Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Fri, 15 Dec 2023 16:21:45 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH 1/2] arm: perf: Fix ARCH=arm build with GCC in armv8pmu_write_evtype() |
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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 >
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