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 <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Yu-cheng Yu <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 629e7abcd6c997bf3e049e6957073dc517aa102d..2dca7c65319cd790d874d040ad4a329330093c1a 100644 (file)
--- 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);