1 files changed, 876 insertions, 0 deletions

diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
new file mode 100644
index 00000000000..ac74c2f261e
--- /dev/null
+++ b/arch/arm64/kernel/signal32.c
@@ -0,0 +1,876 @@
+/*
+ * Based on arch/arm/kernel/signal.c
+ *
+ * Copyright (C) 1995-2009 Russell King
+ * Copyright (C) 2012 ARM Ltd.
+ * Modified by Will Deacon <will.deacon@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define __SYSCALL_COMPAT
+
+#include <linux/compat.h>
+#include <linux/signal.h>
+#include <linux/syscalls.h>
+#include <linux/ratelimit.h>
+
+#include <asm/fpsimd.h>
+#include <asm/signal32.h>
+#include <asm/uaccess.h>
+#include <asm/unistd.h>
+
+typedef struct compat_siginfo {
+	int si_signo;
+	int si_errno;
+	int si_code;
+
+	union {
+		/* The padding is the same size as AArch64. */
+		int _pad[SI_PAD_SIZE];
+
+		/* kill() */
+		struct {
+			compat_pid_t _pid;	/* sender's pid */
+			__compat_uid32_t _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 */
+		} _timer;
+
+		/* POSIX.1b signals */
+		struct {
+			compat_pid_t _pid;	/* sender's pid */
+			__compat_uid32_t _uid;	/* sender's uid */
+			compat_sigval_t _sigval;
+		} _rt;
+
+		/* SIGCHLD */
+		struct {
+			compat_pid_t _pid;	/* which child */
+			__compat_uid32_t _uid;	/* sender's uid */
+			int _status;		/* exit code */
+			compat_clock_t _utime;
+			compat_clock_t _stime;
+		} _sigchld;
+
+		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
+		struct {
+			compat_uptr_t _addr; /* faulting insn/memory ref. */
+			short _addr_lsb; /* LSB of the reported address */
+		} _sigfault;
+
+		/* SIGPOLL */
+		struct {
+			compat_long_t _band;	/* POLL_IN, POLL_OUT, POLL_MSG */
+			int _fd;
+		} _sigpoll;
+	} _sifields;
+} compat_siginfo_t;
+
+struct compat_sigaction {
+	compat_uptr_t			sa_handler;
+	compat_ulong_t			sa_flags;
+	compat_uptr_t			sa_restorer;
+	compat_sigset_t			sa_mask;
+};
+
+struct compat_old_sigaction {
+	compat_uptr_t			sa_handler;
+	compat_old_sigset_t		sa_mask;
+	compat_ulong_t			sa_flags;
+	compat_uptr_t			sa_restorer;
+};
+
+typedef struct compat_sigaltstack {
+	compat_uptr_t			ss_sp;
+	int				ss_flags;
+	compat_size_t			ss_size;
+} compat_stack_t;
+
+struct compat_sigcontext {
+	/* We always set these two fields to 0 */
+	compat_ulong_t			trap_no;
+	compat_ulong_t			error_code;
+
+	compat_ulong_t			oldmask;
+	compat_ulong_t			arm_r0;
+	compat_ulong_t			arm_r1;
+	compat_ulong_t			arm_r2;
+	compat_ulong_t			arm_r3;
+	compat_ulong_t			arm_r4;
+	compat_ulong_t			arm_r5;
+	compat_ulong_t			arm_r6;
+	compat_ulong_t			arm_r7;
+	compat_ulong_t			arm_r8;
+	compat_ulong_t			arm_r9;
+	compat_ulong_t			arm_r10;
+	compat_ulong_t			arm_fp;
+	compat_ulong_t			arm_ip;
+	compat_ulong_t			arm_sp;
+	compat_ulong_t			arm_lr;
+	compat_ulong_t			arm_pc;
+	compat_ulong_t			arm_cpsr;
+	compat_ulong_t			fault_address;
+};
+
+struct compat_ucontext {
+	compat_ulong_t			uc_flags;
+	struct compat_ucontext		*uc_link;
+	compat_stack_t			uc_stack;
+	struct compat_sigcontext	uc_mcontext;
+	compat_sigset_t			uc_sigmask;
+	int		__unused[32 - (sizeof (compat_sigset_t) / sizeof (int))];
+	compat_ulong_t	uc_regspace[128] __attribute__((__aligned__(8)));
+};
+
+struct compat_vfp_sigframe {
+	compat_ulong_t	magic;
+	compat_ulong_t	size;
+	struct compat_user_vfp {
+		compat_u64	fpregs[32];
+		compat_ulong_t	fpscr;
+	} ufp;
+	struct compat_user_vfp_exc {
+		compat_ulong_t	fpexc;
+		compat_ulong_t	fpinst;
+		compat_ulong_t	fpinst2;
+	} ufp_exc;
+} __attribute__((__aligned__(8)));
+
+#define VFP_MAGIC		0x56465001
+#define VFP_STORAGE_SIZE	sizeof(struct compat_vfp_sigframe)
+
+struct compat_aux_sigframe {
+	struct compat_vfp_sigframe	vfp;
+
+	/* Something that isn't a valid magic number for any coprocessor.  */
+	unsigned long			end_magic;
+} __attribute__((__aligned__(8)));
+
+struct compat_sigframe {
+	struct compat_ucontext	uc;
+	compat_ulong_t		retcode[2];
+};
+
+struct compat_rt_sigframe {
+	struct compat_siginfo info;
+	struct compat_sigframe sig;
+};
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+/*
+ * For ARM syscalls, the syscall number has to be loaded into r7.
+ * We do not support an OABI userspace.
+ */
+#define MOV_R7_NR_SIGRETURN	(0xe3a07000 | __NR_sigreturn)
+#define SVC_SYS_SIGRETURN	(0xef000000 | __NR_sigreturn)
+#define MOV_R7_NR_RT_SIGRETURN	(0xe3a07000 | __NR_rt_sigreturn)
+#define SVC_SYS_RT_SIGRETURN	(0xef000000 | __NR_rt_sigreturn)
+
+/*
+ * For Thumb syscalls, we also pass the syscall number via r7. We therefore
+ * need two 16-bit instructions.
+ */
+#define SVC_THUMB_SIGRETURN	(((0xdf00 | __NR_sigreturn) << 16) | \
+				   0x2700 | __NR_sigreturn)
+#define SVC_THUMB_RT_SIGRETURN	(((0xdf00 | __NR_rt_sigreturn) << 16) | \
+				   0x2700 | __NR_rt_sigreturn)
+
+const compat_ulong_t aarch32_sigret_code[6] = {
+	/*
+	 * AArch32 sigreturn code.
+	 * We don't construct an OABI SWI - instead we just set the imm24 field
+	 * to the EABI syscall number so that we create a sane disassembly.
+	 */
+	MOV_R7_NR_SIGRETURN,    SVC_SYS_SIGRETURN,    SVC_THUMB_SIGRETURN,
+	MOV_R7_NR_RT_SIGRETURN, SVC_SYS_RT_SIGRETURN, SVC_THUMB_RT_SIGRETURN,
+};
+
+static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set)
+{
+	compat_sigset_t	cset;
+
+	cset.sig[0] = set->sig[0] & 0xffffffffull;
+	cset.sig[1] = set->sig[0] >> 32;
+
+	return copy_to_user(uset, &cset, sizeof(*uset));
+}
+
+static inline int get_sigset_t(sigset_t *set,
+			       const compat_sigset_t __user *uset)
+{
+	compat_sigset_t s32;
+
+	if (copy_from_user(&s32, uset, sizeof(*uset)))
+		return -EFAULT;
+
+	set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32);
+	return 0;
+}
+
+int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
+{
+	int err;
+
+	if (!access_ok(VERIFY_WRITE, to, sizeof(*to)))
+		return -EFAULT;
+
+	/* If you change siginfo_t structure, please be sure
+	 * 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.
+	 * This routine must convert siginfo from 64bit to 32bit as well
+	 * at the same time.
+	 */
+	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 |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad,
+				      SI_PAD_SIZE);
+	else switch (from->si_code & __SI_MASK) {
+	case __SI_KILL:
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		break;
+	case __SI_TIMER:
+		 err |= __put_user(from->si_tid, &to->si_tid);
+		 err |= __put_user(from->si_overrun, &to->si_overrun);
+		 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr,
+				   &to->si_ptr);
+		break;
+	case __SI_POLL:
+		err |= __put_user(from->si_band, &to->si_band);
+		err |= __put_user(from->si_fd, &to->si_fd);
+		break;
+	case __SI_FAULT:
+		err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr,
+				  &to->si_addr);
+#ifdef BUS_MCEERR_AO
+		/*
+		 * Other callers might not initialize the si_lsb field,
+		 * so check explicitely for the right codes here.
+		 */
+		if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
+			err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
+#endif
+		break;
+	case __SI_CHLD:
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		err |= __put_user(from->si_status, &to->si_status);
+		err |= __put_user(from->si_utime, &to->si_utime);
+		err |= __put_user(from->si_stime, &to->si_stime);
+		break;
+	case __SI_RT: /* This is not generated by the kernel as of now. */
+	case __SI_MESGQ: /* But this is */
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr);
+		break;
+	default: /* this is just in case for now ... */
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		break;
+	}
+	return err;
+}
+
+int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
+{
+	memset(to, 0, sizeof *to);
+
+	if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) ||
+	    copy_from_user(to->_sifields._pad,
+			   from->_sifields._pad, SI_PAD_SIZE))
+		return -EFAULT;
+
+	return 0;
+}
+
+/*
+ * VFP save/restore code.
+ */
+static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
+{
+	struct fpsimd_state *fpsimd = &current->thread.fpsimd_state;
+	compat_ulong_t magic = VFP_MAGIC;
+	compat_ulong_t size = VFP_STORAGE_SIZE;
+	compat_ulong_t fpscr, fpexc;
+	int err = 0;
+
+	/*
+	 * Save the hardware registers to the fpsimd_state structure.
+	 * Note that this also saves V16-31, which aren't visible
+	 * in AArch32.
+	 */
+	fpsimd_save_state(fpsimd);
+
+	/* Place structure header on the stack */
+	__put_user_error(magic, &frame->magic, err);
+	__put_user_error(size, &frame->size, err);
+
+	/*
+	 * Now copy the FP registers. Since the registers are packed,
+	 * we can copy the prefix we want (V0-V15) as it is.
+	 * FIXME: Won't work if big endian.
+	 */
+	err |= __copy_to_user(&frame->ufp.fpregs, fpsimd->vregs,
+			      sizeof(frame->ufp.fpregs));
+
+	/* Create an AArch32 fpscr from the fpsr and the fpcr. */
+	fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) |
+		(fpsimd->fpcr & VFP_FPSCR_CTRL_MASK);
+	__put_user_error(fpscr, &frame->ufp.fpscr, err);
+
+	/*
+	 * The exception register aren't available so we fake up a
+	 * basic FPEXC and zero everything else.
+	 */
+	fpexc = (1 << 30);
+	__put_user_error(fpexc, &frame->ufp_exc.fpexc, err);
+	__put_user_error(0, &frame->ufp_exc.fpinst, err);
+	__put_user_error(0, &frame->ufp_exc.fpinst2, err);
+
+	return err ? -EFAULT : 0;
+}
+
+static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
+{
+	struct fpsimd_state fpsimd;
+	compat_ulong_t magic = VFP_MAGIC;
+	compat_ulong_t size = VFP_STORAGE_SIZE;
+	compat_ulong_t fpscr;
+	int err = 0;
+
+	__get_user_error(magic, &frame->magic, err);
+	__get_user_error(size, &frame->size, err);
+
+	if (err)
+		return -EFAULT;
+	if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
+		return -EINVAL;
+
+	/*
+	 * Copy the FP registers into the start of the fpsimd_state.
+	 * FIXME: Won't work if big endian.
+	 */
+	err |= __copy_from_user(fpsimd.vregs, frame->ufp.fpregs,
+				sizeof(frame->ufp.fpregs));
+
+	/* Extract the fpsr and the fpcr from the fpscr */
+	__get_user_error(fpscr, &frame->ufp.fpscr, err);
+	fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK;
+	fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
+
+	/*
+	 * We don't need to touch the exception register, so
+	 * reload the hardware state.
+	 */
+	if (!err) {
+		preempt_disable();
+		fpsimd_load_state(&fpsimd);
+		preempt_enable();
+	}
+
+	return err ? -EFAULT : 0;
+}
+
+/*
+ * atomically swap in the new signal mask, and wait for a signal.
+ */
+asmlinkage int compat_sys_sigsuspend(int restart, compat_ulong_t oldmask,
+				     compat_old_sigset_t mask)
+{
+	sigset_t blocked;
+
+	siginitset(&current->blocked, mask);
+	return sigsuspend(&blocked);
+}
+
+asmlinkage int compat_sys_sigaction(int sig,
+				    const struct compat_old_sigaction __user *act,
+				    struct compat_old_sigaction __user *oact)
+{
+	struct k_sigaction new_ka, old_ka;
+	int ret;
+	compat_old_sigset_t mask;
+	compat_uptr_t handler, restorer;
+
+	if (act) {
+		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
+		    __get_user(handler, &act->sa_handler) ||
+		    __get_user(restorer, &act->sa_restorer) ||
+		    __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
+		    __get_user(mask, &act->sa_mask))
+			return -EFAULT;
+
+		new_ka.sa.sa_handler = compat_ptr(handler);
+		new_ka.sa.sa_restorer = compat_ptr(restorer);
+		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(ptr_to_compat(old_ka.sa.sa_handler),
+			       &oact->sa_handler) ||
+		    __put_user(ptr_to_compat(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 compat_sys_rt_sigaction(int sig,
+				       const struct compat_sigaction __user *act,
+				       struct compat_sigaction __user *oact,
+				       compat_size_t sigsetsize)
+{
+	struct k_sigaction new_ka, old_ka;
+	int ret;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(compat_sigset_t))
+		return -EINVAL;
+
+	if (act) {
+		compat_uptr_t handler, restorer;
+
+		ret = get_user(handler, &act->sa_handler);
+		new_ka.sa.sa_handler = compat_ptr(handler);
+		ret |= get_user(restorer, &act->sa_restorer);
+		new_ka.sa.sa_restorer = compat_ptr(restorer);
+		ret |= get_sigset_t(&new_ka.sa.sa_mask, &act->sa_mask);
+		ret |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
+		if (ret)
+			return -EFAULT;
+	}
+
+	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+	if (!ret && oact) {
+		ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler);
+		ret |= put_sigset_t(&oact->sa_mask, &old_ka.sa.sa_mask);
+		ret |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+	}
+	return ret;
+}
+
+int compat_do_sigaltstack(compat_uptr_t compat_uss, compat_uptr_t compat_uoss,
+			  compat_ulong_t sp)
+{
+	compat_stack_t __user *newstack = compat_ptr(compat_uss);
+	compat_stack_t __user *oldstack = compat_ptr(compat_uoss);
+	compat_uptr_t ss_sp;
+	int ret;
+	mm_segment_t old_fs;
+	stack_t uss, uoss;
+
+	/* Marshall the compat new stack into a stack_t */
+	if (newstack) {
+		if (get_user(ss_sp, &newstack->ss_sp) ||
+		    __get_user(uss.ss_flags, &newstack->ss_flags) ||
+		    __get_user(uss.ss_size, &newstack->ss_size))
+			return -EFAULT;
+		uss.ss_sp = compat_ptr(ss_sp);
+	}
+
+	old_fs = get_fs();
+	set_fs(KERNEL_DS);
+	/* The __user pointer casts are valid because of the set_fs() */
+	ret = do_sigaltstack(
+		newstack ? (stack_t __user *) &uss : NULL,
+		oldstack ? (stack_t __user *) &uoss : NULL,
+		(unsigned long)sp);
+	set_fs(old_fs);
+
+	/* Convert the old stack_t into a compat stack. */
+	if (!ret && oldstack &&
+		(put_user(ptr_to_compat(uoss.ss_sp), &oldstack->ss_sp) ||
+		 __put_user(uoss.ss_flags, &oldstack->ss_flags) ||
+		 __put_user(uoss.ss_size, &oldstack->ss_size)))
+		return -EFAULT;
+	return ret;
+}
+
+static int compat_restore_sigframe(struct pt_regs *regs,
+				   struct compat_sigframe __user *sf)
+{
+	int err;
+	sigset_t set;
+	struct compat_aux_sigframe __user *aux;
+
+	err = get_sigset_t(&set, &sf->uc.uc_sigmask);
+	if (err == 0) {
+		sigdelsetmask(&set, ~_BLOCKABLE);
+		set_current_blocked(&set);
+	}
+
+	__get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
+	__get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
+	__get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
+	__get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
+	__get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
+	__get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
+	__get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
+	__get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
+	__get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
+	__get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
+	__get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
+	__get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
+	__get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
+	__get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
+	__get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
+	__get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
+	__get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
+
+	/*
+	 * Avoid compat_sys_sigreturn() restarting.
+	 */
+	regs->syscallno = ~0UL;
+
+	err |= !valid_user_regs(&regs->user_regs);
+
+	aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
+	if (err == 0)
+		err |= compat_restore_vfp_context(&aux->vfp);
+
+	return err;
+}
+
+asmlinkage int compat_sys_sigreturn(struct pt_regs *regs)
+{
+	struct compat_sigframe __user *frame;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
+	/*
+	 * Since we stacked the signal on a 64-bit boundary,
+	 * then 'sp' should be word aligned here.  If it's
+	 * not, then the user is trying to mess with us.
+	 */
+	if (regs->compat_sp & 7)
+		goto badframe;
+
+	frame = (struct compat_sigframe __user *)regs->compat_sp;
+
+	if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
+		goto badframe;
+
+	if (compat_restore_sigframe(regs, frame))
+		goto badframe;
+
+	return regs->regs[0];
+
+badframe:
+	if (show_unhandled_signals)
+		pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
+				    current->comm, task_pid_nr(current), __func__,
+				    regs->pc, regs->sp);
+	force_sig(SIGSEGV, current);
+	return 0;
+}
+
+asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs)
+{
+	struct compat_rt_sigframe __user *frame;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
+	/*
+	 * Since we stacked the signal on a 64-bit boundary,
+	 * then 'sp' should be word aligned here.  If it's
+	 * not, then the user is trying to mess with us.
+	 */
+	if (regs->compat_sp & 7)
+		goto badframe;
+
+	frame = (struct compat_rt_sigframe __user *)regs->compat_sp;
+
+	if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
+		goto badframe;
+
+	if (compat_restore_sigframe(regs, &frame->sig))
+		goto badframe;
+
+	if (compat_do_sigaltstack(ptr_to_compat(&frame->sig.uc.uc_stack),
+				 ptr_to_compat((void __user *)NULL),
+				 regs->compat_sp) == -EFAULT)
+		goto badframe;
+
+	return regs->regs[0];
+
+badframe:
+	if (show_unhandled_signals)
+		pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
+				    current->comm, task_pid_nr(current), __func__,
+				    regs->pc, regs->sp);
+	force_sig(SIGSEGV, current);
+	return 0;
+}
+
+static inline void __user *compat_get_sigframe(struct k_sigaction *ka,
+					       struct pt_regs *regs,
+					       int framesize)
+{
+	compat_ulong_t sp = regs->compat_sp;
+	void __user *frame;
+
+	/*
+	 * This is the X/Open sanctioned signal stack switching.
+	 */
+	if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
+		sp = current->sas_ss_sp + current->sas_ss_size;
+
+	/*
+	 * ATPCS B01 mandates 8-byte alignment
+	 */
+	frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7));
+
+	/*
+	 * Check that we can actually write to the signal frame.
+	 */
+	if (!access_ok(VERIFY_WRITE, frame, framesize))
+		frame = NULL;
+
+	return frame;
+}
+
+static int compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
+			       compat_ulong_t __user *rc, void __user *frame,
+			       int usig)
+{
+	compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler);
+	compat_ulong_t retcode;
+	compat_ulong_t spsr = regs->pstate & ~PSR_f;
+	int thumb;
+
+	/* Check if the handler is written for ARM or Thumb */
+	thumb = handler & 1;
+
+	if (thumb) {
+		spsr |= COMPAT_PSR_T_BIT;
+		spsr &= ~COMPAT_PSR_IT_MASK;
+	} else {
+		spsr &= ~COMPAT_PSR_T_BIT;
+	}
+
+	if (ka->sa.sa_flags & SA_RESTORER) {
+		retcode = ptr_to_compat(ka->sa.sa_restorer);
+	} else {
+		/* Set up sigreturn pointer */
+		unsigned int idx = thumb << 1;
+
+		if (ka->sa.sa_flags & SA_SIGINFO)
+			idx += 3;
+
+		retcode = AARCH32_VECTORS_BASE +
+			  AARCH32_KERN_SIGRET_CODE_OFFSET +
+			  (idx << 2) + thumb;
+	}
+
+	regs->regs[0]	= usig;
+	regs->compat_sp	= ptr_to_compat(frame);
+	regs->compat_lr	= retcode;
+	regs->pc	= handler;
+	regs->pstate	= spsr;
+
+	return 0;
+}
+
+static int compat_setup_sigframe(struct compat_sigframe __user *sf,
+				 struct pt_regs *regs, sigset_t *set)
+{
+	struct compat_aux_sigframe __user *aux;
+	int err = 0;
+
+	__put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
+	__put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
+	__put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
+	__put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
+	__put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
+	__put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
+	__put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
+	__put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
+	__put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
+	__put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
+	__put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
+	__put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
+	__put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
+	__put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
+	__put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
+	__put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
+	__put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
+
+	__put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err);
+	__put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.error_code, err);
+	__put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
+	__put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
+
+	err |= put_sigset_t(&sf->uc.uc_sigmask, set);
+
+	aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
+
+	if (err == 0)
+		err |= compat_preserve_vfp_context(&aux->vfp);
+	__put_user_error(0, &aux->end_magic, err);
+
+	return err;
+}
+
+/*
+ * 32-bit signal handling routines called from signal.c
+ */
+int compat_setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
+			  sigset_t *set, struct pt_regs *regs)
+{
+	struct compat_rt_sigframe __user *frame;
+	compat_stack_t stack;
+	int err = 0;
+
+	frame = compat_get_sigframe(ka, regs, sizeof(*frame));
+
+	if (!frame)
+		return 1;
+
+	err |= copy_siginfo_to_user32(&frame->info, info);
+
+	__put_user_error(0, &frame->sig.uc.uc_flags, err);
+	__put_user_error(NULL, &frame->sig.uc.uc_link, err);
+
+	memset(&stack, 0, sizeof(stack));
+	stack.ss_sp = (compat_uptr_t)current->sas_ss_sp;
+	stack.ss_flags = sas_ss_flags(regs->compat_sp);
+	stack.ss_size = current->sas_ss_size;
+	err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
+
+	err |= compat_setup_sigframe(&frame->sig, regs, set);
+	if (err == 0)
+		err = compat_setup_return(regs, ka, frame->sig.retcode, frame,
+					  usig);
+
+	if (err == 0) {
+		regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info;
+		regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc;
+	}
+
+	return err;
+}
+
+int compat_setup_frame(int usig, struct k_sigaction *ka, sigset_t *set,
+		       struct pt_regs *regs)
+{
+	struct compat_sigframe __user *frame;
+	int err = 0;
+
+	frame = compat_get_sigframe(ka, regs, sizeof(*frame));
+
+	if (!frame)
+		return 1;
+
+	__put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
+
+	err |= compat_setup_sigframe(frame, regs, set);
+	if (err == 0)
+		err = compat_setup_return(regs, ka, frame->retcode, frame, usig);
+
+	return err;
+}
+
+/*
+ * RT signals don't have generic compat wrappers.
+ * See arch/powerpc/kernel/signal_32.c
+ */
+asmlinkage int compat_sys_rt_sigprocmask(int how, compat_sigset_t __user *set,
+					 compat_sigset_t __user *oset,
+					 compat_size_t sigsetsize)
+{
+	sigset_t s;
+	sigset_t __user *up;
+	int ret;
+	mm_segment_t old_fs = get_fs();
+
+	if (set) {
+		if (get_sigset_t(&s, set))
+			return -EFAULT;
+	}
+
+	set_fs(KERNEL_DS);
+	/* This is valid because of the set_fs() */
+	up = (sigset_t __user *) &s;
+	ret = sys_rt_sigprocmask(how, set ? up : NULL, oset ? up : NULL,
+				 sigsetsize);
+	set_fs(old_fs);
+	if (ret)
+		return ret;
+	if (oset) {
+		if (put_sigset_t(oset, &s))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+asmlinkage int compat_sys_rt_sigpending(compat_sigset_t __user *set,
+					compat_size_t sigsetsize)
+{
+	sigset_t s;
+	int ret;
+	mm_segment_t old_fs = get_fs();
+
+	set_fs(KERNEL_DS);
+	/* The __user pointer cast is valid because of the set_fs() */
+	ret = sys_rt_sigpending((sigset_t __user *) &s, sigsetsize);
+	set_fs(old_fs);
+	if (!ret) {
+		if (put_sigset_t(set, &s))
+			return -EFAULT;
+	}
+	return ret;
+}
+
+asmlinkage int compat_sys_rt_sigqueueinfo(int pid, int sig,
+					  compat_siginfo_t __user *uinfo)
+{
+	siginfo_t info;
+	int ret;
+	mm_segment_t old_fs = get_fs();
+
+	ret = copy_siginfo_from_user32(&info, uinfo);
+	if (unlikely(ret))
+		return ret;
+
+	set_fs (KERNEL_DS);
+	/* The __user pointer cast is valid because of the set_fs() */
+	ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __user *) &info);
+	set_fs (old_fs);
+	return ret;
+}
+
+void compat_setup_restart_syscall(struct pt_regs *regs)
+{
+       regs->regs[7] = __NR_restart_syscall;
+}