diff options
| author | Ingo Molnar <mingo@elte.hu> | 2009-03-18 08:59:21 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-04-06 09:30:14 +0200 |
| commit | 7bb497bd885eedd0f56dfe3cc1b5ff20710d33b9 (patch) | |
| tree | 4f743d26a10f0a978ad2cfd0ef23c936c5ea0034 | |
| parent | 4e193bd4dfdc983d12969b51439b4a1fbaf2daad (diff) | |
perf_counter: fix crash on perfmon v1 systems
Impact: fix boot crash on Intel Perfmon Version 1 systems
Intel Perfmon v1 does not support the global MSRs, nor does
it offer the generalized MSR ranges. So support v2 and later
CPUs only.
Also mark pmc_ops as read-mostly - to avoid false cacheline
sharing.
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 22dab06c08a..6cba9d47b71 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -57,12 +57,14 @@ struct pmc_x86_ops { int max_events; }; -static struct pmc_x86_ops *pmc_ops; +static struct pmc_x86_ops *pmc_ops __read_mostly; static DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters) = { .enabled = 1, }; +static __read_mostly int intel_perfmon_version; + /* * Intel PerfMon v3. Used on Core2 and later. */ @@ -613,7 +615,7 @@ void perf_counter_print_debug(void) cpu = smp_processor_id(); cpuc = &per_cpu(cpu_hw_counters, cpu); - if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) { + if (intel_perfmon_version >= 2) { rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl); rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status); rdmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, overflow); @@ -930,10 +932,10 @@ static struct pmc_x86_ops pmc_amd_ops = { static struct pmc_x86_ops *pmc_intel_init(void) { + union cpuid10_edx edx; union cpuid10_eax eax; - unsigned int ebx; unsigned int unused; - union cpuid10_edx edx; + unsigned int ebx; /* * Check whether the Architectural PerfMon supports @@ -943,8 +945,12 @@ static struct pmc_x86_ops *pmc_intel_init(void) if (eax.split.mask_length <= ARCH_PERFMON_BRANCH_MISSES_RETIRED) return NULL; + intel_perfmon_version = eax.split.version_id; + if (intel_perfmon_version < 2) + return NULL; + pr_info("Intel Performance Monitoring support detected.\n"); - pr_info("... version: %d\n", eax.split.version_id); + pr_info("... version: %d\n", intel_perfmon_version); pr_info("... bit width: %d\n", eax.split.bit_width); pr_info("... mask length: %d\n", eax.split.mask_length); |