x86/fpu: Use using_compacted_format() instead of open coded X86_FEATURE_XSAVES

This is the canonical method to use.

Signed-off-by: Eric Biggers <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Kevin Hao <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Michael Halcrow <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Wanpeng Li <[email protected]>
Cc: Yu-cheng Yu <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

Author: ebiggers

arch/x86/kernel/fpu/regset.c

@@ -134,7 +134,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
 
 	fpu__prepare_write(fpu);
 
-	if (boot_cpu_has(X86_FEATURE_XSAVES)) {
+	if (using_compacted_format()) {
 		if (kbuf)
 			ret = copy_kernel_to_xstate(xsave, kbuf);
 		else