1 /* $NetBSD: freebsd_machdep.c,v 1.5 2021/09/07 11:43:03 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Charles M. Hannum. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: freebsd_machdep.c,v 1.5 2021/09/07 11:43:03 riastradh Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/signalvar.h> 38 #include <sys/proc.h> 39 #include <sys/exec.h> 40 #include <sys/mount.h> 41 42 #include <compat/sys/signal.h> 43 44 #include <machine/cpufunc.h> 45 #include <x86/fpu.h> 46 #include <machine/reg.h> 47 #include <machine/vmparam.h> 48 #include <compat/freebsd/freebsd_machdep.h> 49 50 51 #include <compat/freebsd/freebsd_syscallargs.h> 52 #include <compat/freebsd/freebsd_exec.h> 53 #include <compat/freebsd/freebsd_signal.h> 54 55 void 56 freebsd_setregs(struct lwp *l, struct exec_package *epp, vaddr_t stack) 57 { 58 59 setregs(l, epp, stack); 60 fpu_set_default_cw(l, __FreeBSD_NPXCW__); 61 } 62 63 /* 64 * signal support 65 */ 66 67 /* 68 * Send an interrupt to process. 69 * 70 * Stack is set up to allow sigcode stored 71 * in u. to call routine, followed by kcall 72 * to sigreturn routine below. After sigreturn 73 * resets the signal mask, the stack, and the 74 * frame pointer, it returns to the user 75 * specified pc, psl. 76 */ 77 void 78 freebsd_sendsig(const ksiginfo_t *ksi, const sigset_t *mask) 79 { 80 int sig = ksi->ksi_signo; 81 u_long code = KSI_TRAPCODE(ksi); 82 struct lwp *l = curlwp; 83 struct proc *p = l->l_proc; 84 int onstack, error; 85 struct freebsd_sigframe *fp = getframe(l, sig, &onstack), frame; 86 sig_t catcher = SIGACTION(p, sig).sa_handler; 87 struct trapframe *tf = l->l_md.md_regs; 88 89 fp--; 90 91 memset(&frame, 0, sizeof(frame)); 92 93 /* Build stack frame for signal trampoline. */ 94 frame.sf_signum = sig; 95 frame.sf_code = code; 96 frame.sf_scp = &fp->sf_sc; 97 frame.sf_addr = (char *)rcr2(); 98 frame.sf_handler = catcher; 99 100 /* Save context. */ 101 frame.sf_sc.sc_gs = tf->tf_gs; 102 frame.sf_sc.sc_fs = tf->tf_fs; 103 frame.sf_sc.sc_es = tf->tf_es; 104 frame.sf_sc.sc_ds = tf->tf_ds; 105 frame.sf_sc.sc_efl = tf->tf_eflags; 106 107 frame.sf_sc.sc_edi = tf->tf_edi; 108 frame.sf_sc.sc_esi = tf->tf_esi; 109 frame.sf_sc.sc_ebp = tf->tf_ebp; 110 frame.sf_sc.sc_isp = 0; /* don't have to pass kernel sp to user. */ 111 frame.sf_sc.sc_ebx = tf->tf_ebx; 112 frame.sf_sc.sc_edx = tf->tf_edx; 113 frame.sf_sc.sc_ecx = tf->tf_ecx; 114 frame.sf_sc.sc_eax = tf->tf_eax; 115 frame.sf_sc.sc_eip = tf->tf_eip; 116 frame.sf_sc.sc_cs = tf->tf_cs; 117 frame.sf_sc.sc_esp = tf->tf_esp; 118 frame.sf_sc.sc_ss = tf->tf_ss; 119 120 /* Save signal stack. */ 121 frame.sf_sc.sc_onstack = l->l_sigstk.ss_flags & SS_ONSTACK; 122 123 /* Save signal mask. */ 124 /* XXX freebsd_osigcontext compat? */ 125 frame.sf_sc.sc_mask = *mask; 126 127 sendsig_reset(l, sig); 128 129 mutex_exit(p->p_lock); 130 error = copyout(&frame, fp, sizeof(frame)); 131 mutex_enter(p->p_lock); 132 133 if (error != 0) { 134 /* 135 * Process has trashed its stack; give it an illegal 136 * instruction to halt it in its tracks. 137 */ 138 sigexit(l, SIGILL); 139 /* NOTREACHED */ 140 } 141 142 buildcontext(l, GUCODEBIG_SEL, p->p_sigctx.ps_sigcode, fp); 143 144 /* Remember that we're now on the signal stack. */ 145 if (onstack) 146 l->l_sigstk.ss_flags |= SS_ONSTACK; 147 } 148 149 /* 150 * System call to cleanup state after a signal 151 * has been taken. Reset signal mask and 152 * stack state from context left by sendsig (above). 153 * Return to previous pc and psl as specified by 154 * context left by sendsig. Check carefully to 155 * make sure that the user has not modified the 156 * psl to gain improper privileges or to cause 157 * a machine fault. 158 */ 159 int 160 freebsd_sys_sigreturn(struct lwp *l, const struct freebsd_sys_sigreturn_args *uap, register_t *retval) 161 { 162 /* { 163 syscallarg(struct freebsd_sigcontext *) scp; 164 } */ 165 struct proc *p = l->l_proc; 166 struct freebsd_sigcontext *scp, context; 167 struct trapframe *tf; 168 sigset_t mask; 169 170 /* 171 * The trampoline code hands us the context. 172 * It is unsafe to keep track of it ourselves, in the event that a 173 * program jumps out of a signal handler. 174 */ 175 scp = SCARG(uap, scp); 176 if (copyin((void *)scp, &context, sizeof(*scp)) != 0) 177 return (EFAULT); 178 179 /* Restore register context. */ 180 tf = l->l_md.md_regs; 181 182 /* 183 * Check for security violations. If we're returning to 184 * protected mode, the CPU will validate the segment registers 185 * automatically and generate a trap on violations. We handle 186 * the trap, rather than doing all of the checking here. 187 */ 188 if (((context.sc_efl ^ tf->tf_eflags) & PSL_USERSTATIC) != 0 || 189 !USERMODE(context.sc_cs)) 190 return (EINVAL); 191 192 tf->tf_gs = context.sc_gs; 193 tf->tf_fs = context.sc_fs; 194 tf->tf_es = context.sc_es; 195 tf->tf_ds = context.sc_ds; 196 tf->tf_eflags &= ~PSL_USER; 197 tf->tf_eflags |= context.sc_efl & PSL_USER; 198 199 tf->tf_edi = context.sc_edi; 200 tf->tf_esi = context.sc_esi; 201 tf->tf_ebp = context.sc_ebp; 202 /* FreeBSD's context.sc_isp is useless. (`popal' ignores it.) */ 203 tf->tf_ebx = context.sc_ebx; 204 tf->tf_edx = context.sc_edx; 205 tf->tf_ecx = context.sc_ecx; 206 tf->tf_eax = context.sc_eax; 207 tf->tf_eip = context.sc_eip; 208 tf->tf_cs = context.sc_cs; 209 tf->tf_esp = context.sc_esp; 210 tf->tf_ss = context.sc_ss; 211 212 mutex_enter(p->p_lock); 213 /* Restore signal stack. */ 214 if (context.sc_onstack & SS_ONSTACK) 215 l->l_sigstk.ss_flags |= SS_ONSTACK; 216 else 217 l->l_sigstk.ss_flags &= ~SS_ONSTACK; 218 /* Restore signal mask. */ 219 /* XXX freebsd_osigcontext compat? */ 220 mask = context.sc_mask; 221 (void) sigprocmask1(l, SIG_SETMASK, &mask, 0); 222 mutex_exit(p->p_lock); 223 224 return (EJUSTRETURN); 225 } 226
Indexes created Sat Sep 20 22:09:52 GMT 2025