x86, xsave: reorganization of signal save/restore fpstate code layout

move 64bit routines that saves/restores fpstate in/from user stack from
signal_64.c to xsave.c

restore_i387_xstate() now handles the condition when user passes
NULL fpstate.

Other misc changes for prepartion of xsave/xrstor sigcontext support.

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>

1 files changed, 31 insertions, 13 deletions

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 51fb288a2c97..7daf3a011dd9 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -21,9 +21,10 @@
 # include <asm/sigcontext32.h>
 # include <asm/user32.h>
 #else
-# define save_i387_ia32         save_i387
-# define restore_i387_ia32      restore_i387
+# define save_i387_xstate_ia32          save_i387_xstate
+# define restore_i387_xstate_ia32       restore_i387_xstate
 # define _fpstate_ia32          _fpstate
+# define _xstate_ia32           _xstate
 # define sig_xstate_ia32_size   sig_xstate_size
 # define user_i387_ia32_struct  user_i387_struct
 # define user32_fxsr_struct     user_fxsr_struct
@@ -424,7 +425,6 @@ static inline int save_i387_fsave(struct _fpstate_ia32 __user *buf)
         struct task_struct *tsk = current;
         struct i387_fsave_struct *fp = &tsk->thread.xstate->fsave;
 
-        unlazy_fpu(tsk);
         fp->status = fp->swd;
         if (__copy_to_user(buf, fp, sizeof(struct i387_fsave_struct)))
                 return -1;
@@ -438,8 +438,6 @@ static int save_i387_fxsave(struct _fpstate_ia32 __user *buf)
         struct user_i387_ia32_struct env;
         int err = 0;
 
-        unlazy_fpu(tsk);
-
         convert_from_fxsr(&env, tsk);
         if (__copy_to_user(buf, &env, sizeof(env)))
                 return -1;
@@ -455,10 +453,16 @@ static int save_i387_fxsave(struct _fpstate_ia32 __user *buf)
         return 1;
 }
 
-int save_i387_ia32(struct _fpstate_ia32 __user *buf)
+int save_i387_xstate_ia32(void __user *buf)
 {
+        struct _fpstate_ia32 __user *fp = (struct _fpstate_ia32 __user *) buf;
+        struct task_struct *tsk = current;
+
         if (!used_math())
                 return 0;
+
+        if (!access_ok(VERIFY_WRITE, buf, sig_xstate_ia32_size))
+                return -EACCES;
         /*
          * This will cause a "finit" to be triggered by the next
          * attempted FPU operation by the 'current' process.
@@ -468,13 +472,15 @@ int save_i387_ia32(struct _fpstate_ia32 __user *buf)
         if (!HAVE_HWFP) {
                 return fpregs_soft_get(current, NULL,
                                        0, sizeof(struct user_i387_ia32_struct),
-                                       NULL, buf) ? -1 : 1;
+                                       NULL, fp) ? -1 : 1;
         }
 
+        unlazy_fpu(tsk);
+
         if (cpu_has_fxsr)
-                return save_i387_fxsave(buf);
+                return save_i387_fxsave(fp);
         else
-                return save_i387_fsave(buf);
+                return save_i387_fsave(fp);
 }
 
 static inline int restore_i387_fsave(struct _fpstate_ia32 __user *buf)
@@ -502,14 +508,26 @@ static int restore_i387_fxsave(struct _fpstate_ia32 __user *buf)
         return 0;
 }
 
-int restore_i387_ia32(struct _fpstate_ia32 __user *buf)
+int restore_i387_xstate_ia32(void __user *buf)
 {
         int err;
         struct task_struct *tsk = current;
+        struct _fpstate_ia32 __user *fp = (struct _fpstate_ia32 __user *) buf;
 
         if (HAVE_HWFP)
                 clear_fpu(tsk);
 
+        if (!buf) {
+                if (used_math()) {
+                        clear_fpu(tsk);
+                        clear_used_math();
+                }
+
+                return 0;
+        } else
+                if (!access_ok(VERIFY_READ, buf, sig_xstate_ia32_size))
+                        return -EACCES;
+
         if (!used_math()) {
                 err = init_fpu(tsk);
                 if (err)
@@ -518,13 +536,13 @@ int restore_i387_ia32(struct _fpstate_ia32 __user *buf)
 
         if (HAVE_HWFP) {
                 if (cpu_has_fxsr)
-                        err = restore_i387_fxsave(buf);
+                        err = restore_i387_fxsave(fp);
                 else
-                        err = restore_i387_fsave(buf);
+                        err = restore_i387_fsave(fp);
         } else {
                 err = fpregs_soft_set(current, NULL,
                                       0, sizeof(struct user_i387_ia32_struct),
-                                      NULL, buf) != 0;
+                                      NULL, fp) != 0;
         }
         set_used_math();