linux-kernel - Re: [PATCH v7 05/11] arm64: perf: Include threshold control fields in PMEVTYPER mask

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Date: Fri, 15 Dec 2023 12:43:44 +0000
From: James Clark <james.clark@....com>
To: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
 Will Deacon <will@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, linux-perf-users@...r.kernel.org,
 suzuki.poulose@....com, mark.rutland@....com, anshuman.khandual@....com,
 namhyung@...il.com, Catalin Marinas <catalin.marinas@....com>,
 Jonathan Corbet <corbet@....net>, Peter Zijlstra <peterz@...radead.org>,
 Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Jiri Olsa <jolsa@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
 Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>,
 Russell King <linux@...linux.org.uk>, Marc Zyngier <maz@...nel.org>,
 Oliver Upton <oliver.upton@...ux.dev>, James Morse <james.morse@....com>,
 Zenghui Yu <yuzenghui@...wei.com>, Paolo Bonzini <pbonzini@...hat.com>,
 Shuah Khan <shuah@...nel.org>, Zaid Al-Bassam <zalbassam@...gle.com>,
 Raghavendra Rao Ananta <rananta@...gle.com>, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, kvmarm@...ts.linux.dev, kvm@...r.kernel.org,
 linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v7 05/11] arm64: perf: Include threshold control fields in
 PMEVTYPER mask



On 15/12/2023 12:08, Uwe Kleine-König wrote:
> Hello,
> 
> On Mon, Dec 11, 2023 at 04:13:17PM +0000, James Clark wrote:
>> FEAT_PMUv3_TH (Armv8.8) adds two new fields to PMEVTYPER, so include
>> them in the mask. These aren't writable on 32 bit kernels as they are in
>> the high part of the register, so only include them for arm64.
>>
>> It would be difficult to do this statically in the asm header files for
>> each platform without resulting in circular includes or #ifdefs inline
>> in the code. For that reason the ARMV8_PMU_EVTYPE_MASK definition has
>> been removed and the mask is constructed programmatically.
>>
>> Reviewed-by: Suzuki K Poulose <suzuki.poulose@....com>
>> Reviewed-by: Anshuman Khandual <anshuman.khandual@....com>
>> Signed-off-by: James Clark <james.clark@....com>
> 
> This change is in today's next as commit
> 3115ee021bfb04efde2e96507bfcc1330261a6a1. this breaks allmodconfig
> building on ARCH=arm:
> 
> 	In file included from include/linux/ratelimit_types.h:5,
> 			 from include/linux/printk.h:9,
> 			 from include/asm-generic/bug.h:22,
> 			 from arch/arm/include/asm/bug.h:60,
> 			 from include/linux/bug.h:5,
> 			 from include/linux/mmdebug.h:5,
> 			 from include/linux/percpu.h:5,
> 			 from include/asm-generic/irq_regs.h:11,
> 			 from ./arch/arm/include/generated/asm/irq_regs.h:1,
> 			 from drivers/perf/arm_pmuv3.c:11:
> 	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) & \
> 	      |                             ^~
> 	include/linux/bits.h:37:38: note: in expansion of macro ‘__GENMASK’
> 	   37 |         (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
> 	      |                                      ^~~~~~~~~
> 	include/linux/perf/arm_pmuv3.h:238:33: note: in expansion of macro ‘GENMASK’
> 	  238 | #define ARMV8_PMU_EVTYPE_TC     GENMASK(63, 61)
> 	      |                                 ^~~~~~~
> 	drivers/perf/arm_pmuv3.c:567:25: note: in expansion of macro ‘ARMV8_PMU_EVTYPE_TC’
> 	  567 |                 mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH;
> 	      |                         ^~~~~~~~~~~~~~~~~~~
> 	include/linux/bits.h:35:18: error: right shift count is negative [-Werror=shift-count-negative]
> 	   35 |          (~UL(0) >> (BITS_PER_LONG - 1 - (h))))
> 	      |                  ^~
> 	include/linux/bits.h:37:38: note: in expansion of macro ‘__GENMASK’
> 	   37 |         (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
> 	      |                                      ^~~~~~~~~
> 	include/linux/perf/arm_pmuv3.h:238:33: note: in expansion of macro ‘GENMASK’
> 	  238 | #define ARMV8_PMU_EVTYPE_TC     GENMASK(63, 61)
> 	      |                                 ^~~~~~~
> 	drivers/perf/arm_pmuv3.c:567:25: note: in expansion of macro ‘ARMV8_PMU_EVTYPE_TC’
> 	  567 |                 mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH;
> 	      |                         ^~~~~~~~~~~~~~~~~~~
> 	include/linux/bits.h:34:29: error: left shift count >= width of type [-Werror=shift-count-overflow]
> 	   34 |         (((~UL(0)) - (UL(1) << (l)) + 1) & \
> 	      |                             ^~
> 	include/linux/bits.h:37:38: note: in expansion of macro ‘__GENMASK’
> 	   37 |         (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
> 	      |                                      ^~~~~~~~~
> 	include/linux/perf/arm_pmuv3.h:237:33: note: in expansion of macro ‘GENMASK’
> 	  237 | #define ARMV8_PMU_EVTYPE_TH     GENMASK(43, 32)
> 	      |                                 ^~~~~~~
> 	drivers/perf/arm_pmuv3.c:567:47: note: in expansion of macro ‘ARMV8_PMU_EVTYPE_TH’
> 	  567 |                 mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH;
> 	      |                                               ^~~~~~~~~~~~~~~~~~~
> 	include/linux/bits.h:35:18: error: right shift count is negative [-Werror=shift-count-negative]
> 	   35 |          (~UL(0) >> (BITS_PER_LONG - 1 - (h))))
> 	      |                  ^~
> 	include/linux/bits.h:37:38: note: in expansion of macro ‘__GENMASK’
> 	   37 |         (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
> 	      |                                      ^~~~~~~~~
> 	include/linux/perf/arm_pmuv3.h:237:33: note: in expansion of macro ‘GENMASK’
> 	  237 | #define ARMV8_PMU_EVTYPE_TH     GENMASK(43, 32)
> 	      |                                 ^~~~~~~
> 	drivers/perf/arm_pmuv3.c:567:47: note: in expansion of macro ‘ARMV8_PMU_EVTYPE_TH’
> 	  567 |                 mask |= ARMV8_PMU_EVTYPE_TC | ARMV8_PMU_EVTYPE_TH;
> 	      |                                               ^~~~~~~~~~~~~~~~~~~
> 
> I guess that's easy to fix but I didn't look into that.
> 
> Best regards
> Uwe
> 

Thanks for the report. I see that the build is only broken with GCC and
is working with LLVM. I will look into a fix.

Worst case the if can be changed to an #ifdef

James