x86, fpu: split FPU state from task struct - v5
Split the FPU save area from the task struct. This allows easy migration
of FPU context, and it's generally cleaner. It also allows the following
two optimizations:
1) only allocate when the application actually uses FPU, so in the first
lazy FPU trap. This could save memory for non-fpu using apps. Next patch
does this lazy allocation.
2) allocate the right size for the actual cpu rather than 512 bytes always.
Patches enabling xsave/xrstor support (coming shortly) will take advantage
of this.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index 4bab3b1..6e38d87 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -678,7 +678,7 @@
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
- struct i387_soft_struct *s387 = &target->thread.i387.soft;
+ struct i387_soft_struct *s387 = &target->thread.xstate->soft;
void *space = s387->st_space;
int ret;
int offset, other, i, tags, regnr, tag, newtop;
@@ -730,7 +730,7 @@
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
- struct i387_soft_struct *s387 = &target->thread.i387.soft;
+ struct i387_soft_struct *s387 = &target->thread.xstate->soft;
const void *space = s387->st_space;
int ret;
int offset = (S387->ftop & 7) * 10, other = 80 - offset;