x86/fpu: Improve the initialization logic of 'err' around xstate_fault() constraints

There's a confusing aspect of how xstate_fault() constraints are
handled by the FPU register/memory copying functions in
fpu/internal.h: they use "0" (0) to signal that the asm code
will not always set 'err' to a valid value.

But 'err' is already initialized to 0 in C code, which is duplicated
by the asm() constraint. Should the initialization value ever be
changed, it might become subtly inconsistent with the not too clear
asm() constraint.

Use 'err' as the value of the input variable instead, to clarify
this all.

Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions