/* $NetBSD: compat_16_machdep.c,v 1.34 2022/08/20 23:49:31 riastradh Exp $ */ /*- * Copyright (c) 1996, 1997, 1998, 2000 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Charles M. Hannum. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include __KERNEL_RCSID(0, "$NetBSD: compat_16_machdep.c,v 1.34 2022/08/20 23:49:31 riastradh Exp $"); #ifdef _KERNEL_OPT #include "opt_compat_netbsd.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(COMPAT_16) #include #include /* * System call to cleanup state after a signal * has been taken. Reset signal mask and * stack state from context left by sendsig (above). * Return to previous pc and psl as specified by * context left by sendsig. Check carefully to * make sure that the user has not modified the * psl to gain improper privileges or to cause * a machine fault. */ int compat_16_sys___sigreturn14(struct lwp *, const struct compat_16_sys___sigreturn14_args *, register_t *); int compat_16_sys___sigreturn14(struct lwp *l, const struct compat_16_sys___sigreturn14_args *uap, register_t *retval) { /* { syscallarg(struct sigcontext *) sigcntxp; } */ struct proc *p = l->l_proc; struct sigcontext *scp, context; struct trapframe *tf; /* * The trampoline code hands us the context. * It is unsafe to keep track of it ourselves, in the event that a * program jumps out of a signal handler. */ scp = SCARG(uap, sigcntxp); if (copyin((void *)scp, &context, sizeof(*scp)) != 0) return (EFAULT); /* Restore register context. */ tf = l->l_md.md_regs; /* * Check for security violations. If we're returning to * protected mode, the CPU will validate the segment registers * automatically and generate a trap on violations. We handle * the trap, rather than doing all of the checking here. */ if (((context.sc_eflags ^ tf->tf_eflags) & PSL_USERSTATIC) != 0 || !USERMODE(context.sc_cs)) return (EINVAL); tf->tf_gs = context.sc_gs; tf->tf_fs = context.sc_fs; tf->tf_es = context.sc_es; tf->tf_ds = context.sc_ds; tf->tf_eflags &= ~PSL_USER; tf->tf_eflags |= context.sc_eflags & PSL_USER; tf->tf_edi = context.sc_edi; tf->tf_esi = context.sc_esi; tf->tf_ebp = context.sc_ebp; tf->tf_ebx = context.sc_ebx; tf->tf_edx = context.sc_edx; tf->tf_ecx = context.sc_ecx; tf->tf_eax = context.sc_eax; tf->tf_eip = context.sc_eip; tf->tf_cs = context.sc_cs; tf->tf_esp = context.sc_esp; tf->tf_ss = context.sc_ss; /* Restore signal stack. */ mutex_enter(p->p_lock); if (context.sc_onstack & SS_ONSTACK) l->l_sigstk.ss_flags |= SS_ONSTACK; else l->l_sigstk.ss_flags &= ~SS_ONSTACK; /* Restore signal mask. */ (void) sigprocmask1(l, SIG_SETMASK, &context.sc_mask, 0); mutex_exit(p->p_lock); return (EJUSTRETURN); } #endif #ifdef COMPAT_16 /* * Send an interrupt to process. * * Stack is set up to allow sigcode stored * in u. to call routine, followed by kcall * to sigreturn routine below. After sigreturn * resets the signal mask, the stack, and the * frame pointer, it returns to the user * specified pc, psl. */ void sendsig_sigcontext(const ksiginfo_t *ksi, const sigset_t *mask) { struct lwp *l = curlwp; struct proc *p = l->l_proc; struct pmap *pmap = vm_map_pmap(&p->p_vmspace->vm_map); int sel = pmap->pm_hiexec > I386_MAX_EXE_ADDR ? GUCODEBIG_SEL : GUCODE_SEL; struct sigacts *ps = p->p_sigacts; struct trapframe *tf = l->l_md.md_regs; int onstack, error; int sig = ksi->ksi_signo; u_long code = KSI_TRAPCODE(ksi); struct sigframe_sigcontext *fp = getframe(l, sig, &onstack), frame; sig_t catcher = SIGACTION(p, sig).sa_handler; fp--; /* Build stack frame for signal trampoline. */ switch (ps->sa_sigdesc[sig].sd_vers) { case __SIGTRAMP_SIGCODE_VERSION: /* legacy on-stack sigtramp */ frame.sf_ra = (int)p->p_sigctx.ps_sigcode; break; case __SIGTRAMP_SIGCONTEXT_VERSION: frame.sf_ra = (int)ps->sa_sigdesc[sig].sd_tramp; break; default: /* Don't know what trampoline version; kill it. */ sigexit(l, SIGILL); } frame.sf_signum = sig; frame.sf_code = code; frame.sf_scp = &fp->sf_sc; /* Save register context. */ frame.sf_sc.sc_gs = tf->tf_gs; frame.sf_sc.sc_fs = tf->tf_fs; frame.sf_sc.sc_es = tf->tf_es; frame.sf_sc.sc_ds = tf->tf_ds; frame.sf_sc.sc_eflags = tf->tf_eflags; frame.sf_sc.sc_edi = tf->tf_edi; frame.sf_sc.sc_esi = tf->tf_esi; frame.sf_sc.sc_ebp = tf->tf_ebp; frame.sf_sc.sc_ebx = tf->tf_ebx; frame.sf_sc.sc_edx = tf->tf_edx; frame.sf_sc.sc_ecx = tf->tf_ecx; frame.sf_sc.sc_eax = tf->tf_eax; frame.sf_sc.sc_eip = tf->tf_eip; frame.sf_sc.sc_cs = tf->tf_cs; frame.sf_sc.sc_esp = tf->tf_esp; frame.sf_sc.sc_ss = tf->tf_ss; frame.sf_sc.sc_trapno = tf->tf_trapno; frame.sf_sc.sc_err = tf->tf_err; /* Save signal stack. */ frame.sf_sc.sc_onstack = l->l_sigstk.ss_flags & SS_ONSTACK; /* Save signal mask. */ frame.sf_sc.sc_mask = *mask; #ifdef COMPAT_13 /* * XXX We always have to save an old style signal mask because * XXX we might be delivering a signal to a process which will * XXX escape from the signal in a non-standard way and invoke * XXX sigreturn() directly. */ native_sigset_to_sigset13(mask, &frame.sf_sc.__sc_mask13); #endif sendsig_reset(l, sig); mutex_exit(p->p_lock); error = copyout(&frame, fp, sizeof(frame)); mutex_enter(p->p_lock); if (error != 0) { /* * Process has trashed its stack; give it an illegal * instruction to halt it in its tracks. */ sigexit(l, SIGILL); /* NOTREACHED */ } buildcontext(l, sel, catcher, fp); /* Remember that we're now on the signal stack. */ if (onstack) l->l_sigstk.ss_flags |= SS_ONSTACK; } #endif