arch/sparc64/kernel/signal32.c

/*  arch/sparc64/kernel/signal32.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 *  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)
 */

#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/unistd.h>
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/compat.h>
#include <linux/bitops.h>

#include <asm/uaccess.h>
#include <asm/ptrace.h>
#include <asm/pgtable.h>
#include <asm/psrcompat.h>
#include <asm/fpumacro.h>
#include <asm/visasm.h>
#include <asm/compat_signal.h>

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

/* This magic should be in g_upper[0] for all upper parts
 * to be valid.
 */
#define SIGINFO_EXTRA_V8PLUS_MAGIC	0x130e269
typedef struct {
	unsigned int g_upper[8];
	unsigned int o_upper[8];
	unsigned int asi;
} siginfo_extra_v8plus_t;

struct signal_frame32 {
	struct sparc_stackf32	ss;
	__siginfo32_t		info;
	/* __siginfo_fpu32_t * */ u32 fpu_save;
	unsigned int		insns[2];
	unsigned int		extramask[_COMPAT_NSIG_WORDS - 1];
	unsigned int		extra_size; /* Should be sizeof(siginfo_extra_v8plus_t) */
	/* Only valid if (info.si_regs.psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS */
	siginfo_extra_v8plus_t	v8plus;
	__siginfo_fpu_t		fpu_state;
};

typedef struct compat_siginfo{
	int si_signo;
	int si_errno;
	int si_code;

	union {
		int _pad[SI_PAD_SIZE32];

		/* kill() */
		struct {
			compat_pid_t _pid;		/* sender's pid */
			unsigned int _uid;		/* sender's uid */
		} _kill;

		/* POSIX.1b timers */
		struct {
			compat_timer_t _tid;			/* timer id */
			int _overrun;			/* overrun count */
			compat_sigval_t _sigval;		/* same as below */
			int _sys_private;		/* not to be passed to user */
		} _timer;

		/* POSIX.1b signals */
		struct {
			compat_pid_t _pid;		/* sender's pid */
			unsigned int _uid;		/* sender's uid */
			compat_sigval_t _sigval;
		} _rt;

		/* SIGCHLD */
		struct {
			compat_pid_t _pid;		/* which child */
			unsigned int _uid;		/* sender's uid */
			int _status;			/* exit code */
			compat_clock_t _utime;
			compat_clock_t _stime;
		} _sigchld;

		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGEMT */
		struct {
			u32 _addr; /* faulting insn/memory ref. */
			int _trapno;
		} _sigfault;

		/* SIGPOLL */
		struct {
			int _band;	/* POLL_IN, POLL_OUT, POLL_MSG */
			int _fd;
		} _sigpoll;
	} _sifields;
}compat_siginfo_t;

struct rt_signal_frame32 {
	struct sparc_stackf32	ss;
	compat_siginfo_t	info;
	struct pt_regs32	regs;
	compat_sigset_t		mask;
	/* __siginfo_fpu32_t * */ u32 fpu_save;
	unsigned int		insns[2];
	stack_t32		stack;
	unsigned int		extra_size; /* Should be sizeof(siginfo_extra_v8plus_t) */
	/* Only valid if (regs.psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS */
	siginfo_extra_v8plus_t	v8plus;
	__siginfo_fpu_t		fpu_state;
};

/* Align macros */
#define SF_ALIGNEDSZ  (((sizeof(struct signal_frame32) + 7) & (~7)))
#define RT_ALIGNEDSZ  (((sizeof(struct rt_signal_frame32) + 7) & (~7)))

int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
{
	int err;

	if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
		return -EFAULT;

	/* If you change siginfo_t structure, please be sure
	   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.
	   This routine must convert siginfo from 64bit to 32bit as well
	   at the same time.  */
	err = __put_user(from->si_signo, &to->si_signo);
	err |= __put_user(from->si_errno, &to->si_errno);
	err |= __put_user((short)from->si_code, &to->si_code);
	if (from->si_code < 0)
		err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
	else {
		switch (from->si_code >> 16) {
		case __SI_TIMER >> 16:
			err |= __put_user(from->si_tid, &to->si_tid);
			err |= __put_user(from->si_overrun, &to->si_overrun);
			err |= __put_user(from->si_int, &to->si_int);
			break;
		case __SI_CHLD >> 16:
			err |= __put_user(from->si_utime, &to->si_utime);
			err |= __put_user(from->si_stime, &to->si_stime);
			err |= __put_user(from->si_status, &to->si_status);
		default:
			err |= __put_user(from->si_pid, &to->si_pid);
			err |= __put_user(from->si_uid, &to->si_uid);
			break;
		case __SI_FAULT >> 16:
			err |= __put_user(from->si_trapno, &to->si_trapno);
			err |= __put_user((unsigned long)from->si_addr, &to->si_addr);
			break;
		case __SI_POLL >> 16:
			err |= __put_user(from->si_band, &to->si_band);
			err |= __put_user(from->si_fd, &to->si_fd);
			break;
		case __SI_RT >> 16: /* This is not generated by the kernel as of now.  */
		case __SI_MESGQ >> 16:
			err |= __put_user(from->si_pid, &to->si_pid);
			err |= __put_user(from->si_uid, &to->si_uid);
			err |= __put_user(from->si_int, &to->si_int);
			break;
		}
	}
	return err;
}

/* CAUTION: This is just a very minimalist implementation for the
 *          sake of compat_sys_rt_sigqueueinfo()
 */
int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
{
	if (!access_ok(VERIFY_WRITE, from, sizeof(compat_siginfo_t)))
		return -EFAULT;

	if (copy_from_user(to, from, 3*sizeof(int)) ||
	    copy_from_user(to->_sifields._pad, from->_sifields._pad,
			   SI_PAD_SIZE))
		return -EFAULT;

	return 0;
}

static int restore_fpu_state32(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
{
	unsigned long *fpregs = current_thread_info()->fpregs;
	unsigned long fprs;
	int err;
	
	err = __get_user(fprs, &fpu->si_fprs);
	fprs_write(0);
	regs->tstate &= ~TSTATE_PEF;
	if (fprs & FPRS_DL)
		err |= copy_from_user(fpregs, &fpu->si_float_regs[0], (sizeof(unsigned int) * 32));
	if (fprs & FPRS_DU)
		err |= copy_from_user(fpregs+16, &fpu->si_float_regs[32], (sizeof(unsigned int) * 32));
	err |= __get_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
	err |= __get_user(current_thread_info()->gsr[0], &fpu->si_gsr);
	current_thread_info()->fpsaved[0] |= fprs;
	return err;
}

void do_sigreturn32(struct pt_regs *regs)
{
	struct signal_frame32 __user *sf;
	unsigned int psr;
	unsigned pc, npc, fpu_save;
	sigset_t set;
	unsigned seta[_COMPAT_NSIG_WORDS];
	int err, i;
	
	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	synchronize_user_stack();

	regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
	sf = (struct signal_frame32 __user *) regs->u_regs[UREG_FP];

	/* 1. Make sure we are not getting garbage from the user */
	if (!access_ok(VERIFY_READ, sf, sizeof(*sf)) ||
	    (((unsigned long) sf) & 3))
		goto segv;

	get_user(pc, &sf->info.si_regs.pc);
	__get_user(npc, &sf->info.si_regs.npc);

	if ((pc | npc) & 3)
		goto segv;

	if (test_thread_flag(TIF_32BIT)) {
		pc &= 0xffffffff;
		npc &= 0xffffffff;
	}
	regs->tpc = pc;
	regs->tnpc = npc;

	/* 2. Restore the state */
	err = __get_user(regs->y, &sf->info.si_regs.y);
	err |= __get_user(psr, &sf->info.si_regs.psr);

	for (i = UREG_G1; i <= UREG_I7; i++)
		err |= __get_user(regs->u_regs[i], &sf->info.si_regs.u_regs[i]);
	if ((psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS) {
		err |= __get_user(i, &sf->v8plus.g_upper[0]);
		if (i == SIGINFO_EXTRA_V8PLUS_MAGIC) {
			unsigned long asi;

			for (i = UREG_G1; i <= UREG_I7; i++)
				err |= __get_user(((u32 *)regs->u_regs)[2*i], &sf->v8plus.g_upper[i]);
			err |= __get_user(asi, &sf->v8plus.asi);
			regs->tstate &= ~TSTATE_ASI;
			regs->tstate |= ((asi & 0xffUL) << 24UL);
		}
	}

	/* User can only change condition codes in %tstate. */
	regs->tstate &= ~(TSTATE_ICC|TSTATE_XCC);
	regs->tstate |= psr_to_tstate_icc(psr);

	err |= __get_user(fpu_save, &sf->fpu_save);
	if (fpu_save)
		err |= restore_fpu_state32(regs, &sf->fpu_state);
	err |= __get_user(seta[0], &sf->info.si_mask);
	err |= copy_from_user(seta+1, &sf->extramask,
			      (_COMPAT_NSIG_WORDS - 1) * sizeof(unsigned int));
	if (err)
	    	goto segv;
	switch (_NSIG_WORDS) {
		case 4: set.sig[3] = seta[6] + (((long)seta[7]) << 32);
		case 3: set.sig[2] = seta[4] + (((long)seta[5]) << 32);
		case 2: set.sig[1] = seta[2] + (((long)seta[3]) << 32);
		case 1: set.sig[0] = seta[0] + (((long)seta[1]) << 32);
	}
	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	return;

segv:
	force_sig(SIGSEGV, current);
}

asmlinkage void do_rt_sigreturn32(struct pt_regs *regs)
{
	struct rt_signal_frame32 __user *sf;
	unsigned int psr, pc, npc, fpu_save, u_ss_sp;
	mm_segment_t old_fs;
	sigset_t set;
	compat_sigset_t seta;
	stack_t st;
	int err, i;
	
	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	synchronize_user_stack();
	regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
	sf = (struct rt_signal_frame32 __user *) regs->u_regs[UREG_FP];

	/* 1. Make sure we are not getting garbage from the user */
	if (!access_ok(VERIFY_READ, sf, sizeof(*sf)) ||
	    (((unsigned long) sf) & 3))
		goto segv;

	get_user(pc, &sf->regs.pc);
	__get_user(npc, &sf->regs.npc);

	if ((pc | npc) & 3)
		goto segv;

	if (test_thread_flag(TIF_32BIT)) {
		pc &= 0xffffffff;
		npc &= 0xffffffff;
	}
	regs->tpc = pc;
	regs->tnpc = npc;

	/* 2. Restore the state */
	err = __get_user(regs->y, &sf->regs.y);
	err |= __get_user(psr, &sf->regs.psr);
	
	for (i = UREG_G1; i <= UREG_I7; i++)
		err |= __get_user(regs->u_regs[i], &sf->regs.u_regs[i]);
	if ((psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS) {
		err |= __get_user(i, &sf->v8plus.g_upper[0]);
		if (i == SIGINFO_EXTRA_V8PLUS_MAGIC) {
			unsigned long asi;

			for (i = UREG_G1; i <= UREG_I7; i++)
				err |= __get_user(((u32 *)regs->u_regs)[2*i], &sf->v8plus.g_upper[i]);
			err |= __get_user(asi, &sf->v8plus.asi);
			regs->tstate &= ~TSTATE_ASI;
			regs->tstate |= ((asi & 0xffUL) << 24UL);
		}
	}

	/* User can only change condition codes in %tstate. */
	regs->tstate &= ~(TSTATE_ICC|TSTATE_XCC);
	regs->tstate |= psr_to_tstate_icc(psr);

	err |= __get_user(fpu_save, &sf->fpu_save);
	if (fpu_save)
		err |= restore_fpu_state32(regs, &sf->fpu_state);
	err |= copy_from_user(&seta, &sf->mask, sizeof(compat_sigset_t));
	err |= __get_user(u_ss_sp, &sf->stack.ss_sp);
	st.ss_sp = compat_ptr(u_ss_sp);
	err |= __get_user(st.ss_flags, &sf->stack.ss_flags);
	err |= __get_user(st.ss_size, &sf->stack.ss_size);
	if (err)
		goto segv;
		
	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	old_fs = get_fs();
	set_fs(KERNEL_DS);
	do_sigaltstack((stack_t __user *) &st, NULL, (unsigned long)sf);
	set_fs(old_fs);
	
	switch (_NSIG_WORDS) {
		case 4: set.sig[3] = seta.sig[6] + (((long)seta.sig[7]) << 32);
		case 3: set.sig[2] = seta.sig[4] + (((long)seta.sig[5]) << 32);
		case 2: set.sig[1] = seta.sig[2] + (((long)seta.sig[3]) << 32);
		case 1: set.sig[0] = seta.sig[0] + (((long)seta.sig[1]) << 32);
	}
	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	return;
segv:
	force_sig(SIGSEGV, current);
}

/* Checks if the fp is valid */
static int invalid_frame_pointer(void __user *fp, int fplen)
{
	if ((((unsigned long) fp) & 7) || ((unsigned long)fp) > 0x100000000ULL - fplen)
		return 1;
	return 0;
}

static void __user *get_sigframe(struct sigaction *sa, struct pt_regs *regs, unsigned long framesize)
{
	unsigned long sp;
	
	regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
	sp = regs->u_regs[UREG_FP];
	
	/* This is the X/Open sanctioned signal stack switching.  */
	if (sa->sa_flags & SA_ONSTACK) {
		if (!on_sig_stack(sp) && !((current->sas_ss_sp + current->sas_ss_size) & 7))
			sp = current->sas_ss_sp + current->sas_ss_size;
	}
	return (void __user *)(sp - framesize);
}

static int save_fpu_state32(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
{
	unsigned long *fpregs = current_thread_info()->fpregs;
	unsigned long fprs;
	int err = 0;
	
	fprs = current_thread_info()->fpsaved[0];
	if (fprs & FPRS_DL)
		err |= copy_to_user(&fpu->si_float_regs[0], fpregs,
				    (sizeof(unsigned int) * 32));
	if (fprs & FPRS_DU)
		err |= copy_to_user(&fpu->si_float_regs[32], fpregs+16,
				    (sizeof(unsigned int) * 32));
	err |= __put_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
	err |= __put_user(current_thread_info()->gsr[0], &fpu->si_gsr);
	err |= __put_user(fprs, &fpu->si_fprs);

	return err;
}

static void setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
			  int signo, sigset_t *oldset)
{
	struct signal_frame32 __user *sf;
	int sigframe_size;
	u32 psr;
	int i, err;
	unsigned int seta[_COMPAT_NSIG_WORDS];

	/* 1. Make sure everything is clean */
	synchronize_user_stack();
	save_and_clear_fpu();
	
	sigframe_size = SF_ALIGNEDSZ;
	if (!(current_thread_info()->fpsaved[0] & FPRS_FEF))
		sigframe_size -= sizeof(__siginfo_fpu_t);

	sf = (struct signal_frame32 __user *)
		get_sigframe(&ka->sa, regs, sigframe_size);
	
	if (invalid_frame_pointer(sf, sigframe_size))
		goto sigill;

	if (get_thread_wsaved() != 0)
		goto sigill;

	/* 2. Save the current process state */
	if (test_thread_flag(TIF_32BIT)) {
		regs->tpc &= 0xffffffff;
		regs->tnpc &= 0xffffffff;
	}
	err  = put_user(regs->tpc, &sf->info.si_regs.pc);
	err |= __put_user(regs->tnpc, &sf->info.si_regs.npc);
	err |= __put_user(regs->y, &sf->info.si_regs.y);
	psr = tstate_to_psr(regs->tstate);
	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
		psr |= PSR_EF;
	err |= __put_user(psr, &sf->info.si_regs.psr);
	for (i = 0; i < 16; i++)
		err |= __put_user(regs->u_regs[i], &sf->info.si_regs.u_regs[i]);
	err |= __put_user(sizeof(siginfo_extra_v8plus_t), &sf->extra_size);
	err |= __put_user(SIGINFO_EXTRA_V8PLUS_MAGIC, &sf->v8plus.g_upper[0]);
	for (i = 1; i < 16; i++)
		err |= __put_user(((u32 *)regs->u_regs)[2*i],
				  &sf->v8plus.g_upper[i]);
	err |= __put_user((regs->tstate & TSTATE_ASI) >> 24UL,
			  &sf->v8plus.asi);

	if (psr & PSR_EF) {
		err |= save_fpu_state32(regs, &sf->fpu_state);
		err |= __put_user((u64)&sf->fpu_state, &sf->fpu_save);
	} else {
		err |= __put_user(0, &sf->fpu_save);
	}

	switch (_NSIG_WORDS) {
	case 4: seta[7] = (oldset->sig[3] >> 32);
	        seta[6] = oldset->sig[3];
	case 3: seta[5] = (oldset->sig[2] >> 32);
	        seta[4] = oldset->sig[2];
	case 2: seta[3] = (oldset->sig[1] >> 32);
	        seta[2] = oldset->sig[1];
	case 1: seta[1] = (oldset->sig[0] >> 32);
	        seta[0] = oldset->sig[0];
	}
	err |= __put_user(seta[0], &sf->info.si_mask);
	err |= __copy_to_user(sf->extramask, seta + 1,
			      (_COMPAT_NSIG_WORDS - 1) * sizeof(unsigned int));

	err |= copy_in_user((u32 __user *)sf,
			    (u32 __user *)(regs->u_regs[UREG_FP]),
			    sizeof(struct reg_window32));
	
	if (err)
		goto sigsegv;

	/* 3. signal handler back-trampoline and parameters */
	regs->u_regs[UREG_FP] = (unsigned long) sf;
	regs->u_regs[UREG_I0] = signo;
	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
	regs->u_regs[UREG_I2] = (unsigned long) &sf->info;

	/* 4. signal handler */
	regs->tpc = (unsigned long) ka->sa.sa_handler;
	regs->tnpc = (regs->tpc + 4);
	if (test_thread_flag(TIF_32BIT)) {
		regs->tpc &= 0xffffffff;
		regs->tnpc &= 0xffffffff;
	}

	/* 5. return to kernel instructions */
	if (ka->ka_restorer) {
		regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
	} else {
		/* Flush instruction space. */
		unsigned long address = ((unsigned long)&(sf->insns[0]));
		pgd_t *pgdp = pgd_offset(current->mm, address);
		pud_t *pudp = pud_offset(pgdp, address);
		pmd_t *pmdp = pmd_offset(pudp, address);
		pte_t *ptep;
		pte_t pte;

		regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
	
		err  = __put_user(0x821020d8, &sf->insns[0]); /*mov __NR_sigreturn, %g1*/
		err |= __put_user(0x91d02010, &sf->insns[1]); /*t 0x10*/
		if (err)
			goto sigsegv;

		preempt_disable();
		ptep = pte_offset_map(pmdp, address);
		pte = *ptep;
		if (pte_present(pte)) {
			unsigned long page = (unsigned long)
				page_address(pte_page(pte));

			wmb();
			__asm__ __volatile__("flush	%0 + %1"
					     : /* no outputs */
					     : "r" (page),
					       "r" (address & (PAGE_SIZE - 1))
					     : "memory");
		}
		pte_unmap(ptep);
		preempt_enable();
	}
	return;

sigill:
	do_exit(SIGILL);
sigsegv:
	force_sigsegv(signo, current);
}

static void setup_rt_frame32(struct k_sigaction *ka, struct pt_regs *regs,
			     unsigned long signr, sigset_t *oldset,
			     siginfo_t *info)
{
	struct rt_signal_frame32 __user *sf;
	int sigframe_size;
	u32 psr;
	int i, err;
	compat_sigset_t seta;

	/* 1. Make sure everything is clean */
	synchronize_user_stack();
	save_and_clear_fpu();
	
	sigframe_size = RT_ALIGNEDSZ;
	if (!(current_thread_info()->fpsaved[0] & FPRS_FEF))
		sigframe_size -= sizeof(__siginfo_fpu_t);

	sf = (struct rt_signal_frame32 __user *)
		get_sigframe(&ka->sa, regs, sigframe_size);
	
	if (invalid_frame_pointer(sf, sigframe_size))
		goto sigill;

	if (get_thread_wsaved() != 0)
		goto sigill;

	/* 2. Save the current process state */
	if (test_thread_flag(TIF_32BIT)) {
		regs->tpc &= 0xffffffff;
		regs->tnpc &= 0xffffffff;
	}
	err  = put_user(regs->tpc, &sf->regs.pc);
	err |= __put_user(regs->tnpc, &sf->regs.npc);
	err |= __put_user(regs->y, &sf->regs.y);
	psr = tstate_to_psr(regs->tstate);
	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
		psr |= PSR_EF;
	err |= __put_user(psr, &sf->regs.psr);
	for (i = 0; i < 16; i++)
		err |= __put_user(regs->u_regs[i], &sf->regs.u_regs[i]);
	err |= __put_user(sizeof(siginfo_extra_v8plus_t), &sf->extra_size);
	err |= __put_user(SIGINFO_EXTRA_V8PLUS_MAGIC, &sf->v8plus.g_upper[0]);
	for (i = 1; i < 16; i++)
		err |= __put_user(((u32 *)regs->u_regs)[2*i],
				  &sf->v8plus.g_upper[i]);
	err |= __put_user((regs->tstate & TSTATE_ASI) >> 24UL,
			  &sf->v8plus.asi);

	if (psr & PSR_EF) {
		err |= save_fpu_state32(regs, &sf->fpu_state);
		err |= __put_user((u64)&sf->fpu_state, &sf->fpu_save);
	} else {
		err |= __put_user(0, &sf->fpu_save);
	}

	/* Update the siginfo structure.  */
	err |= copy_siginfo_to_user32(&sf->info, info);
	
	/* Setup sigaltstack */
	err |= __put_user(current->sas_ss_sp, &sf->stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &sf->stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &sf->stack.ss_size);

	switch (_NSIG_WORDS) {
	case 4: seta.sig[7] = (oldset->sig[3] >> 32);
		seta.sig[6] = oldset->sig[3];
	case 3: seta.sig[5] = (oldset->sig[2] >> 32);
		seta.sig[4] = oldset->sig[2];
	case 2: seta.sig[3] = (oldset->sig[1] >> 32);
		seta.sig[2] = oldset->sig[1];
	case 1: seta.sig[1] = (oldset->sig[0] >> 32);
		seta.sig[0] = oldset->sig[0];
	}
	err |= __copy_to_user(&sf->mask, &seta, sizeof(compat_sigset_t));

	err |= copy_in_user((u32 __user *)sf,
			    (u32 __user *)(regs->u_regs[UREG_FP]),
			    sizeof(struct reg_window32));
	if (err)
		goto sigsegv;
	
	/* 3. signal handler back-trampoline and parameters */
	regs->u_regs[UREG_FP] = (unsigned long) sf;
	regs->u_regs[UREG_I0] = signr;
	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
	regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;

	/* 4. signal handler */
	regs->tpc = (unsigned long) ka->sa.sa_handler;
	regs->tnpc = (regs->tpc + 4);
	if (test_thread_flag(TIF_32BIT)) {
		regs->tpc &= 0xffffffff;
		regs->tnpc &= 0xffffffff;
	}

	/* 5. return to kernel instructions */
	if (ka->ka_restorer)
		regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
	else {
		/* Flush instruction space. */
		unsigned long address = ((unsigned long)&(sf->insns[0]));
		pgd_t *pgdp = pgd_offset(current->mm, address);
		pud_t *pudp = pud_offset(pgdp, address);
		pmd_t *pmdp = pmd_offset(pudp, address);
		pte_t *ptep;

		regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
	
		/* mov __NR_rt_sigreturn, %g1 */
		err |= __put_user(0x82102065, &sf->insns[0]);

		/* t 0x10 */
		err |= __put_user(0x91d02010, &sf->insns[1]);
		if (err)
			goto sigsegv;

		preempt_disable();
		ptep = pte_offset_map(pmdp, address);
		if (pte_present(*ptep)) {
			unsigned long page = (unsigned long)
				page_address(pte_page(*ptep));

			wmb();
			__asm__ __volatile__("flush	%0 + %1"
					     : /* no outputs */
					     : "r" (page),
					       "r" (address & (PAGE_SIZE - 1))
					     : "memory");
		}
		pte_unmap(ptep);
		preempt_enable();
	}
	return;

sigill:
	do_exit(SIGILL);
sigsegv:
	force_sigsegv(signr, current);
}

static inline void handle_signal32(unsigned long signr, struct k_sigaction *ka,
				   siginfo_t *info,
				   sigset_t *oldset, struct pt_regs *regs)
{
	if (ka->sa.sa_flags & SA_SIGINFO)
		setup_rt_frame32(ka, regs, signr, oldset, info);
	else
		setup_frame32(ka, regs, signr, oldset);

	spin_lock_irq(&current->sighand->siglock);
	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
	if (!(ka->sa.sa_flags & SA_NOMASK))
		sigaddset(&current->blocked,signr);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
}

static inline void syscall_restart32(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;
		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.
 */
void do_signal32(sigset_t *oldset, struct pt_regs * regs,
		 struct signal_deliver_cookie *cookie)
{
	struct k_sigaction ka;
	siginfo_t info;
	int signr;
	
	signr = get_signal_to_deliver(&info, &ka, regs, cookie);
	if (signr > 0) {
		if (cookie->restart_syscall)
			syscall_restart32(cookie->orig_i0, regs, &ka.sa);
		handle_signal32(signr, &ka, &info, oldset, regs);

		/* a signal was successfully delivered; the saved
		 * sigmask will have been stored in the signal frame,
		 * and will be restored by sigreturn, so we can simply
		 * clear the TIF_RESTORE_SIGMASK flag.
		 */
		if (test_thread_flag(TIF_RESTORE_SIGMASK))
			clear_thread_flag(TIF_RESTORE_SIGMASK);
		return;
	}
	if (cookie->restart_syscall &&
	    (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
	     regs->u_regs[UREG_I0] == ERESTARTSYS ||
	     regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
		/* replay the system call when we are done */
		regs->u_regs[UREG_I0] = cookie->orig_i0;
		regs->tpc -= 4;
		regs->tnpc -= 4;
	}
	if (cookie->restart_syscall &&
	    regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
		regs->u_regs[UREG_G1] = __NR_restart_syscall;
		regs->tpc -= 4;
		regs->tnpc -= 4;
	}

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

struct sigstack32 {
	u32 the_stack;
	int cur_status;
};

asmlinkage int do_sys32_sigstack(u32 u_ssptr, u32 u_ossptr, unsigned long sp)
{
	struct sigstack32 __user *ssptr =
		(struct sigstack32 __user *)((unsigned long)(u_ssptr));
	struct sigstack32 __user *ossptr =
		(struct sigstack32 __user *)((unsigned long)(u_ossptr));
	int ret = -EFAULT;

	/* First see if old state is wanted. */
	if (ossptr) {
		if (put_user(current->sas_ss_sp + current->sas_ss_size,
			     &ossptr->the_stack) ||
		    __put_user(on_sig_stack(sp), &ossptr->cur_status))
			goto out;
	}
	
	/* Now see if we want to update the new state. */
	if (ssptr) {
		u32 ss_sp;

		if (get_user(ss_sp, &ssptr->the_stack))
			goto out;

		/* If the current stack was set with sigaltstack, don't
		 * swap stacks while we are on it.
		 */
		ret = -EPERM;
		if (current->sas_ss_sp && on_sig_stack(sp))
			goto out;
			
		/* Since we don't know the extent of the stack, and we don't
		 * track onstack-ness, but rather calculate it, we must
		 * presume a size.  Ho hum this interface is lossy.
		 */
		current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ;
		current->sas_ss_size = SIGSTKSZ;
	}
	
	ret = 0;
out:
	return ret;
}

asmlinkage long do_sys32_sigaltstack(u32 ussa, u32 uossa, unsigned long sp)
{
	stack_t uss, uoss;
	u32 u_ss_sp = 0;
	int ret;
	mm_segment_t old_fs;
	stack_t32 __user *uss32 = compat_ptr(ussa);
	stack_t32 __user *uoss32 = compat_ptr(uossa);
	
	if (ussa && (get_user(u_ss_sp, &uss32->ss_sp) ||
		    __get_user(uss.ss_flags, &uss32->ss_flags) ||
		    __get_user(uss.ss_size, &uss32->ss_size)))
		return -EFAULT;
	uss.ss_sp = compat_ptr(u_ss_sp);
	old_fs = get_fs();
	set_fs(KERNEL_DS);
	ret = do_sigaltstack(ussa ? (stack_t __user *) &uss : NULL,
			     uossa ? (stack_t __user *) &uoss : NULL, sp);
	set_fs(old_fs);
	if (!ret && uossa && (put_user(ptr_to_compat(uoss.ss_sp), &uoss32->ss_sp) ||
		    __put_user(uoss.ss_flags, &uoss32->ss_flags) ||
		    __put_user(uoss.ss_size, &uoss32->ss_size)))
		return -EFAULT;
	return ret;
}