x86/fpu: Split the state handling in fpu__drop()
authorIngo Molnar <mingo@kernel.org>
Sat, 23 Sep 2017 13:00:00 +0000 (15:00 +0200)
committerIngo Molnar <mingo@kernel.org>
Sun, 24 Sep 2017 11:04:34 +0000 (13:04 +0200)
commitb6aa85558d7e7b18fc3470d2bc1731d2205dd275
tree36f8fdcaa749ba225152a88e946fe9e5c19d7683
parenta10b6a16cdad88170f546d008c77453cddf918e6
x86/fpu: Split the state handling in fpu__drop()

Prepare fpu__drop() to use fpu->fpregs_active.

There are two distinct usecases for fpu__drop() in this context:
exit_thread() when called for 'current' in exit(), and when called
for another task in fork().

This patch does not change behavior, it only adds a couple of
debug checks and structures the code to make the ->fpregs_active
change more obviously correct.

All the complications will be removed later on.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-18-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/kernel/fpu/core.c