microblaze_v8: Signal support

Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: John Linn <john.linn@xilinx.com>
Acked-by: John Williams <john.williams@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>

2 files changed, 703 insertions, 0 deletions

diff --git a/arch/microblaze/include/asm/signal.h b/arch/microblaze/include/asm/signal.h
new file mode 100644
index 000000000000..9676fad3486c
--- /dev/null
+++ b/arch/microblaze/include/asm/signal.h
@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2006 Atmark Techno, Inc.
+ *      Yasushi SHOJI <yashi@atmark-techno.com>
+ *      Tetsuya OHKAWA <tetsuya@atmark-techno.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#ifndef _ASM_MICROBLAZE_SIGNAL_H
+#define _ASM_MICROBLAZE_SIGNAL_H
+
+#define SIGHUP          1
+#define SIGINT          2
+#define SIGQUIT         3
+#define SIGILL          4
+#define SIGTRAP         5
+#define SIGABRT         6
+#define SIGIOT          6
+#define SIGBUS          7
+#define SIGFPE          8
+#define SIGKILL         9
+#define SIGUSR1         10
+#define SIGSEGV         11
+#define SIGUSR2         12
+#define SIGPIPE         13
+#define SIGALRM         14
+#define SIGTERM         15
+#define SIGSTKFLT       16
+#define SIGCHLD         17
+#define SIGCONT         18
+#define SIGSTOP         19
+#define SIGTSTP         20
+#define SIGTTIN         21
+#define SIGTTOU         22
+#define SIGURG          23
+#define SIGXCPU         24
+#define SIGXFSZ         25
+#define SIGVTALRM       26
+#define SIGPROF         27
+#define SIGWINCH        28
+#define SIGIO           29
+#define SIGPOLL         SIGIO
+/*
+#define SIGLOST         29
+*/
+#define SIGPWR          30
+#define SIGSYS          31
+#define SIGUNUSED       31
+
+/* These should not be considered constants from userland. */
+#define SIGRTMIN        32
+#define SIGRTMAX        _NSIG
+
+/*
+ * SA_FLAGS values:
+ *
+ * SA_ONSTACK indicates that a registered stack_t will be used.
+ * SA_RESTART flag to get restarting signals (which were the default long ago)
+ * SA_NOCLDSTOP flag to turn off SIGCHLD when children stop.
+ * SA_RESETHAND clears the handler when the signal is delivered.
+ * SA_NOCLDWAIT flag on SIGCHLD to inhibit zombies.
+ * SA_NODEFER prevents the current signal from being masked in the handler.
+ *
+ * SA_ONESHOT and SA_NOMASK are the historical Linux names for the Single
+ * Unix names RESETHAND and NODEFER respectively.
+ */
+#define SA_NOCLDSTOP    0x00000001
+#define SA_NOCLDWAIT    0x00000002
+#define SA_SIGINFO      0x00000004
+#define SA_ONSTACK      0x08000000
+#define SA_RESTART      0x10000000
+#define SA_NODEFER      0x40000000
+#define SA_RESETHAND    0x80000000
+
+#define SA_NOMASK       SA_NODEFER
+#define SA_ONESHOT      SA_RESETHAND
+
+#define SA_RESTORER     0x04000000
+
+/*
+ * sigaltstack controls
+ */
+#define SS_ONSTACK      1
+#define SS_DISABLE      2
+
+#define MINSIGSTKSZ     2048
+#define SIGSTKSZ        8192
+
+# ifndef __ASSEMBLY__
+# include <linux/types.h>
+# include <asm-generic/signal.h>
+
+/* Avoid too many header ordering problems. */
+struct siginfo;
+
+#  ifdef __KERNEL__
+/*
+ * Most things should be clean enough to redefine this at will, if care
+ * is taken to make libc match.
+ */
+#  define _NSIG         64
+#  define _NSIG_BPW     32
+#  define _NSIG_WORDS   (_NSIG / _NSIG_BPW)
+
+typedef unsigned long old_sigset_t; /* at least 32 bits */
+
+typedef struct {
+        unsigned long sig[_NSIG_WORDS];
+} sigset_t;
+
+struct old_sigaction {
+        __sighandler_t sa_handler;
+        old_sigset_t sa_mask;
+        unsigned long sa_flags;
+        void (*sa_restorer)(void);
+};
+
+struct sigaction {
+        __sighandler_t sa_handler;
+        unsigned long sa_flags;
+        void (*sa_restorer)(void);
+        sigset_t sa_mask; /* mask last for extensibility */
+};
+
+struct k_sigaction {
+        struct sigaction sa;
+};
+
+#  include <asm/sigcontext.h>
+#  undef __HAVE_ARCH_SIG_BITOPS
+
+#  define ptrace_signal_deliver(regs, cookie) do { } while (0)
+
+#  else /* !__KERNEL__ */
+
+/* Here we must cater to libcs that poke about in kernel headers. */
+
+#  define NSIG          32
+typedef unsigned long sigset_t;
+
+struct sigaction {
+        union {
+        __sighandler_t _sa_handler;
+        void (*_sa_sigaction)(int, struct siginfo *, void *);
+        } _u;
+        sigset_t sa_mask;
+        unsigned long sa_flags;
+        void (*sa_restorer)(void);
+};
+
+#  define sa_handler    _u._sa_handler
+#  define sa_sigaction  _u._sa_sigaction
+
+#  endif /* __KERNEL__ */
+
+typedef struct sigaltstack {
+        void *ss_sp;
+        int ss_flags;
+        size_t ss_size;
+} stack_t;
+
+# endif /* __ASSEMBLY__ */
+#endif /* _ASM_MICROBLAZE_SIGNAL_H */
diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
new file mode 100644
index 000000000000..ff347b98863a
--- /dev/null
+++ b/arch/microblaze/kernel/signal.c
@@ -0,0 +1,538 @@
+/*
+ * Signal handling
+ *
+ * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
+ * Copyright (C) 2008-2009 PetaLogix
+ * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
+ * Copyright (C) 2001 NEC Corporation
+ * Copyright (C) 2001 Miles Bader <miles@gnu.org>
+ * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
+ * Copyright (C) 1991,1992 Linus Torvalds
+ *
+ * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
+ *
+ * This file was was derived from the sh version, arch/sh/kernel/signal.c
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file COPYING in the main directory of this
+ * archive for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/ptrace.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/personality.h>
+#include <linux/percpu.h>
+#include <linux/linkage.h>
+#include <asm/entry.h>
+#include <asm/ucontext.h>
+#include <linux/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <linux/signal.h>
+#include <linux/syscalls.h>
+#include <asm/cacheflush.h>
+#include <asm/syscalls.h>
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+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,
+                struct pt_regs *regs)
+{
+        return do_sigaltstack(uss, uoss, regs->r1);
+}
+
+/*
+ * Do a signal return; undo the signal stack.
+ */
+
+struct sigframe {
+        struct sigcontext sc;
+        unsigned long extramask[_NSIG_WORDS-1];
+        unsigned long tramp[2]; /* signal trampoline */
+};
+
+struct rt_sigframe {
+        struct siginfo info;
+        struct ucontext uc;
+        unsigned long tramp[2]; /* signal trampoline */
+};
+
+static int
+restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *rval_p)
+{
+        unsigned int err = 0;
+
+#define COPY(x)         {err |= __get_user(regs->x, &sc->regs.x); }
+        COPY(r0);
+        COPY(r1);
+        COPY(r2);       COPY(r3);       COPY(r4);       COPY(r5);
+        COPY(r6);       COPY(r7);       COPY(r8);       COPY(r9);
+        COPY(r10);      COPY(r11);      COPY(r12);      COPY(r13);
+        COPY(r14);      COPY(r15);      COPY(r16);      COPY(r17);
+        COPY(r18);      COPY(r19);      COPY(r20);      COPY(r21);
+        COPY(r22);      COPY(r23);      COPY(r24);      COPY(r25);
+        COPY(r26);      COPY(r27);      COPY(r28);      COPY(r29);
+        COPY(r30);      COPY(r31);
+        COPY(pc);       COPY(ear);      COPY(esr);      COPY(fsr);
+#undef COPY
+
+        *rval_p = regs->r3;
+
+        return err;
+}
+
+asmlinkage int sys_sigreturn(struct pt_regs *regs)
+{
+        struct sigframe *frame = (struct sigframe *)regs->r1;
+        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)
+{
+        struct rt_sigframe *frame = (struct rt_sigframe *)regs->r1;
+        sigset_t set;
+        stack_t st;
+        int rval;
+
+        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+                goto badframe;
+
+        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+                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->uc.uc_mcontext, &rval))
+                goto badframe;
+
+        if (__copy_from_user((void *)&st, &frame->uc.uc_stack, sizeof(st)))
+                goto badframe;
+        /* It is more difficult to avoid calling this function than to
+         call it and ignore errors. */
+        do_sigaltstack(&st, NULL, regs->r1);
+
+        return rval;
+
+badframe:
+        force_sig(SIGSEGV, current);
+        return 0;
+}
+
+/*
+ * Set up a signal frame.
+ */
+
+static int
+setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
+                unsigned long mask)
+{
+        int err = 0;
+
+#define COPY(x)         {err |= __put_user(regs->x, &sc->regs.x); }
+        COPY(r0);
+        COPY(r1);
+        COPY(r2);       COPY(r3);       COPY(r4);       COPY(r5);
+        COPY(r6);       COPY(r7);       COPY(r8);       COPY(r9);
+        COPY(r10);      COPY(r11);      COPY(r12);      COPY(r13);
+        COPY(r14);      COPY(r15);      COPY(r16);      COPY(r17);
+        COPY(r18);      COPY(r19);      COPY(r20);      COPY(r21);
+        COPY(r22);      COPY(r23);      COPY(r24);      COPY(r25);
+        COPY(r26);      COPY(r27);      COPY(r28);      COPY(r29);
+        COPY(r30);      COPY(r31);
+        COPY(pc);       COPY(ear);      COPY(esr);      COPY(fsr);
+#undef COPY
+
+        err |= __put_user(mask, &sc->oldmask);
+
+        return err;
+}
+
+/*
+ * Determine which stack to use..
+ */
+static inline void *
+get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
+{
+        /* Default to using normal stack */
+        unsigned long sp = regs->r1;
+
+        if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack(sp))
+                sp = current->sas_ss_sp + current->sas_ss_size;
+
+        return (void *)((sp - frame_size) & -8UL);
+}
+
+static void setup_frame(int sig, struct k_sigaction *ka,
+                        sigset_t *set, struct pt_regs *regs)
+{
+        struct sigframe *frame;
+        int err = 0;
+        int signal;
+
+        frame = get_sigframe(ka, regs, sizeof(*frame));
+
+        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+                goto give_sigsegv;
+
+        signal = current_thread_info()->exec_domain
+                && current_thread_info()->exec_domain->signal_invmap
+                && sig < 32
+                ? current_thread_info()->exec_domain->signal_invmap[sig]
+                : sig;
+
+        err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
+
+        if (_NSIG_WORDS > 1) {
+                err |= __copy_to_user(frame->extramask, &set->sig[1],
+                                        sizeof(frame->extramask));
+        }
+
+        /* Set up to return from userspace. If provided, use a stub
+         already in userspace. */
+        /* minus 8 is offset to cater for "rtsd r15,8" offset */
+        if (ka->sa.sa_flags & SA_RESTORER) {
+                regs->r15 = ((unsigned long)ka->sa.sa_restorer)-8;
+        } else {
+                /* Note, these encodings are _big endian_! */
+
+                /* addi r12, r0, __NR_sigreturn */
+                err |= __put_user(0x31800000 | __NR_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;
+
+        /* Set up registers for signal handler */
+        regs->r1 = (unsigned long) frame;
+        /* Signal handler args: */
+        regs->r5 = signal; /* Arg 0: signum */
+        regs->r6 = (unsigned long) &frame->sc; /* arg 1: sigcontext */
+
+        /* Offset of 4 to handle microblaze rtid r14, 0 */
+        regs->pc = (unsigned long)ka->sa.sa_handler;
+
+        set_fs(USER_DS);
+
+#ifdef DEBUG_SIG
+        printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n",
+                current->comm, current->pid, frame, regs->pc);
+#endif
+
+        return;
+
+give_sigsegv:
+        if (sig == SIGSEGV)
+                ka->sa.sa_handler = SIG_DFL;
+        force_sig(SIGSEGV, current);
+}
+
+static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+                        sigset_t *set, struct pt_regs *regs)
+{
+        struct rt_sigframe *frame;
+        int err = 0;
+        int signal;
+
+        frame = get_sigframe(ka, regs, sizeof(*frame));
+
+        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+                goto give_sigsegv;
+
+        signal = current_thread_info()->exec_domain
+                && current_thread_info()->exec_domain->signal_invmap
+                && sig < 32
+                ? current_thread_info()->exec_domain->signal_invmap[sig]
+                : sig;
+
+        err |= copy_siginfo_to_user(&frame->info, info);
+
+        /* Create the ucontext. */
+        err |= __put_user(0, &frame->uc.uc_flags);
+        err |= __put_user(0, &frame->uc.uc_link);
+        err |= __put_user((void *)current->sas_ss_sp,
+                        &frame->uc.uc_stack.ss_sp);
+        err |= __put_user(sas_ss_flags(regs->r1),
+                        &frame->uc.uc_stack.ss_flags);
+        err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+        err |= setup_sigcontext(&frame->uc.uc_mcontext,
+                        regs, set->sig[0]);
+        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+        /* 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);
+        }
+
+        if (err)
+                goto give_sigsegv;
+
+        /* Set up registers for signal handler */
+        regs->r1 = (unsigned long) frame;
+        /* Signal handler args: */
+        regs->r5 = signal; /* arg 0: signum */
+        regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
+        regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
+        /* Offset to handle microblaze rtid r14, 0 */
+        regs->pc = (unsigned long)ka->sa.sa_handler;
+
+        set_fs(USER_DS);
+
+#ifdef DEBUG_SIG
+        printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n",
+                current->comm, current->pid, frame, regs->pc);
+#endif
+
+        return;
+
+give_sigsegv:
+        if (sig == SIGSEGV)
+                ka->sa.sa_handler = SIG_DFL;
+        force_sig(SIGSEGV, current);
+}
+
+/* Handle restarting system calls */
+static inline void
+handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
+{
+        switch (regs->r3) {
+        case -ERESTART_RESTARTBLOCK:
+        case -ERESTARTNOHAND:
+                if (!has_handler)
+                        goto do_restart;
+                regs->r3 = -EINTR;
+                break;
+        case -ERESTARTSYS:
+                if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
+                        regs->r3 = -EINTR;
+                        break;
+        }
+        /* fallthrough */
+        case -ERESTARTNOINTR:
+do_restart:
+                /* offset of 4 bytes to re-execute trap (brki) instruction */
+                regs->pc -= 4;
+                break;
+        }
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+
+static void
+handle_signal(unsigned long sig, struct k_sigaction *ka,
+                siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
+{
+        /* Set up the stack frame */
+        if (ka->sa.sa_flags & SA_SIGINFO)
+                setup_rt_frame(sig, ka, info, oldset, regs);
+        else
+                setup_frame(sig, ka, oldset, regs);
+
+        if (ka->sa.sa_flags & SA_ONESHOT)
+                ka->sa.sa_handler = SIG_DFL;
+
+        if (!(ka->sa.sa_flags & SA_NODEFER)) {
+                spin_lock_irq(&current->sighand->siglock);
+                sigorsets(&current->blocked,
+                                &current->blocked, &ka->sa.sa_mask);
+                sigaddset(&current->blocked, sig);
+                recalc_sigpending();
+                spin_unlock_irq(&current->sighand->siglock);
+        }
+}
+
+/*
+ * Note that 'init' is a special process: it doesn't get signals it doesn't
+ * want to handle. Thus you cannot kill init even with a SIGKILL even by
+ * mistake.
+ *
+ * Note that we go through the signals twice: once to check the signals that
+ * the kernel can handle, and then we build all the user-level signal handling
+ * stack-frames in one go after that.
+ */
+int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_syscall)
+{
+        siginfo_t info;
+        int signr;
+        struct k_sigaction ka;
+#ifdef DEBUG_SIG
+        printk(KERN_INFO "do signal: %p %p %d\n", regs, oldset, in_syscall);
+        printk(KERN_INFO "do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
+                        regs->r12, current_thread_info()->flags);
+#endif
+        /*
+         * We want the common case to go fast, which
+         * is why we may in certain cases get here from
+         * kernel mode. Just return without doing anything
+         * if so.
+         */
+        if (kernel_mode(regs))
+                return 1;
+
+        if (!oldset)
+                oldset = &current->blocked;
+
+        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
+        if (signr > 0) {
+                /* Whee! Actually deliver the signal. */
+                if (in_syscall)
+                        handle_restart(regs, &ka, 1);
+                handle_signal(signr, &ka, &info, oldset, regs);
+                return 1;
+        }
+
+        if (in_syscall)
+                handle_restart(regs, NULL, 0);
+
+        /* Did we come from a system call? */
+        return 0;
+}