x86/fpu: Rename xstate related 'fx' references to 'xstate'

So the xstate code was probably first copied from the fxregs code,
hence it carried over the 'fx' naming for the state pointer variable.

But this is slightly confusing, as we usually on call the (legacy)
MMX/SSE state 'fx', both in data structures and in the functions
build around FXSAVE/FXRSTOR.

So rename it to 'xstate' to make it more apparent what it is related to.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
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: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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

@@ -232,7 +232,7 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
  * This function is called only during boot time when x86 caps are not set
  * up and alternative can not be used yet.
  */
-static inline int copy_xregs_to_kernel_booting(struct xregs_state *fx)
+static inline int copy_xregs_to_kernel_booting(struct xregs_state *xstate)
 {
 	u64 mask = -1;
 	u32 lmask = mask;
@@ -245,13 +245,13 @@ static inline int copy_xregs_to_kernel_booting(struct xregs_state *fx)
 		asm volatile("1:"XSAVES"\n\t"
 			"2:\n\t"
 			     xstate_fault(err)
-			: "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+			: "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask)
 			:   "memory");
 	else
 		asm volatile("1:"XSAVE"\n\t"
 			"2:\n\t"
 			     xstate_fault(err)
-			: "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+			: "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask)
 			:   "memory");
 	return err;
 }
@@ -260,7 +260,7 @@ static inline int copy_xregs_to_kernel_booting(struct xregs_state *fx)
  * This function is called only during boot time when x86 caps are not set
  * up and alternative can not be used yet.
  */
-static inline int copy_kernel_to_xregs_booting(struct xregs_state *fx, u64 mask)
+static inline int copy_kernel_to_xregs_booting(struct xregs_state *xstate, u64 mask)
 {
 	u32 lmask = mask;
 	u32 hmask = mask >> 32;
@@ -272,21 +272,21 @@ static inline int copy_kernel_to_xregs_booting(struct xregs_state *fx, u64 mask)
 		asm volatile("1:"XRSTORS"\n\t"
 			"2:\n\t"
 			     xstate_fault(err)
-			: "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+			: "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask)
 			:   "memory");
 	else
 		asm volatile("1:"XRSTOR"\n\t"
 			"2:\n\t"
 			     xstate_fault(err)
-			: "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+			: "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask)
 			:   "memory");
 	return err;
 }
 
 /*
  * Save processor xstate to xsave area.
  */
-static inline int copy_xregs_to_kernel(struct xregs_state *fx)
+static inline int copy_xregs_to_kernel(struct xregs_state *xstate)
 {
 	u64 mask = -1;
 	u32 lmask = mask;
@@ -312,7 +312,7 @@ static inline int copy_xregs_to_kernel(struct xregs_state *fx)
 		X86_FEATURE_XSAVEOPT,
 		XSAVES,
 		X86_FEATURE_XSAVES,
-		[fx] "D" (fx), "a" (lmask), "d" (hmask) :
+		[xstate] "D" (xstate), "a" (lmask), "d" (hmask) :
 		"memory");
 	asm volatile("2:\n\t"
 		     xstate_fault(err)
@@ -325,7 +325,7 @@ static inline int copy_xregs_to_kernel(struct xregs_state *fx)
 /*
  * Restore processor xstate from xsave area.
  */
-static inline int copy_kernel_to_xregs(struct xregs_state *fx, u64 mask)
+static inline int copy_kernel_to_xregs(struct xregs_state *xstate, u64 mask)
 {
 	int err = 0;
 	u32 lmask = mask;
@@ -339,7 +339,7 @@ static inline int copy_kernel_to_xregs(struct xregs_state *fx, u64 mask)
 		"1: " XRSTOR,
 		XRSTORS,
 		X86_FEATURE_XSAVES,
-		"D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+		"D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask)
 		: "memory");
 
 	asm volatile("2:\n"
@@ -426,7 +426,7 @@ static inline int copy_fpregs_to_fpstate(struct fpu *fpu)
 	 * Legacy FPU register saving, FNSAVE always clears FPU registers,
 	 * so we have to mark them inactive:
 	 */
-	asm volatile("fnsave %[fx]; fwait" : [fx] "=m" (fpu->state.fsave));
+	asm volatile("fnsave %[fp]; fwait" : [fp] "=m" (fpu->state.fsave));
 
 	return 0;
 }
@@ -459,7 +459,7 @@ static inline int copy_fpstate_to_fpregs(struct fpu *fpu)
 	return __copy_fpstate_to_fpregs(fpu);
 }
 
-extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fx, int size);
+extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fp, int size);
 
 /*
  * FPU context switch related helper methods: