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authorAndi Kleen <ak@linux.intel.com>2017-09-23 15:00:06 +0200
committerIngo Molnar <mingo@kernel.org>2017-09-24 13:04:35 +0200
commit03eaec81ac09814817e9f0307d572ffe8365f980 (patch)
treefa929a49abb4d2b11c4d1b44201977c9f6dd0c1e
parent4f8cef59bad29344aca0e2e6b0ad18dadd078fd0 (diff)
x86/fpu: Turn WARN_ON() in context switch into WARN_ON_FPU()
copy_xregs_to_kernel checks if the alternatives have been already patched. This WARN_ON() is always executed in every context switch. All the other checks in fpu internal.h are WARN_ON_FPU(), but this one is plain WARN_ON(). I assume it was forgotten to switch it. So switch it to WARN_ON_FPU() too to avoid some unnecessary code in the context switch, and a potentially expensive cache line miss for the global variable. Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Link: http://lkml.kernel.org/r/20170329062605.4970-1-andi@firstfloor.org Link: http://lkml.kernel.org/r/20170923130016.21448-24-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/include/asm/fpu/internal.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 629e7abcd6c9..2dca7c65319c 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -350,7 +350,7 @@ static inline void copy_xregs_to_kernel(struct xregs_state *xstate)
u32 hmask = mask >> 32;
int err;
- WARN_ON(!alternatives_patched);
+ WARN_ON_FPU(!alternatives_patched);
XSTATE_XSAVE(xstate, lmask, hmask, err);

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