1 files changed, 26 insertions, 26 deletions

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index e5042463c1bc..3e581865c8e2 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -61,8 +61,7 @@
         regs->seg = GET_SEG(seg) | 3;                   \
 } while (0)
 
-int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
-                       unsigned long *pax)
+int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 {
         void __user *buf;
         unsigned int tmpflags;
@@ -81,7 +80,7 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
 #endif /* CONFIG_X86_32 */
 
                 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
-                COPY(dx); COPY(cx); COPY(ip);
+                COPY(dx); COPY(cx); COPY(ip); COPY(ax);
 
 #ifdef CONFIG_X86_64
                 COPY(r8);
@@ -94,27 +93,20 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
                 COPY(r15);
 #endif /* CONFIG_X86_64 */
 
-#ifdef CONFIG_X86_32
                 COPY_SEG_CPL3(cs);
                 COPY_SEG_CPL3(ss);
-#else /* !CONFIG_X86_32 */
-                /* Kernel saves and restores only the CS segment register on signals,
-                 * which is the bare minimum needed to allow mixed 32/64-bit code.
-                 * App's signal handler can save/restore other segments if needed. */
-                COPY_SEG_CPL3(cs);
-#endif /* CONFIG_X86_32 */
 
                 get_user_ex(tmpflags, &sc->flags);
                 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
                 regs->orig_ax = -1;             /* disable syscall checks */
 
                 get_user_ex(buf, &sc->fpstate);
-
-                get_user_ex(*pax, &sc->ax);
         } get_user_catch(err);
 
         err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));
 
+        force_iret();
+
         return err;
 }
 
@@ -162,8 +154,9 @@ int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 #else /* !CONFIG_X86_32 */
                 put_user_ex(regs->flags, &sc->flags);
                 put_user_ex(regs->cs, &sc->cs);
-                put_user_ex(0, &sc->gs);
-                put_user_ex(0, &sc->fs);
+                put_user_ex(0, &sc->__pad2);
+                put_user_ex(0, &sc->__pad1);
+                put_user_ex(regs->ss, &sc->ss);
 #endif /* CONFIG_X86_32 */
 
                 put_user_ex(fpstate, &sc->fpstate);
@@ -457,9 +450,19 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
 
         regs->sp = (unsigned long)frame;
 
-        /* Set up the CS register to run signal handlers in 64-bit mode,
-           even if the handler happens to be interrupting 32-bit code. */
+        /*
+         * Set up the CS and SS registers to run signal handlers in
+         * 64-bit mode, even if the handler happens to be interrupting
+         * 32-bit or 16-bit code.
+         *
+         * SS is subtle.  In 64-bit mode, we don't need any particular
+         * SS descriptor, but we do need SS to be valid.  It's possible
+         * that the old SS is entirely bogus -- this can happen if the
+         * signal we're trying to deliver is #GP or #SS caused by a bad
+         * SS value.
+         */
         regs->cs = __USER_CS;
+        regs->ss = __USER_DS;
 
         return 0;
 }
@@ -539,7 +542,6 @@ asmlinkage unsigned long sys_sigreturn(void)
 {
         struct pt_regs *regs = current_pt_regs();
         struct sigframe __user *frame;
-        unsigned long ax;
         sigset_t set;
 
         frame = (struct sigframe __user *)(regs->sp - 8);
@@ -553,9 +555,9 @@ asmlinkage unsigned long sys_sigreturn(void)
 
         set_current_blocked(&set);
 
-        if (restore_sigcontext(regs, &frame->sc, &ax))
+        if (restore_sigcontext(regs, &frame->sc))
                 goto badframe;
-        return ax;
+        return regs->ax;
 
 badframe:
         signal_fault(regs, frame, "sigreturn");
@@ -568,7 +570,6 @@ asmlinkage long sys_rt_sigreturn(void)
 {
         struct pt_regs *regs = current_pt_regs();
         struct rt_sigframe __user *frame;
-        unsigned long ax;
         sigset_t set;
 
         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
@@ -579,13 +580,13 @@ asmlinkage long sys_rt_sigreturn(void)
 
         set_current_blocked(&set);
 
-        if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
+        if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
                 goto badframe;
 
         if (restore_altstack(&frame->uc.uc_stack))
                 goto badframe;
 
-        return ax;
+        return regs->ax;
 
 badframe:
         signal_fault(regs, frame, "rt_sigreturn");
@@ -679,7 +680,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
                  * Ensure the signal handler starts with the new fpu state.
                  */
                 if (used_math())
-                        drop_init_fpu(current);
+                        fpu_reset_state(current);
         }
         signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP));
 }
@@ -780,7 +781,6 @@ asmlinkage long sys32_x32_rt_sigreturn(void)
         struct pt_regs *regs = current_pt_regs();
         struct rt_sigframe_x32 __user *frame;
         sigset_t set;
-        unsigned long ax;
 
         frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
 
@@ -791,13 +791,13 @@ asmlinkage long sys32_x32_rt_sigreturn(void)
 
         set_current_blocked(&set);
 
-        if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
+        if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
                 goto badframe;
 
         if (compat_restore_altstack(&frame->uc.uc_stack))
                 goto badframe;
 
-        return ax;
+        return regs->ax;
 
 badframe:
         signal_fault(regs, frame, "x32 rt_sigreturn");