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>

3 files changed, 13 insertions, 2 deletions

diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h
index dc3745e8040a..d3dda7161954 100644
--- a/include/asm-x86/i387.h
+++ b/include/asm-x86/i387.h
@@ -31,8 +31,10 @@ extern user_regset_active_fn fpregs_active, xfpregs_active;
 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 @@ static inline void clear_fpu_state(struct task_struct *tsk)
                           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;
 
diff --git a/include/asm-x86/ucontext.h b/include/asm-x86/ucontext.h
index 9948dd328084..89eaa5456a7e 100644
--- a/include/asm-x86/ucontext.h
+++ b/include/asm-x86/ucontext.h
@@ -1,6 +1,12 @@
 #ifndef ASM_X86__UCONTEXT_H
 #define ASM_X86__UCONTEXT_H
 
+#define UC_FP_XSTATE    0x1     /* indicates the presence of extended state
+                                 * information in the memory layout pointed
+                                 * by the fpstate pointer in the ucontext's
+                                 * sigcontext struct (uc_mcontext).
+                                 */
+
 struct ucontext {
         unsigned long     uc_flags;
         struct ucontext  *uc_link;
diff --git a/include/asm-x86/xsave.h b/include/asm-x86/xsave.h
index b716511aede2..b7f64b9fcd94 100644
--- a/include/asm-x86/xsave.h
+++ b/include/asm-x86/xsave.h
@@ -29,6 +29,9 @@ extern struct xsave_struct *init_xstate_buf;
 extern void xsave_cntxt_init(void);
 extern void xsave_init(void);
 extern int init_fpu(struct task_struct *child);
+extern int check_for_xstate(struct i387_fxsave_struct __user *buf,
+                            void __user *fpstate,
+                            struct _fpx_sw_bytes *sw);
 
 static inline int xrstor_checking(struct xsave_struct *fx)
 {
@@ -48,7 +51,7 @@ static inline int xrstor_checking(struct xsave_struct *fx)
         return err;
 }
 
-static inline int xsave_check(struct xsave_struct __user *buf)
+static inline int xsave_user(struct xsave_struct __user *buf)
 {
         int err;
         __asm__ __volatile__("1: .byte " REX_PREFIX "0x0f,0xae,0x27\n"