diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2016-05-10 10:20:33 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-05-10 10:28:31 +0300 |
| commit | 8d415ee225a3d15d3e3029524350e8237a4de7b8 (patch) | |
| tree | 7352acadefca3b72f6f3d374f2d5436dd4468cb9 | |
| parent | 4abac0d0bbc628df5f26845fe05ffc6b3a6533dd (diff) | |
| download | linux-8d415ee225a3d15d3e3029524350e8237a4de7b8.tar.xz | |
x86/topology: Set x86_max_cores to 1 for CONFIG_SMP=n
Josef reported that the uncore driver trips over with CONFIG_SMP=n because
x86_max_cores is 16 instead of 12.
The reason is, that for SMP=n the extended topology detection is a NOOP and
the cache leaf is used to determine the number of cores. That's wrong in two
aspects:
1) The cache leaf enumerates the maximum addressable number of cores in the
package, which is obviously not correct
2) UP has no business with topology bits at all.
Make intel_num_cpu_cores() return 1 for CONFIG_SMP=n
Reported-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team <Kernel-team@fb.com>
Cc: Kan Liang <kan.liang@intel.com>
Link: http://lkml.kernel.org/r/761b4a2a-0332-7954-f030-c6639f949612@fb.com
| -rw-r--r-- | arch/x86/kernel/cpu/intel.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 1f7fdb91a818..e4393bfc7f0d 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -336,7 +336,7 @@ static int intel_num_cpu_cores(struct cpuinfo_x86 *c) { unsigned int eax, ebx, ecx, edx; - if (c->cpuid_level < 4) + if (!IS_ENABLED(CONFIG_SMP) || c->cpuid_level < 4) return 1; /* Intel has a non-standard dependency on %ecx for this CPUID level. */ |