/*
   * Copyright (C) 2003 PathScale, Inc.
   * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   * Licensed under the GPL
   */
  
  
  #include <linux/personality.h>
  #include <linux/ptrace.h>
  #include <linux/kernel.h>
  #include <asm/unistd.h>
  #include <asm/uaccess.h>
  #include <asm/ucontext.h>
  #include <frame_kern.h>
  #include <skas.h>
  
  #ifdef CONFIG_X86_32
  
  /*
   * FPU tag word conversions.
   */
  
  static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
  {
  	unsigned int tmp; /* to avoid 16 bit prefixes in the code */
  
  	/* Transform each pair of bits into 01 (valid) or 00 (empty) */
  	tmp = ~twd;
  	tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
  	/* and move the valid bits to the lower byte. */
  	tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
  	tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
  	tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
  	return tmp;
  }
  
  static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
  {
  	struct _fpxreg *st = NULL;
  	unsigned long twd = (unsigned long) fxsave->twd;
  	unsigned long tag;
  	unsigned long ret = 0xffff0000;
  	int i;
  
  #define FPREG_ADDR(f, n)	((char *)&(f)->st_space + (n) * 16)
  
  	for (i = 0; i < 8; i++) {
  		if (twd & 0x1) {
  			st = (struct _fpxreg *) FPREG_ADDR(fxsave, i);
  
  			switch (st->exponent & 0x7fff) {
  			case 0x7fff:
  				tag = 2;		/* Special */
  				break;
  			case 0x0000:
  				if ( !st->significand[0] &&
  				     !st->significand[1] &&
  				     !st->significand[2] &&
  				     !st->significand[3] ) {
  					tag = 1;	/* Zero */
  				} else {
  					tag = 2;	/* Special */
  				}
  				break;
  			default:
  				if (st->significand[3] & 0x8000) {
  					tag = 0;	/* Valid */
  				} else {
  					tag = 2;	/* Special */
  				}
  				break;
  			}
  		} else {
  			tag = 3;			/* Empty */
  		}
  		ret |= (tag << (2 * i));
  		twd = twd >> 1;
  	}
  	return ret;
  }
  
  static int convert_fxsr_to_user(struct _fpstate __user *buf,
  				struct user_fxsr_struct *fxsave)
  {
  	unsigned long env[7];
  	struct _fpreg __user *to;
  	struct _fpxreg *from;
  	int i;
  
  	env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
  	env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
  	env[2] = twd_fxsr_to_i387(fxsave);
  	env[3] = fxsave->fip;
  	env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
  	env[5] = fxsave->foo;
  	env[6] = fxsave->fos;
  
  	if (__copy_to_user(buf, env, 7 * sizeof(unsigned long)))
  		return 1;
  
  	to = &buf->_st[0];
  	from = (struct _fpxreg *) &fxsave->st_space[0];
  	for (i = 0; i < 8; i++, to++, from++) {
  		unsigned long __user *t = (unsigned long __user *)to;
  		unsigned long *f = (unsigned long *)from;
  
  		if (__put_user(*f, t) ||
  				__put_user(*(f + 1), t + 1) ||
  				__put_user(from->exponent, &to->exponent))
  			return 1;
  	}
  	return 0;
  }
  
  static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave,
  				  struct _fpstate __user *buf)
  {
  	unsigned long env[7];
  	struct _fpxreg *to;
  	struct _fpreg __user *from;
  	int i;
  
  	if (copy_from_user( env, buf, 7 * sizeof(long)))
  		return 1;
  
  	fxsave->cwd = (unsigned short)(env[0] & 0xffff);
  	fxsave->swd = (unsigned short)(env[1] & 0xffff);
  	fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
  	fxsave->fip = env[3];
  	fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
  	fxsave->fcs = (env[4] & 0xffff);
  	fxsave->foo = env[5];
  	fxsave->fos = env[6];
  
  	to = (struct _fpxreg *) &fxsave->st_space[0];
  	from = &buf->_st[0];
  	for (i = 0; i < 8; i++, to++, from++) {
  		unsigned long *t = (unsigned long *)to;
  		unsigned long __user *f = (unsigned long __user *)from;
  
  		if (__get_user(*t, f) ||
  		    __get_user(*(t + 1), f + 1) ||
  		    __get_user(to->exponent, &from->exponent))
  			return 1;
  	}
  	return 0;
  }
  
  extern int have_fpx_regs;
  
  #endif
  
  static int copy_sc_from_user(struct pt_regs *regs,
  			     struct sigcontext __user *from)
  {
  	struct sigcontext sc;
  	int err, pid;
  
  	/* Always make any pending restarted system calls return -EINTR */
  	current_thread_info()->restart_block.fn = do_no_restart_syscall;
  
  	err = copy_from_user(&sc, from, sizeof(sc));
  	if (err)
  		return err;
  
  #define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname
  
  #ifdef CONFIG_X86_32
  	GETREG(GS, gs);
  	GETREG(FS, fs);
  	GETREG(ES, es);
  	GETREG(DS, ds);
  #endif
  	GETREG(DI, di);
  	GETREG(SI, si);
  	GETREG(BP, bp);
  	GETREG(SP, sp);
  	GETREG(BX, bx);
  	GETREG(DX, dx);
  	GETREG(CX, cx);
  	GETREG(AX, ax);
  	GETREG(IP, ip);
  
  #ifdef CONFIG_X86_64
  	GETREG(R8, r8);
  	GETREG(R9, r9);
  	GETREG(R10, r10);
  	GETREG(R11, r11);
  	GETREG(R12, r12);
  	GETREG(R13, r13);
  	GETREG(R14, r14);
  	GETREG(R15, r15);
  #endif
  
  	GETREG(CS, cs);
  	GETREG(EFLAGS, flags);
  #ifdef CONFIG_X86_32
  	GETREG(SS, ss);
  #endif
  
  #undef GETREG
  
  	pid = userspace_pid[current_thread_info()->cpu];
  #ifdef CONFIG_X86_32
  	if (have_fpx_regs) {
  		struct user_fxsr_struct fpx;
  
  		err = copy_from_user(&fpx,
  			&((struct _fpstate __user *)sc.fpstate)->_fxsr_env[0],
  				     sizeof(struct user_fxsr_struct));
  		if (err)
  			return 1;
  
  		err = convert_fxsr_from_user(&fpx, sc.fpstate);
  		if (err)
  			return 1;
  
  		err = restore_fpx_registers(pid, (unsigned long *) &fpx);
  		if (err < 0) {
  			printk(KERN_ERR "copy_sc_from_user - "
  			       "restore_fpx_registers failed, errno = %d
  ",
  			       -err);
  			return 1;
  		}
  	} else
  #endif
  	{
  		struct user_i387_struct fp;
  
  		err = copy_from_user(&fp, sc.fpstate,
  				     sizeof(struct user_i387_struct));
  		if (err)
  			return 1;
  
  		err = restore_fp_registers(pid, (unsigned long *) &fp);
  		if (err < 0) {
  			printk(KERN_ERR "copy_sc_from_user - "
  			       "restore_fp_registers failed, errno = %d
  ",
  			       -err);
  			return 1;
  		}
  	}
  	return 0;
  }
  
  static int copy_sc_to_user(struct sigcontext __user *to,
  			   struct _fpstate __user *to_fp, struct pt_regs *regs,
  			   unsigned long mask)
  {
  	struct sigcontext sc;
  	struct faultinfo * fi = &current->thread.arch.faultinfo;
  	int err, pid;
  	memset(&sc, 0, sizeof(struct sigcontext));
  
  #define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno]
  
  #ifdef CONFIG_X86_32
  	PUTREG(GS, gs);
  	PUTREG(FS, fs);
  	PUTREG(ES, es);
  	PUTREG(DS, ds);
  #endif
  	PUTREG(DI, di);
  	PUTREG(SI, si);
  	PUTREG(BP, bp);
  	PUTREG(SP, sp);
  	PUTREG(BX, bx);
  	PUTREG(DX, dx);
  	PUTREG(CX, cx);
  	PUTREG(AX, ax);
  #ifdef CONFIG_X86_64
  	PUTREG(R8, r8);
  	PUTREG(R9, r9);
  	PUTREG(R10, r10);
  	PUTREG(R11, r11);
  	PUTREG(R12, r12);
  	PUTREG(R13, r13);
  	PUTREG(R14, r14);
  	PUTREG(R15, r15);
  #endif
  
  	sc.cr2 = fi->cr2;
  	sc.err = fi->error_code;
  	sc.trapno = fi->trap_no;
  	PUTREG(IP, ip);
  	PUTREG(CS, cs);
  	PUTREG(EFLAGS, flags);
  #ifdef CONFIG_X86_32
  	PUTREG(SP, sp_at_signal);
  	PUTREG(SS, ss);
  #endif
  #undef PUTREG
  	sc.oldmask = mask;
  	sc.fpstate = to_fp;
  
  	err = copy_to_user(to, &sc, sizeof(struct sigcontext));
  	if (err)
  		return 1;
  
  	pid = userspace_pid[current_thread_info()->cpu];
  
  #ifdef CONFIG_X86_32
  	if (have_fpx_regs) {
  		struct user_fxsr_struct fpx;
  
  		err = save_fpx_registers(pid, (unsigned long *) &fpx);
  		if (err < 0){
  			printk(KERN_ERR "copy_sc_to_user - save_fpx_registers "
  			       "failed, errno = %d
  ", err);
  			return 1;
  		}
  
  		err = convert_fxsr_to_user(to_fp, &fpx);
  		if (err)
  			return 1;
  
  		err |= __put_user(fpx.swd, &to_fp->status);
  		err |= __put_user(X86_FXSR_MAGIC, &to_fp->magic);
  		if (err)
  			return 1;
  
  		if (copy_to_user(&to_fp->_fxsr_env[0], &fpx,
  				 sizeof(struct user_fxsr_struct)))
  			return 1;
  	} else
  #endif
  	{
  		struct user_i387_struct fp;
  
  		err = save_fp_registers(pid, (unsigned long *) &fp);
  		if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct)))
  			return 1;
  	}
  
  	return 0;
  }
  
  #ifdef CONFIG_X86_32
  static int copy_ucontext_to_user(struct ucontext __user *uc,
  				 struct _fpstate __user *fp, sigset_t *set,
  				 unsigned long sp)
  {
  	int err = 0;
  
  	err |= __save_altstack(&uc->uc_stack, sp);
  	err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, 0);
  	err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
  	return err;
  }
  
  struct sigframe
  {
  	char __user *pretcode;
  	int sig;
  	struct sigcontext sc;
  	struct _fpstate fpstate;
  	unsigned long extramask[_NSIG_WORDS-1];
  	char retcode[8];
  };
  
  struct rt_sigframe
  {
  	char __user *pretcode;
  	int sig;
  	struct siginfo __user *pinfo;
  	void __user *puc;
  	struct siginfo info;
  	struct ucontext uc;
  	struct _fpstate fpstate;
  	char retcode[8];
  };
  
  int setup_signal_stack_sc(unsigned long stack_top, int sig,
  			  struct k_sigaction *ka, struct pt_regs *regs,
  			  sigset_t *mask)
  {
  	struct sigframe __user *frame;
  	void __user *restorer;
  	int err = 0;
  
  	/* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
  	stack_top = ((stack_top + 4) & -16UL) - 4;
  	frame = (struct sigframe __user *) stack_top - 1;
  	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  		return 1;
  
  	restorer = frame->retcode;
  	if (ka->sa.sa_flags & SA_RESTORER)
  		restorer = ka->sa.sa_restorer;
  
  	err |= __put_user(restorer, &frame->pretcode);
  	err |= __put_user(sig, &frame->sig);
  	err |= copy_sc_to_user(&frame->sc, &frame->fpstate, regs, mask->sig[0]);
  	if (_NSIG_WORDS > 1)
  		err |= __copy_to_user(&frame->extramask, &mask->sig[1],
  				      sizeof(frame->extramask));
  
  	/*
  	 * This is popl %eax ; movl $,%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(0xb858, (short __user *)(frame->retcode+0));
  	err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
  	err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
  
  	if (err)
  		return err;
  
  	PT_REGS_SP(regs) = (unsigned long) frame;
  	PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
  	PT_REGS_AX(regs) = (unsigned long) sig;
  	PT_REGS_DX(regs) = (unsigned long) 0;
  	PT_REGS_CX(regs) = (unsigned long) 0;
  	return 0;
  }
  
  int setup_signal_stack_si(unsigned long stack_top, int sig,
  			  struct k_sigaction *ka, struct pt_regs *regs,
  			  siginfo_t *info, sigset_t *mask)
  {
  	struct rt_sigframe __user *frame;
  	void __user *restorer;
  	int err = 0;
  
  	stack_top &= -8UL;
  	frame = (struct rt_sigframe __user *) stack_top - 1;
  	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  		return 1;
  
  	restorer = frame->retcode;
  	if (ka->sa.sa_flags & SA_RESTORER)
  		restorer = ka->sa.sa_restorer;
  
  	err |= __put_user(restorer, &frame->pretcode);
  	err |= __put_user(sig, &frame->sig);
  	err |= __put_user(&frame->info, &frame->pinfo);
  	err |= __put_user(&frame->uc, &frame->puc);
  	err |= copy_siginfo_to_user(&frame->info, info);
  	err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
  					PT_REGS_SP(regs));
  
  	/*
  	 * This is movl $,%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(0xb8, (char __user *)(frame->retcode+0));
  	err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
  	err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
  
  	if (err)
  		return err;
  
  	PT_REGS_SP(regs) = (unsigned long) frame;
  	PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
  	PT_REGS_AX(regs) = (unsigned long) sig;
  	PT_REGS_DX(regs) = (unsigned long) &frame->info;
  	PT_REGS_CX(regs) = (unsigned long) &frame->uc;
  	return 0;
  }
  
  long sys_sigreturn(void)
  {
  	unsigned long sp = PT_REGS_SP(&current->thread.regs);
  	struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
  	sigset_t set;
  	struct sigcontext __user *sc = &frame->sc;
  	unsigned long __user *oldmask = &sc->oldmask;
  	unsigned long __user *extramask = frame->extramask;
  	int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
  
  	if (copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) ||
  	    copy_from_user(&set.sig[1], extramask, sig_size))
  		goto segfault;
  
  	set_current_blocked(&set);
  
  	if (copy_sc_from_user(&current->thread.regs, sc))
  		goto segfault;
  
  	/* Avoid ERESTART handling */
  	PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
  	return PT_REGS_SYSCALL_RET(&current->thread.regs);
  
   segfault:
  	force_sig(SIGSEGV, current);
  	return 0;
  }
  
  #else
  
  struct rt_sigframe
  {
  	char __user *pretcode;
  	struct ucontext uc;
  	struct siginfo info;
  	struct _fpstate fpstate;
  };
  
  int setup_signal_stack_si(unsigned long stack_top, int sig,
  			  struct k_sigaction *ka, struct pt_regs * regs,
  			  siginfo_t *info, sigset_t *set)
  {
  	struct rt_sigframe __user *frame;
  	int err = 0;
  
  	frame = (struct rt_sigframe __user *)
  		round_down(stack_top - sizeof(struct rt_sigframe), 16);
  	/* Subtract 128 for a red zone and 8 for proper alignment */
  	frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
  
  	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  		goto out;
  
  	if (ka->sa.sa_flags & SA_SIGINFO) {
  		err |= copy_siginfo_to_user(&frame->info, info);
  		if (err)
  			goto out;
  	}
  
  	/* Create the ucontext.  */
  	err |= __put_user(0, &frame->uc.uc_flags);
  	err |= __put_user(0, &frame->uc.uc_link);
  	err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));
  	err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
  			       set->sig[0]);
  	err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate);
  	if (sizeof(*set) == 16) {
  		err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
  		err |= __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
  	}
  	else
  		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)
  		err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
  	else
  		/* could use a vstub here */
  		return err;
  
  	if (err)
  		return err;
  
  	/* Set up registers for signal handler */
  	{
  		struct exec_domain *ed = current_thread_info()->exec_domain;
  		if (unlikely(ed && ed->signal_invmap && sig < 32))
  			sig = ed->signal_invmap[sig];
  	}
  
  	PT_REGS_SP(regs) = (unsigned long) frame;
  	PT_REGS_DI(regs) = sig;
  	/* In case the signal handler was declared without prototypes */
  	PT_REGS_AX(regs) = 0;
  
  	/*
  	 * This also works for non SA_SIGINFO handlers because they expect the
  	 * next argument after the signal number on the stack.
  	 */
  	PT_REGS_SI(regs) = (unsigned long) &frame->info;
  	PT_REGS_DX(regs) = (unsigned long) &frame->uc;
  	PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
   out:
  	return err;
  }
  #endif
  
  long sys_rt_sigreturn(void)
  {
  	unsigned long sp = PT_REGS_SP(&current->thread.regs);
  	struct rt_sigframe __user *frame =
  		(struct rt_sigframe __user *)(sp - sizeof(long));
  	struct ucontext __user *uc = &frame->uc;
  	sigset_t set;
  
  	if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
  		goto segfault;
  
  	set_current_blocked(&set);
  
  	if (copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
  		goto segfault;
  
  	/* Avoid ERESTART handling */
  	PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
  	return PT_REGS_SYSCALL_RET(&current->thread.regs);
  
   segfault:
  	force_sig(SIGSEGV, current);
  	return 0;
  }