_index;
return;
}

/*
* A counter has overflowed; update its count and record
* things if requested. Note that interrupts are hard-disabled
Expand Down

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