microblaze: clean up signal handling

When legacy signal handling is disabled, the
arch/microblaze/kernel/signal.c implementation can
be much simpler, as most of it is handled generically
from kernel/signal.c.

This is also a prerequisite for using the generic
asm/unistd.h, which does not provide __NR_sigreturn,
because this macro is referenced by the current signal.c
implementation.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michal Simek <monstr@monstr.eu>

4 files changed, 39 insertions, 170 deletions

diff --git a/arch/microblaze/kernel/entry-nommu.S b/arch/microblaze/kernel/entry-nommu.S
index 1fce6b803f54..2eaf3946cb42 100644
--- a/arch/microblaze/kernel/entry-nommu.S
+++ b/arch/microblaze/kernel/entry-nommu.S
@@ -563,18 +563,10 @@ sys_execve_wrapper:
         brid    sys_execve
         addk    r8, r1, r0
 
-sys_sigreturn_wrapper:
-        brid    sys_sigreturn
-        addk    r5, r1, r0
-
 sys_rt_sigreturn_wrapper:
         brid    sys_rt_sigreturn
         addk    r5, r1, r0
 
-sys_sigsuspend_wrapper:
-        brid    sys_rt_sigsuspend
-        addk    r6, r1, r0
-
 sys_rt_sigsuspend_wrapper:
         brid    sys_rt_sigsuspend
         addk    r7, r1, r0
diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index 91a0e7b185dd..ea7107652d8d 100644
--- a/arch/microblaze/kernel/entry.S
+++ b/arch/microblaze/kernel/entry.S
@@ -449,17 +449,6 @@ C_ENTRY(sys_execve_wrapper):
         brid    sys_execve;     /* Do real work (tail-call).*/
         nop;
 
-C_ENTRY(sys_sigsuspend_wrapper):
-        swi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
-        swi     r4, r1, PTO+PT_R4;
-        la      r6, r1, PTO;            /* add user context as 2nd arg */
-        bralid  r15, sys_sigsuspend; /* Do real work.*/
-        nop;
-        lwi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
-        lwi     r4, r1, PTO+PT_R4;
-        bri ret_from_trap /* fall through will not work here due to align */
-        nop;
-
 C_ENTRY(sys_rt_sigsuspend_wrapper):
         swi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
         swi     r4, r1, PTO+PT_R4;
@@ -471,18 +460,6 @@ C_ENTRY(sys_rt_sigsuspend_wrapper):
         bri ret_from_trap /* fall through will not work here due to align */
         nop;
 
-
-C_ENTRY(sys_sigreturn_wrapper):
-        swi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
-        swi     r4, r1, PTO+PT_R4;
-        la      r5, r1, PTO;            /* add user context as 1st arg */
-        brlid   r15, sys_sigreturn;     /* Do real work.*/
-        nop;
-        lwi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
-        lwi     r4, r1, PTO+PT_R4;
-        bri ret_from_trap /* fall through will not work here due to align */
-        nop;
-
 C_ENTRY(sys_rt_sigreturn_wrapper):
         swi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
         swi     r4, r1, PTO+PT_R4;
diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
index 4c0e6521b114..2e5862c3002a 100644
--- a/arch/microblaze/kernel/signal.c
+++ b/arch/microblaze/kernel/signal.c
@@ -45,89 +45,6 @@
 
 asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_sycall);
 
-/*
- * Atomically swap in the new signal mask, and wait for a signal.
- */
-asmlinkage int
-sys_sigsuspend(old_sigset_t mask, struct pt_regs *regs)
-{
-        sigset_t saveset;
-
-        mask &= _BLOCKABLE;
-        spin_lock_irq(&current->sighand->siglock);
-        saveset = current->blocked;
-        siginitset(&current->blocked, mask);
-        recalc_sigpending();
-        spin_unlock_irq(&current->sighand->siglock);
-
-        regs->r3 = -EINTR;
-        while (1) {
-                current->state = TASK_INTERRUPTIBLE;
-                schedule();
-                if (do_signal(regs, &saveset, 1))
-                        return -EINTR;
-        }
-}
-
-asmlinkage int
-sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize,
-                struct pt_regs *regs)
-{
-        sigset_t saveset, newset;
-
-        /* XXX: Don't preclude handling different sized sigset_t's. */
-        if (sigsetsize != sizeof(sigset_t))
-                return -EINVAL;
-
-        if (copy_from_user(&newset, unewset, sizeof(newset)))
-                return -EFAULT;
-        sigdelsetmask(&newset, ~_BLOCKABLE);
-        spin_lock_irq(&current->sighand->siglock);
-        saveset = current->blocked;
-        current->blocked = newset;
-        recalc_sigpending();
-        spin_unlock_irq(&current->sighand->siglock);
-
-        regs->r3 = -EINTR;
-        while (1) {
-                current->state = TASK_INTERRUPTIBLE;
-                schedule();
-                if (do_signal(regs, &saveset, 1))
-                        return -EINTR;
-        }
-}
-
-asmlinkage int
-sys_sigaction(int sig, const struct old_sigaction *act,
-                struct old_sigaction *oact)
-{
-        struct k_sigaction new_ka, old_ka;
-        int ret;
-
-        if (act) {
-                old_sigset_t mask;
-                if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
-                        __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
-                        __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
-                        return -EFAULT;
-                __get_user(new_ka.sa.sa_flags, &act->sa_flags);
-                __get_user(mask, &act->sa_mask);
-                siginitset(&new_ka.sa.sa_mask, mask);
-        }
-
-        ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
-
-        if (!ret && oact) {
-                if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
-                        __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
-                        __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
-                        return -EFAULT;
-                __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
-                __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
-        }
-
-        return ret;
-}
 
 asmlinkage int
 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
@@ -139,7 +56,6 @@ sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 /*
  * Do a signal return; undo the signal stack.
  */
-
 struct sigframe {
         struct sigcontext sc;
         unsigned long extramask[_NSIG_WORDS-1];
@@ -176,40 +92,7 @@ static int restore_sigcontext(struct pt_regs *regs,
         return err;
 }
 
-asmlinkage int sys_sigreturn(struct pt_regs *regs)
-{
-        struct sigframe *frame =
-                        (struct sigframe *)(regs->r1 + STATE_SAVE_ARG_SPACE);
-
-        sigset_t set;
-        int rval;
-
-        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
-                goto badframe;
-
-        if (__get_user(set.sig[0], &frame->sc.oldmask)
-                || (_NSIG_WORDS > 1
-                && __copy_from_user(&set.sig[1], &frame->extramask,
-                                        sizeof(frame->extramask))))
-                goto badframe;
-
-        sigdelsetmask(&set, ~_BLOCKABLE);
-
-        spin_lock_irq(&current->sighand->siglock);
-        current->blocked = set;
-        recalc_sigpending();
-        spin_unlock_irq(&current->sighand->siglock);
-
-        if (restore_sigcontext(regs, &frame->sc, &rval))
-                goto badframe;
-        return rval;
-
-badframe:
-        force_sig(SIGSEGV, current);
-        return 0;
-}
-
-asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
+asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
 {
         struct rt_sigframe __user *frame =
                 (struct rt_sigframe __user *)(regs->r1 + STATE_SAVE_ARG_SPACE);
@@ -324,21 +207,17 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
         /* Set up to return from userspace. If provided, use a stub
          already in userspace. */
         /* minus 8 is offset to cater for "rtsd r15,8" */
-        if (ka->sa.sa_flags & SA_RESTORER) {
-                regs->r15 = ((unsigned long)ka->sa.sa_restorer)-8;
-        } else {
-                /* addi r12, r0, __NR_sigreturn */
-                err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
-                                frame->tramp + 0);
-                /* brki r14, 0x8 */
-                err |= __put_user(0xb9cc0008, frame->tramp + 1);
-
-                /* Return from sighandler will jump to the tramp.
-                 Negative 8 offset because return is rtsd r15, 8 */
-                regs->r15 = ((unsigned long)frame->tramp)-8;
-
-                __invalidate_cache_sigtramp((unsigned long)frame->tramp);
-        }
+        /* addi r12, r0, __NR_sigreturn */
+        err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
+                        frame->tramp + 0);
+        /* brki r14, 0x8 */
+        err |= __put_user(0xb9cc0008, frame->tramp + 1);
+
+        /* Return from sighandler will jump to the tramp.
+         Negative 8 offset because return is rtsd r15, 8 */
+        regs->r15 = ((unsigned long)frame->tramp)-8;
+
+        __invalidate_cache_sigtramp((unsigned long)frame->tramp);
 
         if (err)
                 goto give_sigsegv;
@@ -405,7 +284,7 @@ do_restart:
  * OK, we're invoking a handler
  */
 
-static void
+static int
 handle_signal(unsigned long sig, struct k_sigaction *ka,
                 siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
 {
@@ -426,6 +305,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
                 recalc_sigpending();
                 spin_unlock_irq(&current->sighand->siglock);
         }
+        return 1;
 }
 
 /*
@@ -456,7 +336,9 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_syscall)
         if (kernel_mode(regs))
                 return 1;
 
-        if (!oldset)
+        if (current_thread_info()->status & TS_RESTORE_SIGMASK)
+                oldset = &current->saved_sigmask;
+        else
                 oldset = &current->blocked;
 
         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
@@ -464,13 +346,31 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_syscall)
                 /* Whee! Actually deliver the signal. */
                 if (in_syscall)
                         handle_restart(regs, &ka, 1);
-                handle_signal(signr, &ka, &info, oldset, regs);
+                if (handle_signal(signr, &ka, &info, oldset, regs)) {
+                        /*
+                         * A signal was successfully delivered; the saved
+                         * sigmask will have been stored in the signal frame,
+                         * and will be restored by sigreturn, so we can simply
+                         * clear the TS_RESTORE_SIGMASK flag.
+                         */
+                        current_thread_info()->status &=
+                            ~TS_RESTORE_SIGMASK;
+                }
                 return 1;
         }
 
         if (in_syscall)
                 handle_restart(regs, NULL, 0);
 
+        /*
+         * If there's no signal to deliver, we just put the saved sigmask
+         * back.
+         */
+        if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
+                current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
+                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
+        }
+
         /* Did we come from a system call? */
         return 0;
 }
diff --git a/arch/microblaze/kernel/syscall_table.S b/arch/microblaze/kernel/syscall_table.S
index 376d1789f7c0..ef0e8932af33 100644
--- a/arch/microblaze/kernel/syscall_table.S
+++ b/arch/microblaze/kernel/syscall_table.S
@@ -71,12 +71,12 @@ ENTRY(sys_call_table)
         .long sys_getppid
         .long sys_getpgrp               /* 65 */
         .long sys_setsid
-        .long sys_sigaction
+        .long sys_ni_syscall            /* sys_sigaction */
         .long sys_sgetmask
         .long sys_ssetmask
         .long sys_setreuid              /* 70 */
         .long sys_setregid
-        .long sys_sigsuspend_wrapper
+        .long sys_ni_syscall            /* sys_sigsuspend_wrapper */
         .long sys_sigpending
         .long sys_sethostname
         .long sys_setrlimit             /* 75 */
@@ -123,7 +123,7 @@ ENTRY(sys_call_table)
         .long sys_sysinfo
         .long sys_ipc
         .long sys_fsync
-        .long sys_sigreturn_wrapper
+        .long sys_ni_syscall            /* sys_sigreturn_wrapper */
         .long sys_clone_wrapper         /* 120 */
         .long sys_setdomainname
         .long sys_newuname