| From | Ingo Molnar <> | Subject | [PATCH 23/33] x86/fpu: Turn WARN_ON() in context switch into WARN_ON_FPU() | Date | Sat, 23 Sep 2017 15:00:06 +0200 |
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From: Andi Kleen <ak@linux.intel.com>
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: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170329062605.4970-1-andi@firstfloor.org Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/include/asm/fpu/internal.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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); -- 2.11.0
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