x86/fpu: Get rid of two redundant clts() calls

CR0.TS is cleared by a direct CR0 write in fpu__init_cpu_generic().
We don't need to call clts() two more times right after that.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm list <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/476d2d5066eda24838853426ea74c94140b50c85.1477951965.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 1a09d133c801049344bd0501d7c1a198b0730421..60dece392b3a7ab0ef67ce57edc10f79332686eb 100644 (file)
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -9,15 +9,6 @@
 #include <linux/sched.h>
 #include <linux/init.h>
 
-/*
- * Initialize the TS bit in CR0 according to the style of context-switches
- * we are using:
- */
-static void fpu__init_cpu_ctx_switch(void)
-{
-       clts();
-}
-
 /*
  * Initialize the registers found in all CPUs, CR0 and CR4:
  */
@@ -55,7 +46,6 @@ void fpu__init_cpu(void)
 {
        fpu__init_cpu_generic();
        fpu__init_cpu_xstate();
-       fpu__init_cpu_ctx_switch();
 }
 
 /*
@@ -290,14 +280,6 @@ void __init fpu__init_system(struct cpuinfo_x86 *c)
         */
        fpu__init_cpu();
 
-       /*
-        * But don't leave CR0::TS set yet, as some of the FPU setup
-        * methods depend on being able to execute FPU instructions
-        * that will fault on a set TS, such as the FXSAVE in
-        * fpu__init_system_mxcsr().
-        */
-       clts();
-
        fpu__init_system_generic();
        fpu__init_system_xstate_size_legacy();
        fpu__init_system_xstate();