Consider a scenario where user creates two events:
1st event:
attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
attr.branch_sample_type = PERF_SAMPLE_BRANCH_ANY;
fd = perf_event_open(attr, 0, 1, -1, 0);
This sets cpuhw->bhrb_filter to 0 and returns valid fd.
2nd event:
attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
attr.branch_sample_type = PERF_SAMPLE_BRANCH_CALL;
fd = perf_event_open(attr, 0, 1, -1, 0);
It overrides cpuhw->bhrb_filter to -1 and returns with error.
Now if power_pmu_enable() gets called by any path other than
power_pmu_add(), ppmu->config_bhrb(-1) will set mmcra to -1.
Signed-off-by: Ravi Bangoria <[email protected]>
---
arch/powerpc/perf/core-book3s.c | 6 ++++--
arch/powerpc/perf/power8-pmu.c | 3 +++
arch/powerpc/perf/power9-pmu.c | 3 +++
3 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index b0723002a396..8eb5dc5df62b 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1846,6 +1846,7 @@ static int power_pmu_event_init(struct perf_event *event)
int n;
int err;
struct cpu_hw_events *cpuhw;
+ u64 bhrb_filter;
if (!ppmu)
return -ENOENT;
@@ -1951,13 +1952,14 @@ static int power_pmu_event_init(struct perf_event *event)
err = power_check_constraints(cpuhw, events, cflags, n + 1);
if (has_branch_stack(event)) {
- cpuhw->bhrb_filter = ppmu->bhrb_filter_map(
+ bhrb_filter = ppmu->bhrb_filter_map(
event->attr.branch_sample_type);
- if (cpuhw->bhrb_filter == -1) {
+ if (bhrb_filter == -1) {
put_cpu_var(cpu_hw_events);
return -EOPNOTSUPP;
}
+ cpuhw->bhrb_filter = bhrb_filter;
}
put_cpu_var(cpu_hw_events);
diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c
index d12a2db26353..d10feef93b6b 100644
--- a/arch/powerpc/perf/power8-pmu.c
+++ b/arch/powerpc/perf/power8-pmu.c
@@ -29,6 +29,7 @@ enum {
#define POWER8_MMCRA_IFM1 0x0000000040000000UL
#define POWER8_MMCRA_IFM2 0x0000000080000000UL
#define POWER8_MMCRA_IFM3 0x00000000C0000000UL
+#define POWER8_MMCRA_BHRB_MASK 0x00000000C0000000UL
/*
* Raw event encoding for PowerISA v2.07 (Power8):
@@ -243,6 +244,8 @@ static u64 power8_bhrb_filter_map(u64 branch_sample_type)
static void power8_config_bhrb(u64 pmu_bhrb_filter)
{
+ pmu_bhrb_filter &= POWER8_MMCRA_BHRB_MASK;
+
/* Enable BHRB filter in PMU */
mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter));
}
diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c
index 030544e35959..f3987915cadc 100644
--- a/arch/powerpc/perf/power9-pmu.c
+++ b/arch/powerpc/perf/power9-pmu.c
@@ -92,6 +92,7 @@ enum {
#define POWER9_MMCRA_IFM1 0x0000000040000000UL
#define POWER9_MMCRA_IFM2 0x0000000080000000UL
#define POWER9_MMCRA_IFM3 0x00000000C0000000UL
+#define POWER9_MMCRA_BHRB_MASK 0x00000000C0000000UL
/* Nasty Power9 specific hack */
#define PVR_POWER9_CUMULUS 0x00002000
@@ -300,6 +301,8 @@ static u64 power9_bhrb_filter_map(u64 branch_sample_type)
static void power9_config_bhrb(u64 pmu_bhrb_filter)
{
+ pmu_bhrb_filter &= POWER9_MMCRA_BHRB_MASK;
+
/* Enable BHRB filter in PMU */
mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter));
}
--
2.20.1
On 5/11/19 8:12 AM, Ravi Bangoria wrote:
> Consider a scenario where user creates two events:
>
> 1st event:
> attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
> attr.branch_sample_type = PERF_SAMPLE_BRANCH_ANY;
> fd = perf_event_open(attr, 0, 1, -1, 0);
>
> This sets cpuhw->bhrb_filter to 0 and returns valid fd.
>
> 2nd event:
> attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
> attr.branch_sample_type = PERF_SAMPLE_BRANCH_CALL;
> fd = perf_event_open(attr, 0, 1, -1, 0);
>
> It overrides cpuhw->bhrb_filter to -1 and returns with error.
>
> Now if power_pmu_enable() gets called by any path other than
> power_pmu_add(), ppmu->config_bhrb(-1) will set mmcra to -1.
>
> Signed-off-by: Ravi Bangoria <[email protected]>
Fixes: 3925f46bb590 ("powerpc/perf: Enable branch stack sampling framework")
On 11/05/19 8:12 AM, Ravi Bangoria wrote:
> Consider a scenario where user creates two events:
>
> 1st event:
> attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
> attr.branch_sample_type = PERF_SAMPLE_BRANCH_ANY;
> fd = perf_event_open(attr, 0, 1, -1, 0);
>
> This sets cpuhw->bhrb_filter to 0 and returns valid fd.
>
> 2nd event:
> attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
> attr.branch_sample_type = PERF_SAMPLE_BRANCH_CALL;
> fd = perf_event_open(attr, 0, 1, -1, 0);
>
> It overrides cpuhw->bhrb_filter to -1 and returns with error.
>
> Now if power_pmu_enable() gets called by any path other than
> power_pmu_add(), ppmu->config_bhrb(-1) will set mmcra to -1.
Reviewed-by: Madhavan Srinivasan <[email protected]>
> Signed-off-by: Ravi Bangoria <[email protected]>
> ---
> arch/powerpc/perf/core-book3s.c | 6 ++++--
> arch/powerpc/perf/power8-pmu.c | 3 +++
> arch/powerpc/perf/power9-pmu.c | 3 +++
> 3 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
> index b0723002a396..8eb5dc5df62b 100644
> --- a/arch/powerpc/perf/core-book3s.c
> +++ b/arch/powerpc/perf/core-book3s.c
> @@ -1846,6 +1846,7 @@ static int power_pmu_event_init(struct perf_event *event)
> int n;
> int err;
> struct cpu_hw_events *cpuhw;
> + u64 bhrb_filter;
>
> if (!ppmu)
> return -ENOENT;
> @@ -1951,13 +1952,14 @@ static int power_pmu_event_init(struct perf_event *event)
> err = power_check_constraints(cpuhw, events, cflags, n + 1);
>
> if (has_branch_stack(event)) {
> - cpuhw->bhrb_filter = ppmu->bhrb_filter_map(
> + bhrb_filter = ppmu->bhrb_filter_map(
> event->attr.branch_sample_type);
>
> - if (cpuhw->bhrb_filter == -1) {
> + if (bhrb_filter == -1) {
> put_cpu_var(cpu_hw_events);
> return -EOPNOTSUPP;
> }
> + cpuhw->bhrb_filter = bhrb_filter;
> }
>
> put_cpu_var(cpu_hw_events);
> diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c
> index d12a2db26353..d10feef93b6b 100644
> --- a/arch/powerpc/perf/power8-pmu.c
> +++ b/arch/powerpc/perf/power8-pmu.c
> @@ -29,6 +29,7 @@ enum {
> #define POWER8_MMCRA_IFM1 0x0000000040000000UL
> #define POWER8_MMCRA_IFM2 0x0000000080000000UL
> #define POWER8_MMCRA_IFM3 0x00000000C0000000UL
> +#define POWER8_MMCRA_BHRB_MASK 0x00000000C0000000UL
>
> /*
> * Raw event encoding for PowerISA v2.07 (Power8):
> @@ -243,6 +244,8 @@ static u64 power8_bhrb_filter_map(u64 branch_sample_type)
>
> static void power8_config_bhrb(u64 pmu_bhrb_filter)
> {
> + pmu_bhrb_filter &= POWER8_MMCRA_BHRB_MASK;
> +
> /* Enable BHRB filter in PMU */
> mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter));
> }
> diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c
> index 030544e35959..f3987915cadc 100644
> --- a/arch/powerpc/perf/power9-pmu.c
> +++ b/arch/powerpc/perf/power9-pmu.c
> @@ -92,6 +92,7 @@ enum {
> #define POWER9_MMCRA_IFM1 0x0000000040000000UL
> #define POWER9_MMCRA_IFM2 0x0000000080000000UL
> #define POWER9_MMCRA_IFM3 0x00000000C0000000UL
> +#define POWER9_MMCRA_BHRB_MASK 0x00000000C0000000UL
>
> /* Nasty Power9 specific hack */
> #define PVR_POWER9_CUMULUS 0x00002000
> @@ -300,6 +301,8 @@ static u64 power9_bhrb_filter_map(u64 branch_sample_type)
>
> static void power9_config_bhrb(u64 pmu_bhrb_filter)
> {
> + pmu_bhrb_filter &= POWER9_MMCRA_BHRB_MASK;
> +
> /* Enable BHRB filter in PMU */
> mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter));
> }
On Sat, 2019-05-11 at 02:42:17 UTC, Ravi Bangoria wrote:
> Consider a scenario where user creates two events:
>
> 1st event:
> attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
> attr.branch_sample_type = PERF_SAMPLE_BRANCH_ANY;
> fd = perf_event_open(attr, 0, 1, -1, 0);
>
> This sets cpuhw->bhrb_filter to 0 and returns valid fd.
>
> 2nd event:
> attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
> attr.branch_sample_type = PERF_SAMPLE_BRANCH_CALL;
> fd = perf_event_open(attr, 0, 1, -1, 0);
>
> It overrides cpuhw->bhrb_filter to -1 and returns with error.
>
> Now if power_pmu_enable() gets called by any path other than
> power_pmu_add(), ppmu->config_bhrb(-1) will set mmcra to -1.
>
> Signed-off-by: Ravi Bangoria <[email protected]>
> Reviewed-by: Madhavan Srinivasan <[email protected]>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/3202e35ec1c8fc19cea24253ff83edf7
cheers