new helpers: __save_altstack/__compat_save_altstack, switch x86 and um to those

note that they are relying on access_ok() already checked by caller.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 7 deletions

diff --git a/arch/x86/um/signal.c b/arch/x86/um/signal.c
index bdaa08cfbcf4..71cef48ea5cd 100644
--- a/arch/x86/um/signal.c
+++ b/arch/x86/um/signal.c
@@ -342,9 +342,7 @@ static int copy_ucontext_to_user(struct ucontext __user *uc,
 {
         int err = 0;
 
-        err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
-        err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
-        err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
+        err |= __save_altstack(&uc->uc_stack, sp);
         err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, 0);
         err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
         return err;
@@ -529,10 +527,7 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
         /* 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(PT_REGS_SP(regs)),
-                          &frame->uc.uc_stack.ss_flags);
-        err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
+        err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));
         err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
                                set->sig[0]);
         err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate);