x86/oprofile/ppro: Do not use __this_cpu*() in preemptible context

suryasaimadhu · KAGA-KOKO · commit a743bbeef27b · 2017-11-08T13:01:54.000+01:00
The warning below says it all:

  BUG: using __this_cpu_read() in preemptible [00000000] code: swapper/0/1
  caller is __this_cpu_preempt_check
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.0-rc8 #4
  Call Trace:
   dump_stack
   check_preemption_disabled
   ? do_early_param
   __this_cpu_preempt_check
   arch_perfmon_init
   op_nmi_init
   ? alloc_pci_root_info
   oprofile_arch_init
   oprofile_init
   do_one_initcall
   ...

These accessors should not have been used in the first place: it is PPro so
no mixed silicon revisions and thus it can simply use boot_cpu_data.

Reported-by: Fengguang Wu &lt;fengguang.wu@intel.com&gt;
Tested-by: Fengguang Wu &lt;fengguang.wu@intel.com&gt;
Fix-creation-mandated-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Robert Richter &lt;rric@kernel.org&gt;
Cc: x86@kernel.org
Cc: stable@vger.kernel.org
diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
@@ -212,8 +212,8 @@ static void arch_perfmon_setup_counters(void)
 	eax.full = cpuid_eax(0xa);
 
 	/* Workaround for BIOS bugs in 6/15. Taken from perfmon2 */
-	if (eax.split.version_id == 0 && __this_cpu_read(cpu_info.x86) == 6 &&
-		__this_cpu_read(cpu_info.x86_model) == 15) {
+	if (eax.split.version_id == 0 && boot_cpu_data.x86 == 6 &&
+	    boot_cpu_data.x86_model == 15) {
 		eax.split.version_id = 2;
 		eax.split.num_counters = 2;
 		eax.split.bit_width = 40;
