mips: switch to generic sigaltstack

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

7 files changed, 20 insertions, 127 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 2ac626ab9d43..a8a41e091d04 100644
--- a/arch/mips/Kconfig
+++ b/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"
 
diff --git a/arch/mips/include/asm/compat.h b/arch/mips/include/asm/compat.h
index 3c5d1464b7bd..ebaae9649f8a 100644
--- a/arch/mips/include/asm/compat.h
+++ b/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);
diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index c29ac197f446..7388e25984b2 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/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
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index cf3e75e46650..07fcd818ad3a 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/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
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index 4d790d1f03d6..eab30865b2bd 100644
--- a/arch/mips/kernel/signal.c
+++ b/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));
 
diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c
index da1b56a39ac7..c51e5df4297b 100644
--- a/arch/mips/kernel/signal32.c
+++ b/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 @@ badframe:
 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);
 
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);