| 1 | /* $NetBSD: syscall.c,v 1.14 2016/07/07 06:55:40 msaitoh Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 1998, 2000, 2009 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: syscall.c,v 1.14 2016/07/07 06:55:40 msaitoh 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/ktrace.h> |
| 40 | #include <sys/syscall.h> |
| 41 | #include <sys/syscallvar.h> |
| 42 | #include <sys/syscall_stats.h> |
| 43 | |
| 44 | #include <uvm/uvm_extern.h> |
| 45 | |
| 46 | #include <machine/cpu.h> |
| 47 | #include <machine/psl.h> |
| 48 | #include <machine/userret.h> |
| 49 | |
| 50 | #include "opt_dtrace.h" |
| 51 | |
| 52 | #ifndef __x86_64__ |
| 53 | #include "opt_vm86.h" |
| 54 | #ifdef VM86 |
| 55 | void syscall_vm86(struct trapframe *); |
| 56 | #endif |
| 57 | int x86_copyargs(void *, void *, size_t); |
| 58 | #endif |
| 59 | |
| 60 | void syscall_intern(struct proc *); |
| 61 | static void syscall(struct trapframe *); |
| 62 | |
| 63 | void |
| 64 | child_return(void *arg) |
| 65 | { |
| 66 | struct lwp *l = arg; |
| 67 | struct trapframe *tf = l->l_md.md_regs; |
| 68 | struct proc *p = l->l_proc; |
| 69 | |
| 70 | if (p->p_slflag & PSL_TRACED) { |
| 71 | ksiginfo_t ksi; |
| 72 | |
| 73 | mutex_enter(proc_lock); |
| 74 | KSI_INIT_EMPTY(&ksi); |
| 75 | ksi.ksi_signo = SIGTRAP; |
| 76 | ksi.ksi_lid = l->l_lid; |
| 77 | kpsignal(p, &ksi, NULL); |
| 78 | mutex_exit(proc_lock); |
| 79 | } |
| 80 | |
| 81 | X86_TF_RAX(tf) = 0; |
| 82 | X86_TF_RFLAGS(tf) &= ~PSL_C; |
| 83 | |
| 84 | userret(l); |
| 85 | ktrsysret(SYS_fork, 0, 0); |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * Process the tail end of a posix_spawn() for the child. |
| 90 | */ |
| 91 | void |
| 92 | cpu_spawn_return(struct lwp *l) |
| 93 | { |
| 94 | |
| 95 | userret(l); |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * syscall(frame): |
| 100 | * System call request from POSIX system call gate interface to kernel. |
| 101 | * Like trap(), argument is call by reference. |
| 102 | */ |
| 103 | #ifdef KDTRACE_HOOKS |
| 104 | void syscall(struct trapframe *); |
| 105 | #else |
| 106 | static |
| 107 | #endif |
| 108 | void |
| 109 | syscall(struct trapframe *frame) |
| 110 | { |
| 111 | const struct sysent *callp; |
| 112 | struct proc *p; |
| 113 | struct lwp *l; |
| 114 | int error; |
| 115 | register_t code, rval[2]; |
| 116 | #ifdef __x86_64__ |
| 117 | /* Verify that the syscall args will fit in the trapframe space */ |
| 118 | CTASSERT(offsetof(struct trapframe, tf_arg9) >= |
| 119 | sizeof(register_t) * (2 + SYS_MAXSYSARGS - 1)); |
| 120 | #define args (&frame->tf_rdi) |
| 121 | #else |
| 122 | register_t args[2 + SYS_MAXSYSARGS]; |
| 123 | #endif |
| 124 | |
| 125 | l = curlwp; |
| 126 | p = l->l_proc; |
| 127 | LWP_CACHE_CREDS(l, p); |
| 128 | |
| 129 | code = X86_TF_RAX(frame) & (SYS_NSYSENT - 1); |
| 130 | callp = p->p_emul->e_sysent + code; |
| 131 | |
| 132 | SYSCALL_COUNT(syscall_counts, code); |
| 133 | SYSCALL_TIME_SYS_ENTRY(l, syscall_times, code); |
| 134 | |
| 135 | #ifdef __x86_64__ |
| 136 | /* |
| 137 | * The first 6 syscall args are passed in rdi, rsi, rdx, r10, r8 and r9 |
| 138 | * (rcx gets copied to r10 in the libc stub because the syscall |
| 139 | * instruction overwrites %cx) and are together in the trap frame |
| 140 | * with space following for 4 more entries. |
| 141 | */ |
| 142 | if (__predict_false(callp->sy_argsize > 6 * 8)) { |
| 143 | error = copyin((register_t *)frame->tf_rsp + 1, |
| 144 | &frame->tf_arg6, callp->sy_argsize - 6 * 8); |
| 145 | if (error != 0) |
| 146 | goto bad; |
| 147 | } |
| 148 | #else |
| 149 | if (callp->sy_argsize) { |
| 150 | error = x86_copyargs((char *)frame->tf_esp + sizeof(int), args, |
| 151 | callp->sy_argsize); |
| 152 | if (__predict_false(error != 0)) |
| 153 | goto bad; |
| 154 | } |
| 155 | #endif |
| 156 | error = sy_invoke(callp, l, args, rval, code); |
| 157 | |
| 158 | if (__predict_true(error == 0)) { |
| 159 | X86_TF_RAX(frame) = rval[0]; |
| 160 | X86_TF_RDX(frame) = rval[1]; |
| 161 | X86_TF_RFLAGS(frame) &= ~PSL_C; /* carry bit */ |
| 162 | } else { |
| 163 | switch (error) { |
| 164 | case ERESTART: |
| 165 | /* |
| 166 | * The offset to adjust the PC by depends on whether we |
| 167 | * entered the kernel through the trap or call gate. |
| 168 | * We saved the instruction size in tf_err on entry. |
| 169 | */ |
| 170 | X86_TF_RIP(frame) -= frame->tf_err; |
| 171 | break; |
| 172 | case EJUSTRETURN: |
| 173 | /* nothing to do */ |
| 174 | break; |
| 175 | default: |
| 176 | bad: |
| 177 | X86_TF_RAX(frame) = error; |
| 178 | X86_TF_RFLAGS(frame) |= PSL_C; /* carry bit */ |
| 179 | break; |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | SYSCALL_TIME_SYS_EXIT(l); |
| 184 | userret(l); |
| 185 | } |
| 186 | |
| 187 | void |
| 188 | syscall_intern(struct proc *p) |
| 189 | { |
| 190 | |
| 191 | p->p_md.md_syscall = syscall; |
| 192 | } |
| 193 | |
| 194 | #ifdef VM86 |
| 195 | |
| 196 | void |
| 197 | syscall_vm86(struct trapframe *frame) |
| 198 | { |
| 199 | struct lwp *l; |
| 200 | struct proc *p; |
| 201 | ksiginfo_t ksi; |
| 202 | |
| 203 | KSI_INIT_TRAP(&ksi); |
| 204 | ksi.ksi_signo = SIGBUS; |
| 205 | ksi.ksi_code = BUS_OBJERR; |
| 206 | ksi.ksi_trap = T_PROTFLT; |
| 207 | ksi.ksi_addr = (void *)frame->tf_eip; |
| 208 | |
| 209 | l = curlwp; |
| 210 | p = l->l_proc; |
| 211 | |
| 212 | (*p->p_emul->e_trapsignal)(l, &ksi); |
| 213 | userret(l); |
| 214 | } |
| 215 | |
| 216 | #endif |
| 217 | |