text: /*
   *  arch/sparc64/kernel/signal.c
   *
   *  Copyright (C) 1991, 1992  Linus Torvalds
   *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
   *  Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
   *  Copyright (C) 1997 Eddie C. Dost   (ecd@skynet.be)
   *  Copyright (C) 1997,1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
   */
  
  #ifdef CONFIG_COMPAT
  #include <linux/compat.h>	/* for compat_old_sigset_t */
  #endif
  #include <linux/sched.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/mm.h>
  #include <linux/tty.h>
  #include <linux/binfmts.h>
  #include <linux/bitops.h>
  #include <linux/context_tracking.h>
  
  #include <asm/uaccess.h>
  #include <asm/ptrace.h>
  #include <asm/pgtable.h>
  #include <asm/fpumacro.h>
  #include <asm/uctx.h>
  #include <asm/siginfo.h>
  #include <asm/visasm.h>
  #include <asm/switch_to.h>
  #include <asm/cacheflush.h>
  
  #include "entry.h"
  #include "systbls.h"
  #include "sigutil.h"
  
  /* {set, get}context() needed for 64-bit SparcLinux userland. */
  asmlinkage void sparc64_set_context(struct pt_regs *regs)
  {
  	struct ucontext __user *ucp = (struct ucontext __user *)
  		regs->u_regs[UREG_I0];
  	enum ctx_state prev_state = exception_enter();
  	mc_gregset_t __user *grp;
  	unsigned long pc, npc, tstate;
  	unsigned long fp, i7;
  	unsigned char fenab;
  	int err;
  
  	flush_user_windows();
  	if (get_thread_wsaved()					||
  	    (((unsigned long)ucp) & (sizeof(unsigned long)-1))	||
  	    (!__access_ok(ucp, sizeof(*ucp))))
  		goto do_sigsegv;
  	grp  = &ucp->uc_mcontext.mc_gregs;
  	err  = __get_user(pc, &((*grp)[MC_PC]));
  	err |= __get_user(npc, &((*grp)[MC_NPC]));
  	if (err || ((pc | npc) & 3))
  		goto do_sigsegv;
  	if (regs->u_regs[UREG_I1]) {
  		sigset_t set;
  
  		if (_NSIG_WORDS == 1) {
  			if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
  				goto do_sigsegv;
  		} else {
  			if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
  				goto do_sigsegv;
  		}
  		set_current_blocked(&set);
  	}
  	if (test_thread_flag(TIF_32BIT)) {
  		pc &= 0xffffffff;
  		npc &= 0xffffffff;
  	}
  	regs->tpc = pc;
  	regs->tnpc = npc;
  	err |= __get_user(regs->y, &((*grp)[MC_Y]));
  	err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
  	regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
  	regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
  	err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
  	err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
  	err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
  	err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
  	err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
  	err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));
  
  	/* Skip %g7 as that's the thread register in userspace.  */
  
  	err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0]));
  	err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1]));
  	err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2]));
  	err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3]));
  	err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4]));
  	err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5]));
  	err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6]));
  	err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7]));
  
  	err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp));
  	err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7));
  	err |= __put_user(fp,
  	      (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
  	err |= __put_user(i7,
  	      (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
  
  	err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab));
  	if (fenab) {
  		unsigned long *fpregs = current_thread_info()->fpregs;
  		unsigned long fprs;
  		
  		fprs_write(0);
  		err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs));
  		if (fprs & FPRS_DL)
  			err |= copy_from_user(fpregs,
  					      &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs),
  					      (sizeof(unsigned int) * 32));
  		if (fprs & FPRS_DU)
  			err |= copy_from_user(fpregs+16,
  			 ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16,
  			 (sizeof(unsigned int) * 32));
  		err |= __get_user(current_thread_info()->xfsr[0],
  				  &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr));
  		err |= __get_user(current_thread_info()->gsr[0],
  				  &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr));
  		regs->tstate &= ~TSTATE_PEF;
  	}
  	if (err)
  		goto do_sigsegv;
  out:
  	exception_exit(prev_state);
  	return;
  do_sigsegv:
  	force_sig(SIGSEGV, current);
  	goto out;
  }
  
  asmlinkage void sparc64_get_context(struct pt_regs *regs)
  {
  	struct ucontext __user *ucp = (struct ucontext __user *)
  		regs->u_regs[UREG_I0];
  	enum ctx_state prev_state = exception_enter();
  	mc_gregset_t __user *grp;
  	mcontext_t __user *mcp;
  	unsigned long fp, i7;
  	unsigned char fenab;
  	int err;
  
  	synchronize_user_stack();
  	if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp)))
  		goto do_sigsegv;
  
  #if 1
  	fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */
  #else
  	fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF);
  #endif
  		
  	mcp = &ucp->uc_mcontext;
  	grp = &mcp->mc_gregs;
  
  	/* Skip over the trap instruction, first. */
  	if (test_thread_flag(TIF_32BIT)) {
  		regs->tpc   = (regs->tnpc & 0xffffffff);
  		regs->tnpc  = (regs->tnpc + 4) & 0xffffffff;
  	} else {
  		regs->tpc   = regs->tnpc;
  		regs->tnpc += 4;
  	}
  	err = 0;
  	if (_NSIG_WORDS == 1)
  		err |= __put_user(current->blocked.sig[0],
  				  (unsigned long __user *)&ucp->uc_sigmask);
  	else
  		err |= __copy_to_user(&ucp->uc_sigmask, &current->blocked,
  				      sizeof(sigset_t));
  
  	err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE]));
  	err |= __put_user(regs->tpc, &((*grp)[MC_PC]));
  	err |= __put_user(regs->tnpc, &((*grp)[MC_NPC]));
  	err |= __put_user(regs->y, &((*grp)[MC_Y]));
  	err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1]));
  	err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2]));
  	err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3]));
  	err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4]));
  	err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5]));
  	err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6]));
  	err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7]));
  	err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0]));
  	err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1]));
  	err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2]));
  	err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3]));
  	err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4]));
  	err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5]));
  	err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6]));
  	err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7]));
  
  	err |= __get_user(fp,
  		 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
  	err |= __get_user(i7,
  		 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
  	err |= __put_user(fp, &(mcp->mc_fp));
  	err |= __put_user(i7, &(mcp->mc_i7));
  
  	err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab));
  	if (fenab) {
  		unsigned long *fpregs = current_thread_info()->fpregs;
  		unsigned long fprs;
  		
  		fprs = current_thread_info()->fpsaved[0];
  		if (fprs & FPRS_DL)
  			err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs,
  					    (sizeof(unsigned int) * 32));
  		if (fprs & FPRS_DU)
  			err |= copy_to_user(
                            ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16,
  			  (sizeof(unsigned int) * 32));
  		err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr));
  		err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr));
  		err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs));
  	}
  	if (err)
  		goto do_sigsegv;
  out:
  	exception_exit(prev_state);
  	return;
  do_sigsegv:
  	force_sig(SIGSEGV, current);
  	goto out;
  }
  
  struct rt_signal_frame {
  	struct sparc_stackf	ss;
  	siginfo_t		info;
  	struct pt_regs		regs;
  	__siginfo_fpu_t __user	*fpu_save;
  	stack_t			stack;
  	sigset_t		mask;
  	__siginfo_rwin_t	*rwin_save;
  };
  
  void do_rt_sigreturn(struct pt_regs *regs)
  {
  	struct rt_signal_frame __user *sf;
  	unsigned long tpc, tnpc, tstate;
  	__siginfo_fpu_t __user *fpu_save;
  	__siginfo_rwin_t __user *rwin_save;
  	sigset_t set;
  	int err;
  
  	/* Always make any pending restarted system calls return -EINTR */
  	current_thread_info()->restart_block.fn = do_no_restart_syscall;
  
  	synchronize_user_stack ();
  	sf = (struct rt_signal_frame __user *)
  		(regs->u_regs [UREG_FP] + STACK_BIAS);
  
  	/* 1. Make sure we are not getting garbage from the user */
  	if (((unsigned long) sf) & 3)
  		goto segv;
  
  	err = get_user(tpc, &sf->regs.tpc);
  	err |= __get_user(tnpc, &sf->regs.tnpc);
  	if (test_thread_flag(TIF_32BIT)) {
  		tpc &= 0xffffffff;
  		tnpc &= 0xffffffff;
  	}
  	err |= ((tpc | tnpc) & 3);
  
  	/* 2. Restore the state */
  	err |= __get_user(regs->y, &sf->regs.y);
  	err |= __get_user(tstate, &sf->regs.tstate);
  	err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));
  
  	/* User can only change condition codes and %asi in %tstate. */
  	regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
  	regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
  
  	err |= __get_user(fpu_save, &sf->fpu_save);
  	if (!err && fpu_save)
  		err |= restore_fpu_state(regs, fpu_save);
  
  	err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
  	err |= restore_altstack(&sf->stack);
  	if (err)
  		goto segv;
  
  	err |= __get_user(rwin_save, &sf->rwin_save);
  	if (!err && rwin_save) {
  		if (restore_rwin_state(rwin_save))
  			goto segv;
  	}
  
  	regs->tpc = tpc;
  	regs->tnpc = tnpc;
  
  	/* Prevent syscall restart.  */
  	pt_regs_clear_syscall(regs);
  
  	set_current_blocked(&set);
  	return;
  segv:
  	force_sig(SIGSEGV, current);
  }
  
  /* Checks if the fp is valid */
  static int invalid_frame_pointer(void __user *fp)
  {
  	if (((unsigned long) fp) & 15)
  		return 1;
  	return 0;
  }
  
  static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
  {
  	unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;
  
  	/*
  	 * 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 (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
  		return (void __user *) -1L;
  
  	/* This is the X/Open sanctioned signal stack switching.  */
  	sp = sigsp(sp, ksig) - framesize;
  
  	/* Always align the stack frame.  This handles two cases.  First,
  	 * sigaltstack need not be mindful of platform specific stack
  	 * alignment.  Second, if we took this signal because the stack
  	 * is not aligned properly, we'd like to take the signal cleanly
  	 * and report that.
  	 */
  	sp &= ~15UL;
  
  	return (void __user *) sp;
  }
  
  static inline int
  setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
  {
  	struct rt_signal_frame __user *sf;
  	int wsaved, err, sf_size;
  	void __user *tail;
  
  	/* 1. Make sure everything is clean */
  	synchronize_user_stack();
  	save_and_clear_fpu();
  	
  	wsaved = get_thread_wsaved();
  
  	sf_size = sizeof(struct rt_signal_frame);
  	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
  		sf_size += sizeof(__siginfo_fpu_t);
  	if (wsaved)
  		sf_size += sizeof(__siginfo_rwin_t);
  	sf = (struct rt_signal_frame __user *)
  		get_sigframe(ksig, regs, sf_size);
  
  	if (invalid_frame_pointer (sf)) {
  		do_exit(SIGILL);	/* won't return, actually */
  		return -EINVAL;
  	}
  
  	tail = (sf + 1);
  
  	/* 2. Save the current process state */
  	err = copy_to_user(&sf->regs, regs, sizeof (*regs));
  
  	if (current_thread_info()->fpsaved[0] & FPRS_FEF) {
  		__siginfo_fpu_t __user *fpu_save = tail;
  		tail += sizeof(__siginfo_fpu_t);
  		err |= save_fpu_state(regs, fpu_save);
  		err |= __put_user((u64)fpu_save, &sf->fpu_save);
  	} else {
  		err |= __put_user(0, &sf->fpu_save);
  	}
  	if (wsaved) {
  		__siginfo_rwin_t __user *rwin_save = tail;
  		tail += sizeof(__siginfo_rwin_t);
  		err |= save_rwin_state(wsaved, rwin_save);
  		err |= __put_user((u64)rwin_save, &sf->rwin_save);
  		set_thread_wsaved(0);
  	} else {
  		err |= __put_user(0, &sf->rwin_save);
  	}
  	
  	/* Setup sigaltstack */
  	err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]);
  
  	err |= copy_to_user(&sf->mask, sigmask_to_save(), sizeof(sigset_t));
  
  	if (!wsaved) {
  		err |= copy_in_user((u64 __user *)sf,
  				    (u64 __user *)(regs->u_regs[UREG_FP] +
  						   STACK_BIAS),
  				    sizeof(struct reg_window));
  	} else {
  		struct reg_window *rp;
  
  		rp = &current_thread_info()->reg_window[wsaved - 1];
  		err |= copy_to_user(sf, rp, sizeof(struct reg_window));
  	}
  	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
  		err |= copy_siginfo_to_user(&sf->info, &ksig->info);
  	else {
  		err |= __put_user(ksig->sig, &sf->info.si_signo);
  		err |= __put_user(SI_NOINFO, &sf->info.si_code);
  	}
  	if (err)
  		return err;
  	
  	/* 3. signal handler back-trampoline and parameters */
  	regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
  	regs->u_regs[UREG_I0] = ksig->sig;
  	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
  
  	/* The sigcontext is passed in this way because of how it
  	 * is defined in GLIBC's /usr/include/bits/sigcontext.h
  	 * for sparc64.  It includes the 128 bytes of siginfo_t.
  	 */
  	regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
  
  	/* 5. signal handler */
  	regs->tpc = (unsigned long) ksig->ka.sa.sa_handler;
  	regs->tnpc = (regs->tpc + 4);
  	if (test_thread_flag(TIF_32BIT)) {
  		regs->tpc &= 0xffffffff;
  		regs->tnpc &= 0xffffffff;
  	}
  	/* 4. return to kernel instructions */
  	regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
  	return 0;
  }
  
  static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
  				   struct sigaction *sa)
  {
  	switch (regs->u_regs[UREG_I0]) {
  	case ERESTART_RESTARTBLOCK:
  	case ERESTARTNOHAND:
  	no_system_call_restart:
  		regs->u_regs[UREG_I0] = EINTR;
  		regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY);
  		break;
  	case ERESTARTSYS:
  		if (!(sa->sa_flags & SA_RESTART))
  			goto no_system_call_restart;
  		/* fallthrough */
  	case ERESTARTNOINTR:
  		regs->u_regs[UREG_I0] = orig_i0;
  		regs->tpc -= 4;
  		regs->tnpc -= 4;
  	}
  }
  
  /* 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, unsigned long orig_i0)
  {
  	struct ksignal ksig;
  	int restart_syscall;
  	bool has_handler;
  	
  	/* It's a lot of work and synchronization to add a new ptrace
  	 * register for GDB to save and restore in order to get
  	 * orig_i0 correct for syscall restarts when debugging.
  	 *
  	 * Although it should be the case that most of the global
  	 * registers are volatile across a system call, glibc already
  	 * depends upon that fact that we preserve them.  So we can't
  	 * just use any global register to save away the orig_i0 value.
  	 *
  	 * In particular %g2, %g3, %g4, and %g5 are all assumed to be
  	 * preserved across a system call trap by various pieces of
  	 * code in glibc.
  	 *
  	 * %g7 is used as the "thread register".   %g6 is not used in
  	 * any fixed manner.  %g6 is used as a scratch register and
  	 * a compiler temporary, but it's value is never used across
  	 * a system call.  Therefore %g6 is usable for orig_i0 storage.
  	 */
  	if (pt_regs_is_syscall(regs) &&
  	    (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY)))
  		regs->u_regs[UREG_G6] = orig_i0;
  
  #ifdef CONFIG_COMPAT
  	if (test_thread_flag(TIF_32BIT)) {
  		extern void do_signal32(struct pt_regs *);
  		do_signal32(regs);
  		return;
  	}
  #endif	
  
  	has_handler = get_signal(&ksig);
  
  	restart_syscall = 0;
  	if (pt_regs_is_syscall(regs) &&
  	    (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
  		restart_syscall = 1;
  		orig_i0 = regs->u_regs[UREG_G6];
  	}
  
  	if (has_handler) {
  		if (restart_syscall)
  			syscall_restart(orig_i0, regs, &ksig.ka.sa);
  		signal_setup_done(setup_rt_frame(&ksig, regs), &ksig, 0);
  	} else {
  		if (restart_syscall) {
  			switch (regs->u_regs[UREG_I0]) {
  			case ERESTARTNOHAND:
  	     		case ERESTARTSYS:
  			case ERESTARTNOINTR:
  				/* replay the system call when we are done */
  				regs->u_regs[UREG_I0] = orig_i0;
  				regs->tpc -= 4;
  				regs->tnpc -= 4;
  				pt_regs_clear_syscall(regs);
  			case ERESTART_RESTARTBLOCK:
  				regs->u_regs[UREG_G1] = __NR_restart_syscall;
  				regs->tpc -= 4;
  				regs->tnpc -= 4;
  				pt_regs_clear_syscall(regs);
  			}
  		}
  		restore_saved_sigmask();
  	}
  }
  
  void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
  {
  	user_exit();
  	if (thread_info_flags & _TIF_SIGPENDING)
  		do_signal(regs, orig_i0);
  	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
  		clear_thread_flag(TIF_NOTIFY_RESUME);
  		tracehook_notify_resume(regs);
  	}
  	user_enter();
  }
  
  