path: root/arch/m68k/kernel/signal.c

/*
 *  linux/arch/m68k/kernel/signal.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 * 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.
 */

/*
 * Linux/m68k support by Hamish Macdonald
 *
 * 68060 fixes by Jesper Skov
 *
 * 1997-12-01  Modified for POSIX.1b signals by Andreas Schwab
 *
 * mathemu support by Roman Zippel
 *  (Note: fpstate in the signal context is completely ignored for the emulator
 *         and the internal floating point format is put on stack)
 */

/*
 * ++roman (07/09/96): implemented signal stacks (specially for tosemu on
 * Atari :-) Current limitation: Only one sigstack can be active at one time.
 * If a second signal with SA_ONSTACK set arrives while working on a sigstack,
 * SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
 * signal handlers!
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/module.h>
#include <linux/tracehook.h>

#include <asm/setup.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/traps.h>
#include <asm/ucontext.h>

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

#ifdef CONFIG_MMU

/*
 * Handle the slight differences in classic 68k and ColdFire trap frames.
 */
#ifdef CONFIG_COLDFIRE
#define	FORMAT		4
#define	FMT4SIZE	0
#else
#define	FORMAT		0
#define	FMT4SIZE	sizeof(((struct frame *)0)->un.fmt4)
#endif

static const int frame_size_change[16] = {
  [1]	= -1, /* sizeof(((struct frame *)0)->un.fmt1), */
  [2]	= sizeof(((struct frame *)0)->un.fmt2),
  [3]	= sizeof(((struct frame *)0)->un.fmt3),
  [4]	= FMT4SIZE,
  [5]	= -1, /* sizeof(((struct frame *)0)->un.fmt5), */
  [6]	= -1, /* sizeof(((struct frame *)0)->un.fmt6), */
  [7]	= sizeof(((struct frame *)0)->un.fmt7),
  [8]	= -1, /* sizeof(((struct frame *)0)->un.fmt8), */
  [9]	= sizeof(((struct frame *)0)->un.fmt9),
  [10]	= sizeof(((struct frame *)0)->un.fmta),
  [11]	= sizeof(((struct frame *)0)->un.fmtb),
  [12]	= -1, /* sizeof(((struct frame *)0)->un.fmtc), */
  [13]	= -1, /* sizeof(((struct frame *)0)->un.fmtd), */
  [14]	= -1, /* sizeof(((struct frame *)0)->un.fmte), */
  [15]	= -1, /* sizeof(((struct frame *)0)->un.fmtf), */
};

static inline int frame_extra_sizes(int f)
{
	return frame_size_change[f];
}

int handle_kernel_fault(struct pt_regs *regs)
{
	const struct exception_table_entry *fixup;
	struct pt_regs *tregs;

	/* Are we prepared to handle this kernel fault? */
	fixup = search_exception_tables(regs->pc);
	if (!fixup)
		return 0;

	/* Create a new four word stack frame, discarding the old one. */
	regs->stkadj = frame_extra_sizes(regs->format);
	tregs =	(struct pt_regs *)((long)regs + regs->stkadj);
	tregs->vector = regs->vector;
	tregs->format = FORMAT;
	tregs->pc = fixup->fixup;
	tregs->sr = regs->sr;

	return 1;
}

void ptrace_signal_deliver(struct pt_regs *regs, void *cookie)
{
	if (regs->orig_d0 < 0)
		return;
	switch (regs->d0) {
	case -ERESTARTNOHAND:
	case -ERESTARTSYS:
	case -ERESTARTNOINTR:
		regs->d0 = regs->orig_d0;
		regs->orig_d0 = -1;
		regs->pc -= 2;
		break;
	}
}

static inline void push_cache (unsigned long vaddr)
{
	/*
	 * Using the old cache_push_v() was really a big waste.
	 *
	 * What we are trying to do is to flush 8 bytes to ram.
	 * Flushing 2 cache lines of 16 bytes is much cheaper than
	 * flushing 1 or 2 pages, as previously done in
	 * cache_push_v().
	 *                                                     Jes
	 */
	if (CPU_IS_040) {
		unsigned long temp;

		__asm__ __volatile__ (".chip 68040\n\t"
				      "nop\n\t"
				      "ptestr (%1)\n\t"
				      "movec %%mmusr,%0\n\t"
				      ".chip 68k"
				      : "=r" (temp)
				      : "a" (vaddr));

		temp &= PAGE_MASK;
		temp |= vaddr & ~PAGE_MASK;

		__asm__ __volatile__ (".chip 68040\n\t"
				      "nop\n\t"
				      "cpushl %%bc,(%0)\n\t"
				      ".chip 68k"
				      : : "a" (temp));
	}
	else if (CPU_IS_060) {
		unsigned long temp;
		__asm__ __volatile__ (".chip 68060\n\t"
				      "plpar (%0)\n\t"
				      ".chip 68k"
				      : "=a" (temp)
				      : "0" (vaddr));
		__asm__ __volatile__ (".chip 68060\n\t"
				      "cpushl %%bc,(%0)\n\t"
				      ".chip 68k"
				      : : "a" (temp));
	} else if (!CPU_IS_COLDFIRE) {
		/*
		 * 68030/68020 have no writeback cache;
		 * still need to clear icache.
		 * Note that vaddr is guaranteed to be long word aligned.
		 */
		unsigned long temp;
		asm volatile ("movec %%cacr,%0" : "=r" (temp));
		temp += 4;
		asm volatile ("movec %0,%%caar\n\t"
			      "movec %1,%%cacr"
			      : : "r" (vaddr), "r" (temp));
		asm volatile ("movec %0,%%caar\n\t"
			      "movec %1,%%cacr"
			      : : "r" (vaddr + 4), "r" (temp));
	}
}

static inline void adjustformat(struct pt_regs *regs)
{
}

static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
{
}

#else /* CONFIG_MMU */

void ret_from_user_signal(void);
void ret_from_user_rt_signal(void);

static inline int frame_extra_sizes(int f)
{
	/* No frame size adjustments required on non-MMU CPUs */
	return 0;
}

static inline void adjustformat(struct pt_regs *regs)
{
	((struct switch_stack *)regs - 1)->a5 = current->mm->start_data;
	/*
	 * set format byte to make stack appear modulo 4, which it will
	 * be when doing the rte
	 */
	regs->format = 0x4;
}

static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
{
	sc->sc_a5 = ((struct switch_stack *)regs - 1)->a5;
}

static inline void push_cache(unsigned long vaddr)
{
}

#endif /* CONFIG_MMU */

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */
asmlinkage int
sys_sigsuspend(int unused0, int unused1, old_sigset_t mask)
{
	sigset_t blocked;
	siginitset(&blocked, mask);
	return sigsuspend(&blocked);
}

asmlinkage int
sys_sigaction(int sig, const struct old_sigaction __user *act,
	      struct old_sigaction __user *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) ||
		    __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
		    __get_user(mask, &act->sa_mask))
			return -EFAULT;
		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) ||
		    __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
		    __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
			return -EFAULT;
	}

	return ret;
}

asmlinkage int
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
	return do_sigaltstack(uss, uoss, rdusp());
}


/*
 * Do a signal return; undo the signal stack.
 *
 * Keep the return code on the stack quadword aligned!
 * That makes the cache flush below easier.
 */

struct sigframe
{
	char __user *pretcode;
	int sig;
	int code;
	struct sigcontext __user *psc;
	char retcode[8];
	unsigned long extramask[_NSIG_WORDS-1];
	struct sigcontext sc;
};

struct rt_sigframe
{
	char __user *pretcode;
	int sig;
	struct siginfo __user *pinfo;
	void __user *puc;
	char retcode[8];
	struct siginfo info;
	struct ucontext uc;
};

#define FPCONTEXT_SIZE	216
#define uc_fpstate	uc_filler[0]
#define uc_formatvec	uc_filler[FPCONTEXT_SIZE/4]
#define uc_extra	uc_filler[FPCONTEXT_SIZE/4+1]

#ifdef CONFIG_FPU

static unsigned char fpu_version;	/* version number of fpu, set by setup_frame */

static inline int restore_fpu_state(struct sigcontext *sc)
{
	int err = 1;

	if (FPU_IS_EMU) {
	    /* restore registers */
	    memcpy(current->thread.fpcntl, sc->sc_fpcntl, 12);
	    memcpy(current->thread.fp, sc->sc_fpregs, 24);
	    return 0;
	}

	if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
	    /* Verify the frame format.  */
	    if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
		 (sc->sc_fpstate[0] != fpu_version))
		goto out;
	    if (CPU_IS_020_OR_030) {
		if (m68k_fputype & FPU_68881 &&
		    !(sc->sc_fpstate[1] == 0x18 || sc->sc_fpstate[1] == 0xb4))
		    goto out;
		if (m68k_fputype & FPU_68882 &&
		    !(sc->sc_fpstate[1] == 0x38 || sc->sc_fpstate[1] == 0xd4))
		    goto out;
	    } else if (CPU_IS_040) {
		if (!(sc->sc_fpstate[1] == 0x00 ||
                      sc->sc_fpstate[1] == 0x28 ||
                      sc->sc_fpstate[1] == 0x60))
		    goto out;
	    } else if (CPU_IS_060) {
		if (!(sc->sc_fpstate[3] == 0x00 ||
                      sc->sc_fpstate[3] == 0x60 ||
		      sc->sc_fpstate[3] == 0xe0))
		    goto out;
	    } else if (CPU_IS_COLDFIRE) {
		if (!(sc->sc_fpstate[0] == 0x00 ||
		      sc->sc_fpstate[0] == 0x05 ||
		      sc->sc_fpstate[0] == 0xe5))
		    goto out;
	    } else
		goto out;

	    if (CPU_IS_COLDFIRE) {
		__asm__ volatile ("fmovemd %0,%%fp0-%%fp1\n\t"
				  "fmovel %1,%%fpcr\n\t"
				  "fmovel %2,%%fpsr\n\t"
				  "fmovel %3,%%fpiar"
				  : /* no outputs */
				  : "m" (sc->sc_fpregs[0]),
				    "m" (sc->sc_fpcntl[0]),
				    "m" (sc->sc_fpcntl[1]),
				    "m" (sc->sc_fpcntl[2]));
	    } else {
		__asm__ volatile (".chip 68k/68881\n\t"
				  "fmovemx %0,%%fp0-%%fp1\n\t"
				  "fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
				  ".chip 68k"
				  : /* no outputs */
				  : "m" (*sc->sc_fpregs),
				    "m" (*sc->sc_fpcntl));
	    }
	}

	if (CPU_IS_COLDFIRE) {
		__asm__ volatile ("frestore %0" : : "m" (*sc->sc_fpstate));
	} else {
		__asm__ volatile (".chip 68k/68881\n\t"
				  "frestore %0\n\t"
				  ".chip 68k"
				  : : "m" (*sc->sc_fpstate));
	}
	err = 0;

out:
	return err;
}

static inline int rt_restore_fpu_state(struct ucontext __user *uc)
{
	unsigned char fpstate[FPCONTEXT_SIZE];
	int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
	fpregset_t fpregs;
	int err = 1;

	if (FPU_IS_EMU) {
		/* restore fpu control register */
		if (__copy_from_user(current->thread.fpcntl,
				uc->uc_mcontext.fpregs.f_fpcntl, 12))
			goto out;
		/* restore all other fpu register */
		if (__copy_from_user(current->thread.fp,
				uc->uc_mcontext.fpregs.f_fpregs, 96))
			goto out;
		return 0;
	}

	if (__get_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate))
		goto out;
	if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
		if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
			context_size = fpstate[1];
		/* Verify the frame format.  */
		if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
		     (fpstate[0] != fpu_version))
			goto out;
		if (CPU_IS_020_OR_030) {
			if (m68k_fputype & FPU_68881 &&
			    !(context_size == 0x18 || context_size == 0xb4))
				goto out;
			if (m68k_fputype & FPU_68882 &&
			    !(context_size == 0x38 || context_size == 0xd4))
				goto out;
		} else if (CPU_IS_040) {
			if (!(context_size == 0x00 ||
			      context_size == 0x28 ||
			      context_size == 0x60))
				goto out;
		} else if (CPU_IS_060) {
			if (!(fpstate[3] == 0x00 ||
			      fpstate[3] == 0x60 ||
			      fpstate[3] == 0xe0))
				goto out;
		} else if (CPU_IS_COLDFIRE) {
			if (!(fpstate[3] == 0x00 ||
			      fpstate[3] == 0x05 ||
			      fpstate[3] == 0xe5))
				goto out;
		} else
			goto out;
		if (__copy_from_user(&fpregs, &uc->uc_mcontext.fpregs,
				     sizeof(fpregs)))
			goto out;

		if (CPU_IS_COLDFIRE) {
			__asm__ volatile ("fmovemd %0,%%fp0-%%fp7\n\t"
					  "fmovel %1,%%fpcr\n\t"
					  "fmovel %2,%%fpsr\n\t"
					  "fmovel %3,%%fpiar"
					  : /* no outputs */
					  : "m" (fpregs.f_fpregs[0]),
					    "m" (fpregs.f_fpcntl[0]),
					    "m" (fpregs.f_fpcntl[1]),
					    "m" (fpregs.f_fpcntl[2]));
		} else {
			__asm__ volatile (".chip 68k/68881\n\t"
					  "fmovemx %0,%%fp0-%%fp7\n\t"
					  "fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
					  ".chip 68k"
					  : /* no outputs */
					  : "m" (*fpregs.f_fpregs),
					    "m" (*fpregs.f_fpcntl));
		}
	}
	if (context_size &&
	    __copy_from_user(fpstate + 4, (long __user *)&uc->uc_fpstate + 1,
			     context_size))
		goto out;

	if (CPU_IS_COLDFIRE) {
		__asm__ volatile ("frestore %0" : : "m" (*fpstate));
	} else {
		__asm__ volatile (".chip 68k/68881\n\t"
				  "frestore %0\n\t"
				  ".chip 68k"
				  : : "m" (*fpstate));
	}
	err = 0;

out:
	return err;
}

/*
 * Set up a signal frame.
 */
static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
{
	if (FPU_IS_EMU) {
		/* save registers */
		memcpy(sc->sc_fpcntl, current->thread.fpcntl, 12);
		memcpy(sc->sc_fpregs, current->thread.fp, 24);
		return;
	}

	if (CPU_IS_COLDFIRE) {
		__asm__ volatile ("fsave %0"
				  : : "m" (*sc->sc_fpstate) : "memory");
	} else {
		__asm__ volatile (".chip 68k/68881\n\t"
				  "fsave %0\n\t"
				  ".chip 68k"
				  : : "m" (*sc->sc_fpstate) : "memory");
	}

	if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
		fpu_version = sc->sc_fpstate[0];
		if (CPU_IS_020_OR_030 &&
		    regs->vector >= (VEC_FPBRUC * 4) &&
		    regs->vector <= (VEC_FPNAN * 4)) {
			/* Clear pending exception in 68882 idle frame */
			if (*(unsigned short *) sc->sc_fpstate == 0x1f38)
				sc->sc_fpstate[0x38] |= 1 << 3;
		}

		if (CPU_IS_COLDFIRE) {
			__asm__ volatile ("fmovemd %%fp0-%%fp1,%0\n\t"
					  "fmovel %%fpcr,%1\n\t"
					  "fmovel %%fpsr,%2\n\t"
					  "fmovel %%fpiar,%3"
					  : "=m" (sc->sc_fpregs[0]),
					    "=m" (sc->sc_fpcntl[0]),
					    "=m" (sc->sc_fpcntl[1]),
					    "=m" (sc->sc_fpcntl[2])
					  : /* no inputs */
					  : "memory");
		} else {
			__asm__ volatile (".chip 68k/68881\n\t"
					  "fmovemx %%fp0-%%fp1,%0\n\t"
					  "fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
					  ".chip 68k"
					  : "=m" (*sc->sc_fpregs),
					    "=m" (*sc->sc_fpcntl)
					  : /* no inputs */
					  : "memory");
		}
	}
}

static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
{
	unsigned char fpstate[FPCONTEXT_SIZE];
	int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
	int err = 0;

	if (FPU_IS_EMU) {
		/* save fpu control register */
		err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpcntl,
				current->thread.fpcntl, 12);
		/* save all other fpu register */
		err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpregs,
				current->thread.fp, 96);
		return err;
	}

	if (CPU_IS_COLDFIRE) {
		__asm__ volatile ("fsave %0" : : "m" (*fpstate) : "memory");
	} else {
		__asm__ volatile (".chip 68k/68881\n\t"
				  "fsave %0\n\t"
				  ".chip 68k"
				  : : "m" (*fpstate) : "memory");
	}

	err |= __put_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate);
	if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
		fpregset_t fpregs;
		if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
			context_size = fpstate[1];
		fpu_version = fpstate[0];
		if (CPU_IS_020_OR_030 &&
		    regs->vector >= (VEC_FPBRUC * 4) &&
		    regs->vector <= (VEC_FPNAN * 4)) {
			/* Clear pending exception in 68882 idle frame */
			if (*(unsigned short *) fpstate == 0x1f38)
				fpstate[0x38] |= 1 << 3;
		}
		if (CPU_IS_COLDFIRE) {
			__asm__ volatile ("fmovemd %%fp0-%%fp7,%0\n\t"
					  "fmovel %%fpcr,%1\n\t"
					  "fmovel %%fpsr,%2\n\t"
					  "fmovel %%fpiar,%3"
					  : "=m" (fpregs.f_fpregs[0]),
					    "=m" (fpregs.f_fpcntl[0]),
					    "=m" (fpregs.f_fpcntl[1]),
					    "=m" (fpregs.f_fpcntl[2])
					  : /* no inputs */
					  : "memory");
		} else {
			__asm__ volatile (".chip 68k/68881\n\t"
					  "fmovemx %%fp0-%%fp7,%0\n\t"
					  "fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
					  ".chip 68k"
					  : "=m" (*fpregs.f_fpregs),
					    "=m" (*fpregs.f_fpcntl)
					  : /* no inputs */
					  : "memory");
		}
		err |= copy_to_user(&uc->uc_mcontext.fpregs, &fpregs,
				    sizeof(fpregs));
	}
	if (context_size)
		err |= copy_to_user((long __user *)&uc->uc_fpstate + 1, fpstate + 4,
				    context_size);
	return err;
}

#else /* CONFIG_FPU */

/*
 * For the case with no FPU configured these all do nothing.
 */
static inline int restore_fpu_state(struct sigcontext *sc)
{
	return 0;
}

static inline int rt_restore_fpu_state(struct ucontext __user *uc)
{
	return 0;
}

static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
{
}

static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
{
	return 0;
}

#endif /* CONFIG_FPU */

static int mangle_kernel_stack(struct pt_regs *regs, int formatvec,
			       void __user *fp)
{
	int fsize = frame_extra_sizes(formatvec >> 12);
	if (fsize < 0) {
		/*
		 * user process trying to return with weird frame format
		 */
#ifdef DEBUG
		printk("user process returning with weird frame format\n");
#endif
		return 1;
	}
	if (!fsize) {
		regs->format = formatvec >> 12;
		regs->vector = formatvec & 0xfff;
	} else {
		struct switch_stack *sw = (struct switch_stack *)regs - 1;
		unsigned long buf[fsize / 2]; /* yes, twice as much */

		/* that'll make sure that expansion won't crap over data */
		if (copy_from_user(buf + fsize / 4, fp, fsize))
			return 1;

		/* point of no return */
		regs->format = formatvec >> 12;
		regs->vector = formatvec & 0xfff;
#define frame_offset (sizeof(struct pt_regs)+sizeof(struct switch_stack))
		__asm__ __volatile__ (
#ifdef CONFIG_COLDFIRE
			 "   movel %0,%/sp\n\t"
			 "   bra ret_from_signal\n"
#else
			 "   movel %0,%/a0\n\t"
			 "   subl %1,%/a0\n\t"     /* make room on stack */
			 "   movel %/a0,%/sp\n\t"  /* set stack pointer */
			 /* move switch_stack and pt_regs */
			 "1: movel %0@+,%/a0@+\n\t"
			 "   dbra %2,1b\n\t"
			 "   lea %/sp@(%c3),%/a0\n\t" /* add offset of fmt */
			 "   lsrl  #2,%1\n\t"
			 "   subql #1,%1\n\t"
			 /* copy to the gap we'd made */
			 "2: movel %4@+,%/a0@+\n\t"
			 "   dbra %1,2b\n\t"
			 "   bral ret_from_signal\n"
#endif
			 : /* no outputs, it doesn't ever return */
			 : "a" (sw), "d" (fsize), "d" (frame_offset/4-1),
			   "n" (frame_offset), "a" (buf + fsize/4)
			 : "a0");
#undef frame_offset
	}
	return 0;
}

static inline int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __user *fp)
{
	int formatvec;
	struct sigcontext context;
	int err = 0;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	/* get previous context */
	if (copy_from_user(&context, usc, sizeof(context)))
		goto badframe;

	/* restore passed registers */
	regs->d0 = context.sc_d0;
	regs->d1 = context.sc_d1;
	regs->a0 = context.sc_a0;
	regs->a1 = context.sc_a1;
	regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff);
	regs->pc = context.sc_pc;
	regs->orig_d0 = -1;		/* disable syscall checks */
	wrusp(context.sc_usp);
	formatvec = context.sc_formatvec;

	err = restore_fpu_state(&context);

	if (err || mangle_kernel_stack(regs, formatvec, fp))
		goto badframe;

	return 0;

badframe:
	return 1;
}

static inline int
rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw,
		    struct ucontext __user *uc)
{
	int temp;
	greg_t __user *gregs = uc->uc_mcontext.gregs;
	unsigned long usp;
	int err;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	err = __get_user(temp, &uc->uc_mcontext.version);
	if (temp != MCONTEXT_VERSION)
		goto badframe;
	/* restore passed registers */
	err |= __get_user(regs->d0, &gregs[0]);
	err |= __get_user(regs->d1, &gregs[1]);
	err |= __get_user(regs->d2, &gregs[2]);
	err |= __get_user(regs->d3, &gregs[3]);
	err |= __get_user(regs->d4, &gregs[4]);
	err |= __get_user(regs->d5, &gregs[5]);
	err |= __get_user(sw->d6, &gregs[6]);
	err |= __get_user(sw->d7, &gregs[7]);
	err |= __get_user(regs->a0, &gregs[8]);
	err |= __get_user(regs->a1, &gregs[9]);
	err |= __get_user(regs->a2, &gregs[10]);
	err |= __get_user(sw->a3, &gregs[11]);
	err |= __get_user(sw->a4, &gregs[12]);
	err |= __get_user(sw->a5, &gregs[13]);
	err |= __get_user(sw->a6, &gregs[14]);
	err |= __get_user(usp, &gregs[15]);
	wrusp(usp);
	err |= __get_user(regs->pc, &gregs[16]);
	err |= __get_user(temp, &gregs[17]);
	regs->sr = (regs->sr & 0xff00) | (temp & 0xff);
	regs->orig_d0 = -1;		/* disable syscall checks */
	err |= __get_user(temp, &uc->uc_formatvec);

	err |= rt_restore_fpu_state(uc);

	if (err || do_sigaltstack(&uc->uc_stack, NULL, usp) == -EFAULT)
		goto badframe;

	if (mangle_kernel_stack(regs, temp, &uc->uc_extra))
		goto badframe;

	return 0;

badframe:
	return 1;
}

asmlinkage int do_sigreturn(unsigned long __unused)
{
	struct switch_stack *sw = (struct switch_stack *) &__unused;
	struct pt_regs *regs = (struct pt_regs *) (sw + 1);
	unsigned long usp = rdusp();
	struct sigframe __user *frame = (struct sigframe __user *)(usp - 4);
	sigset_t set;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__get_user(set.sig[0], &frame->sc.sc_mask) ||
	    (_NSIG_WORDS > 1 &&
	     __copy_from_user(&set.sig[1], &frame->extramask,
			      sizeof(frame->extramask))))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	set_current_blocked(&set);

	if (restore_sigcontext(regs, &frame->sc, frame + 1))
		goto badframe;
	return regs->d0;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

asmlinkage int do_rt_sigreturn(unsigned long __unused)
{
	struct switch_stack *sw = (struct switch_stack *) &__unused;
	struct pt_regs *regs = (struct pt_regs *) (sw + 1);
	unsigned long usp = rdusp();
	struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(usp - 4);
	sigset_t set;

	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);
	set_current_blocked(&set);

	if (rt_restore_ucontext(regs, sw, &frame->uc))
		goto badframe;
	return regs->d0;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

static void setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
			     unsigned long mask)
{
	sc->sc_mask = mask;
	sc->sc_usp = rdusp();
	sc->sc_d0 = regs->d0;
	sc->sc_d1 = regs->d1;
	sc->sc_a0 = regs->a0;
	sc->sc_a1 = regs->a1;
	sc->sc_sr = regs->sr;
	sc->sc_pc = regs->pc;
	sc->sc_formatvec = regs->format << 12 | regs->vector;
	save_a5_state(sc, regs);
	save_fpu_state(sc, regs);
}

static inline int rt_setup_ucontext(struct ucontext __user *uc, struct pt_regs *regs)
{
	struct switch_stack *sw = (struct switch_stack *)regs - 1;
	greg_t __user *gregs = uc->uc_mcontext.gregs;
	int err = 0;

	err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
	err |= __put_user(regs->d0, &gregs[0]);
	err |= __put_user(regs->d1, &gregs[1]);
	err |= __put_user(regs->d2, &gregs[2]);
	err |= __put_user(regs->d3, &gregs[3]);
	err |= __put_user(regs->d4, &gregs[4]);
	err |= __put_user(regs->d5, &gregs[5]);
	err |= __put_user(sw->d6, &gregs[6]);
	err |= __put_user(sw->d7, &gregs[7]);
	err |= __put_user(regs->a0, &gregs[8]);
	err |= __put_user(regs->a1, &gregs[9]);
	err |= __put_user(regs->a2, &gregs[10]);
	err |= __put_user(sw->a3, &gregs[11]);
	err |= __put_user(sw->a4, &gregs[12]);
	err |= __put_user(sw->a5, &gregs[13]);
	err |= __put_user(sw->a6, &gregs[14]);
	err |= __put_user(rdusp(), &gregs[15]);
	err |= __put_user(regs->pc, &gregs[16]);
	err |= __put_user(regs->sr, &gregs[17]);
	err |= __put_user((regs->format << 12) | regs->vector, &uc->uc_formatvec);
	err |= rt_save_fpu_state(uc, regs);
	return err;
}

static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
{
	unsigned long usp;

	/* Default to using normal stack.  */
	usp = rdusp();

	/* This is the X/Open sanctioned signal stack switching.  */
	if (ka->sa.sa_flags & SA_ONSTACK) {
		if (!sas_ss_flags(usp))
			usp = current->sas_ss_sp + current->sas_ss_size;
	}
	return (void __user *)((usp - frame_size) & -8UL);
}

static int setup_frame (int sig, struct k_sigaction *ka,
			 sigset_t *set, struct pt_regs *regs)
{
	struct sigframe __user *frame;
	int fsize = frame_extra_sizes(regs->format);
	struct sigcontext context;
	int err = 0;

	if (fsize < 0) {
#ifdef DEBUG
		printk ("setup_frame: Unknown frame format %#x\n",
			regs->format);
#endif
		goto give_sigsegv;
	}

	frame = get_sigframe(ka, regs, sizeof(*frame) + fsize);

	if (fsize)
		err |= copy_to_user (frame + 1, regs + 1, fsize);

	err |= __put_user((current_thread_info()->exec_domain
			   && current_thread_info()->exec_domain->signal_invmap
			   && sig < 32
			   ? current_thread_info()->exec_domain->signal_invmap[sig]
			   : sig),
			  &frame->sig);

	err |= __put_user(regs->vector, &frame->code);
	err |= __put_user(&frame->sc, &frame->psc);

	if (_NSIG_WORDS > 1)
		err |= copy_to_user(frame->extramask, &set->sig[1],
				    sizeof(frame->extramask));

	setup_sigcontext(&context, regs, set->sig[0]);
	err |= copy_to_user (&frame->sc, &context, sizeof(context));

	/* Set up to return from userspace.  */
#ifdef CONFIG_MMU
	err |= __put_user(frame->retcode, &frame->pretcode);
	/* moveq #,d0; trap #0 */
	err |= __put_user(0x70004e40 + (__NR_sigreturn << 16),
			  (long __user *)(frame->retcode));
#else
	err |= __put_user((void *) ret_from_user_signal, &frame->pretcode);
#endif

	if (err)
		goto give_sigsegv;

	push_cache ((unsigned long) &frame->retcode);

	/*
	 * Set up registers for signal handler.  All the state we are about
	 * to destroy is successfully copied to sigframe.
	 */
	wrusp ((unsigned long) frame);
	regs->pc = (unsigned long) ka->sa.sa_handler;
	adjustformat(regs);

	/*
	 * This is subtle; if we build more than one sigframe, all but the
	 * first one will see frame format 0 and have fsize == 0, so we won't
	 * screw stkadj.
	 */
	if (fsize)
		regs->stkadj = fsize;

	/* Prepare to skip over the extra stuff in the exception frame.  */
	if (regs->stkadj) {
		struct pt_regs *tregs =
			(struct pt_regs *)((ulong)regs + regs->stkadj);
#ifdef DEBUG
		printk("Performing stackadjust=%04x\n", regs->stkadj);
#endif
		/* This must be copied with decreasing addresses to
                   handle overlaps.  */
		tregs->vector = 0;
		tregs->format = 0;
		tregs->pc = regs->pc;
		tregs->sr = regs->sr;
	}
	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return err;
}

static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
			    sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	int fsize = frame_extra_sizes(regs->format);
	int err = 0;

	if (fsize < 0) {
#ifdef DEBUG
		printk ("setup_frame: Unknown frame format %#x\n",
			regs->format);
#endif
		goto give_sigsegv;
	}

	frame = get_sigframe(ka, regs, sizeof(*frame));

	if (fsize)
		err |= copy_to_user (&frame->uc.uc_extra, regs + 1, fsize);

	err |= __put_user((current_thread_info()->exec_domain
			   && current_thread_info()->exec_domain->signal_invmap
			   && sig < 32
			   ? current_thread_info()->exec_domain->signal_invmap[sig]
			   : sig),
			  &frame->sig);
	err |= __put_user(&frame->info, &frame->pinfo);
	err |= __put_user(&frame->uc, &frame->puc);
	err |= copy_siginfo_to_user(&frame->info, info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(NULL, &frame->uc.uc_link);
	err |= __put_user((void __user *)current->sas_ss_sp,
			  &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(rdusp()),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= rt_setup_ucontext(&frame->uc, regs);
	err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Set up to return from userspace.  */
#ifdef CONFIG_MMU
	err |= __put_user(frame->retcode, &frame->pretcode);
#ifdef __mcoldfire__
	/* movel #__NR_rt_sigreturn,d0; trap #0 */
	err |= __put_user(0x203c0000, (long __user *)(frame->retcode + 0));
	err |= __put_user(0x00004e40 + (__NR_rt_sigreturn << 16),
			  (long __user *)(frame->retcode + 4));
#else
	/* moveq #,d0; notb d0; trap #0 */
	err |= __put_user(0x70004600 + ((__NR_rt_sigreturn ^ 0xff) << 16),
			  (long __user *)(frame->retcode + 0));
	err |= __put_user(0x4e40, (short __user *)(frame->retcode + 4));
#endif
#else
	err |= __put_user((void *) ret_from_user_rt_signal, &frame->pretcode);
#endif /* CONFIG_MMU */

	if (err)
		goto give_sigsegv;

	push_cache ((unsigned long) &frame->retcode);

	/*
	 * Set up registers for signal handler.  All the state we are about
	 * to destroy is successfully copied to sigframe.
	 */
	wrusp ((unsigned long) frame);
	regs->pc = (unsigned long) ka->sa.sa_handler;
	adjustformat(regs);

	/*
	 * This is subtle; if we build more than one sigframe, all but the
	 * first one will see frame format 0 and have fsize == 0, so we won't
	 * screw stkadj.
	 */
	if (fsize)
		regs->stkadj = fsize;

	/* Prepare to skip over the extra stuff in the exception frame.  */
	if (regs->stkadj) {
		struct pt_regs *tregs =
			(struct pt_regs *)((ulong)regs + regs->stkadj);
#ifdef DEBUG
		printk("Performing stackadjust=%04x\n", regs->stkadj);
#endif
		/* This must be copied with decreasing addresses to
                   handle overlaps.  */
		tregs->vector = 0;
		tregs->format = 0;
		tregs->pc = regs->pc;
		tregs->sr = regs->sr;
	}
	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return err;
}

static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
	switch (regs->d0) {
	case -ERESTARTNOHAND:
		if (!has_handler)
			goto do_restart;
		regs->d0 = -EINTR;
		break;

	case -ERESTART_RESTARTBLOCK:
		if (!has_handler) {
			regs->d0 = __NR_restart_syscall;
			regs->pc -= 2;
			break;
		}
		regs->d0 = -EINTR;
		break;

	case -ERESTARTSYS:
		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
			regs->d0 = -EINTR;
			break;
		}
	/* fallthrough */
	case -ERESTARTNOINTR:
	do_restart:
		regs->d0 = regs->orig_d0;
		regs->pc -= 2;
		break;
	}
}

/*
 * OK, we're invoking a handler
 */
static void
handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
	      sigset_t *oldset, struct pt_regs *regs)
{
	int err;
	/* are we from a system call? */
	if (regs->orig_d0 >= 0)
		/* If so, check system call restarting.. */
		handle_restart(regs, ka, 1);

	/* set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
		err = setup_rt_frame(sig, ka, info, oldset, regs);
	else
		err = setup_frame(sig, ka, oldset, regs);

	if (err)
		return;

	block_sigmask(ka, sig);

	if (test_thread_flag(TIF_DELAYED_TRACE)) {
		regs->sr &= ~0x8000;
		send_sig(SIGTRAP, current, 1);
	}

	clear_thread_flag(TIF_RESTORE_SIGMASK);
}

/*
 * 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.
 */
static void do_signal(struct pt_regs *regs)
{
	siginfo_t info;
	struct k_sigaction ka;
	int signr;
	sigset_t *oldset;

	current->thread.esp0 = (unsigned long) regs;

	if (test_thread_flag(TIF_RESTORE_SIGMASK))
		oldset = &current->saved_sigmask;
	else
		oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
		/* Whee!  Actually deliver the signal.  */
		handle_signal(signr, &ka, &info, oldset, regs);
		return;
	}

	/* Did we come from a system call? */
	if (regs->orig_d0 >= 0)
		/* Restart the system call - no handlers present */
		handle_restart(regs, NULL, 0);

	/* If there's no signal to deliver, we just restore the saved mask.  */
	restore_saved_sigmask();
}

void do_notify_resume(struct pt_regs *regs)
{
	if (test_thread_flag(TIF_SIGPENDING))
		do_signal(regs);

	if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
		tracehook_notify_resume(regs);
}