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      1 /* $NetBSD: compat_13_machdep.c,v 1.22 2017/03/16 16:13:20 chs Exp $ */
      2 
      3 /*
      4  * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
      5  * All rights reserved.
      6  *
      7  * Author: Chris G. Demetriou
      8  *
      9  * Permission to use, copy, modify and distribute this software and
     10  * its documentation is hereby granted, provided that both the copyright
     11  * notice and this permission notice appear in all copies of the
     12  * software, derivative works or modified versions, and any portions
     13  * thereof, and that both notices appear in supporting documentation.
     14  *
     15  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     16  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
     17  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     18  *
     19  * Carnegie Mellon requests users of this software to return to
     20  *
     21  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     22  *  School of Computer Science
     23  *  Carnegie Mellon University
     24  *  Pittsburgh PA 15213-3890
     25  *
     26  * any improvements or extensions that they make and grant Carnegie the
     27  * rights to redistribute these changes.
     28  */
     29 
     30 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
     31 
     32 __KERNEL_RCSID(0, "$NetBSD: compat_13_machdep.c,v 1.22 2017/03/16 16:13:20 chs Exp $");
     33 
     34 #include <sys/param.h>
     35 #include <sys/systm.h>
     36 #include <sys/signalvar.h>
     37 #include <sys/kernel.h>
     38 #include <sys/proc.h>
     39 #include <sys/mount.h>
     40 #include <sys/syscallargs.h>
     41 
     42 #include <compat/sys/signal.h>
     43 #include <compat/sys/signalvar.h>
     44 
     45 #include <machine/cpu.h>
     46 #include <machine/reg.h>
     47 #include <machine/alpha.h>
     48 
     49 /*
     50  * System call to cleanup state after a signal
     51  * has been taken.  Reset signal mask and
     52  * stack state from context left by sendsig (above).
     53  * Return to previous pc and psl as specified by
     54  * context left by sendsig. Check carefully to
     55  * make sure that the user has not modified the
     56  * psl to gain improper privileges or to cause
     57  * a machine fault.
     58  */
     59 /* ARGSUSED */
     60 int
     61 compat_13_sys_sigreturn(struct lwp *l, const struct compat_13_sys_sigreturn_args *uap, register_t *retval)
     62 {
     63 	/* {
     64 		syscallarg(struct sigcontext13 *) sigcntxp;
     65 	} */
     66 	struct sigcontext13 *scp, ksc;
     67 	struct proc *p = l->l_proc;
     68 	struct pcb *pcb;
     69 	sigset13_t mask13;
     70 	sigset_t mask;
     71 
     72 	/*
     73 	 * The trampoline code hands us the context.
     74 	 * It is unsafe to keep track of it ourselves, in the event that a
     75 	 * program jumps out of a signal handler.
     76 	 */
     77 	scp = SCARG(uap, sigcntxp);
     78 	if (ALIGN(scp) != (uint64_t)scp)
     79 		return (EINVAL);
     80 
     81 	if (copyin((void *)scp, &ksc, sizeof(ksc)) != 0)
     82 		return (EFAULT);
     83 
     84 	if (ksc.sc_regs[R_ZERO] != 0xACEDBADE)		/* magic number */
     85 		return (EINVAL);
     86 
     87 	/* Restore register context. */
     88 	l->l_md.md_tf->tf_regs[FRAME_PC] = ksc.sc_pc;
     89 	l->l_md.md_tf->tf_regs[FRAME_PS] =
     90 	    (ksc.sc_ps | ALPHA_PSL_USERSET) & ~ALPHA_PSL_USERCLR;
     91 
     92 	regtoframe((struct reg *)ksc.sc_regs, l->l_md.md_tf);
     93 	alpha_pal_wrusp(ksc.sc_regs[R_SP]);
     94 
     95 	/* XXX ksc.sc_ownedfp ? */
     96 	pcb = lwp_getpcb(l);
     97 	fpu_discard(l, true);
     98 	memcpy(&pcb->pcb_fp, (struct fpreg *)ksc.sc_fpregs,
     99 	    sizeof(struct fpreg));
    100 	/* XXX ksc.sc_fp_control ? */
    101 
    102 	mutex_enter(p->p_lock);
    103 	/* Restore signal stack. */
    104 	if (ksc.sc_onstack & SS_ONSTACK)
    105 		l->l_sigstk.ss_flags |= SS_ONSTACK;
    106 	else
    107 		l->l_sigstk.ss_flags &= ~SS_ONSTACK;
    108 	/*
    109 	 * Restore signal mask.  Note the mask is a "long" in the stack
    110 	 * frame.
    111 	 */
    112 	mask13 = ksc.sc_mask;
    113 	native_sigset13_to_sigset(&mask13, &mask);
    114 	(void) sigprocmask1(l, SIG_SETMASK, &mask, 0);
    115 	mutex_exit(p->p_lock);
    116 
    117 	return (EJUSTRETURN);
    118 }
    119