X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=include%2Fasm-x86_64%2Fi387.h;h=0217b74cc9fc0cd30456d40929e6196229680178;hb=43a145a3440c5c5f24ff2888801e40e2242187e6;hp=876eb9a2fe7868a7c7ce01ef694403b3150f4601;hpb=bf785ee0aeea7a3e717cb1e11df4135b6cbde7da;p=powerpc.git

diff --git a/include/asm-x86_64/i387.h b/include/asm-x86_64/i387.h
index 876eb9a2fe..0217b74cc9 100644
--- a/include/asm-x86_64/i387.h
+++ b/include/asm-x86_64/i387.h
@@ -24,6 +24,7 @@ extern unsigned int mxcsr_feature_mask;
 extern void mxcsr_feature_mask_init(void);
 extern void init_fpu(struct task_struct *child);
 extern int save_i387(struct _fpstate __user *buf);
+extern asmlinkage void math_state_restore(void);
 
 /*
  * FPU lazy state save handling...
@@ -31,7 +32,9 @@ extern int save_i387(struct _fpstate __user *buf);
 
 #define unlazy_fpu(tsk) do { \
 	if (task_thread_info(tsk)->status & TS_USEDFPU) \
-		save_init_fpu(tsk); \
+		save_init_fpu(tsk); 			\
+	else						\
+		tsk->fpu_counter = 0;			\
 } while (0)
 
 /* Ignore delayed exceptions from user space */
@@ -72,6 +75,23 @@ extern int set_fpregs(struct task_struct *tsk,
 #define set_fpu_swd(t,val) ((t)->thread.i387.fxsave.swd = (val))
 #define set_fpu_fxsr_twd(t,val) ((t)->thread.i387.fxsave.twd = (val))
 
+#define X87_FSW_ES (1 << 7)	/* Exception Summary */
+
+/* AMD CPUs don't save/restore FDP/FIP/FOP unless an exception
+   is pending. Clear the x87 state here by setting it to fixed
+   values. The kernel data segment can be sometimes 0 and sometimes
+   new user value. Both should be ok.
+   Use the PDA as safe address because it should be already in L1. */
+static inline void clear_fpu_state(struct i387_fxsave_struct *fx)
+{
+	if (unlikely(fx->swd & X87_FSW_ES))
+		 asm volatile("fnclex");
+	alternative_input(ASM_NOP8 ASM_NOP2,
+	     	     "    emms\n"		/* clear stack tags */
+	     	     "    fildl %%gs:0",	/* load to clear state */
+		     X86_FEATURE_FXSAVE_LEAK);
+}
+
 static inline int restore_fpu_checking(struct i387_fxsave_struct *fx) 
 { 
 	int err;
@@ -117,8 +137,9 @@ static inline int save_i387_checking(struct i387_fxsave_struct __user *fx)
 #else
 		     : [fx] "cdaSDb" (fx), "0" (0));
 #endif
-	if (unlikely(err))
-		__clear_user(fx, sizeof(struct i387_fxsave_struct));
+	if (unlikely(err) && __clear_user(fx, sizeof(struct i387_fxsave_struct)))
+		err = -EFAULT;
+	/* No need to clear here because the caller clears USED_MATH */
 	return err;
 } 
 
@@ -149,7 +170,7 @@ static inline void __fxsave_clear(struct task_struct *tsk)
 				"i" (offsetof(__typeof__(*tsk),
 					      thread.i387.fxsave)));
 #endif
-	__asm__ __volatile__("fnclex");
+	clear_fpu_state(&tsk->thread.i387.fxsave);
 }
 
 static inline void kernel_fpu_begin(void)