mips: switch to generic sigaltstack

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

1 files changed, 3 insertions, 35 deletions

diff --git a/arch/mips/kernel/signal_n32.c b/arch/mips/kernel/signal_n32.c
index 3574c145511b..e62e2bc63a81 100644
--- a/arch/mips/kernel/signal_n32.c
+++ b/arch/mips/kernel/signal_n32.c
@@ -50,18 +50,10 @@
 extern int setup_sigcontext(struct pt_regs *, struct sigcontext __user *);
 extern int restore_sigcontext(struct pt_regs *, struct sigcontext __user *);
 
-
-/* IRIX compatible stack_t  */
-typedef struct sigaltstack32 {
-	s32 ss_sp;
-	compat_size_t ss_size;
-	int ss_flags;
-} stack32_t;
-
 struct ucontextn32 {
 	u32                 uc_flags;
 	s32                 uc_link;
-	stack32_t           uc_stack;
+	compat_stack_t      uc_stack;
 	struct sigcontext   uc_mcontext;
 	compat_sigset_t     uc_sigmask;   /* mask last for extensibility */
 };
@@ -97,10 +89,7 @@ asmlinkage int sysn32_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 {
 	struct rt_sigframe_n32 __user *frame;
-	mm_segment_t old_fs;
 	sigset_t set;
-	stack_t st;
-	s32 sp;
 	int sig;
 
 	frame = (struct rt_sigframe_n32 __user *) regs.regs[29];
@@ -117,22 +106,8 @@ asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	else if (sig)
 		force_sig(sig, current);
 
-	/* The ucontext contains a stack32_t, so we must convert!  */
-	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
-		goto badframe;
-	st.ss_sp = (void __user *)(long) sp;
-	if (__get_user(st.ss_size, &frame->rs_uc.uc_stack.ss_size))
+	if (compat_restore_altstack(&frame->rs_uc.uc_stack))
 		goto badframe;
-	if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
-		goto badframe;
-
-	/* It is more difficult to avoid calling this function than to
-	   call it and ignore errors.  */
-	old_fs = get_fs();
-	set_fs(KERNEL_DS);
-	do_sigaltstack((stack_t __user *)&st, NULL, regs.regs[29]);
-	set_fs(old_fs);
-
 
 	/*
 	 * Don't let your children do this ...
@@ -153,7 +128,6 @@ static int setup_rt_frame_n32(void *sig_return, struct k_sigaction *ka,
 {
 	struct rt_sigframe_n32 __user *frame;
 	int err = 0;
-	s32 sp;
 
 	frame = get_sigframe(ka, regs, sizeof(*frame));
 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
@@ -165,13 +139,7 @@ static int setup_rt_frame_n32(void *sig_return, struct k_sigaction *ka,
 	/* Create the ucontext.  */
 	err |= __put_user(0, &frame->rs_uc.uc_flags);
 	err |= __put_user(0, &frame->rs_uc.uc_link);
-	sp = (int) (long) current->sas_ss_sp;
-	err |= __put_user(sp,
-	                  &frame->rs_uc.uc_stack.ss_sp);
-	err |= __put_user(sas_ss_flags(regs->regs[29]),
-	                  &frame->rs_uc.uc_stack.ss_flags);
-	err |= __put_user(current->sas_ss_size,
-	                  &frame->rs_uc.uc_stack.ss_size);
+	err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
 	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 	err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);