microblaze_v8: Signal support
Michal Simek [Fri, 27 Mar 2009 13:25:14 +0000 (14:25 +0100)]
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>

arch/microblaze/include/asm/signal.h [new file with mode: 0644]
arch/microblaze/kernel/signal.c [new file with mode: 0644]

diff --git a/arch/microblaze/include/asm/signal.h b/arch/microblaze/include/asm/signal.h
new file mode 100644 (file)
index 0000000..9676fad
--- /dev/null
@@ -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 (file)
index 0000000..ff347b9
--- /dev/null
@@ -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;
+}