From a833581e372a4adae2319d8dc379493edbc444e9 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra <peterz@infradead.org> Date: Thu, 9 Jul 2015 19:23:38 +0200 Subject: [PATCH] x86, perf: Fix static_key bug in load_mm_cr4() 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 <mpatocka@redhat.com> Tested-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Vince Weaver <vince@deater.net> Cc: hillf.zj <hillf.zj@alibaba-inc.com> 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 <mingo@kernel.org> --- 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 5e8daee7c5c94..804a3a6030ca0 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