1 /* $NetBSD: freebsd_syscall.c,v 1.2 2017/08/08 08:04:06 maxv 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_syscall.c,v 1.2 2017/08/08 08:04:06 maxv Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/proc.h> 38 #include <sys/signal.h> 39 #include <sys/syscall.h> 40 #include <sys/syscallvar.h> 41 42 #include <uvm/uvm_extern.h> 43 44 #include <machine/cpu.h> 45 #include <machine/psl.h> 46 #include <machine/userret.h> 47 48 #include <compat/sys/signal.h> 49 50 #include <compat/freebsd/freebsd_machdep.h> 51 #include <compat/freebsd/freebsd_syscall.h> 52 53 void freebsd_syscall(struct trapframe *); 54 55 void 56 freebsd_syscall_intern(struct proc *p) 57 { 58 59 p->p_md.md_syscall = freebsd_syscall; 60 } 61 62 /* 63 * syscall(frame): 64 * System call request from POSIX system call gate interface to kernel. 65 * Like trap(), argument is call by reference. 66 */ 67 void 68 freebsd_syscall(struct trapframe *frame) 69 { 70 char *params; 71 const struct sysent *callp; 72 struct lwp *l; 73 struct proc *p; 74 int error; 75 size_t argsize; 76 register_t code, args[8], rval[2]; 77 78 l = curlwp; 79 p = l->l_proc; 80 LWP_CACHE_CREDS(l, p); 81 82 code = frame->tf_eax; 83 callp = p->p_emul->e_sysent; 84 params = (char *)frame->tf_esp + sizeof(int); 85 86 switch (code) { 87 case SYS_syscall: 88 /* 89 * Code is first argument, followed by actual args. 90 */ 91 code = fuword(params); 92 params += sizeof(int); 93 break; 94 case SYS___syscall: 95 /* 96 * Like syscall, but code is a quad, so as to maintain 97 * quad alignment for the rest of the arguments. 98 */ 99 code = fuword(params + _QUAD_LOWWORD * sizeof(int)); 100 params += sizeof(quad_t); 101 break; 102 default: 103 break; 104 } 105 106 code &= (SYS_NSYSENT - 1); 107 callp += code; 108 argsize = callp->sy_argsize; 109 if (argsize) { 110 error = copyin(params, (void *)args, argsize); 111 if (error) 112 goto bad; 113 } 114 115 if (!__predict_false(p->p_trace_enabled || KDTRACE_ENTRY(callp->sy_entry)) 116 || (error = trace_enter(code, callp, args)) == 0) { 117 rval[0] = 0; 118 rval[1] = frame->tf_edx; /* need to keep edx for shared FreeBSD bins */ 119 error = sy_call(callp, l, args, rval); 120 } 121 122 switch (error) { 123 case 0: 124 frame->tf_eax = rval[0]; 125 frame->tf_edx = rval[1]; 126 frame->tf_eflags &= ~PSL_C; /* carry bit */ 127 break; 128 case ERESTART: 129 /* 130 * The offset to adjust the PC by depends on whether we entered 131 * the kernel through the trap or call gate. We pushed the 132 * size of the instruction into tf_err on entry. 133 */ 134 frame->tf_eip -= frame->tf_err; 135 break; 136 case EJUSTRETURN: 137 /* nothing to do */ 138 break; 139 default: 140 bad: 141 frame->tf_eax = error; 142 frame->tf_eflags |= PSL_C; /* carry bit */ 143 break; 144 } 145 146 if (__predict_false(p->p_trace_enabled || KDTRACE_ENTRY(callp->sy_return))) 147 trace_exit(code, callp, args, rval, error); 148 149 userret(l); 150 } 151