/*
   *  linux/arch/x86_64/ia32/ia32_signal.c
   *
   *  Copyright (C) 1991, 1992  Linus Torvalds
   *
   *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
   *  2000-12-*   x86-64 compatibility mode signal handling 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/unistd.h>
  #include <linux/stddef.h>
  #include <linux/personality.h>
  #include <linux/compat.h>

  #include <linux/binfmts.h>

  #include <asm/ucontext.h>
  #include <asm/uaccess.h>
  #include <asm/i387.h>

  #include <asm/ptrace.h>
  #include <asm/ia32_unistd.h>
  #include <asm/user32.h>
  #include <asm/sigcontext32.h>

  #include <asm/proto.h>

  #include <asm/vdso.h>

  #include <asm/sigframe.h>

  #include <asm/sys_ia32.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)

  void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
  
  int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
  {

  	int err = 0;

  
  	if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))

  		return -EFAULT;

  	put_user_try {
  		/* If you change siginfo_t structure, please make sure that
  		   this code is fixed accordingly.
  		   It should never copy any pad contained in the structure
  		   to avoid security leaks, but must copy the generic
  		   3 ints plus the relevant union member.  */
  		put_user_ex(from->si_signo, &to->si_signo);
  		put_user_ex(from->si_errno, &to->si_errno);
  		put_user_ex((short)from->si_code, &to->si_code);
  
  		if (from->si_code < 0) {
  			put_user_ex(from->si_pid, &to->si_pid);
  			put_user_ex(from->si_uid, &to->si_uid);
  			put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
  		} else {
  			/*
  			 * First 32bits of unions are always present:
  			 * si_pid === si_band === si_tid === si_addr(LS half)
  			 */
  			put_user_ex(from->_sifields._pad[0],
  					  &to->_sifields._pad[0]);
  			switch (from->si_code >> 16) {
  			case __SI_FAULT >> 16:
  				break;
  			case __SI_CHLD >> 16:
  				put_user_ex(from->si_utime, &to->si_utime);
  				put_user_ex(from->si_stime, &to->si_stime);
  				put_user_ex(from->si_status, &to->si_status);
  				/* FALL THROUGH */
  			default:
  			case __SI_KILL >> 16:
  				put_user_ex(from->si_uid, &to->si_uid);
  				break;
  			case __SI_POLL >> 16:
  				put_user_ex(from->si_fd, &to->si_fd);
  				break;
  			case __SI_TIMER >> 16:
  				put_user_ex(from->si_overrun, &to->si_overrun);
  				put_user_ex(ptr_to_compat(from->si_ptr),
  					    &to->si_ptr);
  				break;
  				 /* This is not generated by the kernel as of now.  */
  			case __SI_RT >> 16:
  			case __SI_MESGQ >> 16:
  				put_user_ex(from->si_uid, &to->si_uid);
  				put_user_ex(from->si_int, &to->si_int);
  				break;
  			}

  		}

  	} put_user_catch(err);

  	return err;
  }
  
  int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
  {

  	int err = 0;

  	u32 ptr32;

  
  	if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))

  		return -EFAULT;

  	get_user_try {
  		get_user_ex(to->si_signo, &from->si_signo);
  		get_user_ex(to->si_errno, &from->si_errno);
  		get_user_ex(to->si_code, &from->si_code);

  		get_user_ex(to->si_pid, &from->si_pid);
  		get_user_ex(to->si_uid, &from->si_uid);
  		get_user_ex(ptr32, &from->si_ptr);
  		to->si_ptr = compat_ptr(ptr32);
  	} get_user_catch(err);

  
  	return err;
  }

  asmlinkage long sys32_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 long sys32_sigaltstack(const stack_ia32_t __user *uss_ptr,
  				  stack_ia32_t __user *uoss_ptr,
  				  struct pt_regs *regs)

  {

  	stack_t uss, uoss;

  	int ret, err = 0;

  	mm_segment_t seg;
  
  	if (uss_ptr) {

  		u32 ptr;

  
  		memset(&uss, 0, sizeof(stack_t));

  		if (!access_ok(VERIFY_READ, uss_ptr, sizeof(stack_ia32_t)))
  			return -EFAULT;
  
  		get_user_try {
  			get_user_ex(ptr, &uss_ptr->ss_sp);
  			get_user_ex(uss.ss_flags, &uss_ptr->ss_flags);
  			get_user_ex(uss.ss_size, &uss_ptr->ss_size);
  		} get_user_catch(err);
  
  		if (err)

  			return -EFAULT;
  		uss.ss_sp = compat_ptr(ptr);
  	}

  	seg = get_fs();
  	set_fs(KERNEL_DS);

  	ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, regs->sp);

  	set_fs(seg);

  	if (ret >= 0 && uoss_ptr)  {

  		if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_ia32_t)))
  			return -EFAULT;
  
  		put_user_try {
  			put_user_ex(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp);
  			put_user_ex(uoss.ss_flags, &uoss_ptr->ss_flags);
  			put_user_ex(uoss.ss_size, &uoss_ptr->ss_size);
  		} put_user_catch(err);
  
  		if (err)

  			ret = -EFAULT;

  	}
  	return ret;

  }
  
  /*
   * Do a signal return; undo the signal stack.
   */

  #define loadsegment_gs(v)	load_gs_index(v)
  #define loadsegment_fs(v)	loadsegment(fs, v)
  #define loadsegment_ds(v)	loadsegment(ds, v)
  #define loadsegment_es(v)	loadsegment(es, v)
  
  #define get_user_seg(seg)	({ unsigned int v; savesegment(seg, v); v; })
  #define set_user_seg(seg, v)	loadsegment_##seg(v)

  #define COPY(x)			{		\

  	get_user_ex(regs->x, &sc->x);		\

  }

  #define GET_SEG(seg)		({			\
  	unsigned short tmp;				\
  	get_user_ex(tmp, &sc->seg);			\
  	tmp;						\
  })
  
  #define COPY_SEG_CPL3(seg)	do {			\
  	regs->seg = GET_SEG(seg) | 3;			\
  } while (0)

  #define RELOAD_SEG(seg)		{		\

  	unsigned int pre = GET_SEG(seg);	\
  	unsigned int cur = get_user_seg(seg);	\

  	pre |= 3;				\
  	if (pre != cur)				\

  		set_user_seg(seg, pre);		\

  }

  
  static int ia32_restore_sigcontext(struct pt_regs *regs,
  				   struct sigcontext_ia32 __user *sc,

  				   unsigned int *pax)

  {

  	unsigned int tmpflags, err = 0;

  	void __user *buf;

  	u32 tmp;
  
  	/* Always make any pending restarted system calls return -EINTR */
  	current_thread_info()->restart_block.fn = do_no_restart_syscall;

  	get_user_try {
  		/*
  		 * Reload fs and gs if they have changed in the signal
  		 * handler.  This does not handle long fs/gs base changes in
  		 * the handler, but does not clobber them at least in the
  		 * normal case.
  		 */

  		RELOAD_SEG(gs);

  		RELOAD_SEG(fs);
  		RELOAD_SEG(ds);
  		RELOAD_SEG(es);
  
  		COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  		COPY(dx); COPY(cx); COPY(ip);
  		/* Don't touch extended registers */
  
  		COPY_SEG_CPL3(cs);
  		COPY_SEG_CPL3(ss);
  
  		get_user_ex(tmpflags, &sc->flags);
  		regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
  		/* disable syscall checks */
  		regs->orig_ax = -1;
  
  		get_user_ex(tmp, &sc->fpstate);
  		buf = compat_ptr(tmp);
  		err |= restore_i387_xstate_ia32(buf);
  
  		get_user_ex(*pax, &sc->ax);
  	} get_user_catch(err);

  	return err;

  }
  
  asmlinkage long sys32_sigreturn(struct pt_regs *regs)
  {

  	struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8);

  	sigset_t set;

  	unsigned int ax;

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

  		&& __copy_from_user((((char *) &set.sig) + 4),
  				    &frame->extramask,

  				    sizeof(frame->extramask))))
  		goto badframe;
  
  	sigdelsetmask(&set, ~_BLOCKABLE);

  	set_current_blocked(&set);

  	if (ia32_restore_sigcontext(regs, &frame->sc, &ax))

  		goto badframe;

  	return ax;

  
  badframe:
  	signal_fault(regs, frame, "32bit sigreturn");
  	return 0;

  }

  
  asmlinkage long sys32_rt_sigreturn(struct pt_regs *regs)
  {

  	struct rt_sigframe_ia32 __user *frame;

  	sigset_t set;

  	unsigned int ax;

  	struct pt_regs tregs;

  	frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4);

  
  	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 (ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))

  		goto badframe;
  
  	tregs = *regs;
  	if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)
  		goto badframe;

  	return ax;

  
  badframe:

  	signal_fault(regs, frame, "32bit rt sigreturn");

  	return 0;

  }

  
  /*
   * Set up a signal frame.
   */

  static int ia32_setup_sigcontext(struct sigcontext_ia32 __user *sc,

  				 void __user *fpstate,

  				 struct pt_regs *regs, unsigned int mask)

  {

  	int err = 0;

  	put_user_try {

  		put_user_ex(get_user_seg(gs), (unsigned int __user *)&sc->gs);
  		put_user_ex(get_user_seg(fs), (unsigned int __user *)&sc->fs);
  		put_user_ex(get_user_seg(ds), (unsigned int __user *)&sc->ds);
  		put_user_ex(get_user_seg(es), (unsigned int __user *)&sc->es);

  
  		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);
  		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);
  		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);
  
  		put_user_ex(ptr_to_compat(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;
  }
  
  /*
   * Determine which stack to use..
   */

  static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,

  				 size_t frame_size,

  				 void **fpstate)

  {

  	unsigned long sp;

  
  	/* Default to using normal stack */

  	sp = regs->sp;

  
  	/* This is the X/Open sanctioned signal stack switching.  */
  	if (ka->sa.sa_flags & SA_ONSTACK) {

  		if (sas_ss_flags(sp) == 0)
  			sp = current->sas_ss_sp + current->sas_ss_size;

  	}
  
  	/* This is the legacy signal stack switching. */

  	else if ((regs->ss & 0xffff) != __USER32_DS &&

  		!(ka->sa.sa_flags & SA_RESTORER) &&

  		 ka->sa.sa_restorer)

  		sp = (unsigned long) ka->sa.sa_restorer;

  	if (used_math()) {
  		sp = sp - sig_xstate_ia32_size;
  		*fpstate = (struct _fpstate_ia32 *) sp;

  		if (save_i387_xstate_ia32(*fpstate) < 0)
  			return (void __user *) -1L;

  	}

  	sp -= frame_size;

  	/* 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;
  	return (void __user *) sp;

  }

  int ia32_setup_frame(int sig, struct k_sigaction *ka,

  		     compat_sigset_t *set, struct pt_regs *regs)

  {

  	struct sigframe_ia32 __user *frame;

  	void __user *restorer;

  	int err = 0;

  	void __user *fpstate = NULL;

  	/* copy_to_user optimizes that into a single 8 byte store */
  	static const struct {
  		u16 poplmovl;
  		u32 val;
  		u16 int80;

  	} __attribute__((packed)) code = {
  		0xb858,		 /* popl %eax ; movl $...,%eax */
  		__NR_ia32_sigreturn,
  		0x80cd,		/* int $0x80 */

  	};

  	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 (ia32_setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))

  		return -EFAULT;

  
  	if (_COMPAT_NSIG_WORDS > 1) {

  		if (__copy_to_user(frame->extramask, &set->sig[1],
  				   sizeof(frame->extramask)))

  			return -EFAULT;

  	}

  	if (ka->sa.sa_flags & SA_RESTORER) {

  		restorer = ka->sa.sa_restorer;

  	} else {
  		/* Return stub is in 32bit vsyscall page */

  		if (current->mm->context.vdso)

  			restorer = VDSO32_SYMBOL(current->mm->context.vdso,
  						 sigreturn);
  		else

  			restorer = &frame->retcode;

  	}

  	put_user_try {
  		put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
  
  		/*
  		 * These are actually not used anymore, but left because some
  		 * gdb versions depend on them as a marker.
  		 */
  		put_user_ex(*((u64 *)&code), (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;

  	/* Make -mregparm=3 work */

  	regs->ax = sig;
  	regs->dx = 0;
  	regs->cx = 0;

  	loadsegment(ds, __USER32_DS);
  	loadsegment(es, __USER32_DS);

  	regs->cs = __USER32_CS;
  	regs->ss = __USER32_DS;

  	return 0;

  }

  int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,

  			compat_sigset_t *set, struct pt_regs *regs)

  {

  	struct rt_sigframe_ia32 __user *frame;

  	void __user *restorer;

  	int err = 0;

  	void __user *fpstate = NULL;

  	/* __copy_to_user optimizes that into a single 8 byte store */
  	static const struct {
  		u8 movl;
  		u32 val;
  		u16 int80;

  		u8  pad;

  	} __attribute__((packed)) code = {
  		0xb8,
  		__NR_ia32_rt_sigreturn,
  		0x80cd,
  		0,
  	};

  	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(ptr_to_compat(&frame->info), &frame->pinfo);
  		put_user_ex(ptr_to_compat(&frame->uc), &frame->puc);
  		err |= copy_siginfo_to_user32(&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 |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
  					     regs, set->sig[0]);
  		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
  
  		if (ka->sa.sa_flags & SA_RESTORER)
  			restorer = ka->sa.sa_restorer;
  		else
  			restorer = VDSO32_SYMBOL(current->mm->context.vdso,
  						 rt_sigreturn);
  		put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
  
  		/*
  		 * Not actually used anymore, but left because some gdb
  		 * versions need it.
  		 */
  		put_user_ex(*((u64 *)&code), (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;

  	/* Make -mregparm=3 work */

  	regs->ax = sig;
  	regs->dx = (unsigned long) &frame->info;
  	regs->cx = (unsigned long) &frame->uc;

  	loadsegment(ds, __USER32_DS);
  	loadsegment(es, __USER32_DS);

  
  	regs->cs = __USER32_CS;
  	regs->ss = __USER32_DS;

  	return 0;

  }