commit 9254aaa0fea4e8aa4e83539c379aecb41a975ca6
author Ingo Molnar <mingo@kernel.org> Fri Apr 24 10:02:32 2015 +0200
committer Ingo Molnar <mingo@kernel.org> Tue May 19 15:47:33 2015 +0200
tree bdf4154a776bee05a54f58784f319bf0f81353b4
parent 84246fe4e3a0e412a9602983ba37f4e4dbebb3e8

x86/fpu: Move XCR0 manipulation to the FPU code proper

The suspend code accesses FPU state internals, add a helper for
it and isolate it.

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/fpu/api.h

diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index f1eddcc..5bdde8c 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -23,6 +23,7 @@
 extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
 extern void fpu__restore(void);
 extern void fpu__init_check_bugs(void);
+extern void fpu__resume_cpu(void);
 
 extern bool irq_fpu_usable(void);
 

arch/x86/kernel/fpu/xsave.c

diff --git a/arch/x86/kernel/fpu/xsave.c b/arch/x86/kernel/fpu/xsave.c
index 1d0e271..a485180 100644
--- a/arch/x86/kernel/fpu/xsave.c
+++ b/arch/x86/kernel/fpu/xsave.c
@@ -735,6 +735,18 @@
 }
 
 /*
+ * Restore minimal FPU state after suspend:
+ */
+void fpu__resume_cpu(void)
+{
+	/*
+	 * Restore XCR0 on xsave capable CPUs:
+	 */
+	if (cpu_has_xsave)
+		xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask);
+}
+
+/*
  * Given the xsave area and a state inside, this function returns the
  * address of the state.
  *

arch/x86/power/cpu.c

diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 62054ac..ad0ce6b 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -18,10 +18,8 @@
 #include <asm/mtrr.h>
 #include <asm/page.h>
 #include <asm/mce.h>
-#include <asm/xcr.h>
 #include <asm/suspend.h>
 #include <asm/debugreg.h>
-#include <asm/fpu/internal.h> /* xfeatures_mask */
 #include <asm/cpu.h>
 
 #ifdef CONFIG_X86_32
@@ -155,6 +153,8 @@
 #endif
 	load_TR_desc();				/* This does ltr */
 	load_LDT(&current->active_mm->context);	/* This does lldt */
+
+	fpu__resume_cpu();
 }
 
 /**
@@ -221,12 +221,6 @@
 	wrmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);
 #endif
 
-	/*
-	 * restore XCR0 for xsave capable cpu's.
-	 */
-	if (cpu_has_xsave)
-		xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask);
-
 	fix_processor_context();
 
 	do_fpu_end();