x86, xsave: save/restore the extended state context in sigframe

On cpu's supporting xsave/xrstor, fpstate pointer in the sigcontext, will
include the extended state information along with fpstate information. Presence
of extended state information is indicated by the presence
of FP_XSTATE_MAGIC1 at fpstate.sw_reserved.magic1 and FP_XSTATE_MAGIC2
at fpstate + (fpstate.sw_reserved.extended_size - FP_XSTATE_MAGIC2_SIZE).

Extended feature bit mask that is saved in the memory layout is represented
by the fpstate.sw_reserved.xstate_bv

For RT signal frames, UC_FP_XSTATE in the uc_flags also indicate the
presence of extended state information in the sigcontext's fpstate
pointer.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h
index dc3745e..d3dda71 100644
--- a/include/asm-x86/i387.h
+++ b/include/asm-x86/i387.h
@@ -31,8 +31,10 @@
 extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get;
 extern user_regset_set_fn fpregs_set, xfpregs_set, fpregs_soft_set;
 
+extern struct _fpx_sw_bytes fx_sw_reserved;
 #ifdef CONFIG_IA32_EMULATION
 extern unsigned int sig_xstate_ia32_size;
+extern struct _fpx_sw_bytes fx_sw_reserved_ia32;
 struct _fpstate_ia32;
 struct _xstate_ia32;
 extern int save_i387_xstate_ia32(void __user *buf);
@@ -104,7 +106,7 @@
 			  X86_FEATURE_FXSAVE_LEAK);
 }
 
-static inline int save_i387_checking(struct i387_fxsave_struct __user *fx)
+static inline int fxsave_user(struct i387_fxsave_struct __user *fx)
 {
 	int err;