1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * the University of Utah, and William Jolitz. 7 * 8 * %sccs.include.redist.c% 9 * 10 * @(#)trap.c 7.4 (Berkeley) 05/13/91 11 */ 12 13 /* 14 * 386 Trap and System call handleing 15 */ 16 17 #include "machine/cpu.h" 18 #include "machine/psl.h" 19 #include "machine/reg.h" 20 21 #include "param.h" 22 #include "systm.h" 23 #include "proc.h" 24 #include "user.h" 25 #include "seg.h" 26 #include "acct.h" 27 #include "kernel.h" 28 #ifdef KTRACE 29 #include "ktrace.h" 30 #endif 31 32 #include "vm/vm_param.h" 33 #include "vm/pmap.h" 34 #include "vm/vm_map.h" 35 #include "sys/vmmeter.h" 36 37 #include "machine/trap.h" 38 #include "machine/dbg.h" 39 40 41 struct sysent sysent[]; 42 int nsysent; 43 unsigned rcr2(); 44 extern short cpl; 45 46 47 /* 48 * trap(frame): 49 * Exception, fault, and trap interface to BSD kernel. This 50 * common code is called from assembly language IDT gate entry 51 * routines that prepare a suitable stack frame, and restore this 52 * frame after the exception has been processed. Note that the 53 * effect is as if the arguments were passed call by reference. 54 */ 55 56 /*ARGSUSED*/ 57 trap(frame) 58 struct trapframe frame; 59 { 60 register int i; 61 register struct proc *p = curproc; 62 struct timeval syst; 63 int ucode, type, code, eva; 64 65 frame.tf_eflags &= ~PSL_NT; /* clear nested trap XXX */ 66 type = frame.tf_trapno; 67 68 if (curpcb->pcb_onfault && frame.tf_trapno != 0xc) { 69 frame.tf_eip = (int)curpcb->pcb_onfault; 70 return; 71 } 72 73 syst = p->p_stime; 74 if (ISPL(frame.tf_cs) == SEL_UPL) { 75 type |= T_USER; 76 p->p_regs = (int *)&frame; 77 curpcb->pcb_flags |= FM_TRAP; /* used by sendsig */ 78 } 79 80 ucode=0; 81 eva = rcr2(); 82 code = frame.tf_err; 83 switch (type) { 84 85 default: 86 we_re_toast: 87 #ifdef KDB 88 if (kdb_trap(&psl)) 89 return; 90 #endif 91 92 printf("trap type %d code = %x eip = %x cs = %x eflags = %x ", 93 frame.tf_trapno, frame.tf_err, frame.tf_eip, 94 frame.tf_cs, frame.tf_eflags); 95 printf("cr2 %x cpl %x\n", eva, cpl); 96 type &= ~T_USER; 97 panic("trap"); 98 /*NOTREACHED*/ 99 100 case T_SEGNPFLT|T_USER: 101 case T_PROTFLT|T_USER: /* protection fault */ 102 copyfault: 103 ucode = code + BUS_SEGM_FAULT ; 104 i = SIGBUS; 105 break; 106 107 case T_PRIVINFLT|T_USER: /* privileged instruction fault */ 108 case T_RESADFLT|T_USER: /* reserved addressing fault */ 109 case T_RESOPFLT|T_USER: /* reserved operand fault */ 110 case T_FPOPFLT|T_USER: /* coprocessor operand fault */ 111 ucode = type &~ T_USER; 112 i = SIGILL; 113 break; 114 115 case T_ASTFLT|T_USER: /* Allow process switch */ 116 case T_ASTFLT: 117 astoff(); 118 if ((p->p_flag & SOWEUPC) && p->p_stats->p_prof.pr_scale) { 119 addupc(frame.tf_eip, &p->p_stats->p_prof, 1); 120 p->p_flag &= ~SOWEUPC; 121 } 122 goto out; 123 124 case T_DNA|T_USER: 125 #ifdef NPX 126 /* if a transparent fault (due to context switch "late") */ 127 if (npxdna()) return; 128 #endif 129 ucode = FPE_FPU_NP_TRAP; 130 i = SIGFPE; 131 break; 132 133 case T_BOUND|T_USER: 134 ucode = FPE_SUBRNG_TRAP; 135 i = SIGFPE; 136 break; 137 138 case T_OFLOW|T_USER: 139 ucode = FPE_INTOVF_TRAP; 140 i = SIGFPE; 141 break; 142 143 case T_DIVIDE|T_USER: 144 ucode = FPE_INTDIV_TRAP; 145 i = SIGFPE; 146 break; 147 148 case T_ARITHTRAP|T_USER: 149 ucode = code; 150 i = SIGFPE; 151 break; 152 153 case T_PAGEFLT: /* allow page faults in kernel mode */ 154 if (code & PGEX_P) goto we_re_toast; 155 156 /* fall into */ 157 case T_PAGEFLT|T_USER: /* page fault */ 158 { 159 register vm_offset_t va; 160 register struct vmspace *vm = p->p_vmspace; 161 register vm_map_t map; 162 int rv; 163 vm_prot_t ftype; 164 extern vm_map_t kernel_map; 165 unsigned nss,v; 166 167 va = trunc_page((vm_offset_t)eva); 168 /* 169 * It is only a kernel address space fault iff: 170 * 1. (type & T_USER) == 0 and 171 * 2. pcb_onfault not set or 172 * 3. pcb_onfault set but supervisor space fault 173 * The last can occur during an exec() copyin where the 174 * argument space is lazy-allocated. 175 */ 176 if (type == T_PAGEFLT && va >= 0xfe000000) 177 map = kernel_map; 178 else 179 map = &vm->vm_map; 180 if (code & PGEX_W) 181 ftype = VM_PROT_READ | VM_PROT_WRITE; 182 else 183 ftype = VM_PROT_READ; 184 185 #ifdef DEBUG 186 if (map == kernel_map && va == 0) { 187 printf("trap: bad kernel access at %x\n", va); 188 goto we_re_toast; 189 } 190 #endif 191 /* 192 * XXX: rude hack to make stack limits "work" 193 */ 194 nss = 0; 195 if ((caddr_t)va >= vm->vm_maxsaddr && map != kernel_map) { 196 nss = clrnd(btoc(USRSTACK-(unsigned)va)); 197 if (nss > btoc(p->p_rlimit[RLIMIT_STACK].rlim_cur)) { 198 rv = KERN_FAILURE; 199 goto nogo; 200 } 201 } 202 203 /* check if page table is mapped, if not, fault it first */ 204 #define pde_v(v) (PTD[((v)>>PD_SHIFT)&1023].pd_v) 205 if (!pde_v(va)) { 206 v = trunc_page(vtopte(va)); 207 rv = vm_fault(map, v, ftype, FALSE); 208 if (rv != KERN_SUCCESS) goto nogo; 209 /* check if page table fault, increment wiring */ 210 vm_map_pageable(map, v, round_page(v+1), FALSE); 211 } else v=0; 212 rv = vm_fault(map, va, ftype, FALSE); 213 if (rv == KERN_SUCCESS) { 214 /* 215 * XXX: continuation of rude stack hack 216 */ 217 if (nss > vm->vm_ssize) 218 vm->vm_ssize = nss; 219 va = trunc_page(vtopte(va)); 220 /* for page table, increment wiring 221 as long as not a page table fault as well */ 222 if (!v && type != T_PAGEFLT) 223 vm_map_pageable(map, va, round_page(va+1), FALSE); 224 if (type == T_PAGEFLT) 225 return; 226 goto out; 227 } 228 nogo: 229 if (type == T_PAGEFLT) { 230 if (curpcb->pcb_onfault) 231 goto copyfault; 232 printf("vm_fault(%x, %x, %x, 0) -> %x\n", 233 map, va, ftype, rv); 234 printf(" type %x, code %x\n", 235 type, code); 236 goto we_re_toast; 237 } 238 i = (rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV; 239 break; 240 } 241 242 case T_TRCTRAP: /* trace trap -- someone single stepping lcall's */ 243 frame.tf_eflags &= ~PSL_T; 244 245 /* Q: how do we turn it on again? */ 246 return; 247 248 case T_BPTFLT|T_USER: /* bpt instruction fault */ 249 case T_TRCTRAP|T_USER: /* trace trap */ 250 frame.tf_eflags &= ~PSL_T; 251 i = SIGTRAP; 252 break; 253 254 #include "isa.h" 255 #if NISA > 0 256 case T_NMI: 257 case T_NMI|T_USER: 258 /* machine/parity/power fail/"kitchen sink" faults */ 259 if(isa_nmi(code) == 0) return; 260 else goto we_re_toast; 261 #endif 262 } 263 264 trapsignal(p, i, ucode); 265 if ((type & T_USER) == 0) 266 return; 267 out: 268 while (i = CURSIG(p)) 269 psig(i); 270 p->p_pri = p->p_usrpri; 271 if (want_resched) { 272 /* 273 * Since we are curproc, clock will normally just change 274 * our priority without moving us from one queue to another 275 * (since the running process is not on a queue.) 276 * If that happened after we setrq ourselves but before we 277 * swtch()'ed, we might not be on the queue indicated by 278 * our priority. 279 */ 280 (void) splclock(); 281 setrq(p); 282 p->p_stats->p_ru.ru_nivcsw++; 283 swtch(); 284 while (i = CURSIG(p)) 285 psig(i); 286 } 287 if (p->p_stats->p_prof.pr_scale) { 288 int ticks; 289 struct timeval *tv = &p->p_stime; 290 291 ticks = ((tv->tv_sec - syst.tv_sec) * 1000 + 292 (tv->tv_usec - syst.tv_usec) / 1000) / (tick / 1000); 293 if (ticks) { 294 #ifdef PROFTIMER 295 extern int profscale; 296 addupc(frame.tf_eip, &p->p_stats->p_prof, 297 ticks * profscale); 298 #else 299 addupc(frame.tf_eip, &p->p_stats->p_prof, ticks); 300 #endif 301 } 302 } 303 curpri = p->p_pri; 304 curpcb->pcb_flags &= ~FM_TRAP; /* used by sendsig */ 305 spl0(); /*XXX*/ 306 } 307 308 /* 309 * syscall(frame): 310 * System call request from POSIX system call gate interface to kernel. 311 * Like trap(), argument is call by reference. 312 */ 313 /*ARGSUSED*/ 314 syscall(frame) 315 volatile struct syscframe frame; 316 { 317 register int *locr0 = ((int *)&frame); 318 register caddr_t params; 319 register int i; 320 register struct sysent *callp; 321 register struct proc *p = curproc; 322 struct timeval syst; 323 int error, opc; 324 int args[8], rval[2]; 325 int code; 326 327 #ifdef lint 328 r0 = 0; r0 = r0; r1 = 0; r1 = r1; 329 #endif 330 syst = p->p_stime; 331 if (ISPL(frame.sf_cs) != SEL_UPL) 332 panic("syscall"); 333 334 code = frame.sf_eax; 335 p->p_regs = (int *)&frame; 336 params = (caddr_t)frame.sf_esp + sizeof (int) ; 337 338 /* 339 * Reconstruct pc, assuming lcall $X,y is 7 bytes, as it is always. 340 */ 341 opc = frame.sf_eip - 7; 342 callp = (code >= nsysent) ? &sysent[63] : &sysent[code]; 343 if (callp == sysent) { 344 i = fuword(params); 345 params += sizeof (int); 346 callp = (code >= nsysent) ? &sysent[63] : &sysent[code]; 347 } 348 349 if ((i = callp->sy_narg * sizeof (int)) && 350 (error = copyin(params, (caddr_t)args, (u_int)i))) { 351 frame.sf_eax = error; 352 frame.sf_eflags |= PSL_C; /* carry bit */ 353 #ifdef KTRACE 354 if (KTRPOINT(p, KTR_SYSCALL)) 355 ktrsyscall(p->p_tracep, code, callp->sy_narg, &args); 356 #endif 357 goto done; 358 } 359 #ifdef KTRACE 360 if (KTRPOINT(p, KTR_SYSCALL)) 361 ktrsyscall(p->p_tracep, code, callp->sy_narg, &args); 362 #endif 363 rval[0] = 0; 364 rval[1] = frame.sf_edx; 365 error = (*callp->sy_call)(p, args, rval); 366 if (error == ERESTART) 367 frame.sf_eip = opc; 368 else if (error != EJUSTRETURN) { 369 if (error) { 370 frame.sf_eax = error; 371 frame.sf_eflags |= PSL_C; /* carry bit */ 372 } else { 373 frame.sf_eax = rval[0]; 374 frame.sf_edx = rval[1]; 375 frame.sf_eflags &= ~PSL_C; /* carry bit */ 376 } 377 } 378 /* else if (error == EJUSTRETURN) */ 379 /* nothing to do */ 380 done: 381 /* 382 * Reinitialize proc pointer `p' as it may be different 383 * if this is a child returning from fork syscall. 384 */ 385 p = curproc; 386 while (i = CURSIG(p)) 387 psig(i); 388 p->p_pri = p->p_usrpri; 389 if (want_resched) { 390 /* 391 * Since we are curproc, clock will normally just change 392 * our priority without moving us from one queue to another 393 * (since the running process is not on a queue.) 394 * If that happened after we setrq ourselves but before we 395 * swtch()'ed, we might not be on the queue indicated by 396 * our priority. 397 */ 398 (void) splclock(); 399 setrq(p); 400 p->p_stats->p_ru.ru_nivcsw++; 401 swtch(); 402 while (i = CURSIG(p)) 403 psig(i); 404 } 405 if (p->p_stats->p_prof.pr_scale) { 406 int ticks; 407 struct timeval *tv = &p->p_stime; 408 409 ticks = ((tv->tv_sec - syst.tv_sec) * 1000 + 410 (tv->tv_usec - syst.tv_usec) / 1000) / (tick / 1000); 411 if (ticks) { 412 #ifdef PROFTIMER 413 extern int profscale; 414 addupc(frame.sf_eip, &p->p_stats->p_prof, 415 ticks * profscale); 416 #else 417 addupc(frame.sf_eip, &p->p_stats->p_prof, ticks); 418 #endif 419 } 420 } 421 curpri = p->p_pri; 422 #ifdef KTRACE 423 if (KTRPOINT(p, KTR_SYSRET)) 424 ktrsysret(p->p_tracep, code, error, rval[0]); 425 #endif 426 } 427