mips: switch to generic sigaltstack

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

arch/mips/Kconfig

@@ -41,6 +41,7 @@ config MIPS
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_REL if MODULES
 	select MODULES_USE_ELF_RELA if MODULES && 64BIT
+	select GENERIC_SIGALTSTACK
 
 menu "Machine selection"
 

arch/mips/include/asm/compat.h

@@ -288,6 +288,14 @@ struct compat_shmid64_ds {
 	compat_ulong_t	__unused2;
 };
 
+/* MIPS has unusual order of fields in stack_t */
+typedef struct compat_sigaltstack {
+	compat_uptr_t			ss_sp;
+	compat_size_t			ss_size;
+	int				ss_flags;
+} compat_stack_t;
+#define compat_sigaltstack compat_sigaltstack
+
 static inline int is_compat_task(void)
 {
 	return test_thread_flag(TIF_32BIT_ADDR);

arch/mips/kernel/scall64-n32.S

@@ -233,7 +233,7 @@ EXPORT(sysn32_call_table)
 	PTR	compat_sys_rt_sigtimedwait
 	PTR	sys_32_rt_sigqueueinfo
 	PTR	sysn32_rt_sigsuspend
-	PTR	sys32_sigaltstack
+	PTR	compat_sys_sigaltstack
 	PTR	compat_sys_utime		/* 6130 */
 	PTR	sys_mknod
 	PTR	sys_32_personality

arch/mips/kernel/scall64-o32.S

@@ -398,7 +398,7 @@ sys_call_table:
 	PTR	sys_getcwd
 	PTR	sys_capget
 	PTR	sys_capset			/* 4205 */
-	PTR	sys32_sigaltstack
+	PTR	compat_sys_sigaltstack
 	PTR	sys_32_sendfile
 	PTR	sys_ni_syscall
 	PTR	sys_ni_syscall

arch/mips/kernel/signal.c

@@ -313,15 +313,6 @@ SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
 }
 #endif
 
-asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
-{
-	const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
-	stack_t __user *uoss = (stack_t __user *) regs.regs[5];
-	unsigned long usp = regs.regs[29];
-
-	return do_sigaltstack(uss, uoss, usp);
-}
-
 #ifdef CONFIG_TRAD_SIGNALS
 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 {
@@ -378,9 +369,8 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	else if (sig)
 		force_sig(sig, current);
 
-	/* It is more difficult to avoid calling this function than to
-	   call it and ignore errors.  */
-	do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]);
+	if (restore_altstack(&frame->rs_uc.uc_stack))
+		goto badframe;
 
 	/*
 	 * Don't let your children do this ...
@@ -457,12 +447,7 @@ static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
 	/* Create the ucontext.  */
 	err |= __put_user(0, &frame->rs_uc.uc_flags);
 	err |= __put_user(NULL, &frame->rs_uc.uc_link);
-	err |= __put_user((void __user *)current->sas_ss_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 |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
 	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 

arch/mips/kernel/signal32.c

@@ -61,17 +61,10 @@ struct sigaction32 {
 	compat_sigset_t		sa_mask;
 };
 
-/* IRIX compatible stack_t  */
-typedef struct sigaltstack32 {
-	s32 ss_sp;
-	compat_size_t ss_size;
-	int ss_flags;
-} stack32_t;
-
 struct ucontext32 {
 	u32                 uc_flags;
 	s32                 uc_link;
-	stack32_t           uc_stack;
+	compat_stack_t      uc_stack;
 	struct sigcontext32 uc_mcontext;
 	compat_sigset_t     uc_sigmask;   /* mask last for extensibility */
 };
@@ -350,45 +343,6 @@ SYSCALL_DEFINE3(32_sigaction, long, sig, const struct sigaction32 __user *, act,
 	return ret;
 }
 
-asmlinkage int sys32_sigaltstack(nabi_no_regargs struct pt_regs regs)
-{
-	const stack32_t __user *uss = (const stack32_t __user *) regs.regs[4];
-	stack32_t __user *uoss = (stack32_t __user *) regs.regs[5];
-	unsigned long usp = regs.regs[29];
-	stack_t kss, koss;
-	int ret, err = 0;
-	mm_segment_t old_fs = get_fs();
-	s32 sp;
-
-	if (uss) {
-		if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
-			return -EFAULT;
-		err |= __get_user(sp, &uss->ss_sp);
-		kss.ss_sp = (void __user *) (long) sp;
-		err |= __get_user(kss.ss_size, &uss->ss_size);
-		err |= __get_user(kss.ss_flags, &uss->ss_flags);
-		if (err)
-			return -EFAULT;
-	}
-
-	set_fs(KERNEL_DS);
-	ret = do_sigaltstack(uss ? (stack_t __user *)&kss : NULL,
-			     uoss ? (stack_t __user *)&koss : NULL, usp);
-	set_fs(old_fs);
-
-	if (!ret && uoss) {
-		if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
-			return -EFAULT;
-		sp = (int) (unsigned long) koss.ss_sp;
-		err |= __put_user(sp, &uoss->ss_sp);
-		err |= __put_user(koss.ss_size, &uoss->ss_size);
-		err |= __put_user(koss.ss_flags, &uoss->ss_flags);
-		if (err)
-			return -EFAULT;
-	}
-	return ret;
-}
-
 int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
 {
 	int err;
@@ -490,10 +444,7 @@ asmlinkage void sys32_sigreturn(nabi_no_regargs struct pt_regs regs)
 asmlinkage void sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 {
 	struct rt_sigframe32 __user *frame;
-	mm_segment_t old_fs;
 	sigset_t set;
-	stack_t st;
-	s32 sp;
 	int sig;
 
 	frame = (struct rt_sigframe32 __user *) regs.regs[29];
@@ -510,22 +461,9 @@ asmlinkage void sys32_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))
-		goto badframe;
-	if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
+	if (compat_restore_altstack(&frame->rs_uc.uc_stack))
 		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 ...
 	 */
@@ -590,7 +528,6 @@ static int setup_rt_frame_32(void *sig_return, struct k_sigaction *ka,
 {
 	struct rt_sigframe32 __user *frame;
 	int err = 0;
-	s32 sp;
 
 	frame = get_sigframe(ka, regs, sizeof(*frame));
 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
@@ -602,13 +539,7 @@ static int setup_rt_frame_32(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_sigcontext32(regs, &frame->rs_uc.uc_mcontext);
 	err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
 

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);