powerpc/perf: Add an explict flag indicating presence of SLOT field
In perf_ip_adjust() we potentially use the MMCRA[SLOT] field to adjust
the reported IP of a sampled instruction.
Currently the logic is written so that if the backend does NOT have
the PPMU_ALT_SIPR flag set then we assume MMCRA[SLOT] exists.
However on power8 we do not want to set ALT_SIPR (it's in a third
location), and we also do not have MMCRA[SLOT].
So add a new flag which only indicates whether MMCRA[SLOT] exists.
Naively we'd set it on everything except power6/7, because they set
ALT_SIPR, and we've reversed the polarity of the flag. But it's more
complicated than that.
mpc7450 is 32-bit, and uses its own version of perf_ip_adjust()
which doesn't use MMCRA[SLOT], so it doesn't need the new flag set and
the behaviour is unchanged.
PPC970 (and I assume power4) don't have MMCRA[SLOT], so shouldn't have
the new flag set. This is a behaviour change on those cpus, though we
were probably getting lucky and the bits in question were 0.
power5 and power5+ set the new flag, behaviour unchanged.
power6 & power7 do not set the new flag, behaviour unchanged.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 65362e9..eb64480 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -98,11 +98,12 @@
{
unsigned long mmcra = regs->dsisr;
- if ((mmcra & MMCRA_SAMPLE_ENABLE) && !(ppmu->flags & PPMU_ALT_SIPR)) {
+ if ((ppmu->flags & PPMU_HAS_SSLOT) && (mmcra & MMCRA_SAMPLE_ENABLE)) {
unsigned long slot = (mmcra & MMCRA_SLOT) >> MMCRA_SLOT_SHIFT;
if (slot > 1)
return 4 * (slot - 1);
}
+
return 0;
}
diff --git a/arch/powerpc/perf/power5+-pmu.c b/arch/powerpc/perf/power5+-pmu.c
index a8757ba..b03b6dc 100644
--- a/arch/powerpc/perf/power5+-pmu.c
+++ b/arch/powerpc/perf/power5+-pmu.c
@@ -671,7 +671,7 @@
.get_alternatives = power5p_get_alternatives,
.disable_pmc = power5p_disable_pmc,
.limited_pmc_event = power5p_limited_pmc_event,
- .flags = PPMU_LIMITED_PMC5_6,
+ .flags = PPMU_LIMITED_PMC5_6 | PPMU_HAS_SSLOT,
.n_generic = ARRAY_SIZE(power5p_generic_events),
.generic_events = power5p_generic_events,
.cache_events = &power5p_cache_events,
diff --git a/arch/powerpc/perf/power5-pmu.c b/arch/powerpc/perf/power5-pmu.c
index e7f06eb..1e8ce42 100644
--- a/arch/powerpc/perf/power5-pmu.c
+++ b/arch/powerpc/perf/power5-pmu.c
@@ -615,6 +615,7 @@
.n_generic = ARRAY_SIZE(power5_generic_events),
.generic_events = power5_generic_events,
.cache_events = &power5_cache_events,
+ .flags = PPMU_HAS_SSLOT,
};
static int __init init_power5_pmu(void)