x86/fpu: Get rid of PF_USED_MATH usage, convert it to fpu->fpstate_active
Introduce a simple fpu->fpstate_active flag in the fpu context data structure
and use that instead of PF_USED_MATH in task->flags.
Testing for this flag byte should be slightly more efficient than
testing a bit in a bitmask, but the main advantage is that most
FPU functions can now be performed on a 'struct fpu' alone, they
don't need access to 'struct task_struct' anymore.
There's a slight linecount increase, mostly due to the 'fpu' local
variables and due to extra comments. The local variables will go away
once we move most of the FPU methods to pure 'struct fpu' parameters.
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index bffb2c4..e1ec6f9 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -307,6 +307,7 @@
size_t frame_size,
void __user **fpstate)
{
+ struct fpu *fpu = ¤t->thread.fpu;
unsigned long sp;
/* Default to using normal stack */
@@ -321,7 +322,7 @@
ksig->ka.sa.sa_restorer)
sp = (unsigned long) ksig->ka.sa.sa_restorer;
- if (current->flags & PF_USED_MATH) {
+ if (fpu->fpstate_active) {
unsigned long fx_aligned, math_size;
sp = alloc_mathframe(sp, 1, &fx_aligned, &math_size);