From 9254aaa0fea4e8aa4e83539c379aecb41a975ca6 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@kernel.org>
Date: Fri, 24 Apr 2015 10:02:32 +0200
Subject: [PATCH] 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 |  1 +
 arch/x86/kernel/fpu/xsave.c    | 12 ++++++++++++
 arch/x86/power/cpu.c           | 10 ++--------
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index f1eddcccba16..5bdde8ca87bc 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -23,6 +23,7 @@ extern void fpu__clear(struct task_struct *tsk);
 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);
 
diff --git a/arch/x86/kernel/fpu/xsave.c b/arch/x86/kernel/fpu/xsave.c
index 1d0e27128f18..a485180ebc32 100644
--- a/arch/x86/kernel/fpu/xsave.c
+++ b/arch/x86/kernel/fpu/xsave.c
@@ -734,6 +734,18 @@ void __init_refok eager_fpu_init(void)
 		setup_init_fpu_buf();
 }
 
+/*
+ * 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.
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 62054acbd0d8..ad0ce6b70fac 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 @@ static void fix_processor_context(void)
 #endif
 	load_TR_desc();				/* This does ltr */
 	load_LDT(&current->active_mm->context);	/* This does lldt */
+
+	fpu__resume_cpu();
 }
 
 /**
@@ -221,12 +221,6 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
 	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();
-- 
2.20.1