| Message ID | 20231215150040.3342183-2-james.clark@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm: perf: Fix ARCH=arm build with GCC | expand |
Hello, On Fri, Dec 15, 2023 at 03:00:38PM +0000, James Clark wrote: > diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c > index 23fa6c5da82c..3ed2086cefc3 100644 > --- a/drivers/perf/arm_pmuv3.c > +++ b/drivers/perf/arm_pmuv3.c > @@ -631,8 +631,9 @@ static void armv8pmu_write_evtype(int idx, unsigned long val) > ARMV8_PMU_EXCLUDE_EL0 | > ARMV8_PMU_EXCLUDE_EL1; > > - if (IS_ENABLED(CONFIG_ARM64)) > - mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH; > +#if IS_ENABLED(CONFIG_ARM64) > + mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH; > +#endif maybe add a comment about why you used an #if here, to prevent the people sending patches that revert your change? Best regards Uwe
On Fri, Dec 15, 2023 at 03:00:38PM +0000, James Clark wrote: > LLVM ignores everything inside the if statement and doesn't generate > errors, but GCC doesn't ignore it, resulting in the following error: > > drivers/perf/arm_pmuv3.c: In function 'armv8pmu_write_evtype': > include/linux/bits.h:34:29: error: left shift count >= width of type [-Werror=shift-count-overflow] > 34 | (((~UL(0)) - (UL(1) << (l)) + 1) & \ > > Fix it by changing the if to #if. I reckon it'd be cleaner to use GENMASK_ULL for the TH and TC fields, in include/linux/perf/arm_pmu.h have: | /* | * PMXEVTYPER: Event selection reg | */ | #define ARMV8_PMU_EVTYPE_EVENT GENMASK(15, 0) /* Mask for EVENT bits */ | #define ARMV8_PMU_EVTYPE_TH GENMASK_ULL(43, 32) /* arm64 only */ | #define ARMV8_PMU_EVTYPE_TC GENMASK_ULL(63, 61) /* arm64 only */ IIUC that should silence this warning, and it'd remove the need for the ifdeffery and other changes in patch 2. Does that work, or am I missing something? Thanks, Mark. > > Fixes: 3115ee021bfb ("arm64: perf: Include threshold control fields in PMEVTYPER mask") > Reported-by: Uwe Kleine-K"onig <u.kleine-koenig@pengutronix.de> > Closes: https://lore.kernel.org/linux-arm-kernel/20231215120817.h2f3akgv72zhrtqo@pengutronix.de/ > Signed-off-by: James Clark <james.clark@arm.com> > --- > drivers/perf/arm_pmuv3.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c > index 23fa6c5da82c..3ed2086cefc3 100644 > --- a/drivers/perf/arm_pmuv3.c > +++ b/drivers/perf/arm_pmuv3.c > @@ -631,8 +631,9 @@ static void armv8pmu_write_evtype(int idx, unsigned long val) > ARMV8_PMU_EXCLUDE_EL0 | > ARMV8_PMU_EXCLUDE_EL1; > > - if (IS_ENABLED(CONFIG_ARM64)) > - mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH; > +#if IS_ENABLED(CONFIG_ARM64) > + mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH; > +#endif > > val &= mask; > write_pmevtypern(counter, val); > -- > 2.34.1 >
On 15/12/2023 16:21, Mark Rutland wrote: > On Fri, Dec 15, 2023 at 03:00:38PM +0000, James Clark wrote: >> LLVM ignores everything inside the if statement and doesn't generate >> errors, but GCC doesn't ignore it, resulting in the following error: >> >> drivers/perf/arm_pmuv3.c: In function 'armv8pmu_write_evtype': >> include/linux/bits.h:34:29: error: left shift count >= width of type [-Werror=shift-count-overflow] >> 34 | (((~UL(0)) - (UL(1) << (l)) + 1) & \ >> >> Fix it by changing the if to #if. > > I reckon it'd be cleaner to use GENMASK_ULL for the TH and TC fields, in > include/linux/perf/arm_pmu.h have: > > | /* > | * PMXEVTYPER: Event selection reg > | */ > | #define ARMV8_PMU_EVTYPE_EVENT GENMASK(15, 0) /* Mask for EVENT bits */ > | #define ARMV8_PMU_EVTYPE_TH GENMASK_ULL(43, 32) /* arm64 only */ > | #define ARMV8_PMU_EVTYPE_TC GENMASK_ULL(63, 61) /* arm64 only */ > > IIUC that should silence this warning, and it'd remove the need for the > ifdeffery and other changes in patch 2. > > Does that work, or am I missing something? > > Thanks, > Mark. > You're right that does work. For some reason I thought there was some component of writing it to the mask that was the issue as well. I'll send another version with that fix instead. Thanks James >> >> Fixes: 3115ee021bfb ("arm64: perf: Include threshold control fields in PMEVTYPER mask") >> Reported-by: Uwe Kleine-K"onig <u.kleine-koenig@pengutronix.de> >> Closes: https://lore.kernel.org/linux-arm-kernel/20231215120817.h2f3akgv72zhrtqo@pengutronix.de/ >> Signed-off-by: James Clark <james.clark@arm.com> >> --- >> drivers/perf/arm_pmuv3.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c >> index 23fa6c5da82c..3ed2086cefc3 100644 >> --- a/drivers/perf/arm_pmuv3.c >> +++ b/drivers/perf/arm_pmuv3.c >> @@ -631,8 +631,9 @@ static void armv8pmu_write_evtype(int idx, unsigned long val) >> ARMV8_PMU_EXCLUDE_EL0 | >> ARMV8_PMU_EXCLUDE_EL1; >> >> - if (IS_ENABLED(CONFIG_ARM64)) >> - mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH; >> +#if IS_ENABLED(CONFIG_ARM64) >> + mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH; >> +#endif >> >> val &= mask; >> write_pmevtypern(counter, val); >> -- >> 2.34.1 >>
diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c index 23fa6c5da82c..3ed2086cefc3 100644 --- a/drivers/perf/arm_pmuv3.c +++ b/drivers/perf/arm_pmuv3.c @@ -631,8 +631,9 @@ static void armv8pmu_write_evtype(int idx, unsigned long val) ARMV8_PMU_EXCLUDE_EL0 | ARMV8_PMU_EXCLUDE_EL1; - if (IS_ENABLED(CONFIG_ARM64)) - mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH; +#if IS_ENABLED(CONFIG_ARM64) + mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH; +#endif val &= mask; write_pmevtypern(counter, val);
LLVM ignores everything inside the if statement and doesn't generate errors, but GCC doesn't ignore it, resulting in the following error: drivers/perf/arm_pmuv3.c: In function ‘armv8pmu_write_evtype’: include/linux/bits.h:34:29: error: left shift count >= width of type [-Werror=shift-count-overflow] 34 | (((~UL(0)) - (UL(1) << (l)) + 1) & \ Fix it by changing the if to #if. Fixes: 3115ee021bfb ("arm64: perf: Include threshold control fields in PMEVTYPER mask") Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Closes: https://lore.kernel.org/linux-arm-kernel/20231215120817.h2f3akgv72zhrtqo@pengutronix.de/ Signed-off-by: James Clark <james.clark@arm.com> --- drivers/perf/arm_pmuv3.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)