Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] perf/x86: always warn about broken BIOS | Date | Mon, 24 Oct 2016 17:26:37 +0200 |
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The intialization function checks for various failure scenarios, but unfortunately the compiler gets a little confused about the possible combinations, leading to a false-positive build warning when -Wmaybe-uninitialized is set:
arch/x86/events/core.c: In function ‘init_hw_perf_events’: arch/x86/events/core.c:264:3: warning: ‘reg_fail’ may be used uninitialized in this function [-Wmaybe-uninitialized] arch/x86/events/core.c:264:3: warning: ‘val_fail’ may be used uninitialized in this function [-Wmaybe-uninitialized] pr_err(FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x is %Lx)\n",
It seems reasonable to move the check for the broken BIOS a little higher in the function, which will lead to the kernel warning about both the BIOS and and broken hardware if both are faulty, but it has no effect otherwise at runtime.
Moving it ahead of the check for broken hardware however gets rid of the compile-time warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/x86/events/core.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 76697acdc507..185d3b27e881 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -228,6 +228,15 @@ static bool check_hw_exists(void) } /* + * We still allow the PMU driver to operate: + */ + if (bios_fail) { + pr_cont("Broken BIOS detected, complain to your hardware vendor.\n"); + pr_err(FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x is %Lx)\n", + reg_fail, val_fail); + } + + /* * If all the counters are enabled, the below test will always * fail. The tools will also become useless in this scenario. * Just fail and disable the hardware counters. @@ -252,15 +261,6 @@ static bool check_hw_exists(void) if (ret || val != val_new) goto msr_fail; - /* - * We still allow the PMU driver to operate: - */ - if (bios_fail) { - pr_cont("Broken BIOS detected, complain to your hardware vendor.\n"); - pr_err(FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x is %Lx)\n", - reg_fail, val_fail); - } - return true; msr_fail: -- 2.9.0
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