[PATCH] perf: arm_v7_pmu: suppress -Winitializer-overrides for perf maps

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* [PATCH] perf: arm_v7_pmu: suppress -Winitializer-overrides for perf maps
@ 2026-11-11  2:33 Rosen Penev
  2026-11-12 19:48 ` kernel test robot
  0 siblings, 1 reply; 2+ messages in thread
From: Rosen Penev @ 2026-11-11  2:33 UTC (permalink / raw)
  To: Will Deacon, Mark Rutland, Nathan Chancellor
  Cc: Nick Desaulniers, Bill Wendling, Justin Stitt, linux-arm-kernel,
	linux-perf-users, linux-kernel, llvm

The perf_map and cache_map arrays intentionally use a range initializer
to fill all entries with HW_OP_UNSUPPORTED / CACHE_OP_UNSUPPORTED, then
override specific entries with supported event codes. This is valid C99
designated initializer behavior (last initializer wins), but Clang's
-Winitializer-overrides warns about each overridden entry.

Suppress the warning around these array definitions using the kernel's
__diag infrastructure, since the pattern is intentional and widespread
across all CPU-specific perf map variants in this file.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/perf/arm_v7_pmu.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/perf/arm_v7_pmu.c b/drivers/perf/arm_v7_pmu.c
index a1e438101114..9ac28c8adf80 100644
--- a/drivers/perf/arm_v7_pmu.c
+++ b/drivers/perf/arm_v7_pmu.c
@@ -146,6 +146,15 @@
 
 #define SCORPION_ITLB_MISS				0x12021
 
+/*
+ * The perf_map and cache_map arrays use range initializers to fill all
+ * entries with HW_OP_UNSUPPORTED / CACHE_OP_UNSUPPORTED, then override
+ * specific entries with supported event codes. This is valid C99 but
+ * triggers Clang's -Winitializer-overrides.
+ */
+__diag_push();
+__diag_ignore_all("-Winitializer-overrides", "");
+
 /*
  * Cortex-A8 HW events mapping
  *
@@ -530,6 +539,8 @@ static const unsigned scorpion_perf_cache_map[PERF_COUNT_HW_CACHE_MAX]
 	[C(BPU)][C(OP_WRITE)][C(RESULT_MISS)] = ARMV7_PERFCTR_PC_BRANCH_MIS_PRED,
 };
 
+__diag_pop();
+
 PMU_FORMAT_ATTR(event, "config:0-7");
 
 static struct attribute *armv7_pmu_format_attrs[] = {
-- 
2.56.0



^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] perf: arm_v7_pmu: suppress -Winitializer-overrides for perf maps
  2026-11-11  2:33 [PATCH] perf: arm_v7_pmu: suppress -Winitializer-overrides for perf maps Rosen Penev
@ 2026-11-12 19:48 ` kernel test robot
  0 siblings, 0 replies; 2+ messages in thread
From: kernel test robot @ 2026-11-12 19:48 UTC (permalink / raw)
  To: Rosen Penev, Will Deacon, Mark Rutland, Nathan Chancellor
  Cc: oe-kbuild-all, Nick Desaulniers, Bill Wendling, Justin Stitt,
	linux-arm-kernel, linux-perf-users, linux-kernel, llvm

Hi Rosen,

kernel test robot noticed the following build warnings:

[auto build test WARNING on arm-perf/for-next/perf]
[also build test WARNING on linus/master v7.4-rc2 next-20261111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Rosen-Penev/perf-arm_v7_pmu-suppress-Winitializer-overrides-for-perf-maps/20261110-183326
base:   https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git for-next/perf
patch link:    https://lore.kernel.org/r/20261111023326.70922-1-rosenp%40gmail.com
patch subject: [PATCH] perf: arm_v7_pmu: suppress -Winitializer-overrides for perf maps
config: arm-allyesconfig (https://download.01.org/0day-ci/archive/20261113/202611130312.GB4BOZab-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 16.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261113/202611130312.GB4BOZab-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202611130312.GB4BOZab-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/compiler_types.h:173,
                    from <command-line>:
>> include/linux/compiler-gcc.h:118:33: warning: unknown option after '#pragma GCC diagnostic' kind [-Wpragmas]
     118 | #define __diag(s)               _Pragma(__diag_str(GCC diagnostic s))
         |                                 ^~~~~~~
   include/linux/compiler-gcc.h:129:9: note: in expansion of macro '__diag'
     129 |         __diag(__diag_GCC_ignore option)
         |         ^~~~~~
   drivers/perf/arm_v7_pmu.c:156:1: note: in expansion of macro '__diag_ignore_all'
     156 | __diag_ignore_all("-Winitializer-overrides", "");
         | ^~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:78:57: warning: initialized field overwritten [-Woverride-init]
      78 | #define ARMV7_PERFCTR_CPU_CYCLES                        0xFF
         |                                                         ^~~~
   drivers/perf/arm_v7_pmu.c:167:51: note: in expansion of macro 'ARMV7_PERFCTR_CPU_CYCLES'
     167 |         [PERF_COUNT_HW_CPU_CYCLES]              = ARMV7_PERFCTR_CPU_CYCLES,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:78:57: note: (near initialization for 'armv7_a8_perf_map[0]')
   drivers/perf/arm_v7_pmu.c:167:51: note: in expansion of macro 'ARMV7_PERFCTR_CPU_CYCLES'
     167 |         [PERF_COUNT_HW_CPU_CYCLES]              = ARMV7_PERFCTR_CPU_CYCLES,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:45:57: warning: initialized field overwritten [-Woverride-init]
      45 | #define ARMV7_PERFCTR_INSTR_EXECUTED                    0x08
         |                                                         ^~~~
   drivers/perf/arm_v7_pmu.c:168:51: note: in expansion of macro 'ARMV7_PERFCTR_INSTR_EXECUTED'
     168 |         [PERF_COUNT_HW_INSTRUCTIONS]            = ARMV7_PERFCTR_INSTR_EXECUTED,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:45:57: note: (near initialization for 'armv7_a8_perf_map[1]')
   drivers/perf/arm_v7_pmu.c:168:51: note: in expansion of macro 'ARMV7_PERFCTR_INSTR_EXECUTED'
     168 |         [PERF_COUNT_HW_INSTRUCTIONS]            = ARMV7_PERFCTR_INSTR_EXECUTED,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:41:57: warning: initialized field overwritten [-Woverride-init]
      41 | #define ARMV7_PERFCTR_L1_DCACHE_ACCESS                  0x04
         |                                                         ^~~~
   drivers/perf/arm_v7_pmu.c:169:51: note: in expansion of macro 'ARMV7_PERFCTR_L1_DCACHE_ACCESS'
     169 |         [PERF_COUNT_HW_CACHE_REFERENCES]        = ARMV7_PERFCTR_L1_DCACHE_ACCESS,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:41:57: note: (near initialization for 'armv7_a8_perf_map[2]')
   drivers/perf/arm_v7_pmu.c:169:51: note: in expansion of macro 'ARMV7_PERFCTR_L1_DCACHE_ACCESS'
     169 |         [PERF_COUNT_HW_CACHE_REFERENCES]        = ARMV7_PERFCTR_L1_DCACHE_ACCESS,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:40:57: warning: initialized field overwritten [-Woverride-init]
      40 | #define ARMV7_PERFCTR_L1_DCACHE_REFILL                  0x03
         |                                                         ^~~~
   drivers/perf/arm_v7_pmu.c:170:51: note: in expansion of macro 'ARMV7_PERFCTR_L1_DCACHE_REFILL'
     170 |         [PERF_COUNT_HW_CACHE_MISSES]            = ARMV7_PERFCTR_L1_DCACHE_REFILL,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:40:57: note: (near initialization for 'armv7_a8_perf_map[3]')
   drivers/perf/arm_v7_pmu.c:170:51: note: in expansion of macro 'ARMV7_PERFCTR_L1_DCACHE_REFILL'
     170 |         [PERF_COUNT_HW_CACHE_MISSES]            = ARMV7_PERFCTR_L1_DCACHE_REFILL,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:57:57: warning: initialized field overwritten [-Woverride-init]
      57 | #define ARMV7_PERFCTR_PC_WRITE                          0x0C
         |                                                         ^~~~
   drivers/perf/arm_v7_pmu.c:171:51: note: in expansion of macro 'ARMV7_PERFCTR_PC_WRITE'
     171 |         [PERF_COUNT_HW_BRANCH_INSTRUCTIONS]     = ARMV7_PERFCTR_PC_WRITE,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:57:57: note: (near initialization for 'armv7_a8_perf_map[4]')
   drivers/perf/arm_v7_pmu.c:171:51: note: in expansion of macro 'ARMV7_PERFCTR_PC_WRITE'
     171 |         [PERF_COUNT_HW_BRANCH_INSTRUCTIONS]     = ARMV7_PERFCTR_PC_WRITE,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:61:57: warning: initialized field overwritten [-Woverride-init]
      61 | #define ARMV7_PERFCTR_PC_BRANCH_MIS_PRED                0x10
         |                                                         ^~~~
   drivers/perf/arm_v7_pmu.c:172:51: note: in expansion of macro 'ARMV7_PERFCTR_PC_BRANCH_MIS_PRED'
     172 |         [PERF_COUNT_HW_BRANCH_MISSES]           = ARMV7_PERFCTR_PC_BRANCH_MIS_PRED,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:61:57: note: (near initialization for 'armv7_a8_perf_map[5]')
   drivers/perf/arm_v7_pmu.c:172:51: note: in expansion of macro 'ARMV7_PERFCTR_PC_BRANCH_MIS_PRED'
     172 |         [PERF_COUNT_HW_BRANCH_MISSES]           = ARMV7_PERFCTR_PC_BRANCH_MIS_PRED,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:84:57: warning: initialized field overwritten [-Woverride-init]
      84 | #define ARMV7_A8_PERFCTR_STALL_ISIDE                    0x56
         |                                                         ^~~~
   drivers/perf/arm_v7_pmu.c:173:51: note: in expansion of macro 'ARMV7_A8_PERFCTR_STALL_ISIDE'
     173 |         [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = ARMV7_A8_PERFCTR_STALL_ISIDE,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:84:57: note: (near initialization for 'armv7_a8_perf_map[7]')
   drivers/perf/arm_v7_pmu.c:173:51: note: in expansion of macro 'ARMV7_A8_PERFCTR_STALL_ISIDE'
     173 |         [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = ARMV7_A8_PERFCTR_STALL_ISIDE,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:41:57: warning: initialized field overwritten [-Woverride-init]
      41 | #define ARMV7_PERFCTR_L1_DCACHE_ACCESS                  0x04
         |                                                         ^~~~
   drivers/perf/arm_v7_pmu.c:186:51: note: in expansion of macro 'ARMV7_PERFCTR_L1_DCACHE_ACCESS'
     186 |         [C(L1D)][C(OP_READ)][C(RESULT_ACCESS)]  = ARMV7_PERFCTR_L1_DCACHE_ACCESS,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:41:57: note: (near initialization for 'armv7_a8_perf_cache_map[0][0][0]')
   drivers/perf/arm_v7_pmu.c:186:51: note: in expansion of macro 'ARMV7_PERFCTR_L1_DCACHE_ACCESS'
     186 |         [C(L1D)][C(OP_READ)][C(RESULT_ACCESS)]  = ARMV7_PERFCTR_L1_DCACHE_ACCESS,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:40:57: warning: initialized field overwritten [-Woverride-init]
      40 | #define ARMV7_PERFCTR_L1_DCACHE_REFILL                  0x03
         |                                                         ^~~~
   drivers/perf/arm_v7_pmu.c:187:51: note: in expansion of macro 'ARMV7_PERFCTR_L1_DCACHE_REFILL'
     187 |         [C(L1D)][C(OP_READ)][C(RESULT_MISS)]    = ARMV7_PERFCTR_L1_DCACHE_REFILL,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:40:57: note: (near initialization for 'armv7_a8_perf_cache_map[0][0][1]')
   drivers/perf/arm_v7_pmu.c:187:51: note: in expansion of macro 'ARMV7_PERFCTR_L1_DCACHE_REFILL'
     187 |         [C(L1D)][C(OP_READ)][C(RESULT_MISS)]    = ARMV7_PERFCTR_L1_DCACHE_REFILL,
         |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/perf/arm_v7_pmu.c:41:57: warning: initialized field overwritten [-Woverride-init]
      41 | #define ARMV7_PERFCTR_L1_DCACHE_ACCESS                  0x04


vim +118 include/linux/compiler-gcc.h

8793bb7f4a9dd13 Arnd Bergmann 2018-06-19  115  
8793bb7f4a9dd13 Arnd Bergmann 2018-06-19  116  #define __diag_str1(s)		#s
8793bb7f4a9dd13 Arnd Bergmann 2018-06-19  117  #define __diag_str(s)		__diag_str1(s)
8793bb7f4a9dd13 Arnd Bergmann 2018-06-19 @118  #define __diag(s)		_Pragma(__diag_str(GCC diagnostic s))
8793bb7f4a9dd13 Arnd Bergmann 2018-06-19  119  

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki


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