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/include/asm-x86/processor.h b/include/asm-x86/processor.h
index eaf4548..99d2978 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -354,7 +354,7 @@
u32 entry_eip;
};
-union i387_union {
+union thread_xstate {
struct i387_fsave_struct fsave;
struct i387_fxsave_struct fxsave;
struct i387_soft_struct soft;
@@ -365,6 +365,7 @@
#endif
extern void print_cpu_info(struct cpuinfo_x86 *);
+extern unsigned int xstate_size;
extern void init_scattered_cpuid_features(struct cpuinfo_x86 *c);
extern unsigned int init_intel_cacheinfo(struct cpuinfo_x86 *c);
extern unsigned short num_cache_leaves;
@@ -397,8 +398,8 @@
unsigned long cr2;
unsigned long trap_no;
unsigned long error_code;
- /* Floating point info: */
- union i387_union i387 __attribute__((aligned(16)));;
+ /* floating point and extended processor state */
+ union thread_xstate *xstate;
#ifdef CONFIG_X86_32
/* Virtual 86 mode info */
struct vm86_struct __user *vm86_info;