From: Mark Rutland <mark.rutland@arm.com>
To: James Clark <james.clark@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-perf-users@vger.kernel.org, linux-next@vger.kernel.org,
will@kernel.org, u.kleine-koenig@pengutronix.de,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH 1/2] arm: perf: Fix ARCH=arm build with GCC in armv8pmu_write_evtype()
Date: Fri, 15 Dec 2023 16:21:45 +0000 [thread overview]
Message-ID: <ZXx9GW1onSy4eBEB@FVFF77S0Q05N> (raw)
In-Reply-To: <20231215150040.3342183-2-james.clark@arm.com>
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
>
next prev parent reply other threads:[~2023-12-15 16:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-15 15:00 [PATCH 0/2] arm: perf: Fix ARCH=arm build with GCC James Clark
2023-12-15 15:00 ` [PATCH 1/2] arm: perf: Fix ARCH=arm build with GCC in armv8pmu_write_evtype() James Clark
2023-12-15 15:18 ` Uwe Kleine-König
2023-12-15 16:21 ` Mark Rutland [this message]
2023-12-15 17:42 ` James Clark
2023-12-15 15:00 ` [PATCH 2/2] arm: perf: Fix ARCH=arm build with GCC in armv8pmu_set_event_filter() James Clark
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