1 /* $NetBSD: linux_machdep.c,v 1.8 1995/05/07 03:27:37 mycroft Exp $ */ 2 3 /* 4 * Copyright (c) 1995 Frank van der Linden 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed for the NetBSD Project 18 * by Frank van der Linden 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/signalvar.h> 37 #include <sys/kernel.h> 38 #include <sys/map.h> 39 #include <sys/proc.h> 40 #include <sys/user.h> 41 #include <sys/buf.h> 42 #include <sys/reboot.h> 43 #include <sys/conf.h> 44 #include <sys/file.h> 45 #include <sys/callout.h> 46 #include <sys/malloc.h> 47 #include <sys/mbuf.h> 48 #include <sys/msgbuf.h> 49 #include <sys/mount.h> 50 #include <sys/vnode.h> 51 #include <sys/device.h> 52 #include <sys/sysctl.h> 53 #include <sys/syscallargs.h> 54 55 #include <compat/linux/linux_types.h> 56 #include <compat/linux/linux_syscallargs.h> 57 #include <compat/linux/linux_util.h> 58 59 #include <machine/cpu.h> 60 #include <machine/cpufunc.h> 61 #include <machine/psl.h> 62 #include <machine/reg.h> 63 #include <machine/segments.h> 64 #include <machine/specialreg.h> 65 #include <machine/sysarch.h> 66 #include <machine/linux_machdep.h> 67 68 /* 69 * Deal with some i386-specific things in the Linux emulation code. 70 * This means just signals for now, will include stuff like 71 * I/O map permissions and V86 mode sometime. 72 */ 73 74 /* 75 * Send an interrupt to process. 76 * 77 * Stack is set up to allow sigcode stored 78 * in u. to call routine, followed by kcall 79 * to sigreturn routine below. After sigreturn 80 * resets the signal mask, the stack, and the 81 * frame pointer, it returns to the user 82 * specified pc, psl. 83 */ 84 85 void 86 linux_sendsig(catcher, sig, mask, code) 87 sig_t catcher; 88 int sig, mask; 89 u_long code; 90 { 91 register struct proc *p = curproc; 92 register struct trapframe *tf; 93 struct linux_sigframe *fp, frame; 94 struct sigacts *psp = p->p_sigacts; 95 int oonstack; 96 extern char linux_sigcode[], linux_esigcode[]; 97 98 tf = p->p_md.md_regs; 99 oonstack = psp->ps_sigstk.ss_flags & SA_ONSTACK; 100 101 /* 102 * Allocate space for the signal handler context. 103 */ 104 if ((psp->ps_flags & SAS_ALTSTACK) && !oonstack && 105 (psp->ps_sigonstack & sigmask(sig))) { 106 fp = (struct linux_sigframe *)(psp->ps_sigstk.ss_base + 107 psp->ps_sigstk.ss_size - sizeof(struct linux_sigframe)); 108 psp->ps_sigstk.ss_flags |= SA_ONSTACK; 109 } else { 110 fp = (struct linux_sigframe *)tf->tf_esp - 1; 111 } 112 113 frame.sf_handler = catcher; 114 frame.sf_sig = bsd_to_linux_sig(sig); 115 116 /* 117 * Build the signal context to be used by sigreturn. 118 */ 119 frame.sf_sc.sc_mask = mask; 120 #ifdef VM86 121 if (tf->tf_eflags & PSL_VM) { 122 frame.sf_sc.sc_gs = tf->tf_vm86_gs; 123 frame.sf_sc.sc_fs = tf->tf_vm86_fs; 124 frame.sf_sc.sc_es = tf->tf_vm86_es; 125 frame.sf_sc.sc_ds = tf->tf_vm86_ds; 126 } else 127 #else 128 { 129 __asm("movl %%gs,%w0" : "=r" (frame.sf_sc.sc_gs)); 130 __asm("movl %%fs,%w0" : "=r" (frame.sf_sc.sc_fs)); 131 frame.sf_sc.sc_es = tf->tf_es; 132 frame.sf_sc.sc_ds = tf->tf_ds; 133 } 134 #endif 135 frame.sf_sc.sc_edi = tf->tf_edi; 136 frame.sf_sc.sc_esi = tf->tf_esi; 137 frame.sf_sc.sc_ebp = tf->tf_ebp; 138 frame.sf_sc.sc_ebx = tf->tf_ebx; 139 frame.sf_sc.sc_edx = tf->tf_edx; 140 frame.sf_sc.sc_ecx = tf->tf_ecx; 141 frame.sf_sc.sc_eax = tf->tf_eax; 142 frame.sf_sc.sc_eip = tf->tf_eip; 143 frame.sf_sc.sc_cs = tf->tf_cs; 144 frame.sf_sc.sc_eflags = tf->tf_eflags; 145 frame.sf_sc.sc_esp_at_signal = tf->tf_esp; 146 frame.sf_sc.sc_ss = tf->tf_ss; 147 frame.sf_sc.sc_err = tf->tf_err; 148 frame.sf_sc.sc_trapno = tf->tf_trapno; 149 150 if (copyout(&frame, fp, sizeof(frame)) != 0) { 151 /* 152 * Process has trashed its stack; give it an illegal 153 * instruction to halt it in its tracks. 154 */ 155 sigexit(p, SIGILL); 156 /* NOTREACHED */ 157 } 158 159 /* 160 * Build context to run handler in. 161 */ 162 tf->tf_esp = (int)fp; 163 tf->tf_eip = (int)(((char *)PS_STRINGS) - 164 (linux_esigcode - linux_sigcode)); 165 #ifdef VM86 166 tf->tf_eflags &= ~PSL_VM; 167 #endif 168 tf->tf_cs = LSEL(LUCODE_SEL, SEL_UPL); 169 tf->tf_ds = LSEL(LUDATA_SEL, SEL_UPL); 170 tf->tf_es = LSEL(LUDATA_SEL, SEL_UPL); 171 tf->tf_ss = LSEL(LUDATA_SEL, SEL_UPL); 172 } 173 174 /* 175 * System call to cleanup state after a signal 176 * has been taken. Reset signal mask and 177 * stack state from context left by sendsig (above). 178 * Return to previous pc and psl as specified by 179 * context left by sendsig. Check carefully to 180 * make sure that the user has not modified the 181 * psl to gain improper privileges or to cause 182 * a machine fault. 183 */ 184 int 185 linux_sigreturn(p, uap, retval) 186 struct proc *p; 187 struct linux_sigreturn_args /* { 188 syscallarg(struct linux_sigcontext *) scp; 189 } */ *uap; 190 register_t *retval; 191 { 192 struct linux_sigcontext *scp, context; 193 register struct trapframe *tf; 194 195 tf = p->p_md.md_regs; 196 197 /* 198 * The trampoline code hands us the context. 199 * It is unsafe to keep track of it ourselves, in the event that a 200 * program jumps out of a signal handler. 201 */ 202 scp = SCARG(uap, scp); 203 if (copyin((caddr_t)scp, &context, sizeof(*scp)) != 0) 204 return (EFAULT); 205 206 /* 207 * Check for security violations. 208 */ 209 if (((context.sc_eflags ^ tf->tf_eflags) & PSL_USERSTATIC) != 0 || 210 ISPL(context.sc_cs) != SEL_UPL) 211 return (EINVAL); 212 213 p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK; 214 p->p_sigmask = context.sc_mask & ~sigcantmask; 215 216 /* 217 * Restore signal context. 218 */ 219 #ifdef VM86 220 if (context.sc_eflags & PSL_VM) { 221 tf->tf_vm86_gs = context.sc_gs; 222 tf->tf_vm86_fs = context.sc_fs; 223 tf->tf_vm86_es = context.sc_es; 224 tf->tf_vm86_ds = context.sc_ds; 225 } else 226 #endif 227 { 228 /* %fs and %gs were restored by the trampoline. */ 229 tf->tf_es = context.sc_es; 230 tf->tf_ds = context.sc_ds; 231 } 232 tf->tf_edi = context.sc_edi; 233 tf->tf_esi = context.sc_esi; 234 tf->tf_ebp = context.sc_ebp; 235 tf->tf_ebx = context.sc_ebx; 236 tf->tf_edx = context.sc_edx; 237 tf->tf_ecx = context.sc_ecx; 238 tf->tf_eax = context.sc_eax; 239 tf->tf_eip = context.sc_eip; 240 tf->tf_cs = context.sc_cs; 241 tf->tf_eflags = context.sc_eflags; 242 tf->tf_esp = context.sc_esp_at_signal; 243 tf->tf_ss = context.sc_ss; 244 245 return (EJUSTRETURN); 246 } 247 248 #ifdef USER_LDT 249 250 int 251 linux_read_ldt(p, uap, retval) 252 struct proc *p; 253 struct linux_modify_ldt_args /* { 254 syscallarg(int) func; 255 syscallarg(void *) ptr; 256 syscallarg(size_t) bytecount; 257 } */ *uap; 258 register_t *retval; 259 { 260 struct i386_get_ldt_args gl; 261 int error; 262 caddr_t sg; 263 char *parms; 264 265 sg = stackgap_init(); 266 267 gl.start = 0; 268 gl.desc = SCARG(uap, ptr); 269 gl.num = SCARG(uap, bytecount) / sizeof(union descriptor); 270 271 parms = stackgap_alloc(&sg, sizeof(gl)); 272 273 if (error = copyout(&gl, parms, sizeof(gl))) 274 return (error); 275 276 if (error = i386_get_ldt(p, parms, retval)) 277 return (error); 278 279 *retval *= sizeof(union descriptor); 280 return (0); 281 } 282 283 struct linux_ldt_info { 284 u_int entry_number; 285 u_long base_addr; 286 u_int limit; 287 u_int seg_32bit:1; 288 u_int contents:2; 289 u_int read_exec_only:1; 290 u_int limit_in_pages:1; 291 u_int seg_not_present:1; 292 }; 293 294 int 295 linux_write_ldt(p, uap, retval) 296 struct proc *p; 297 struct linux_modify_ldt_args /* { 298 syscallarg(int) func; 299 syscallarg(void *) ptr; 300 syscallarg(size_t) bytecount; 301 } */ *uap; 302 register_t *retval; 303 { 304 struct linux_ldt_info ldt_info; 305 struct segment_descriptor sd; 306 struct i386_set_ldt_args sl; 307 int error; 308 caddr_t sg; 309 char *parms; 310 311 if (SCARG(uap, bytecount) != sizeof(ldt_info)) 312 return (EINVAL); 313 if (error = copyin(SCARG(uap, ptr), &ldt_info, sizeof(ldt_info))) 314 return error; 315 if (ldt_info.contents == 3) 316 return (EINVAL); 317 318 sg = stackgap_init(); 319 320 sd.sd_lobase = ldt_info.base_addr & 0xffffff; 321 sd.sd_hibase = (ldt_info.base_addr >> 24) & 0xff; 322 sd.sd_lolimit = ldt_info.limit & 0xffff; 323 sd.sd_hilimit = (ldt_info.limit >> 16) & 0xf; 324 sd.sd_type = 325 16 | (ldt_info.contents << 2) | (!ldt_info.read_exec_only << 1); 326 sd.sd_dpl = SEL_UPL; 327 sd.sd_p = !ldt_info.seg_not_present; 328 sd.sd_def32 = ldt_info.seg_32bit; 329 sd.sd_gran = ldt_info.limit_in_pages; 330 331 sl.start = ldt_info.entry_number; 332 sl.desc = stackgap_alloc(&sg, sizeof(sd)); 333 sl.num = 1; 334 335 #if 0 336 printf("linux_write_ldt: idx=%d, base=%x, limit=%x\n", 337 ldt_info.entry_number, ldt_info.base_addr, ldt_info.limit); 338 #endif 339 340 parms = stackgap_alloc(&sg, sizeof(sl)); 341 342 if (error = copyout(&sd, sl.desc, sizeof(sd))) 343 return (error); 344 if (error = copyout(&sl, parms, sizeof(sl))) 345 return (error); 346 347 if (error = i386_set_ldt(p, parms, retval)) 348 return (error); 349 350 *retval = 0; 351 return (0); 352 } 353 354 #endif /* USER_LDT */ 355 356 int 357 linux_modify_ldt(p, uap, retval) 358 struct proc *p; 359 struct linux_modify_ldt_args /* { 360 syscallarg(int) func; 361 syscallarg(void *) ptr; 362 syscallarg(size_t) bytecount; 363 } */ *uap; 364 register_t *retval; 365 { 366 367 switch (SCARG(uap, func)) { 368 #ifdef USER_LDT 369 case 0: 370 return (linux_read_ldt(p, uap, retval)); 371 372 case 1: 373 return (linux_write_ldt(p, uap, retval)); 374 #endif /* USER_LDT */ 375 376 default: 377 return (ENOSYS); 378 } 379 } 380