arch/tile/kernel/compat_signal.c - maze/linux - Git at Google

 /*
  * Copyright 2010 Tilera Corporation. All Rights Reserved.
  *
  *   This program is free software; you can redistribute it and/or
  *   modify it under the terms of the GNU General Public License
  *   as published by the Free Software Foundation, version 2.
  *
  *   This program is distributed in the hope that it will be useful, but
  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  *   NON INFRINGEMENT.  See the GNU General Public License for
  *   more details.
  */

 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/kernel.h>
 #include <linux/signal.h>
 #include <linux/errno.h>
 #include <linux/wait.h>
 #include <linux/unistd.h>
 #include <linux/stddef.h>
 #include <linux/personality.h>
 #include <linux/suspend.h>
 #include <linux/ptrace.h>
 #include <linux/elf.h>
 #include <linux/compat.h>
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
 #include <asm/processor.h>
 #include <asm/ucontext.h>
 #include <asm/sigframe.h>
 #include <asm/syscalls.h>
 #include <arch/interrupts.h>

 struct compat_sigaction {
 	compat_uptr_t sa_handler;
 	compat_ulong_t sa_flags;
 	compat_uptr_t sa_restorer;
 	sigset_t sa_mask __packed;
 };

 struct compat_sigaltstack {
 	compat_uptr_t ss_sp;
 	int ss_flags;
 	compat_size_t ss_size;
 };

 struct compat_ucontext {
 	compat_ulong_t	  uc_flags;
 	compat_uptr_t     uc_link;
 	struct compat_sigaltstack	  uc_stack;
 	struct sigcontext uc_mcontext;
 	sigset_t	  uc_sigmask;	/* mask last for extensibility */
 };

 #define COMPAT_SI_PAD_SIZE	((SI_MAX_SIZE - 3 * sizeof(int)) / sizeof(int))

 struct compat_siginfo {
 	int si_signo;
 	int si_errno;
 	int si_code;

 	union {
 		int _pad[COMPAT_SI_PAD_SIZE];

 		/* kill() */
 		struct {
 			unsigned int _pid;	/* sender's pid */
 			unsigned int _uid;	/* sender's uid */
 		} _kill;

 		/* POSIX.1b timers */
 		struct {
 			compat_timer_t _tid;	/* timer id */
 			int _overrun;		/* overrun count */
 			compat_sigval_t _sigval;	/* same as below */
 			int _sys_private;	/* not to be passed to user */
 			int _overrun_incr;	/* amount to add to overrun */
 		} _timer;

 		/* POSIX.1b signals */
 		struct {
 			unsigned int _pid;	/* sender's pid */
 			unsigned int _uid;	/* sender's uid */
 			compat_sigval_t _sigval;
 		} _rt;

 		/* SIGCHLD */
 		struct {
 			unsigned int _pid;	/* which child */
 			unsigned int _uid;	/* sender's uid */
 			int _status;		/* exit code */
 			compat_clock_t _utime;
 			compat_clock_t _stime;
 		} _sigchld;

 		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
 		struct {
 			unsigned int _addr;	/* faulting insn/memory ref. */
 #ifdef __ARCH_SI_TRAPNO
 			int _trapno;	/* TRAP # which caused the signal */
 #endif
 		} _sigfault;

 		/* SIGPOLL */
 		struct {
 			int _band;	/* POLL_IN, POLL_OUT, POLL_MSG */
 			int _fd;
 		} _sigpoll;
 	} _sifields;
 };

 struct compat_rt_sigframe {
 	unsigned char save_area[C_ABI_SAVE_AREA_SIZE]; /* caller save area */
 	struct compat_siginfo info;
 	struct compat_ucontext uc;
 };

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

 long compat_sys_rt_sigaction(int sig, struct compat_sigaction __user *act,
 			     struct compat_sigaction __user *oact,
 			     size_t sigsetsize)
 {
 	struct k_sigaction new_sa, old_sa;
 	int ret = -EINVAL;

 	/* XXX: Don't preclude handling different sized sigset_t's.  */
 	if (sigsetsize != sizeof(sigset_t))
 		goto out;

 	if (act) {
 		compat_uptr_t handler, restorer;

 		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 		    __get_user(handler, &act->sa_handler) ||
 		    __get_user(new_sa.sa.sa_flags, &act->sa_flags) ||
 		    __get_user(restorer, &act->sa_restorer) ||
 		    __copy_from_user(&new_sa.sa.sa_mask, &act->sa_mask,
 				     sizeof(sigset_t)))
 			return -EFAULT;
 		new_sa.sa.sa_handler = compat_ptr(handler);
 		new_sa.sa.sa_restorer = compat_ptr(restorer);
 	}

 	ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);

 	if (!ret && oact) {
 		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 		    __put_user(ptr_to_compat(old_sa.sa.sa_handler),
 			       &oact->sa_handler) ||
 		    __put_user(ptr_to_compat(old_sa.sa.sa_restorer),
 			       &oact->sa_restorer) ||
 		    __put_user(old_sa.sa.sa_flags, &oact->sa_flags) ||
 		    __copy_to_user(&oact->sa_mask, &old_sa.sa.sa_mask,
 				   sizeof(sigset_t)))
 			return -EFAULT;
 	}
 out:
 	return ret;
 }

 long compat_sys_rt_sigqueueinfo(int pid, int sig,
 				struct compat_siginfo __user *uinfo)
 {
 	siginfo_t info;
 	int ret;
 	mm_segment_t old_fs = get_fs();

 	if (copy_siginfo_from_user32(&info, uinfo))
 		return -EFAULT;
 	set_fs(KERNEL_DS);
 	ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __force __user *)&info);
 	set_fs(old_fs);
 	return ret;
 }

 int copy_siginfo_to_user32(struct compat_siginfo __user *to, siginfo_t *from)
 {
 	int err;

 	if (!access_ok(VERIFY_WRITE, to, sizeof(struct compat_siginfo)))
 		return -EFAULT;

 	/* If you change siginfo_t structure, please make sure that
 	   this code is fixed accordingly.
 	   It should never copy any pad contained in the structure
 	   to avoid security leaks, but must copy the generic
 	   3 ints plus the relevant union member.  */
 	err = __put_user(from->si_signo, &to->si_signo);
 	err |= __put_user(from->si_errno, &to->si_errno);
 	err |= __put_user((short)from->si_code, &to->si_code);

 	if (from->si_code < 0) {
 		err |= __put_user(from->si_pid, &to->si_pid);
 		err |= __put_user(from->si_uid, &to->si_uid);
 		err |= __put_user(ptr_to_compat(from->si_ptr), &to->si_ptr);
 	} else {
 		/*
 		 * First 32bits of unions are always present:
 		 * si_pid === si_band === si_tid === si_addr(LS half)
 		 */
 		err |= __put_user(from->_sifields._pad[0],
 				  &to->_sifields._pad[0]);
 		switch (from->si_code >> 16) {
 		case __SI_FAULT >> 16:
 			break;
 		case __SI_CHLD >> 16:
 			err |= __put_user(from->si_utime, &to->si_utime);
 			err |= __put_user(from->si_stime, &to->si_stime);
 			err |= __put_user(from->si_status, &to->si_status);
 			/* FALL THROUGH */
 		default:
 		case __SI_KILL >> 16:
 			err |= __put_user(from->si_uid, &to->si_uid);
 			break;
 		case __SI_POLL >> 16:
 			err |= __put_user(from->si_fd, &to->si_fd);
 			break;
 		case __SI_TIMER >> 16:
 			err |= __put_user(from->si_overrun, &to->si_overrun);
 			err |= __put_user(ptr_to_compat(from->si_ptr),
 					  &to->si_ptr);
 			break;
 			 /* This is not generated by the kernel as of now.  */
 		case __SI_RT >> 16:
 		case __SI_MESGQ >> 16:
 			err |= __put_user(from->si_uid, &to->si_uid);
 			err |= __put_user(from->si_int, &to->si_int);
 			break;
 		}
 	}
 	return err;
 }

 int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from)
 {
 	int err;
 	u32 ptr32;

 	if (!access_ok(VERIFY_READ, from, sizeof(struct compat_siginfo)))
 		return -EFAULT;

 	err = __get_user(to->si_signo, &from->si_signo);
 	err |= __get_user(to->si_errno, &from->si_errno);
 	err |= __get_user(to->si_code, &from->si_code);

 	err |= __get_user(to->si_pid, &from->si_pid);
 	err |= __get_user(to->si_uid, &from->si_uid);
 	err |= __get_user(ptr32, &from->si_ptr);
 	to->si_ptr = compat_ptr(ptr32);

 	return err;
 }

 long compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
 			    struct compat_sigaltstack __user *uoss_ptr,
 			    struct pt_regs *regs)
 {
 	stack_t uss, uoss;
 	int ret;
 	mm_segment_t seg;

 	if (uss_ptr) {
 		u32 ptr;

 		memset(&uss, 0, sizeof(stack_t));
 		if (!access_ok(VERIFY_READ, uss_ptr, sizeof(*uss_ptr)) ||
 			    __get_user(ptr, &uss_ptr->ss_sp) ||
 			    __get_user(uss.ss_flags, &uss_ptr->ss_flags) ||
 			    __get_user(uss.ss_size, &uss_ptr->ss_size))
 			return -EFAULT;
 		uss.ss_sp = compat_ptr(ptr);
 	}
 	seg = get_fs();
 	set_fs(KERNEL_DS);
 	ret = do_sigaltstack(uss_ptr ? (stack_t __user __force *)&uss : NULL,
 			     (stack_t __user __force *)&uoss,
 			     (unsigned long)compat_ptr(regs->sp));
 	set_fs(seg);
 	if (ret >= 0 && uoss_ptr)  {
 		if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(*uoss_ptr)) ||
 		    __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
 		    __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
 		    __put_user(uoss.ss_size, &uoss_ptr->ss_size))
 			ret = -EFAULT;
 	}
 	return ret;
 }

 /* The assembly shim for this function arranges to ignore the return value. */
 long compat_sys_rt_sigreturn(struct pt_regs *regs)
 {
 	struct compat_rt_sigframe __user *frame =
 		(struct compat_rt_sigframe __user *) compat_ptr(regs->sp);
 	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);
 	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))
 		goto badframe;

 	if (compat_sys_sigaltstack(&frame->uc.uc_stack, NULL, regs) != 0)
 		goto badframe;

 	return 0;

 badframe:
 	signal_fault("bad sigreturn frame", regs, frame, 0);
 	return 0;
 }

 /*
  * Determine which stack to use..
  */
 static inline void __user *compat_get_sigframe(struct k_sigaction *ka,
 					       struct pt_regs *regs,
 					       size_t frame_size)
 {
 	unsigned long sp;

 	/* Default to using normal stack */
 	sp = (unsigned long)compat_ptr(regs->sp);

 	/*
 	 * If we are on the alternate signal stack and would overflow
 	 * it, don't.  Return an always-bogus address instead so we
 	 * will die with SIGSEGV.
 	 */
 	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
 		return (void __user __force *)-1UL;

 	/* This is the X/Open sanctioned signal stack switching.  */
 	if (ka->sa.sa_flags & SA_ONSTACK) {
 		if (sas_ss_flags(sp) == 0)
 			sp = current->sas_ss_sp + current->sas_ss_size;
 	}

 	sp -= frame_size;
 	/*
 	 * Align the stack pointer according to the TILE ABI,
 	 * i.e. so that on function entry (sp & 15) == 0.
 	 */
 	sp &= -16UL;
 	return (void __user *) sp;
 }

 int compat_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 			  sigset_t *set, struct pt_regs *regs)
 {
 	unsigned long restorer;
 	struct compat_rt_sigframe __user *frame;
 	int err = 0;
 	int usig;

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

 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		goto give_sigsegv;

 	usig = current_thread_info()->exec_domain
 		&& current_thread_info()->exec_domain->signal_invmap
 		&& sig < 32
 		? current_thread_info()->exec_domain->signal_invmap[sig]
 		: sig;

 	/* Always write at least the signal number for the stack backtracer. */
 	if (ka->sa.sa_flags & SA_SIGINFO) {
 		/* At sigreturn time, restore the callee-save registers too. */
 		err |= copy_siginfo_to_user32(&frame->info, info);
 		regs->flags |= PT_FLAGS_RESTORE_REGS;
 	} else {
 		err |= __put_user(info->si_signo, &frame->info.si_signo);
 	}

 	/* Create the ucontext.  */
 	err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
 	err |= __put_user(0, &frame->uc.uc_flags);
 	err |= __put_user(0, &frame->uc.uc_link);
 	err |= __put_user(ptr_to_compat((void *)(current->sas_ss_sp)),
 			  &frame->uc.uc_stack.ss_sp);
 	err |= __put_user(sas_ss_flags(regs->sp),
 			  &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);
 	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 	if (err)
 		goto give_sigsegv;

 	restorer = VDSO_BASE;
 	if (ka->sa.sa_flags & SA_RESTORER)
 		restorer = ptr_to_compat_reg(ka->sa.sa_restorer);

 	/*
 	 * Set up registers for signal handler.
 	 * Registers that we don't modify keep the value they had from
 	 * user-space at the time we took the signal.
 	 */
 	regs->pc = ptr_to_compat_reg(ka->sa.sa_handler);
 	regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
 	regs->sp = ptr_to_compat_reg(frame);
 	regs->lr = restorer;
 	regs->regs[0] = (unsigned long) usig;

 	if (ka->sa.sa_flags & SA_SIGINFO) {
 		/* Need extra arguments, so mark to restore caller-saves. */
 		regs->regs[1] = ptr_to_compat_reg(&frame->info);
 		regs->regs[2] = ptr_to_compat_reg(&frame->uc);
 		regs->flags |= PT_FLAGS_CALLER_SAVES;
 	}

 	/*
 	 * Notify any tracer that was single-stepping it.
 	 * The tracer may want to single-step inside the
 	 * handler too.
 	 */
 	if (test_thread_flag(TIF_SINGLESTEP))
 		ptrace_notify(SIGTRAP);

 	return 0;

 give_sigsegv:
 	signal_fault("bad setup frame", regs, frame, sig);
 	return -EFAULT;
 }
	/*
	* Copyright 2010 Tilera Corporation. All Rights Reserved.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation, version 2.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
	* NON INFRINGEMENT. See the GNU General Public License for
	* more details.
	*/

	#include <linux/sched.h>
	#include <linux/mm.h>
	#include <linux/smp.h>
	#include <linux/kernel.h>
	#include <linux/signal.h>
	#include <linux/errno.h>
	#include <linux/wait.h>
	#include <linux/unistd.h>
	#include <linux/stddef.h>
	#include <linux/personality.h>
	#include <linux/suspend.h>
	#include <linux/ptrace.h>
	#include <linux/elf.h>
	#include <linux/compat.h>
	#include <linux/syscalls.h>
	#include <linux/uaccess.h>
	#include <asm/processor.h>
	#include <asm/ucontext.h>
	#include <asm/sigframe.h>
	#include <asm/syscalls.h>
	#include <arch/interrupts.h>

	struct compat_sigaction {
	compat_uptr_t sa_handler;
	compat_ulong_t sa_flags;
	compat_uptr_t sa_restorer;
	sigset_t sa_mask __packed;
	};

	struct compat_sigaltstack {
	compat_uptr_t ss_sp;
	int ss_flags;
	compat_size_t ss_size;
	};

	struct compat_ucontext {
	compat_ulong_t uc_flags;
	compat_uptr_t uc_link;
	struct compat_sigaltstack uc_stack;
	struct sigcontext uc_mcontext;
	sigset_t uc_sigmask; /* mask last for extensibility */
	};

	#define COMPAT_SI_PAD_SIZE ((SI_MAX_SIZE - 3 * sizeof(int)) / sizeof(int))

	struct compat_siginfo {
	int si_signo;
	int si_errno;
	int si_code;

	union {
	int _pad[COMPAT_SI_PAD_SIZE];

	/* kill() */
	struct {
	unsigned int _pid; /* sender's pid */
	unsigned int _uid; /* sender's uid */
	} _kill;

	/* POSIX.1b timers */
	struct {
	compat_timer_t _tid; /* timer id */
	int _overrun; /* overrun count */
	compat_sigval_t _sigval; /* same as below */
	int _sys_private; /* not to be passed to user */
	int _overrun_incr; /* amount to add to overrun */
	} _timer;

	/* POSIX.1b signals */
	struct {
	unsigned int _pid; /* sender's pid */
	unsigned int _uid; /* sender's uid */
	compat_sigval_t _sigval;
	} _rt;

	/* SIGCHLD */
	struct {
	unsigned int _pid; /* which child */
	unsigned int _uid; /* sender's uid */
	int _status; /* exit code */
	compat_clock_t _utime;
	compat_clock_t _stime;
	} _sigchld;

	/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
	struct {
	unsigned int _addr; /* faulting insn/memory ref. */
	#ifdef __ARCH_SI_TRAPNO
	int _trapno; /* TRAP # which caused the signal */
	#endif
	} _sigfault;

	/* SIGPOLL */
	struct {
	int _band; /* POLL_IN, POLL_OUT, POLL_MSG */
	int _fd;
	} _sigpoll;
	} _sifields;
	};

	struct compat_rt_sigframe {
	unsigned char save_area[C_ABI_SAVE_AREA_SIZE]; /* caller save area */
	struct compat_siginfo info;
	struct compat_ucontext uc;
	};

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

	long compat_sys_rt_sigaction(int sig, struct compat_sigaction __user *act,
	struct compat_sigaction __user *oact,
	size_t sigsetsize)
	{
	struct k_sigaction new_sa, old_sa;
	int ret = -EINVAL;

	/* XXX: Don't preclude handling different sized sigset_t's. */
	if (sigsetsize != sizeof(sigset_t))
	goto out;

	if (act) {
	compat_uptr_t handler, restorer;

	if (!access_ok(VERIFY_READ, act, sizeof(*act)) \|\|
	__get_user(handler, &act->sa_handler) \|\|
	__get_user(new_sa.sa.sa_flags, &act->sa_flags) \|\|
	__get_user(restorer, &act->sa_restorer) \|\|
	__copy_from_user(&new_sa.sa.sa_mask, &act->sa_mask,
	sizeof(sigset_t)))
	return -EFAULT;
	new_sa.sa.sa_handler = compat_ptr(handler);
	new_sa.sa.sa_restorer = compat_ptr(restorer);
	}

	ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);

	if (!ret && oact) {
	if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) \|\|
	__put_user(ptr_to_compat(old_sa.sa.sa_handler),
	&oact->sa_handler) \|\|
	__put_user(ptr_to_compat(old_sa.sa.sa_restorer),
	&oact->sa_restorer) \|\|
	__put_user(old_sa.sa.sa_flags, &oact->sa_flags) \|\|
	__copy_to_user(&oact->sa_mask, &old_sa.sa.sa_mask,
	sizeof(sigset_t)))
	return -EFAULT;
	}
	out:
	return ret;
	}

	long compat_sys_rt_sigqueueinfo(int pid, int sig,
	struct compat_siginfo __user *uinfo)
	{
	siginfo_t info;
	int ret;
	mm_segment_t old_fs = get_fs();

	if (copy_siginfo_from_user32(&info, uinfo))
	return -EFAULT;
	set_fs(KERNEL_DS);
	ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __force __user *)&info);
	set_fs(old_fs);
	return ret;
	}

	int copy_siginfo_to_user32(struct compat_siginfo __user to, siginfo_t from)
	{
	int err;

	if (!access_ok(VERIFY_WRITE, to, sizeof(struct compat_siginfo)))
	return -EFAULT;

	/* If you change siginfo_t structure, please make sure that
	this code is fixed accordingly.
	It should never copy any pad contained in the structure
	to avoid security leaks, but must copy the generic
	3 ints plus the relevant union member. */
	err = __put_user(from->si_signo, &to->si_signo);
	err \|= __put_user(from->si_errno, &to->si_errno);
	err \|= __put_user((short)from->si_code, &to->si_code);

	if (from->si_code < 0) {
	err \|= __put_user(from->si_pid, &to->si_pid);
	err \|= __put_user(from->si_uid, &to->si_uid);
	err \|= __put_user(ptr_to_compat(from->si_ptr), &to->si_ptr);
	} else {
	/*
	* First 32bits of unions are always present:
	* si_pid === si_band === si_tid === si_addr(LS half)
	*/
	err \|= __put_user(from->_sifields._pad[0],
	&to->_sifields._pad[0]);
	switch (from->si_code >> 16) {
	case __SI_FAULT >> 16:
	break;
	case __SI_CHLD >> 16:
	err \|= __put_user(from->si_utime, &to->si_utime);
	err \|= __put_user(from->si_stime, &to->si_stime);
	err \|= __put_user(from->si_status, &to->si_status);
	/* FALL THROUGH */
	default:
	case __SI_KILL >> 16:
	err \|= __put_user(from->si_uid, &to->si_uid);
	break;
	case __SI_POLL >> 16:
	err \|= __put_user(from->si_fd, &to->si_fd);
	break;
	case __SI_TIMER >> 16:
	err \|= __put_user(from->si_overrun, &to->si_overrun);
	err \|= __put_user(ptr_to_compat(from->si_ptr),
	&to->si_ptr);
	break;
	/* This is not generated by the kernel as of now. */
	case __SI_RT >> 16:
	case __SI_MESGQ >> 16:
	err \|= __put_user(from->si_uid, &to->si_uid);
	err \|= __put_user(from->si_int, &to->si_int);
	break;
	}
	}
	return err;
	}

	int copy_siginfo_from_user32(siginfo_t to, struct compat_siginfo __user from)
	{
	int err;
	u32 ptr32;

	if (!access_ok(VERIFY_READ, from, sizeof(struct compat_siginfo)))
	return -EFAULT;

	err = __get_user(to->si_signo, &from->si_signo);
	err \|= __get_user(to->si_errno, &from->si_errno);
	err \|= __get_user(to->si_code, &from->si_code);

	err \|= __get_user(to->si_pid, &from->si_pid);
	err \|= __get_user(to->si_uid, &from->si_uid);
	err \|= __get_user(ptr32, &from->si_ptr);
	to->si_ptr = compat_ptr(ptr32);

	return err;
	}

	long compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
	struct compat_sigaltstack __user *uoss_ptr,
	struct pt_regs *regs)
	{
	stack_t uss, uoss;
	int ret;
	mm_segment_t seg;

	if (uss_ptr) {
	u32 ptr;

	memset(&uss, 0, sizeof(stack_t));
	if (!access_ok(VERIFY_READ, uss_ptr, sizeof(*uss_ptr)) \|\|
	__get_user(ptr, &uss_ptr->ss_sp) \|\|
	__get_user(uss.ss_flags, &uss_ptr->ss_flags) \|\|
	__get_user(uss.ss_size, &uss_ptr->ss_size))
	return -EFAULT;
	uss.ss_sp = compat_ptr(ptr);
	}
	seg = get_fs();
	set_fs(KERNEL_DS);
	ret = do_sigaltstack(uss_ptr ? (stack_t __user __force *)&uss : NULL,
	(stack_t __user __force *)&uoss,
	(unsigned long)compat_ptr(regs->sp));
	set_fs(seg);
	if (ret >= 0 && uoss_ptr) {
	if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(*uoss_ptr)) \|\|
	__put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) \|\|
	__put_user(uoss.ss_flags, &uoss_ptr->ss_flags) \|\|
	__put_user(uoss.ss_size, &uoss_ptr->ss_size))
	ret = -EFAULT;
	}
	return ret;
	}

	/* The assembly shim for this function arranges to ignore the return value. */
	long compat_sys_rt_sigreturn(struct pt_regs *regs)
	{
	struct compat_rt_sigframe __user *frame =
	(struct compat_rt_sigframe __user *) compat_ptr(regs->sp);
	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);
	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))
	goto badframe;

	if (compat_sys_sigaltstack(&frame->uc.uc_stack, NULL, regs) != 0)
	goto badframe;

	return 0;

	badframe:
	signal_fault("bad sigreturn frame", regs, frame, 0);
	return 0;
	}

	/*
	* Determine which stack to use..
	*/
	static inline void __user compat_get_sigframe(struct k_sigaction ka,
	struct pt_regs *regs,
	size_t frame_size)
	{
	unsigned long sp;

	/* Default to using normal stack */
	sp = (unsigned long)compat_ptr(regs->sp);

	/*
	* If we are on the alternate signal stack and would overflow
	* it, don't. Return an always-bogus address instead so we
	* will die with SIGSEGV.
	*/
	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
	return (void __user __force *)-1UL;

	/* This is the X/Open sanctioned signal stack switching. */
	if (ka->sa.sa_flags & SA_ONSTACK) {
	if (sas_ss_flags(sp) == 0)
	sp = current->sas_ss_sp + current->sas_ss_size;
	}

	sp -= frame_size;
	/*
	* Align the stack pointer according to the TILE ABI,
	* i.e. so that on function entry (sp & 15) == 0.
	*/
	sp &= -16UL;
	return (void __user *) sp;
	}

	int compat_setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	sigset_t set, struct pt_regs regs)
	{
	unsigned long restorer;
	struct compat_rt_sigframe __user *frame;
	int err = 0;
	int usig;

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

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	goto give_sigsegv;

	usig = current_thread_info()->exec_domain
	&& current_thread_info()->exec_domain->signal_invmap
	&& sig < 32
	? current_thread_info()->exec_domain->signal_invmap[sig]
	: sig;

	/* Always write at least the signal number for the stack backtracer. */
	if (ka->sa.sa_flags & SA_SIGINFO) {
	/* At sigreturn time, restore the callee-save registers too. */
	err \|= copy_siginfo_to_user32(&frame->info, info);
	regs->flags \|= PT_FLAGS_RESTORE_REGS;
	} else {
	err \|= __put_user(info->si_signo, &frame->info.si_signo);
	}

	/* Create the ucontext. */
	err \|= __clear_user(&frame->save_area, sizeof(frame->save_area));
	err \|= __put_user(0, &frame->uc.uc_flags);
	err \|= __put_user(0, &frame->uc.uc_link);
	err \|= __put_user(ptr_to_compat((void *)(current->sas_ss_sp)),
	&frame->uc.uc_stack.ss_sp);
	err \|= __put_user(sas_ss_flags(regs->sp),
	&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);
	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
	goto give_sigsegv;

	restorer = VDSO_BASE;
	if (ka->sa.sa_flags & SA_RESTORER)
	restorer = ptr_to_compat_reg(ka->sa.sa_restorer);

	/*
	* Set up registers for signal handler.
	* Registers that we don't modify keep the value they had from
	* user-space at the time we took the signal.
	*/
	regs->pc = ptr_to_compat_reg(ka->sa.sa_handler);
	regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
	regs->sp = ptr_to_compat_reg(frame);
	regs->lr = restorer;
	regs->regs[0] = (unsigned long) usig;

	if (ka->sa.sa_flags & SA_SIGINFO) {
	/* Need extra arguments, so mark to restore caller-saves. */
	regs->regs[1] = ptr_to_compat_reg(&frame->info);
	regs->regs[2] = ptr_to_compat_reg(&frame->uc);
	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	}

	/*
	* Notify any tracer that was single-stepping it.
	* The tracer may want to single-step inside the
	* handler too.
	*/
	if (test_thread_flag(TIF_SINGLESTEP))
	ptrace_notify(SIGTRAP);

	return 0;

	give_sigsegv:
	signal_fault("bad setup frame", regs, frame, sig);
	return -EFAULT;
	}