x86-64: Clean up 'save/restore_i387()' usage

[platform/adaptation/renesas_rcar/renesas_kernel.git] / arch / x86 / kernel / signal_64.c

diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index 827179c..b45ef8d 100644 (file)
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -53,6 +53,59 @@ sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
        return do_sigaltstack(uss, uoss, regs->sp);
 }
 
+/*
+ * 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;
+       }
+       return restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
+}
 
 /*
  * Do a signal return; undo the signal stack.
@@ -285,14 +338,6 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
           even if the handler happens to be interrupting 32-bit code. */
        regs->cs = __USER_CS;
 
-       /* This, by contrast, has nothing to do with segment registers -
-          see include/asm-x86_64/uaccess.h for details. */
-       set_fs(USER_DS);
-
-       regs->flags &= ~(X86_EFLAGS_TF | X86_EFLAGS_DF);
-       if (test_thread_flag(TIF_SINGLESTEP))
-               ptrace_notify(SIGTRAP);
-
        return 0;
 
 give_sigsegv:
@@ -380,6 +425,28 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
        ret = setup_rt_frame(sig, ka, info, oldset, regs);
 
        if (ret == 0) {
+               /*
+                * This has nothing to do with segment registers,
+                * despite the name.  This magic affects uaccess.h
+                * macros' behavior.  Reset it to the normal setting.
+                */
+               set_fs(USER_DS);
+
+               /*
+                * Clear the direction flag as per the ABI for function entry.
+                */
+               regs->flags &= ~X86_EFLAGS_DF;
+
+               /*
+                * Clear TF when entering the signal handler, but
+                * notify any tracer that was single-stepping it.
+                * The tracer may want to single-step inside the
+                * handler too.
+                */
+               regs->flags &= ~X86_EFLAGS_TF;
+               if (test_thread_flag(TIF_SINGLESTEP))
+                       ptrace_notify(SIGTRAP);
+
                spin_lock_irq(&current->sighand->siglock);
                sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
                if (!(ka->sa.sa_flags & SA_NODEFER))
@@ -413,7 +480,7 @@ static void do_signal(struct pt_regs *regs)
        if (!user_mode(regs))
                return;
 
-       if (test_thread_flag(TIF_RESTORE_SIGMASK))
+       if (current_thread_info()->status & TS_RESTORE_SIGMASK)
                oldset = &current->saved_sigmask;
        else
                oldset = &current->blocked;
@@ -430,11 +497,13 @@ static void do_signal(struct pt_regs *regs)
 
                /* Whee!  Actually deliver the signal.  */
                if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
-                       /* a signal was successfully delivered; the saved
+                       /*
+                        * A signal was successfully delivered; the saved
                         * sigmask will have been stored in the signal frame,
                         * and will be restored by sigreturn, so we can simply
-                        * clear the TIF_RESTORE_SIGMASK flag */
-                       clear_thread_flag(TIF_RESTORE_SIGMASK);
+                        * clear the TS_RESTORE_SIGMASK flag.
+                        */
+                       current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
                }
                return;
        }
@@ -462,8 +531,8 @@ static void do_signal(struct pt_regs *regs)
         * If there's no signal to deliver, we just put the saved sigmask
         * back.
         */
-       if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
-               clear_thread_flag(TIF_RESTORE_SIGMASK);
+       if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
+               current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
        }
 }
@@ -471,12 +540,6 @@ static void do_signal(struct pt_regs *regs)
 void do_notify_resume(struct pt_regs *regs, void *unused,
                      __u32 thread_info_flags)
 {
-       /* Pending single-step? */
-       if (thread_info_flags & _TIF_SINGLESTEP) {
-               regs->flags |= X86_EFLAGS_TF;
-               clear_thread_flag(TIF_SINGLESTEP);
-       }
-
 #ifdef CONFIG_X86_MCE
        /* notify userspace of pending MCEs */
        if (thread_info_flags & _TIF_MCE_NOTIFY)
@@ -484,11 +547,8 @@ void do_notify_resume(struct pt_regs *regs, void *unused,
 #endif /* CONFIG_X86_MCE */
 
        /* deal with pending signal delivery */
-       if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
+       if (thread_info_flags & _TIF_SIGPENDING)
                do_signal(regs);
-
-       if (thread_info_flags & _TIF_HRTICK_RESCHED)
-               hrtick_resched();
 }
 
 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)