[openeuler:OLK-5.10 2882/2882] arch/x86/events/amd/brs.c:339:6: warning: no previous prototype for 'perf_amd_brs_lopwr_cb'

[openeuler:OLK-5.10 2882/2882] arch/x86/events/amd/brs.c:339:6: warning: no previous prototype for 'perf_amd_brs_lopwr_cb'

[kernel test robot]

tree:   https://gitee.com/openeuler/kernel.git OLK-5.10
head:   b5ec139da1a4916dfc9644ee3d9426dbd6f23c13
commit: 600130a3b3f73d76dbfa38d63f68d1c2520e582d [2882/2882] kabi: Fix kabi breakage without build warning.
config: x86_64-buildonly-randconfig-2003-20250502 (https://download.01.org/0day-ci/archive/20250604/202506040948.XIX3UmG8-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250604/202506040948.XIX3UmG8-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/202506040948.XIX3UmG8-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/x86/events/amd/brs.c:339:6: warning: no previous prototype for 'perf_amd_brs_lopwr_cb' [-Wmissing-prototypes]
     339 | void perf_amd_brs_lopwr_cb(bool lopwr_in)
         |      ^~~~~~~~~~~~~~~~~~~~~


vim +/perf_amd_brs_lopwr_cb +339 arch/x86/events/amd/brs.c

fb5f22f8054df9 Stephane Eranian 2022-03-22  334  
fb5f22f8054df9 Stephane Eranian 2022-03-22  335  /*
fb5f22f8054df9 Stephane Eranian 2022-03-22  336   * called from ACPI processor_idle.c or acpi_pad.c
fb5f22f8054df9 Stephane Eranian 2022-03-22  337   * with interrupts disabled
fb5f22f8054df9 Stephane Eranian 2022-03-22  338   */
fb5f22f8054df9 Stephane Eranian 2022-03-22 @339  void perf_amd_brs_lopwr_cb(bool lopwr_in)
fb5f22f8054df9 Stephane Eranian 2022-03-22  340  {
fb5f22f8054df9 Stephane Eranian 2022-03-22  341  	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
fb5f22f8054df9 Stephane Eranian 2022-03-22  342  	union amd_debug_extn_cfg cfg;
fb5f22f8054df9 Stephane Eranian 2022-03-22  343  
fb5f22f8054df9 Stephane Eranian 2022-03-22  344  	/*
fb5f22f8054df9 Stephane Eranian 2022-03-22  345  	 * on mwait in, we may end up in non C0 state.
fb5f22f8054df9 Stephane Eranian 2022-03-22  346  	 * we must disable branch sampling to avoid holding the NMI
fb5f22f8054df9 Stephane Eranian 2022-03-22  347  	 * for too long. We disable it in hardware but we
fb5f22f8054df9 Stephane Eranian 2022-03-22  348  	 * keep the state in cpuc, so we can re-enable.
fb5f22f8054df9 Stephane Eranian 2022-03-22  349  	 *
fb5f22f8054df9 Stephane Eranian 2022-03-22  350  	 * The hardware will deliver the NMI if needed when brsmen cleared
fb5f22f8054df9 Stephane Eranian 2022-03-22  351  	 */
fb5f22f8054df9 Stephane Eranian 2022-03-22  352  	if (cpuc->brs_active) {
fb5f22f8054df9 Stephane Eranian 2022-03-22  353  		cfg.val = get_debug_extn_cfg();
fb5f22f8054df9 Stephane Eranian 2022-03-22  354  		cfg.brsmen = !lopwr_in;
fb5f22f8054df9 Stephane Eranian 2022-03-22  355  		set_debug_extn_cfg(cfg.val);
fb5f22f8054df9 Stephane Eranian 2022-03-22  356  	}
fb5f22f8054df9 Stephane Eranian 2022-03-22  357  }
fb5f22f8054df9 Stephane Eranian 2022-03-22  358  

:::::: The code at line 339 was first introduced by commit
:::::: fb5f22f8054df9c6cc2c2e40e54a76ea62fb4824 perf/x86/amd: Add idle hooks for branch sampling

:::::: TO: Stephane Eranian <eranian@google.com>
:::::: CC: Xie Haocheng <haocheng.xie@amd.com>

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https://github.com/intel/lkp-tests/wiki