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perf/x86: Shut up false-positive -Wmaybe-uninitialized warning 

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",

We can't actually run into this case, so this shuts up the warning
by initializing the variables to a known-invalid state.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170719125310.2487451-2-arnd@arndb.de
Link: https://patchwork.kernel.org/patch/9392595/
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Arnd Bergmann 2017-07-19 14:52:59 +02:00 committed by Ingo Molnar
parent 0e7f0b6c23
commit 11d8b05855
1 changed files with 2 additions and 2 deletions
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4
arch/x86/events/core.c
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@ -191,8 +191,8 @@ static void release_pmc_hardware(void) {}
static bool check_hw_exists(void)
{
u64 val, val_fail, val_new= ~0;
int i, reg, reg_fail, ret = 0;
u64 val, val_fail = -1, val_new= ~0;
int i, reg, reg_fail = -1, ret = 0;
int bios_fail = 0;
int reg_safe = -1;