arch/x86/kernel/signal.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *  Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
  *
  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
  *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
  *  2000-2002   x86-64 support by Andi Kleen
  */
 #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/ptrace.h>
 #include <linux/tracehook.h>
 #include <linux/unistd.h>
 #include <linux/stddef.h>
 #include <linux/personality.h>
 #include <linux/uaccess.h>
 #include <linux/user-return-notifier.h>

 #include <asm/processor.h>
 #include <asm/ucontext.h>
 #include <asm/i387.h>
 #include <asm/vdso.h>
 #include <asm/mce.h>

 #ifdef CONFIG_X86_64
 #include <asm/proto.h>
 #include <asm/ia32_unistd.h>
 #endif /* CONFIG_X86_64 */

 #include <asm/syscall.h>
 #include <asm/syscalls.h>

 #include <asm/sigframe.h>

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

 #define __FIX_EFLAGS	(X86_EFLAGS_AC | X86_EFLAGS_OF | \
 			 X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
 			 X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
 			 X86_EFLAGS_CF)

 #ifdef CONFIG_X86_32
 # define FIX_EFLAGS	(__FIX_EFLAGS | X86_EFLAGS_RF)
 #else
 # define FIX_EFLAGS	__FIX_EFLAGS
 #endif

 #define COPY(x)			do {			\
 	get_user_ex(regs->x, &sc->x);			\
 } while (0)

 #define GET_SEG(seg)		({			\
 	unsigned short tmp;				\
 	get_user_ex(tmp, &sc->seg);			\
 	tmp;						\
 })

 #define COPY_SEG(seg)		do {			\
 	regs->seg = GET_SEG(seg);			\
 } while (0)

 #define COPY_SEG_CPL3(seg)	do {			\
 	regs->seg = GET_SEG(seg) | 3;			\
 } while (0)

 static int
 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
 		   unsigned long *pax)
 {
 	void __user *buf;
 	unsigned int tmpflags;
 	unsigned int err = 0;

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

 	get_user_try {

 #ifdef CONFIG_X86_32
 		set_user_gs(regs, GET_SEG(gs));
 		COPY_SEG(fs);
 		COPY_SEG(es);
 		COPY_SEG(ds);
 #endif /* CONFIG_X86_32 */

 		COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
 		COPY(dx); COPY(cx); COPY(ip);

 #ifdef CONFIG_X86_64
 		COPY(r8);
 		COPY(r9);
 		COPY(r10);
 		COPY(r11);
 		COPY(r12);
 		COPY(r13);
 		COPY(r14);
 		COPY(r15);
 #endif /* CONFIG_X86_64 */

 #ifdef CONFIG_X86_32
 		COPY_SEG_CPL3(cs);
 		COPY_SEG_CPL3(ss);
 #else /* !CONFIG_X86_32 */
 		/* Kernel saves and restores only the CS segment register on signals,
 		 * which is the bare minimum needed to allow mixed 32/64-bit code.
 		 * App's signal handler can save/restore other segments if needed. */
 		COPY_SEG_CPL3(cs);
 #endif /* CONFIG_X86_32 */

 		get_user_ex(tmpflags, &sc->flags);
 		regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 		regs->orig_ax = -1;		/* disable syscall checks */

 		get_user_ex(buf, &sc->fpstate);
 		err |= restore_i387_xstate(buf);

 		get_user_ex(*pax, &sc->ax);
 	} get_user_catch(err);

 	return err;
 }

 static int
 setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 		 struct pt_regs *regs, unsigned long mask)
 {
 	int err = 0;

 	put_user_try {

 #ifdef CONFIG_X86_32
 		put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
 		put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
 		put_user_ex(regs->es, (unsigned int __user *)&sc->es);
 		put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
 #endif /* CONFIG_X86_32 */

 		put_user_ex(regs->di, &sc->di);
 		put_user_ex(regs->si, &sc->si);
 		put_user_ex(regs->bp, &sc->bp);
 		put_user_ex(regs->sp, &sc->sp);
 		put_user_ex(regs->bx, &sc->bx);
 		put_user_ex(regs->dx, &sc->dx);
 		put_user_ex(regs->cx, &sc->cx);
 		put_user_ex(regs->ax, &sc->ax);
 #ifdef CONFIG_X86_64
 		put_user_ex(regs->r8, &sc->r8);
 		put_user_ex(regs->r9, &sc->r9);
 		put_user_ex(regs->r10, &sc->r10);
 		put_user_ex(regs->r11, &sc->r11);
 		put_user_ex(regs->r12, &sc->r12);
 		put_user_ex(regs->r13, &sc->r13);
 		put_user_ex(regs->r14, &sc->r14);
 		put_user_ex(regs->r15, &sc->r15);
 #endif /* CONFIG_X86_64 */

 		put_user_ex(current->thread.trap_no, &sc->trapno);
 		put_user_ex(current->thread.error_code, &sc->err);
 		put_user_ex(regs->ip, &sc->ip);
 #ifdef CONFIG_X86_32
 		put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
 		put_user_ex(regs->flags, &sc->flags);
 		put_user_ex(regs->sp, &sc->sp_at_signal);
 		put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
 #else /* !CONFIG_X86_32 */
 		put_user_ex(regs->flags, &sc->flags);
 		put_user_ex(regs->cs, &sc->cs);
 		put_user_ex(0, &sc->gs);
 		put_user_ex(0, &sc->fs);
 #endif /* CONFIG_X86_32 */

 		put_user_ex(fpstate, &sc->fpstate);

 		/* non-iBCS2 extensions.. */
 		put_user_ex(mask, &sc->oldmask);
 		put_user_ex(current->thread.cr2, &sc->cr2);
 	} put_user_catch(err);

 	return err;
 }

 /*
  * Set up a signal frame.
  */

 /*
  * Determine which stack to use..
  */
 static unsigned long align_sigframe(unsigned long sp)
 {
 #ifdef CONFIG_X86_32
 	/*
 	 * Align the stack pointer according to the i386 ABI,
 	 * i.e. so that on function entry ((sp + 4) & 15) == 0.
 	 */
 	sp = ((sp + 4) & -16ul) - 4;
 #else /* !CONFIG_X86_32 */
 	sp = round_down(sp, 16) - 8;
 #endif
 	return sp;
 }

 static inline void __user *
 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 	     void __user **fpstate)
 {
 	/* Default to using normal stack */
 	unsigned long sp = regs->sp;
 	int onsigstack = on_sig_stack(sp);

 #ifdef CONFIG_X86_64
 	/* redzone */
 	sp -= 128;
 #endif /* CONFIG_X86_64 */

 	if (!onsigstack) {
 		/* This is the X/Open sanctioned signal stack switching.  */
 		if (ka->sa.sa_flags & SA_ONSTACK) {
 			if (current->sas_ss_size)
 				sp = current->sas_ss_sp + current->sas_ss_size;
 		} else {
 #ifdef CONFIG_X86_32
 			/* This is the legacy signal stack switching. */
 			if ((regs->ss & 0xffff) != __USER_DS &&
 				!(ka->sa.sa_flags & SA_RESTORER) &&
 					ka->sa.sa_restorer)
 				sp = (unsigned long) ka->sa.sa_restorer;
 #endif /* CONFIG_X86_32 */
 		}
 	}

 	if (used_math()) {
 		sp -= sig_xstate_size;
 #ifdef CONFIG_X86_64
 		sp = round_down(sp, 64);
 #endif /* CONFIG_X86_64 */
 		*fpstate = (void __user *)sp;
 	}

 	sp = align_sigframe(sp - frame_size);

 	/*
 	 * 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 (onsigstack && !likely(on_sig_stack(sp)))
 		return (void __user *)-1L;

 	/* save i387 state */
 	if (used_math() && save_i387_xstate(*fpstate) < 0)
 		return (void __user *)-1L;

 	return (void __user *)sp;
 }

 #ifdef CONFIG_X86_32
 static const struct {
 	u16 poplmovl;
 	u32 val;
 	u16 int80;
 } __attribute__((packed)) retcode = {
 	0xb858,		/* popl %eax; movl $..., %eax */
 	__NR_sigreturn,
 	0x80cd,		/* int $0x80 */
 };

 static const struct {
 	u8  movl;
 	u32 val;
 	u16 int80;
 	u8  pad;
 } __attribute__((packed)) rt_retcode = {
 	0xb8,		/* movl $..., %eax */
 	__NR_rt_sigreturn,
 	0x80cd,		/* int $0x80 */
 	0
 };

 static int
 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 	      struct pt_regs *regs)
 {
 	struct sigframe __user *frame;
 	void __user *restorer;
 	int err = 0;
 	void __user *fpstate = NULL;

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

 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		return -EFAULT;

 	if (__put_user(sig, &frame->sig))
 		return -EFAULT;

 	if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 		return -EFAULT;

 	if (_NSIG_WORDS > 1) {
 		if (__copy_to_user(&frame->extramask, &set->sig[1],
 				   sizeof(frame->extramask)))
 			return -EFAULT;
 	}

 	if (current->mm->context.vdso)
 		restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 	else
 		restorer = &frame->retcode;
 	if (ka->sa.sa_flags & SA_RESTORER)
 		restorer = ka->sa.sa_restorer;

 	/* Set up to return from userspace.  */
 	err |= __put_user(restorer, &frame->pretcode);

 	/*
 	 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 	 *
 	 * WE DO NOT USE IT ANY MORE! It's only left here for historical
 	 * reasons and because gdb uses it as a signature to notice
 	 * signal handler stack frames.
 	 */
 	err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);

 	if (err)
 		return -EFAULT;

 	/* Set up registers for signal handler */
 	regs->sp = (unsigned long)frame;
 	regs->ip = (unsigned long)ka->sa.sa_handler;
 	regs->ax = (unsigned long)sig;
 	regs->dx = 0;
 	regs->cx = 0;

 	regs->ds = __USER_DS;
 	regs->es = __USER_DS;
 	regs->ss = __USER_DS;
 	regs->cs = __USER_CS;

 	return 0;
 }

 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;
 	void __user *restorer;
 	int err = 0;
 	void __user *fpstate = NULL;

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

 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		return -EFAULT;

 	put_user_try {
 		put_user_ex(sig, &frame->sig);
 		put_user_ex(&frame->info, &frame->pinfo);
 		put_user_ex(&frame->uc, &frame->puc);
 		err |= copy_siginfo_to_user(&frame->info, info);

 		/* Create the ucontext.  */
 		if (cpu_has_xsave)
 			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 		else
 			put_user_ex(0, &frame->uc.uc_flags);
 		put_user_ex(0, &frame->uc.uc_link);
 		put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 		put_user_ex(sas_ss_flags(regs->sp),
 			    &frame->uc.uc_stack.ss_flags);
 		put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 		err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 					regs, set->sig[0]);
 		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

 		/* Set up to return from userspace.  */
 		restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 		if (ka->sa.sa_flags & SA_RESTORER)
 			restorer = ka->sa.sa_restorer;
 		put_user_ex(restorer, &frame->pretcode);

 		/*
 		 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 		 *
 		 * WE DO NOT USE IT ANY MORE! It's only left here for historical
 		 * reasons and because gdb uses it as a signature to notice
 		 * signal handler stack frames.
 		 */
 		put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 	} put_user_catch(err);

 	if (err)
 		return -EFAULT;

 	/* Set up registers for signal handler */
 	regs->sp = (unsigned long)frame;
 	regs->ip = (unsigned long)ka->sa.sa_handler;
 	regs->ax = (unsigned long)sig;
 	regs->dx = (unsigned long)&frame->info;
 	regs->cx = (unsigned long)&frame->uc;

 	regs->ds = __USER_DS;
 	regs->es = __USER_DS;
 	regs->ss = __USER_DS;
 	regs->cs = __USER_CS;

 	return 0;
 }
 #else /* !CONFIG_X86_32 */
 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;
 	void __user *fp = NULL;
 	int err = 0;
 	struct task_struct *me = current;

 	frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);

 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		return -EFAULT;

 	if (ka->sa.sa_flags & SA_SIGINFO) {
 		if (copy_siginfo_to_user(&frame->info, info))
 			return -EFAULT;
 	}

 	put_user_try {
 		/* Create the ucontext.  */
 		if (cpu_has_xsave)
 			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 		else
 			put_user_ex(0, &frame->uc.uc_flags);
 		put_user_ex(0, &frame->uc.uc_link);
 		put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 		put_user_ex(sas_ss_flags(regs->sp),
 			    &frame->uc.uc_stack.ss_flags);
 		put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 		err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

 		/* Set up to return from userspace.  If provided, use a stub
 		   already in userspace.  */
 		/* x86-64 should always use SA_RESTORER. */
 		if (ka->sa.sa_flags & SA_RESTORER) {
 			put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
 		} else {
 			/* could use a vstub here */
 			err |= -EFAULT;
 		}
 	} put_user_catch(err);

 	if (err)
 		return -EFAULT;

 	/* Set up registers for signal handler */
 	regs->di = sig;
 	/* In case the signal handler was declared without prototypes */
 	regs->ax = 0;

 	/* This also works for non SA_SIGINFO handlers because they expect the
 	   next argument after the signal number on the stack. */
 	regs->si = (unsigned long)&frame->info;
 	regs->dx = (unsigned long)&frame->uc;
 	regs->ip = (unsigned long) ka->sa.sa_handler;

 	regs->sp = (unsigned long)frame;

 	/* Set up the CS register to run signal handlers in 64-bit mode,
 	   even if the handler happens to be interrupting 32-bit code. */
 	regs->cs = __USER_CS;

 	return 0;
 }
 #endif /* CONFIG_X86_32 */

 #ifdef CONFIG_X86_32
 /*
  * Atomically swap in the new signal mask, and wait for a signal.
  */
 asmlinkage int
 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 {
 	sigset_t blocked;

 	current->saved_sigmask = current->blocked;

 	mask &= _BLOCKABLE;
 	siginitset(&blocked, mask);
 	set_current_blocked(&blocked);

 	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 = 0;

 	if (act) {
 		old_sigset_t mask;

 		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 			return -EFAULT;

 		get_user_try {
 			get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
 			get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
 			get_user_ex(mask, &act->sa_mask);
 			get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
 		} get_user_catch(ret);

 		if (ret)
 			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)))
 			return -EFAULT;

 		put_user_try {
 			put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
 			put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
 			put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 			put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
 		} put_user_catch(ret);

 		if (ret)
 			return -EFAULT;
 	}

 	return ret;
 }
 #endif /* CONFIG_X86_32 */

 long
 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 		struct pt_regs *regs)
 {
 	return do_sigaltstack(uss, uoss, regs->sp);
 }

 /*
  * Do a signal return; undo the signal stack.
  */
 #ifdef CONFIG_X86_32
 unsigned long sys_sigreturn(struct pt_regs *regs)
 {
 	struct sigframe __user *frame;
 	unsigned long ax;
 	sigset_t set;

 	frame = (struct sigframe __user *)(regs->sp - 8);

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

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

 	if (restore_sigcontext(regs, &frame->sc, &ax))
 		goto badframe;
 	return ax;

 badframe:
 	signal_fault(regs, frame, "sigreturn");

 	return 0;
 }
 #endif /* CONFIG_X86_32 */

 long sys_rt_sigreturn(struct pt_regs *regs)
 {
 	struct rt_sigframe __user *frame;
 	unsigned long ax;
 	sigset_t set;

 	frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 	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 (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 		goto badframe;

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

 	return ax;

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

 /*
  * OK, we're invoking a handler:
  */
 static int signr_convert(int sig)
 {
 #ifdef CONFIG_X86_32
 	struct thread_info *info = current_thread_info();

 	if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
 		return info->exec_domain->signal_invmap[sig];
 #endif /* CONFIG_X86_32 */
 	return sig;
 }

 #ifdef CONFIG_X86_32

 #define is_ia32	1
 #define ia32_setup_frame	__setup_frame
 #define ia32_setup_rt_frame	__setup_rt_frame

 #else /* !CONFIG_X86_32 */

 #ifdef CONFIG_IA32_EMULATION
 #define is_ia32	test_thread_flag(TIF_IA32)
 #else /* !CONFIG_IA32_EMULATION */
 #define is_ia32	0
 #endif /* CONFIG_IA32_EMULATION */

 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 		sigset_t *set, struct pt_regs *regs);
 int ia32_setup_frame(int sig, struct k_sigaction *ka,
 		sigset_t *set, struct pt_regs *regs);

 #endif /* CONFIG_X86_32 */

 static int
 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 		struct pt_regs *regs)
 {
 	int usig = signr_convert(sig);
 	sigset_t *set = &current->blocked;
 	int ret;

 	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 		set = &current->saved_sigmask;

 	/* Set up the stack frame */
 	if (is_ia32) {
 		if (ka->sa.sa_flags & SA_SIGINFO)
 			ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
 		else
 			ret = ia32_setup_frame(usig, ka, set, regs);
 	} else
 		ret = __setup_rt_frame(sig, ka, info, set, regs);

 	if (ret) {
 		force_sigsegv(sig, current);
 		return -EFAULT;
 	}

 	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 	return ret;
 }

 static int
 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 		struct pt_regs *regs)
 {
 	int ret;

 	/* Are we from a system call? */
 	if (syscall_get_nr(current, regs) >= 0) {
 		/* If so, check system call restarting.. */
 		switch (syscall_get_error(current, regs)) {
 		case -ERESTART_RESTARTBLOCK:
 		case -ERESTARTNOHAND:
 			regs->ax = -EINTR;
 			break;

 		case -ERESTARTSYS:
 			if (!(ka->sa.sa_flags & SA_RESTART)) {
 				regs->ax = -EINTR;
 				break;
 			}
 		/* fallthrough */
 		case -ERESTARTNOINTR:
 			regs->ax = regs->orig_ax;
 			regs->ip -= 2;
 			break;
 		}
 	}

 	/*
 	 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 	 * flag so that register information in the sigcontext is correct.
 	 */
 	if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 	    likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 		regs->flags &= ~X86_EFLAGS_TF;

 	ret = setup_rt_frame(sig, ka, info, regs);

 	if (ret)
 		return ret;

 	/*
 	 * Clear the direction flag as per the ABI for function entry.
 	 */
 	regs->flags &= ~X86_EFLAGS_DF;

 	/*
 	 * Clear TF when entering the signal handler, but
 	 * notify any tracer that was single-stepping it.
 	 * The tracer may want to single-step inside the
 	 * handler too.
 	 */
 	regs->flags &= ~X86_EFLAGS_TF;

 	block_sigmask(ka, sig);

 	tracehook_signal_handler(sig, info, ka, regs,
 				 test_thread_flag(TIF_SINGLESTEP));

 	return 0;
 }

 #ifdef CONFIG_X86_32
 #define NR_restart_syscall	__NR_restart_syscall
 #else /* !CONFIG_X86_32 */
 #define NR_restart_syscall	\
 	test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 #endif /* CONFIG_X86_32 */

 /*
  * 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)
 {
 	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.
 	 * X86_32: vm86 regs switched out by assembly code before reaching
 	 * here, so testing against kernel CS suffices.
 	 */
 	if (!user_mode(regs))
 		return;

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

 	/* Did we come from a system call? */
 	if (syscall_get_nr(current, regs) >= 0) {
 		/* Restart the system call - no handlers present */
 		switch (syscall_get_error(current, regs)) {
 		case -ERESTARTNOHAND:
 		case -ERESTARTSYS:
 		case -ERESTARTNOINTR:
 			regs->ax = regs->orig_ax;
 			regs->ip -= 2;
 			break;

 		case -ERESTART_RESTARTBLOCK:
 			regs->ax = NR_restart_syscall;
 			regs->ip -= 2;
 			break;
 		}
 	}

 	/*
 	 * If there's no signal to deliver, we just put the saved sigmask
 	 * back.
 	 */
 	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 		set_current_blocked(&current->saved_sigmask);
 	}
 }

 /*
  * notification of userspace execution resumption
  * - triggered by the TIF_WORK_MASK flags
  */
 void
 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 {
 #ifdef CONFIG_X86_MCE
 	/* notify userspace of pending MCEs */
 	if (thread_info_flags & _TIF_MCE_NOTIFY)
 		mce_notify_process();
 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */

 	/* deal with pending signal delivery */
 	if (thread_info_flags & _TIF_SIGPENDING)
 		do_signal(regs);

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

 #ifdef CONFIG_X86_32
 	clear_thread_flag(TIF_IRET);
 #endif /* CONFIG_X86_32 */
 }

 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 {
 	struct task_struct *me = current;

 	if (show_unhandled_signals && printk_ratelimit()) {
 		printk("%s"
 		       "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 		       task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 		       me->comm, me->pid, where, frame,
 		       regs->ip, regs->sp, regs->orig_ax);
 		print_vma_addr(" in ", regs->ip);
 		printk(KERN_CONT "\n");
 	}

 	force_sig(SIGSEGV, me);
 }
	/*
	* Copyright (C) 1991, 1992 Linus Torvalds
	* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
	*
	* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
	* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
	* 2000-2002 x86-64 support by Andi Kleen
	*/
	#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/ptrace.h>
	#include <linux/tracehook.h>
	#include <linux/unistd.h>
	#include <linux/stddef.h>
	#include <linux/personality.h>
	#include <linux/uaccess.h>
	#include <linux/user-return-notifier.h>

	#include <asm/processor.h>
	#include <asm/ucontext.h>
	#include <asm/i387.h>
	#include <asm/vdso.h>
	#include <asm/mce.h>

	#ifdef CONFIG_X86_64
	#include <asm/proto.h>
	#include <asm/ia32_unistd.h>
	#endif /* CONFIG_X86_64 */

	#include <asm/syscall.h>
	#include <asm/syscalls.h>

	#include <asm/sigframe.h>

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

	#define __FIX_EFLAGS (X86_EFLAGS_AC \| X86_EFLAGS_OF \| \
	X86_EFLAGS_DF \| X86_EFLAGS_TF \| X86_EFLAGS_SF \| \
	X86_EFLAGS_ZF \| X86_EFLAGS_AF \| X86_EFLAGS_PF \| \
	X86_EFLAGS_CF)

	#ifdef CONFIG_X86_32
	# define FIX_EFLAGS (__FIX_EFLAGS \| X86_EFLAGS_RF)
	#else
	# define FIX_EFLAGS __FIX_EFLAGS
	#endif

	#define COPY(x) do { \
	get_user_ex(regs->x, &sc->x); \
	} while (0)

	#define GET_SEG(seg) ({ \
	unsigned short tmp; \
	get_user_ex(tmp, &sc->seg); \
	tmp; \
	})

	#define COPY_SEG(seg) do { \
	regs->seg = GET_SEG(seg); \
	} while (0)

	#define COPY_SEG_CPL3(seg) do { \
	regs->seg = GET_SEG(seg) \| 3; \
	} while (0)

	static int
	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc,
	unsigned long *pax)
	{
	void __user *buf;
	unsigned int tmpflags;
	unsigned int err = 0;

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

	get_user_try {

	#ifdef CONFIG_X86_32
	set_user_gs(regs, GET_SEG(gs));
	COPY_SEG(fs);
	COPY_SEG(es);
	COPY_SEG(ds);
	#endif /* CONFIG_X86_32 */

	COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
	COPY(dx); COPY(cx); COPY(ip);

	#ifdef CONFIG_X86_64
	COPY(r8);
	COPY(r9);
	COPY(r10);
	COPY(r11);
	COPY(r12);
	COPY(r13);
	COPY(r14);
	COPY(r15);
	#endif /* CONFIG_X86_64 */

	#ifdef CONFIG_X86_32
	COPY_SEG_CPL3(cs);
	COPY_SEG_CPL3(ss);
	#else /* !CONFIG_X86_32 */
	/* Kernel saves and restores only the CS segment register on signals,
	* which is the bare minimum needed to allow mixed 32/64-bit code.
	* App's signal handler can save/restore other segments if needed. */
	COPY_SEG_CPL3(cs);
	#endif /* CONFIG_X86_32 */

	get_user_ex(tmpflags, &sc->flags);
	regs->flags = (regs->flags & ~FIX_EFLAGS) \| (tmpflags & FIX_EFLAGS);
	regs->orig_ax = -1; /* disable syscall checks */

	get_user_ex(buf, &sc->fpstate);
	err \|= restore_i387_xstate(buf);

	get_user_ex(*pax, &sc->ax);
	} get_user_catch(err);

	return err;
	}

	static int
	setup_sigcontext(struct sigcontext __user sc, void __user fpstate,
	struct pt_regs *regs, unsigned long mask)
	{
	int err = 0;

	put_user_try {

	#ifdef CONFIG_X86_32
	put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
	put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
	put_user_ex(regs->es, (unsigned int __user *)&sc->es);
	put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
	#endif /* CONFIG_X86_32 */

	put_user_ex(regs->di, &sc->di);
	put_user_ex(regs->si, &sc->si);
	put_user_ex(regs->bp, &sc->bp);
	put_user_ex(regs->sp, &sc->sp);
	put_user_ex(regs->bx, &sc->bx);
	put_user_ex(regs->dx, &sc->dx);
	put_user_ex(regs->cx, &sc->cx);
	put_user_ex(regs->ax, &sc->ax);
	#ifdef CONFIG_X86_64
	put_user_ex(regs->r8, &sc->r8);
	put_user_ex(regs->r9, &sc->r9);
	put_user_ex(regs->r10, &sc->r10);
	put_user_ex(regs->r11, &sc->r11);
	put_user_ex(regs->r12, &sc->r12);
	put_user_ex(regs->r13, &sc->r13);
	put_user_ex(regs->r14, &sc->r14);
	put_user_ex(regs->r15, &sc->r15);
	#endif /* CONFIG_X86_64 */

	put_user_ex(current->thread.trap_no, &sc->trapno);
	put_user_ex(current->thread.error_code, &sc->err);
	put_user_ex(regs->ip, &sc->ip);
	#ifdef CONFIG_X86_32
	put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
	put_user_ex(regs->flags, &sc->flags);
	put_user_ex(regs->sp, &sc->sp_at_signal);
	put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
	#else /* !CONFIG_X86_32 */
	put_user_ex(regs->flags, &sc->flags);
	put_user_ex(regs->cs, &sc->cs);
	put_user_ex(0, &sc->gs);
	put_user_ex(0, &sc->fs);
	#endif /* CONFIG_X86_32 */

	put_user_ex(fpstate, &sc->fpstate);

	/* non-iBCS2 extensions.. */
	put_user_ex(mask, &sc->oldmask);
	put_user_ex(current->thread.cr2, &sc->cr2);
	} put_user_catch(err);

	return err;
	}

	/*
	* Set up a signal frame.
	*/

	/*
	* Determine which stack to use..
	*/
	static unsigned long align_sigframe(unsigned long sp)
	{
	#ifdef CONFIG_X86_32
	/*
	* Align the stack pointer according to the i386 ABI,
	* i.e. so that on function entry ((sp + 4) & 15) == 0.
	*/
	sp = ((sp + 4) & -16ul) - 4;
	#else /* !CONFIG_X86_32 */
	sp = round_down(sp, 16) - 8;
	#endif
	return sp;
	}

	static inline void __user *
	get_sigframe(struct k_sigaction ka, struct pt_regs regs, size_t frame_size,
	void __user **fpstate)
	{
	/* Default to using normal stack */
	unsigned long sp = regs->sp;
	int onsigstack = on_sig_stack(sp);

	#ifdef CONFIG_X86_64
	/* redzone */
	sp -= 128;
	#endif /* CONFIG_X86_64 */

	if (!onsigstack) {
	/* This is the X/Open sanctioned signal stack switching. */
	if (ka->sa.sa_flags & SA_ONSTACK) {
	if (current->sas_ss_size)
	sp = current->sas_ss_sp + current->sas_ss_size;
	} else {
	#ifdef CONFIG_X86_32
	/* This is the legacy signal stack switching. */
	if ((regs->ss & 0xffff) != __USER_DS &&
	!(ka->sa.sa_flags & SA_RESTORER) &&
	ka->sa.sa_restorer)
	sp = (unsigned long) ka->sa.sa_restorer;
	#endif /* CONFIG_X86_32 */
	}
	}

	if (used_math()) {
	sp -= sig_xstate_size;
	#ifdef CONFIG_X86_64
	sp = round_down(sp, 64);
	#endif /* CONFIG_X86_64 */
	fpstate = (void __user )sp;
	}

	sp = align_sigframe(sp - frame_size);

	/*
	* 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 (onsigstack && !likely(on_sig_stack(sp)))
	return (void __user *)-1L;

	/* save i387 state */
	if (used_math() && save_i387_xstate(*fpstate) < 0)
	return (void __user *)-1L;

	return (void __user *)sp;
	}

	#ifdef CONFIG_X86_32
	static const struct {
	u16 poplmovl;
	u32 val;
	u16 int80;
	} __attribute__((packed)) retcode = {
	0xb858, /* popl %eax; movl $..., %eax */
	__NR_sigreturn,
	0x80cd, /* int $0x80 */
	};

	static const struct {
	u8 movl;
	u32 val;
	u16 int80;
	u8 pad;
	} __attribute__((packed)) rt_retcode = {
	0xb8, /* movl $..., %eax */
	__NR_rt_sigreturn,
	0x80cd, /* int $0x80 */
	0
	};

	static int
	__setup_frame(int sig, struct k_sigaction ka, sigset_t set,
	struct pt_regs *regs)
	{
	struct sigframe __user *frame;
	void __user *restorer;
	int err = 0;
	void __user *fpstate = NULL;

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

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	return -EFAULT;

	if (__put_user(sig, &frame->sig))
	return -EFAULT;

	if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
	return -EFAULT;

	if (_NSIG_WORDS > 1) {
	if (__copy_to_user(&frame->extramask, &set->sig[1],
	sizeof(frame->extramask)))
	return -EFAULT;
	}

	if (current->mm->context.vdso)
	restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
	else
	restorer = &frame->retcode;
	if (ka->sa.sa_flags & SA_RESTORER)
	restorer = ka->sa.sa_restorer;

	/* Set up to return from userspace. */
	err \|= __put_user(restorer, &frame->pretcode);

	/*
	* This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
	*
	* WE DO NOT USE IT ANY MORE! It's only left here for historical
	* reasons and because gdb uses it as a signature to notice
	* signal handler stack frames.
	*/
	err \|= __put_user(((u64 )&retcode), (u64 *)frame->retcode);

	if (err)
	return -EFAULT;

	/* Set up registers for signal handler */
	regs->sp = (unsigned long)frame;
	regs->ip = (unsigned long)ka->sa.sa_handler;
	regs->ax = (unsigned long)sig;
	regs->dx = 0;
	regs->cx = 0;

	regs->ds = __USER_DS;
	regs->es = __USER_DS;
	regs->ss = __USER_DS;
	regs->cs = __USER_CS;

	return 0;
	}

	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;
	void __user *restorer;
	int err = 0;
	void __user *fpstate = NULL;

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

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	return -EFAULT;

	put_user_try {
	put_user_ex(sig, &frame->sig);
	put_user_ex(&frame->info, &frame->pinfo);
	put_user_ex(&frame->uc, &frame->puc);
	err \|= copy_siginfo_to_user(&frame->info, info);

	/* Create the ucontext. */
	if (cpu_has_xsave)
	put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
	else
	put_user_ex(0, &frame->uc.uc_flags);
	put_user_ex(0, &frame->uc.uc_link);
	put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	put_user_ex(sas_ss_flags(regs->sp),
	&frame->uc.uc_stack.ss_flags);
	put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err \|= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
	regs, set->sig[0]);
	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Set up to return from userspace. */
	restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
	if (ka->sa.sa_flags & SA_RESTORER)
	restorer = ka->sa.sa_restorer;
	put_user_ex(restorer, &frame->pretcode);

	/*
	* This is movl $__NR_rt_sigreturn, %ax ; int $0x80
	*
	* WE DO NOT USE IT ANY MORE! It's only left here for historical
	* reasons and because gdb uses it as a signature to notice
	* signal handler stack frames.
	*/
	put_user_ex(((u64 )&rt_retcode), (u64 *)frame->retcode);
	} put_user_catch(err);

	if (err)
	return -EFAULT;

	/* Set up registers for signal handler */
	regs->sp = (unsigned long)frame;
	regs->ip = (unsigned long)ka->sa.sa_handler;
	regs->ax = (unsigned long)sig;
	regs->dx = (unsigned long)&frame->info;
	regs->cx = (unsigned long)&frame->uc;

	regs->ds = __USER_DS;
	regs->es = __USER_DS;
	regs->ss = __USER_DS;
	regs->cs = __USER_CS;

	return 0;
	}
	#else /* !CONFIG_X86_32 */
	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;
	void __user *fp = NULL;
	int err = 0;
	struct task_struct *me = current;

	frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	return -EFAULT;

	if (ka->sa.sa_flags & SA_SIGINFO) {
	if (copy_siginfo_to_user(&frame->info, info))
	return -EFAULT;
	}

	put_user_try {
	/* Create the ucontext. */
	if (cpu_has_xsave)
	put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
	else
	put_user_ex(0, &frame->uc.uc_flags);
	put_user_ex(0, &frame->uc.uc_link);
	put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	put_user_ex(sas_ss_flags(regs->sp),
	&frame->uc.uc_stack.ss_flags);
	put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err \|= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Set up to return from userspace. If provided, use a stub
	already in userspace. */
	/* x86-64 should always use SA_RESTORER. */
	if (ka->sa.sa_flags & SA_RESTORER) {
	put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
	} else {
	/* could use a vstub here */
	err \|= -EFAULT;
	}
	} put_user_catch(err);

	if (err)
	return -EFAULT;

	/* Set up registers for signal handler */
	regs->di = sig;
	/* In case the signal handler was declared without prototypes */
	regs->ax = 0;

	/* This also works for non SA_SIGINFO handlers because they expect the
	next argument after the signal number on the stack. */
	regs->si = (unsigned long)&frame->info;
	regs->dx = (unsigned long)&frame->uc;
	regs->ip = (unsigned long) ka->sa.sa_handler;

	regs->sp = (unsigned long)frame;

	/* Set up the CS register to run signal handlers in 64-bit mode,
	even if the handler happens to be interrupting 32-bit code. */
	regs->cs = __USER_CS;

	return 0;
	}
	#endif /* CONFIG_X86_32 */

	#ifdef CONFIG_X86_32
	/*
	* Atomically swap in the new signal mask, and wait for a signal.
	*/
	asmlinkage int
	sys_sigsuspend(int history0, int history1, old_sigset_t mask)
	{
	sigset_t blocked;

	current->saved_sigmask = current->blocked;

	mask &= _BLOCKABLE;
	siginitset(&blocked, mask);
	set_current_blocked(&blocked);

	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 = 0;

	if (act) {
	old_sigset_t mask;

	if (!access_ok(VERIFY_READ, act, sizeof(*act)))
	return -EFAULT;

	get_user_try {
	get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
	get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
	get_user_ex(mask, &act->sa_mask);
	get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
	} get_user_catch(ret);

	if (ret)
	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)))
	return -EFAULT;

	put_user_try {
	put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
	put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
	put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
	put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
	} put_user_catch(ret);

	if (ret)
	return -EFAULT;
	}

	return ret;
	}
	#endif /* CONFIG_X86_32 */

	long
	sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	struct pt_regs *regs)
	{
	return do_sigaltstack(uss, uoss, regs->sp);
	}

	/*
	* Do a signal return; undo the signal stack.
	*/
	#ifdef CONFIG_X86_32
	unsigned long sys_sigreturn(struct pt_regs *regs)
	{
	struct sigframe __user *frame;
	unsigned long ax;
	sigset_t set;

	frame = (struct sigframe __user *)(regs->sp - 8);

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

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

	if (restore_sigcontext(regs, &frame->sc, &ax))
	goto badframe;
	return ax;

	badframe:
	signal_fault(regs, frame, "sigreturn");

	return 0;
	}
	#endif /* CONFIG_X86_32 */

	long sys_rt_sigreturn(struct pt_regs *regs)
	{
	struct rt_sigframe __user *frame;
	unsigned long ax;
	sigset_t set;

	frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
	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 (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
	goto badframe;

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

	return ax;

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

	/*
	* OK, we're invoking a handler:
	*/
	static int signr_convert(int sig)
	{
	#ifdef CONFIG_X86_32
	struct thread_info *info = current_thread_info();

	if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
	return info->exec_domain->signal_invmap[sig];
	#endif /* CONFIG_X86_32 */
	return sig;
	}

	#ifdef CONFIG_X86_32

	#define is_ia32 1
	#define ia32_setup_frame __setup_frame
	#define ia32_setup_rt_frame __setup_rt_frame

	#else /* !CONFIG_X86_32 */

	#ifdef CONFIG_IA32_EMULATION
	#define is_ia32 test_thread_flag(TIF_IA32)
	#else /* !CONFIG_IA32_EMULATION */
	#define is_ia32 0
	#endif /* CONFIG_IA32_EMULATION */

	int ia32_setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	sigset_t set, struct pt_regs regs);
	int ia32_setup_frame(int sig, struct k_sigaction *ka,
	sigset_t set, struct pt_regs regs);

	#endif /* CONFIG_X86_32 */

	static int
	setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	struct pt_regs *regs)
	{
	int usig = signr_convert(sig);
	sigset_t *set = &current->blocked;
	int ret;

	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
	set = &current->saved_sigmask;

	/* Set up the stack frame */
	if (is_ia32) {
	if (ka->sa.sa_flags & SA_SIGINFO)
	ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
	else
	ret = ia32_setup_frame(usig, ka, set, regs);
	} else
	ret = __setup_rt_frame(sig, ka, info, set, regs);

	if (ret) {
	force_sigsegv(sig, current);
	return -EFAULT;
	}

	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
	return ret;
	}

	static int
	handle_signal(unsigned long sig, siginfo_t info, struct k_sigaction ka,
	struct pt_regs *regs)
	{
	int ret;

	/* Are we from a system call? */
	if (syscall_get_nr(current, regs) >= 0) {
	/* If so, check system call restarting.. */
	switch (syscall_get_error(current, regs)) {
	case -ERESTART_RESTARTBLOCK:
	case -ERESTARTNOHAND:
	regs->ax = -EINTR;
	break;

	case -ERESTARTSYS:
	if (!(ka->sa.sa_flags & SA_RESTART)) {
	regs->ax = -EINTR;
	break;
	}
	/* fallthrough */
	case -ERESTARTNOINTR:
	regs->ax = regs->orig_ax;
	regs->ip -= 2;
	break;
	}
	}

	/*
	* If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
	* flag so that register information in the sigcontext is correct.
	*/
	if (unlikely(regs->flags & X86_EFLAGS_TF) &&
	likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
	regs->flags &= ~X86_EFLAGS_TF;

	ret = setup_rt_frame(sig, ka, info, regs);

	if (ret)
	return ret;

	/*
	* Clear the direction flag as per the ABI for function entry.
	*/
	regs->flags &= ~X86_EFLAGS_DF;

	/*
	* Clear TF when entering the signal handler, but
	* notify any tracer that was single-stepping it.
	* The tracer may want to single-step inside the
	* handler too.
	*/
	regs->flags &= ~X86_EFLAGS_TF;

	block_sigmask(ka, sig);

	tracehook_signal_handler(sig, info, ka, regs,
	test_thread_flag(TIF_SINGLESTEP));

	return 0;
	}

	#ifdef CONFIG_X86_32
	#define NR_restart_syscall __NR_restart_syscall
	#else /* !CONFIG_X86_32 */
	#define NR_restart_syscall \
	test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
	#endif /* CONFIG_X86_32 */

	/*
	* 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)
	{
	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.
	* X86_32: vm86 regs switched out by assembly code before reaching
	* here, so testing against kernel CS suffices.
	*/
	if (!user_mode(regs))
	return;

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

	/* Did we come from a system call? */
	if (syscall_get_nr(current, regs) >= 0) {
	/* Restart the system call - no handlers present */
	switch (syscall_get_error(current, regs)) {
	case -ERESTARTNOHAND:
	case -ERESTARTSYS:
	case -ERESTARTNOINTR:
	regs->ax = regs->orig_ax;
	regs->ip -= 2;
	break;

	case -ERESTART_RESTARTBLOCK:
	regs->ax = NR_restart_syscall;
	regs->ip -= 2;
	break;
	}
	}

	/*
	* If there's no signal to deliver, we just put the saved sigmask
	* back.
	*/
	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
	set_current_blocked(&current->saved_sigmask);
	}
	}

	/*
	* notification of userspace execution resumption
	* - triggered by the TIF_WORK_MASK flags
	*/
	void
	do_notify_resume(struct pt_regs regs, void unused, __u32 thread_info_flags)
	{
	#ifdef CONFIG_X86_MCE
	/* notify userspace of pending MCEs */
	if (thread_info_flags & _TIF_MCE_NOTIFY)
	mce_notify_process();
	#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */

	/* deal with pending signal delivery */
	if (thread_info_flags & _TIF_SIGPENDING)
	do_signal(regs);

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

	#ifdef CONFIG_X86_32
	clear_thread_flag(TIF_IRET);
	#endif /* CONFIG_X86_32 */
	}

	void signal_fault(struct pt_regs regs, void __user frame, char *where)
	{
	struct task_struct *me = current;

	if (show_unhandled_signals && printk_ratelimit()) {
	printk("%s"
	"%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
	task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
	me->comm, me->pid, where, frame,
	regs->ip, regs->sp, regs->orig_ax);
	print_vma_addr(" in ", regs->ip);
	printk(KERN_CONT "\n");
	}

	force_sig(SIGSEGV, me);
	}