1 files changed, 7 insertions, 26 deletions

diff --git a/arch/x86/um/signal_64.c b/arch/x86/um/signal_64.c
index 4e5b9b07a8c7..74c2598b0b31 100644
--- a/arch/x86/um/signal_64.c
+++ b/arch/x86/um/signal_64.c
@@ -68,7 +68,7 @@ static int copy_sc_from_user(struct pt_regs *regs,
 
 static int copy_sc_to_user(struct sigcontext __user *to,
                            struct _fpstate __user *to_fp, struct pt_regs *regs,
-                           unsigned long mask, unsigned long sp)
+                           unsigned long mask)
 {
         struct faultinfo * fi = &current->thread.arch.faultinfo;
         struct sigcontext sc;
@@ -81,11 +81,7 @@ static int copy_sc_to_user(struct sigcontext __user *to,
         PUTREG(DI, di);
         PUTREG(SI, si);
         PUTREG(BP, bp);
-        /*
-         * Must use original RSP, which is passed in, rather than what's in
-         * signal frame.
-         */
-        sc.sp = sp;
+        PUTREG(SP, sp);
         PUTREG(BX, bx);
         PUTREG(DX, dx);
         PUTREG(CX, cx);
@@ -141,7 +137,6 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
                           siginfo_t *info, sigset_t *set)
 {
         struct rt_sigframe __user *frame;
-        unsigned long save_sp = PT_REGS_RSP(regs);
         int err = 0;
         struct task_struct *me = current;
 
@@ -159,26 +154,15 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
                         goto out;
         }
 
-        /*
-         * Update SP now because the page fault handler refuses to extend
-         * the stack if the faulting address is too far below the current
-         * SP, which frame now certainly is.  If there's an error, the original
-         * value is restored on the way out.
-         * When writing the sigcontext to the stack, we have to write the
-         * original value, so that's passed to copy_sc_to_user, which does
-         * the right thing with it.
-         */
-        PT_REGS_RSP(regs) = (unsigned long) frame;
-
         /* Create the ucontext.  */
         err |= __put_user(0, &frame->uc.uc_flags);
         err |= __put_user(0, &frame->uc.uc_link);
         err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
-        err |= __put_user(sas_ss_flags(save_sp),
+        err |= __put_user(sas_ss_flags(PT_REGS_RSP(regs)),
                           &frame->uc.uc_stack.ss_flags);
         err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
         err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
-                               set->sig[0], save_sp);
+                               set->sig[0]);
         err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate);
         if (sizeof(*set) == 16) {
                 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
@@ -197,10 +181,10 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
                 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
         else
                 /* could use a vstub here */
-                goto restore_sp;
+                return err;
 
         if (err)
-                goto restore_sp;
+                return err;
 
         /* Set up registers for signal handler */
         {
@@ -209,6 +193,7 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
                         sig = ed->signal_invmap[sig];
         }
 
+        PT_REGS_RSP(regs) = (unsigned long) frame;
         PT_REGS_RDI(regs) = sig;
         /* In case the signal handler was declared without prototypes */
         PT_REGS_RAX(regs) = 0;
@@ -222,10 +207,6 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
         PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler;
  out:
         return err;
-
-restore_sp:
-        PT_REGS_RSP(regs) = save_sp;
-        return err;
 }
 
 long sys_rt_sigreturn(struct pt_regs *regs)