perf/x86/intel/p4: Fix unused variable warning in p4_pmu_init()

Browse source

Build the kernel with make W=1 generates the following warning:

  arch/x86/events/intel/p4.c: In function ‘p4_pmu_init’:
  arch/x86/events/intel/p4.c:1370:27: error: variable ‘high’ set but not used [-Werror=unused-but-set-variable]
   1370 |         unsigned int low, high;
        |                           ^~~~

This happens because, although both variables are declared and
initialized by rdmsr, only `low` is used in the subsequent if statement.

This patch uses the rdmsrq() macro instead of the rdmsr() macro.
The rdmsrq() macro avoids the use of high and low variables
because it reads the msr value in a single u64 variable.
Also, replace (1 << 7) with the proper macro.

Running `make W=1` again resolves the error.
I was unable to test the patch because
i do not have the hardware.

Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Aldo Conte <aldocontelk@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260320112302.281549-1-aldocontelk@gmail.com

...

This commit is contained in:

Aldo Conte 2026-03-20 12:23:02 +01:00 • committed by Peter Zijlstra

parent b191aa32be

commit 6ee26b7a22

1 changed files with 3 additions and 3 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

6

arch/x86/events/intel/p4.c

View file