From 68b9e67311ca10a0bdce6ab2939ca0ff3ebac91b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 9 Jul 2015 19:23:38 +0200 Subject: [PATCH] x86, perf: Fix static_key bug in load_mm_cr4() commit a833581e372a4adae2319d8dc379493edbc444e9 upstream. Mikulas reported his K6-3 not booting. This is because the static_key API confusion struck and bit Andy, this wants to be static_key_false(). Reported-by: Mikulas Patocka Tested-by: Mikulas Patocka Signed-off-by: Peter Zijlstra (Intel) Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Valdis Kletnieks Cc: Vince Weaver Cc: hillf.zj Fixes: a66734297f78 ("perf/x86: Add /sys/devices/cpu/rdpmc=2 to allow rdpmc for all tasks") Link: http://lkml.kernel.org/r/20150709172338.GC19282@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/mmu_context.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 883f6b9..e997f70 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -23,7 +23,7 @@ extern struct static_key rdpmc_always_available; static inline void load_mm_cr4(struct mm_struct *mm) { - if (static_key_true(&rdpmc_always_available) || + if (static_key_false(&rdpmc_always_available) || atomic_read(&mm->context.perf_rdpmc_allowed)) cr4_set_bits(X86_CR4_PCE); else -- 2.7.4