x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths

fx_finit() has 2 users but only fpu_finit() needs to nullify xstate,
alloc_bootmem_align() in setup_init_fpu_buf() returns zero-filled
memory.

And note that both memset()'s look confusing. Yes, offsetof() is 0
for ->fxsave or ->fsave, but it would be more clean to turn them into
a single memset() which nullifies fpu->state.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tavis Ormandy <taviso@google.com>
Cc: <x86@kernel.org>
Link: http://lkml.kernel.org/r/20150302183257.GC23085@redhat.com
Signed-off-by: Borislav Petkov <bp@suse.de>
2 files changed