arch/arm/kernel/signal.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  *  linux/arch/arm/kernel/signal.c
  *
  *  Copyright (C) 1995-2002 Russell King
  *
  * 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.
  */
 #include <linux/errno.h>
 #include <linux/signal.h>
 #include <linux/personality.h>
 #include <linux/freezer.h>
 #include <linux/uaccess.h>
 #include <linux/tracehook.h>

 #include <asm/elf.h>
 #include <asm/cacheflush.h>
 #include <asm/ucontext.h>
 #include <asm/unistd.h>

 #include "ptrace.h"
 #include "signal.h"

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

 /*
  * For ARM syscalls, we encode the syscall number into the instruction.
  */
 #define SWI_SYS_SIGRETURN	(0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
 #define SWI_SYS_RT_SIGRETURN	(0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))

 /*
  * With EABI, the syscall number has to be loaded into r7.
  */
 #define MOV_R7_NR_SIGRETURN	(0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
 #define MOV_R7_NR_RT_SIGRETURN	(0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))

 /*
  * For Thumb syscalls, we pass the syscall number via r7.  We therefore
  * need two 16-bit instructions.
  */
 #define SWI_THUMB_SIGRETURN	(0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
 #define SWI_THUMB_RT_SIGRETURN	(0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))

 const unsigned long sigreturn_codes[7] = {
 	MOV_R7_NR_SIGRETURN,    SWI_SYS_SIGRETURN,    SWI_THUMB_SIGRETURN,
 	MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
 };

 /*
  * atomically swap in the new signal mask, and wait for a signal.
  */
 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
 {
 	mask &= _BLOCKABLE;
 	spin_lock_irq(&current->sighand->siglock);
 	current->saved_sigmask = current->blocked;
 	siginitset(&current->blocked, mask);
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);

 	current->state = TASK_INTERRUPTIBLE;
 	schedule();
 	set_restore_sigmask();
 	return -ERESTARTNOHAND;
 }

 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))
 			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;
 }

 #ifdef CONFIG_CRUNCH
 static int preserve_crunch_context(struct crunch_sigframe __user *frame)
 {
 	char kbuf[sizeof(*frame) + 8];
 	struct crunch_sigframe *kframe;

 	/* the crunch context must be 64 bit aligned */
 	kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 	kframe->magic = CRUNCH_MAGIC;
 	kframe->size = CRUNCH_STORAGE_SIZE;
 	crunch_task_copy(current_thread_info(), &kframe->storage);
 	return __copy_to_user(frame, kframe, sizeof(*frame));
 }

 static int restore_crunch_context(struct crunch_sigframe __user *frame)
 {
 	char kbuf[sizeof(*frame) + 8];
 	struct crunch_sigframe *kframe;

 	/* the crunch context must be 64 bit aligned */
 	kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 	if (__copy_from_user(kframe, frame, sizeof(*frame)))
 		return -1;
 	if (kframe->magic != CRUNCH_MAGIC ||
 	    kframe->size != CRUNCH_STORAGE_SIZE)
 		return -1;
 	crunch_task_restore(current_thread_info(), &kframe->storage);
 	return 0;
 }
 #endif

 #ifdef CONFIG_IWMMXT

 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
 {
 	char kbuf[sizeof(*frame) + 8];
 	struct iwmmxt_sigframe *kframe;

 	/* the iWMMXt context must be 64 bit aligned */
 	kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 	kframe->magic = IWMMXT_MAGIC;
 	kframe->size = IWMMXT_STORAGE_SIZE;
 	iwmmxt_task_copy(current_thread_info(), &kframe->storage);
 	return __copy_to_user(frame, kframe, sizeof(*frame));
 }

 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
 {
 	char kbuf[sizeof(*frame) + 8];
 	struct iwmmxt_sigframe *kframe;

 	/* the iWMMXt context must be 64 bit aligned */
 	kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 	if (__copy_from_user(kframe, frame, sizeof(*frame)))
 		return -1;
 	if (kframe->magic != IWMMXT_MAGIC ||
 	    kframe->size != IWMMXT_STORAGE_SIZE)
 		return -1;
 	iwmmxt_task_restore(current_thread_info(), &kframe->storage);
 	return 0;
 }

 #endif

 /*
  * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
  */
 struct sigframe {
 	struct ucontext uc;
 	unsigned long retcode[2];
 };

 struct rt_sigframe {
 	struct siginfo info;
 	struct sigframe sig;
 };

 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
 {
 	struct aux_sigframe __user *aux;
 	sigset_t set;
 	int err;

 	err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
 	if (err == 0) {
 		sigdelsetmask(&set, ~_BLOCKABLE);
 		spin_lock_irq(&current->sighand->siglock);
 		current->blocked = set;
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
 	}

 	__get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 	__get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 	__get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 	__get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 	__get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 	__get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 	__get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 	__get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 	__get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 	__get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 	__get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 	__get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 	__get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 	__get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 	__get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 	__get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 	__get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);

 	err |= !valid_user_regs(regs);

 	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 #ifdef CONFIG_CRUNCH
 	if (err == 0)
 		err |= restore_crunch_context(&aux->crunch);
 #endif
 #ifdef CONFIG_IWMMXT
 	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 		err |= restore_iwmmxt_context(&aux->iwmmxt);
 #endif
 #ifdef CONFIG_VFP
 //	if (err == 0)
 //		err |= vfp_restore_state(&sf->aux.vfp);
 #endif

 	return err;
 }

 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 {
 	struct 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->ARM_sp & 7)
 		goto badframe;

 	frame = (struct sigframe __user *)regs->ARM_sp;

 	if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 		goto badframe;

 	if (restore_sigframe(regs, frame))
 		goto badframe;

 	single_step_trap(current);

 	return regs->ARM_r0;

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

 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 {
 	struct 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->ARM_sp & 7)
 		goto badframe;

 	frame = (struct rt_sigframe __user *)regs->ARM_sp;

 	if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 		goto badframe;

 	if (restore_sigframe(regs, &frame->sig))
 		goto badframe;

 	if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
 		goto badframe;

 	single_step_trap(current);

 	return regs->ARM_r0;

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

 static int
 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
 {
 	struct aux_sigframe __user *aux;
 	int err = 0;

 	__put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 	__put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 	__put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 	__put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 	__put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 	__put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 	__put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 	__put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 	__put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 	__put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 	__put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 	__put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 	__put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 	__put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 	__put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 	__put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 	__put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);

 	__put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
 	__put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
 	__put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
 	__put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);

 	err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));

 	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 #ifdef CONFIG_CRUNCH
 	if (err == 0)
 		err |= preserve_crunch_context(&aux->crunch);
 #endif
 #ifdef CONFIG_IWMMXT
 	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 		err |= preserve_iwmmxt_context(&aux->iwmmxt);
 #endif
 #ifdef CONFIG_VFP
 //	if (err == 0)
 //		err |= vfp_save_state(&sf->aux.vfp);
 #endif
 	__put_user_error(0, &aux->end_magic, err);

 	return err;
 }

 static inline void __user *
 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
 {
 	unsigned long sp = regs->ARM_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 = (void __user *)((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
 setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 	     unsigned long __user *rc, void __user *frame, int usig)
 {
 	unsigned long handler = (unsigned long)ka->sa.sa_handler;
 	unsigned long retcode;
 	int thumb = 0;
 	unsigned long cpsr = regs->ARM_cpsr & ~PSR_f;

 	/*
 	 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
 	 */
 	if (ka->sa.sa_flags & SA_THIRTYTWO)
 		cpsr = (cpsr & ~MODE_MASK) | USR_MODE;

 #ifdef CONFIG_ARM_THUMB
 	if (elf_hwcap & HWCAP_THUMB) {
 		/*
 		 * The LSB of the handler determines if we're going to
 		 * be using THUMB or ARM mode for this signal handler.
 		 */
 		thumb = handler & 1;

 		if (thumb) {
 			cpsr |= PSR_T_BIT;
 #if __LINUX_ARM_ARCH__ >= 7
 			/* clear the If-Then Thumb-2 execution state */
 			cpsr &= ~PSR_IT_MASK;
 #endif
 		} else
 			cpsr &= ~PSR_T_BIT;
 	}
 #endif

 	if (ka->sa.sa_flags & SA_RESTORER) {
 		retcode = (unsigned long)ka->sa.sa_restorer;
 	} else {
 		unsigned int idx = thumb << 1;

 		if (ka->sa.sa_flags & SA_SIGINFO)
 			idx += 3;

 		if (__put_user(sigreturn_codes[idx],   rc) ||
 		    __put_user(sigreturn_codes[idx+1], rc+1))
 			return 1;

 		if (cpsr & MODE32_BIT) {
 			/*
 			 * 32-bit code can use the new high-page
 			 * signal return code support.
 			 */
 			retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
 		} else {
 			/*
 			 * Ensure that the instruction cache sees
 			 * the return code written onto the stack.
 			 */
 			flush_icache_range((unsigned long)rc,
 					   (unsigned long)(rc + 2));

 			retcode = ((unsigned long)rc) + thumb;
 		}
 	}

 	regs->ARM_r0 = usig;
 	regs->ARM_sp = (unsigned long)frame;
 	regs->ARM_lr = retcode;
 	regs->ARM_pc = handler;
 	regs->ARM_cpsr = cpsr;

 	return 0;
 }

 static int
 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
 {
 	struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 	int err = 0;

 	if (!frame)
 		return 1;

 	/*
 	 * Set uc.uc_flags to a value which sc.trap_no would never have.
 	 */
 	__put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);

 	err |= setup_sigframe(frame, regs, set);
 	if (err == 0)
 		err = setup_return(regs, ka, frame->retcode, frame, usig);

 	return err;
 }

 static int
 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 	       sigset_t *set, struct pt_regs *regs)
 {
 	struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 	stack_t stack;
 	int err = 0;

 	if (!frame)
 		return 1;

 	err |= copy_siginfo_to_user(&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 = (void __user *)current->sas_ss_sp;
 	stack.ss_flags = sas_ss_flags(regs->ARM_sp);
 	stack.ss_size = current->sas_ss_size;
 	err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));

 	err |= setup_sigframe(&frame->sig, regs, set);
 	if (err == 0)
 		err = setup_return(regs, ka, frame->sig.retcode, frame, usig);

 	if (err == 0) {
 		/*
 		 * For realtime signals we must also set the second and third
 		 * arguments for the signal handler.
 		 *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
 		 */
 		regs->ARM_r1 = (unsigned long)&frame->info;
 		regs->ARM_r2 = (unsigned long)&frame->sig.uc;
 	}

 	return err;
 }

 static inline void setup_syscall_restart(struct pt_regs *regs)
 {
 	regs->ARM_r0 = regs->ARM_ORIG_r0;
 	regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
 }

 /*
  * OK, we're invoking a handler
  */
 static int
 handle_signal(unsigned long sig, struct k_sigaction *ka,
 	      siginfo_t *info, sigset_t *oldset,
 	      struct pt_regs * regs, int syscall)
 {
 	struct thread_info *thread = current_thread_info();
 	struct task_struct *tsk = current;
 	int usig = sig;
 	int ret;

 	/*
 	 * If we were from a system call, check for system call restarting...
 	 */
 	if (syscall) {
 		switch (regs->ARM_r0) {
 		case -ERESTART_RESTARTBLOCK:
 		case -ERESTARTNOHAND:
 			regs->ARM_r0 = -EINTR;
 			break;
 		case -ERESTARTSYS:
 			if (!(ka->sa.sa_flags & SA_RESTART)) {
 				regs->ARM_r0 = -EINTR;
 				break;
 			}
 			/* fallthrough */
 		case -ERESTARTNOINTR:
 			setup_syscall_restart(regs);
 		}
 	}

 	/*
 	 * translate the signal
 	 */
 	if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
 		usig = thread->exec_domain->signal_invmap[usig];

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

 	/*
 	 * Check that the resulting registers are actually sane.
 	 */
 	ret |= !valid_user_regs(regs);

 	if (ret != 0) {
 		force_sigsegv(sig, tsk);
 		return ret;
 	}

 	/*
 	 * Block the signal if we were successful.
 	 */
 	spin_lock_irq(&tsk->sighand->siglock);
 	sigorsets(&tsk->blocked, &tsk->blocked,
 		  &ka->sa.sa_mask);
 	if (!(ka->sa.sa_flags & SA_NODEFER))
 		sigaddset(&tsk->blocked, sig);
 	recalc_sigpending();
 	spin_unlock_irq(&tsk->sighand->siglock);

 	return 0;
 }

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

 	/*
 	 * 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 (!user_mode(regs))
 		return;

 	if (try_to_freeze())
 		goto no_signal;

 	single_step_clear(current);

 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (signr > 0) {
 		sigset_t *oldset;

 		if (test_thread_flag(TIF_RESTORE_SIGMASK))
 			oldset = &current->saved_sigmask;
 		else
 			oldset = &current->blocked;
 		if (handle_signal(signr, &ka, &info, oldset, regs, syscall) == 0) {
 			/*
 			 * A signal was successfully delivered; the saved
 			 * sigmask will have been stored in the signal frame,
 			 * and will be restored by sigreturn, so we can simply
 			 * clear the TIF_RESTORE_SIGMASK flag.
 			 */
 			if (test_thread_flag(TIF_RESTORE_SIGMASK))
 				clear_thread_flag(TIF_RESTORE_SIGMASK);
 		}
 		single_step_set(current);
 		return;
 	}

  no_signal:
 	/*
 	 * No signal to deliver to the process - restart the syscall.
 	 */
 	if (syscall) {
 		if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
 			if (thumb_mode(regs)) {
 				regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
 				regs->ARM_pc -= 2;
 			} else {
 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
 				regs->ARM_r7 = __NR_restart_syscall;
 				regs->ARM_pc -= 4;
 #else
 				u32 __user *usp;
 				u32 swival = __NR_restart_syscall;

 				regs->ARM_sp -= 12;
 				usp = (u32 __user *)regs->ARM_sp;

 				/*
 				 * Either we supports OABI only, or we have
 				 * EABI with the OABI compat layer enabled.
 				 * In the later case we don't know if user
 				 * space is EABI or not, and if not we must
 				 * not clobber r7.  Always using the OABI
 				 * syscall solves that issue and works for
 				 * all those cases.
 				 */
 				swival = swival - __NR_SYSCALL_BASE + __NR_OABI_SYSCALL_BASE;

 				put_user(regs->ARM_pc, &usp[0]);
 				/* swi __NR_restart_syscall */
 				put_user(0xef000000 | swival, &usp[1]);
 				/* ldr	pc, [sp], #12 */
 				put_user(0xe49df00c, &usp[2]);

 				flush_icache_range((unsigned long)usp,
 						   (unsigned long)(usp + 3));

 				regs->ARM_pc = regs->ARM_sp + 4;
 #endif
 			}
 		}
 		if (regs->ARM_r0 == -ERESTARTNOHAND ||
 		    regs->ARM_r0 == -ERESTARTSYS ||
 		    regs->ARM_r0 == -ERESTARTNOINTR) {
 			setup_syscall_restart(regs);
 		}

 		/* If there's no signal to deliver, we just put the saved sigmask
 		 * back.
 		 */
 		if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 			clear_thread_flag(TIF_RESTORE_SIGMASK);
 			sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 		}
 	}
 	single_step_set(current);
 }

 asmlinkage void
 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 {
 	if (thread_flags & _TIF_SIGPENDING)
 		do_signal(regs, syscall);

 	if (thread_flags & _TIF_NOTIFY_RESUME) {
 		clear_thread_flag(TIF_NOTIFY_RESUME);
 		tracehook_notify_resume(regs);
 		if (current->replacement_session_keyring)
 			key_replace_session_keyring();
 	}
 }
	/*
	* linux/arch/arm/kernel/signal.c
	*
	* Copyright (C) 1995-2002 Russell King
	*
	* 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.
	*/
	#include <linux/errno.h>
	#include <linux/signal.h>
	#include <linux/personality.h>
	#include <linux/freezer.h>
	#include <linux/uaccess.h>
	#include <linux/tracehook.h>

	#include <asm/elf.h>
	#include <asm/cacheflush.h>
	#include <asm/ucontext.h>
	#include <asm/unistd.h>

	#include "ptrace.h"
	#include "signal.h"

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

	/*
	* For ARM syscalls, we encode the syscall number into the instruction.
	*/
	#define SWI_SYS_SIGRETURN (0xef000000\|(__NR_sigreturn)\|(__NR_OABI_SYSCALL_BASE))
	#define SWI_SYS_RT_SIGRETURN (0xef000000\|(__NR_rt_sigreturn)\|(__NR_OABI_SYSCALL_BASE))

	/*
	* With EABI, the syscall number has to be loaded into r7.
	*/
	#define MOV_R7_NR_SIGRETURN (0xe3a07000 \| (__NR_sigreturn - __NR_SYSCALL_BASE))
	#define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 \| (__NR_rt_sigreturn - __NR_SYSCALL_BASE))

	/*
	* For Thumb syscalls, we pass the syscall number via r7. We therefore
	* need two 16-bit instructions.
	*/
	#define SWI_THUMB_SIGRETURN (0xdf00 << 16 \| 0x2700 \| (__NR_sigreturn - __NR_SYSCALL_BASE))
	#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 \| 0x2700 \| (__NR_rt_sigreturn - __NR_SYSCALL_BASE))

	const unsigned long sigreturn_codes[7] = {
	MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
	MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
	};

	/*
	* atomically swap in the new signal mask, and wait for a signal.
	*/
	asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
	{
	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
	current->saved_sigmask = current->blocked;
	siginitset(&current->blocked, mask);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	current->state = TASK_INTERRUPTIBLE;
	schedule();
	set_restore_sigmask();
	return -ERESTARTNOHAND;
	}

	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))
	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;
	}

	#ifdef CONFIG_CRUNCH
	static int preserve_crunch_context(struct crunch_sigframe __user *frame)
	{
	char kbuf[sizeof(*frame) + 8];
	struct crunch_sigframe *kframe;

	/* the crunch context must be 64 bit aligned */
	kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
	kframe->magic = CRUNCH_MAGIC;
	kframe->size = CRUNCH_STORAGE_SIZE;
	crunch_task_copy(current_thread_info(), &kframe->storage);
	return __copy_to_user(frame, kframe, sizeof(*frame));
	}

	static int restore_crunch_context(struct crunch_sigframe __user *frame)
	{
	char kbuf[sizeof(*frame) + 8];
	struct crunch_sigframe *kframe;

	/* the crunch context must be 64 bit aligned */
	kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
	if (__copy_from_user(kframe, frame, sizeof(*frame)))
	return -1;
	if (kframe->magic != CRUNCH_MAGIC \|\|
	kframe->size != CRUNCH_STORAGE_SIZE)
	return -1;
	crunch_task_restore(current_thread_info(), &kframe->storage);
	return 0;
	}
	#endif

	#ifdef CONFIG_IWMMXT

	static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
	{
	char kbuf[sizeof(*frame) + 8];
	struct iwmmxt_sigframe *kframe;

	/* the iWMMXt context must be 64 bit aligned */
	kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
	kframe->magic = IWMMXT_MAGIC;
	kframe->size = IWMMXT_STORAGE_SIZE;
	iwmmxt_task_copy(current_thread_info(), &kframe->storage);
	return __copy_to_user(frame, kframe, sizeof(*frame));
	}

	static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
	{
	char kbuf[sizeof(*frame) + 8];
	struct iwmmxt_sigframe *kframe;

	/* the iWMMXt context must be 64 bit aligned */
	kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
	if (__copy_from_user(kframe, frame, sizeof(*frame)))
	return -1;
	if (kframe->magic != IWMMXT_MAGIC \|\|
	kframe->size != IWMMXT_STORAGE_SIZE)
	return -1;
	iwmmxt_task_restore(current_thread_info(), &kframe->storage);
	return 0;
	}

	#endif

	/*
	* Do a signal return; undo the signal stack. These are aligned to 64-bit.
	*/
	struct sigframe {
	struct ucontext uc;
	unsigned long retcode[2];
	};

	struct rt_sigframe {
	struct siginfo info;
	struct sigframe sig;
	};

	static int restore_sigframe(struct pt_regs regs, struct sigframe __user sf)
	{
	struct aux_sigframe __user *aux;
	sigset_t set;
	int err;

	err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
	if (err == 0) {
	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	}

	__get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
	__get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
	__get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
	__get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
	__get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
	__get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
	__get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
	__get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
	__get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
	__get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
	__get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
	__get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
	__get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
	__get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
	__get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
	__get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
	__get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);

	err \|= !valid_user_regs(regs);

	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
	#ifdef CONFIG_CRUNCH
	if (err == 0)
	err \|= restore_crunch_context(&aux->crunch);
	#endif
	#ifdef CONFIG_IWMMXT
	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
	err \|= restore_iwmmxt_context(&aux->iwmmxt);
	#endif
	#ifdef CONFIG_VFP
	// if (err == 0)
	// err \|= vfp_restore_state(&sf->aux.vfp);
	#endif

	return err;
	}

	asmlinkage int sys_sigreturn(struct pt_regs *regs)
	{
	struct 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->ARM_sp & 7)
	goto badframe;

	frame = (struct sigframe __user *)regs->ARM_sp;

	if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
	goto badframe;

	if (restore_sigframe(regs, frame))
	goto badframe;

	single_step_trap(current);

	return regs->ARM_r0;

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

	asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
	{
	struct 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->ARM_sp & 7)
	goto badframe;

	frame = (struct rt_sigframe __user *)regs->ARM_sp;

	if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
	goto badframe;

	if (restore_sigframe(regs, &frame->sig))
	goto badframe;

	if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
	goto badframe;

	single_step_trap(current);

	return regs->ARM_r0;

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

	static int
	setup_sigframe(struct sigframe __user sf, struct pt_regs regs, sigset_t *set)
	{
	struct aux_sigframe __user *aux;
	int err = 0;

	__put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
	__put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
	__put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
	__put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
	__put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
	__put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
	__put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
	__put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
	__put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
	__put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
	__put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
	__put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
	__put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
	__put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
	__put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
	__put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
	__put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);

	__put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
	__put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
	__put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
	__put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);

	err \|= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));

	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
	#ifdef CONFIG_CRUNCH
	if (err == 0)
	err \|= preserve_crunch_context(&aux->crunch);
	#endif
	#ifdef CONFIG_IWMMXT
	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
	err \|= preserve_iwmmxt_context(&aux->iwmmxt);
	#endif
	#ifdef CONFIG_VFP
	// if (err == 0)
	// err \|= vfp_save_state(&sf->aux.vfp);
	#endif
	__put_user_error(0, &aux->end_magic, err);

	return err;
	}

	static inline void __user *
	get_sigframe(struct k_sigaction ka, struct pt_regs regs, int framesize)
	{
	unsigned long sp = regs->ARM_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 = (void __user *)((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
	setup_return(struct pt_regs regs, struct k_sigaction ka,
	unsigned long __user rc, void __user frame, int usig)
	{
	unsigned long handler = (unsigned long)ka->sa.sa_handler;
	unsigned long retcode;
	int thumb = 0;
	unsigned long cpsr = regs->ARM_cpsr & ~PSR_f;

	/*
	* Maybe we need to deliver a 32-bit signal to a 26-bit task.
	*/
	if (ka->sa.sa_flags & SA_THIRTYTWO)
	cpsr = (cpsr & ~MODE_MASK) \| USR_MODE;

	#ifdef CONFIG_ARM_THUMB
	if (elf_hwcap & HWCAP_THUMB) {
	/*
	* The LSB of the handler determines if we're going to
	* be using THUMB or ARM mode for this signal handler.
	*/
	thumb = handler & 1;

	if (thumb) {
	cpsr \|= PSR_T_BIT;
	#if __LINUX_ARM_ARCH__ >= 7
	/* clear the If-Then Thumb-2 execution state */
	cpsr &= ~PSR_IT_MASK;
	#endif
	} else
	cpsr &= ~PSR_T_BIT;
	}
	#endif

	if (ka->sa.sa_flags & SA_RESTORER) {
	retcode = (unsigned long)ka->sa.sa_restorer;
	} else {
	unsigned int idx = thumb << 1;

	if (ka->sa.sa_flags & SA_SIGINFO)
	idx += 3;

	if (__put_user(sigreturn_codes[idx], rc) \|\|
	__put_user(sigreturn_codes[idx+1], rc+1))
	return 1;

	if (cpsr & MODE32_BIT) {
	/*
	* 32-bit code can use the new high-page
	* signal return code support.
	*/
	retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
	} else {
	/*
	* Ensure that the instruction cache sees
	* the return code written onto the stack.
	*/
	flush_icache_range((unsigned long)rc,
	(unsigned long)(rc + 2));

	retcode = ((unsigned long)rc) + thumb;
	}
	}

	regs->ARM_r0 = usig;
	regs->ARM_sp = (unsigned long)frame;
	regs->ARM_lr = retcode;
	regs->ARM_pc = handler;
	regs->ARM_cpsr = cpsr;

	return 0;
	}

	static int
	setup_frame(int usig, struct k_sigaction ka, sigset_t set, struct pt_regs *regs)
	{
	struct sigframe __user frame = get_sigframe(ka, regs, sizeof(frame));
	int err = 0;

	if (!frame)
	return 1;

	/*
	* Set uc.uc_flags to a value which sc.trap_no would never have.
	*/
	__put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);

	err \|= setup_sigframe(frame, regs, set);
	if (err == 0)
	err = setup_return(regs, ka, frame->retcode, frame, usig);

	return err;
	}

	static int
	setup_rt_frame(int usig, struct k_sigaction ka, siginfo_t info,
	sigset_t set, struct pt_regs regs)
	{
	struct rt_sigframe __user frame = get_sigframe(ka, regs, sizeof(frame));
	stack_t stack;
	int err = 0;

	if (!frame)
	return 1;

	err \|= copy_siginfo_to_user(&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 = (void __user *)current->sas_ss_sp;
	stack.ss_flags = sas_ss_flags(regs->ARM_sp);
	stack.ss_size = current->sas_ss_size;
	err \|= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));

	err \|= setup_sigframe(&frame->sig, regs, set);
	if (err == 0)
	err = setup_return(regs, ka, frame->sig.retcode, frame, usig);

	if (err == 0) {
	/*
	* For realtime signals we must also set the second and third
	* arguments for the signal handler.
	* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
	*/
	regs->ARM_r1 = (unsigned long)&frame->info;
	regs->ARM_r2 = (unsigned long)&frame->sig.uc;
	}

	return err;
	}

	static inline void setup_syscall_restart(struct pt_regs *regs)
	{
	regs->ARM_r0 = regs->ARM_ORIG_r0;
	regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
	}

	/*
	* OK, we're invoking a handler
	*/
	static int
	handle_signal(unsigned long sig, struct k_sigaction *ka,
	siginfo_t info, sigset_t oldset,
	struct pt_regs * regs, int syscall)
	{
	struct thread_info *thread = current_thread_info();
	struct task_struct *tsk = current;
	int usig = sig;
	int ret;

	/*
	* If we were from a system call, check for system call restarting...
	*/
	if (syscall) {
	switch (regs->ARM_r0) {
	case -ERESTART_RESTARTBLOCK:
	case -ERESTARTNOHAND:
	regs->ARM_r0 = -EINTR;
	break;
	case -ERESTARTSYS:
	if (!(ka->sa.sa_flags & SA_RESTART)) {
	regs->ARM_r0 = -EINTR;
	break;
	}
	/* fallthrough */
	case -ERESTARTNOINTR:
	setup_syscall_restart(regs);
	}
	}

	/*
	* translate the signal
	*/
	if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
	usig = thread->exec_domain->signal_invmap[usig];

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

	/*
	* Check that the resulting registers are actually sane.
	*/
	ret \|= !valid_user_regs(regs);

	if (ret != 0) {
	force_sigsegv(sig, tsk);
	return ret;
	}

	/*
	* Block the signal if we were successful.
	*/
	spin_lock_irq(&tsk->sighand->siglock);
	sigorsets(&tsk->blocked, &tsk->blocked,
	&ka->sa.sa_mask);
	if (!(ka->sa.sa_flags & SA_NODEFER))
	sigaddset(&tsk->blocked, sig);
	recalc_sigpending();
	spin_unlock_irq(&tsk->sighand->siglock);

	return 0;
	}

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

	/*
	* 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 (!user_mode(regs))
	return;

	if (try_to_freeze())
	goto no_signal;

	single_step_clear(current);

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
	sigset_t *oldset;

	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	oldset = &current->saved_sigmask;
	else
	oldset = &current->blocked;
	if (handle_signal(signr, &ka, &info, oldset, regs, syscall) == 0) {
	/*
	* A signal was successfully delivered; the saved
	* sigmask will have been stored in the signal frame,
	* and will be restored by sigreturn, so we can simply
	* clear the TIF_RESTORE_SIGMASK flag.
	*/
	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	clear_thread_flag(TIF_RESTORE_SIGMASK);
	}
	single_step_set(current);
	return;
	}

	no_signal:
	/*
	* No signal to deliver to the process - restart the syscall.
	*/
	if (syscall) {
	if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
	if (thumb_mode(regs)) {
	regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
	regs->ARM_pc -= 2;
	} else {
	#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
	regs->ARM_r7 = __NR_restart_syscall;
	regs->ARM_pc -= 4;
	#else
	u32 __user *usp;
	u32 swival = __NR_restart_syscall;

	regs->ARM_sp -= 12;
	usp = (u32 __user *)regs->ARM_sp;

	/*
	* Either we supports OABI only, or we have
	* EABI with the OABI compat layer enabled.
	* In the later case we don't know if user
	* space is EABI or not, and if not we must
	* not clobber r7. Always using the OABI
	* syscall solves that issue and works for
	* all those cases.
	*/
	swival = swival - __NR_SYSCALL_BASE + __NR_OABI_SYSCALL_BASE;

	put_user(regs->ARM_pc, &usp[0]);
	/* swi __NR_restart_syscall */
	put_user(0xef000000 \| swival, &usp[1]);
	/* ldr pc, [sp], #12 */
	put_user(0xe49df00c, &usp[2]);

	flush_icache_range((unsigned long)usp,
	(unsigned long)(usp + 3));

	regs->ARM_pc = regs->ARM_sp + 4;
	#endif
	}
	}
	if (regs->ARM_r0 == -ERESTARTNOHAND \|\|
	regs->ARM_r0 == -ERESTARTSYS \|\|
	regs->ARM_r0 == -ERESTARTNOINTR) {
	setup_syscall_restart(regs);
	}

	/* If there's no signal to deliver, we just put the saved sigmask
	* back.
	*/
	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
	clear_thread_flag(TIF_RESTORE_SIGMASK);
	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	}
	}
	single_step_set(current);
	}

	asmlinkage void
	do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
	{
	if (thread_flags & _TIF_SIGPENDING)
	do_signal(regs, syscall);

	if (thread_flags & _TIF_NOTIFY_RESUME) {
	clear_thread_flag(TIF_NOTIFY_RESUME);
	tracehook_notify_resume(regs);
	if (current->replacement_session_keyring)
	key_replace_session_keyring();
	}
	}