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>

5 files changed, 127 insertions, 135 deletions

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index a05bf0fb7415..c596eabbe98b 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -216,7 +216,7 @@ static int ia32_restore_sigcontext(struct pt_regs *regs,
                                    unsigned int *peax)
 {
         unsigned int tmpflags, gs, oldgs, err = 0;
-        struct _fpstate_ia32 __user *buf;
+        void __user *buf;
         u32 tmp;
 
         /* Always make any pending restarted system calls return -EINTR */
@@ -260,26 +260,12 @@ static int ia32_restore_sigcontext(struct pt_regs *regs,
 
         err |= __get_user(tmp, &sc->fpstate);
         buf = compat_ptr(tmp);
-        if (buf) {
-                if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
-                        goto badframe;
-                err |= restore_i387_ia32(buf);
-        } else {
-                struct task_struct *me = current;
-
-                if (used_math()) {
-                        clear_fpu(me);
-                        clear_used_math();
-                }
-        }
+        err |= restore_i387_xstate_ia32(buf);
 
         err |= __get_user(tmp, &sc->ax);
         *peax = tmp;
 
         return err;
-
-badframe:
-        return 1;
 }
 
 asmlinkage long sys32_sigreturn(struct pt_regs *regs)
@@ -351,7 +337,7 @@ badframe:
  */
 
 static int ia32_setup_sigcontext(struct sigcontext_ia32 __user *sc,
-                                 struct _fpstate_ia32 __user *fpstate,
+                                 void __user *fpstate,
                                  struct pt_regs *regs, unsigned int mask)
 {
         int tmp, err = 0;
@@ -382,7 +368,7 @@ static int ia32_setup_sigcontext(struct sigcontext_ia32 __user *sc,
         err |= __put_user((u32)regs->flags, &sc->flags);
         err |= __put_user((u32)regs->sp, &sc->sp_at_signal);
 
-        tmp = save_i387_ia32(fpstate);
+        tmp = save_i387_xstate_ia32(fpstate);
         if (tmp < 0)
                 err = -EFAULT;
         else {
@@ -404,7 +390,7 @@ static int ia32_setup_sigcontext(struct sigcontext_ia32 __user *sc,
  */
 static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
                                  size_t frame_size,
-                                 struct _fpstate_ia32 **fpstate)
+                                 void **fpstate)
 {
         unsigned long sp;
 
@@ -441,7 +427,7 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka,
         struct sigframe __user *frame;
         void __user *restorer;
         int err = 0;
-        struct _fpstate_ia32 __user *fpstate = NULL;
+        void __user *fpstate = NULL;
 
         /* copy_to_user optimizes that into a single 8 byte store */
         static const struct {
@@ -529,7 +515,7 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
         struct rt_sigframe __user *frame;
         void __user *restorer;
         int err = 0;
-        struct _fpstate_ia32 __user *fpstate = NULL;
+        void __user *fpstate = NULL;
 
         /* __copy_to_user optimizes that into a single 8 byte store */
         static const struct {
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();
 
diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c
index 19a7a5669b5b..690cc616ac07 100644
--- a/arch/x86/kernel/signal_32.c
+++ b/arch/x86/kernel/signal_32.c
@@ -159,28 +159,14 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
         }
 
         {
-                struct _fpstate __user *buf;
+                void __user *buf;
 
                 err |= __get_user(buf, &sc->fpstate);
-                if (buf) {
-                        if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
-                                goto badframe;
-                        err |= restore_i387(buf);
-                } else {
-                        struct task_struct *me = current;
-
-                        if (used_math()) {
-                                clear_fpu(me);
-                                clear_used_math();
-                        }
-                }
+                err |= restore_i387_xstate(buf);
         }
 
         err |= __get_user(*pax, &sc->ax);
         return err;
-
-badframe:
-        return 1;
 }
 
 asmlinkage unsigned long sys_sigreturn(unsigned long __unused)
@@ -262,7 +248,7 @@ badframe:
  * Set up a signal frame.
  */
 static int
-setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
+setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
                  struct pt_regs *regs, unsigned long mask)
 {
         int tmp, err = 0;
@@ -289,7 +275,7 @@ setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
         err |= __put_user(regs->sp, &sc->sp_at_signal);
         err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
 
-        tmp = save_i387(fpstate);
+        tmp = save_i387_xstate(fpstate);
         if (tmp < 0)
                 err = 1;
         else
@@ -307,7 +293,7 @@ setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
  */
 static inline void __user *
 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
-             struct _fpstate **fpstate)
+             void **fpstate)
 {
         unsigned long sp;
 
@@ -356,7 +342,7 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
         void __user *restorer;
         int err = 0;
         int usig;
-        struct _fpstate __user *fpstate = NULL;
+        void __user *fpstate = NULL;
 
         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 
@@ -434,7 +420,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
         void __user *restorer;
         int err = 0;
         int usig;
-        struct _fpstate __user *fpstate = NULL;
+        void __user *fpstate = NULL;
 
         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 
diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index 0deab8eff33f..ddf6123a55c8 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -54,69 +54,6 @@ sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 }
 
 /*
- * Signal frame handlers.
- */
-
-static inline int save_i387(struct _fpstate __user *buf)
-{
-        struct task_struct *tsk = current;
-        int err = 0;
-
-        BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
-                        sizeof(tsk->thread.xstate->fxsave));
-
-        if ((unsigned long)buf % 16)
-                printk("save_i387: bad fpstate %p\n", buf);
-
-        if (!used_math())
-                return 0;
-        clear_used_math(); /* trigger finit */
-        if (task_thread_info(tsk)->status & TS_USEDFPU) {
-                err = save_i387_checking((struct i387_fxsave_struct __user *)
-                                         buf);
-                if (err)
-                        return err;
-                task_thread_info(tsk)->status &= ~TS_USEDFPU;
-                stts();
-        } else {
-                if (__copy_to_user(buf, &tsk->thread.xstate->fxsave,
-                                   sizeof(struct i387_fxsave_struct)))
-                        return -1;
-        }
-        return 1;
-}
-
-/*
- * This restores directly out of user space. Exceptions are handled.
- */
-static inline int restore_i387(struct _fpstate __user *buf)
-{
-        struct task_struct *tsk = current;
-        int err;
-
-        if (!used_math()) {
-                err = init_fpu(tsk);
-                if (err)
-                        return err;
-        }
-
-        if (!(task_thread_info(current)->status & TS_USEDFPU)) {
-                clts();
-                task_thread_info(current)->status |= TS_USEDFPU;
-        }
-        err = restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
-        if (unlikely(err)) {
-                /*
-                 * Encountered an error while doing the restore from the
-                 * user buffer, clear the fpu state.
-                 */
-                clear_fpu(tsk);
-                clear_used_math();
-        }
-        return err;
-}
-
-/*
  * Do a signal return; undo the signal stack.
  */
 static int
@@ -160,25 +97,11 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
         {
                 struct _fpstate __user * buf;
                 err |= __get_user(buf, &sc->fpstate);
-
-                if (buf) {
-                        if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
-                                goto badframe;
-                        err |= restore_i387(buf);
-                } else {
-                        struct task_struct *me = current;
-                        if (used_math()) {
-                                clear_fpu(me);
-                                clear_used_math();
-                        }
-                }
+                err |= restore_i387_xstate(buf);
         }
 
         err |= __get_user(*pax, &sc->ax);
         return err;
-
-badframe:
-        return 1;
 }
 
 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
@@ -276,7 +199,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
                            sigset_t *set, struct pt_regs * regs)
 {
         struct rt_sigframe __user *frame;
-        struct _fpstate __user *fp = NULL; 
+        void __user *fp = NULL;
         int err = 0;
         struct task_struct *me = current;
 
@@ -288,7 +211,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
                 if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
                         goto give_sigsegv;
 
-                if (save_i387(fp) < 0) 
+                if (save_i387_xstate(fp) < 0)
                         err |= -1; 
         } else
                 frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 7ad169e33528..608e72d7ca64 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -12,6 +12,85 @@
  */
 unsigned int pcntxt_hmask, pcntxt_lmask;
 
+#ifdef CONFIG_X86_64
+/*
+ * Signal frame handlers.
+ */
+
+int save_i387_xstate(void __user *buf)
+{
+        struct task_struct *tsk = current;
+        int err = 0;
+
+        if (!access_ok(VERIFY_WRITE, buf, sig_xstate_size))
+                return -EACCES;
+
+        BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
+                        sizeof(tsk->thread.xstate->fxsave));
+
+        if ((unsigned long)buf % 16)
+                printk("save_i387_xstate: bad fpstate %p\n", buf);
+
+        if (!used_math())
+                return 0;
+        clear_used_math(); /* trigger finit */
+        if (task_thread_info(tsk)->status & TS_USEDFPU) {
+                err = save_i387_checking((struct i387_fxsave_struct __user *)
+                                         buf);
+                if (err)
+                        return err;
+                task_thread_info(tsk)->status &= ~TS_USEDFPU;
+                stts();
+        } else {
+                if (__copy_to_user(buf, &tsk->thread.xstate->fxsave,
+                                   xstate_size))
+                        return -1;
+        }
+        return 1;
+}
+
+/*
+ * This restores directly out of user space. Exceptions are handled.
+ */
+int restore_i387_xstate(void __user *buf)
+{
+        struct task_struct *tsk = current;
+        int err;
+
+        if (!buf) {
+                if (used_math()) {
+                        clear_fpu(tsk);
+                        clear_used_math();
+                }
+
+                return 0;
+        } else
+                if (!access_ok(VERIFY_READ, buf, sig_xstate_size))
+                        return -EACCES;
+
+        if (!used_math()) {
+                err = init_fpu(tsk);
+                if (err)
+                        return err;
+        }
+
+        if (!(task_thread_info(current)->status & TS_USEDFPU)) {
+                clts();
+                task_thread_info(current)->status |= TS_USEDFPU;
+        }
+        err = fxrstor_checking((__force struct i387_fxsave_struct *)buf);
+        if (unlikely(err)) {
+                /*
+                 * Encountered an error while doing the restore from the
+                 * user buffer, clear the fpu state.
+                 */
+                clear_fpu(tsk);
+                clear_used_math();
+        }
+        return err;
+}
+#endif
+
 /*
  * Represents init state for the supported extended state.
  */