1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 #include <sys/types.h> 29 #include <sys/reg.h> 30 #include <sys/privregs.h> 31 #include <sys/stack.h> 32 #include <sys/frame.h> 33 34 #include <mdb/mdb_ia32util.h> 35 #include <mdb/mdb_target_impl.h> 36 #include <mdb/mdb_kreg_impl.h> 37 #include <mdb/mdb_debug.h> 38 #include <mdb/mdb_modapi.h> 39 #include <mdb/mdb_err.h> 40 #include <mdb/mdb.h> 41 42 /* 43 * We also define an array of register names and their corresponding 44 * array indices. This is used by the getareg and putareg entry points, 45 * and also by our register variable discipline. 46 */ 47 const mdb_tgt_regdesc_t mdb_ia32_kregs[] = { 48 { "savfp", KREG_SAVFP, MDB_TGT_R_EXPORT }, 49 { "savpc", KREG_SAVPC, MDB_TGT_R_EXPORT }, 50 { "eax", KREG_EAX, MDB_TGT_R_EXPORT }, 51 { "ebx", KREG_EBX, MDB_TGT_R_EXPORT }, 52 { "ecx", KREG_ECX, MDB_TGT_R_EXPORT }, 53 { "edx", KREG_EDX, MDB_TGT_R_EXPORT }, 54 { "esi", KREG_ESI, MDB_TGT_R_EXPORT }, 55 { "edi", KREG_EDI, MDB_TGT_R_EXPORT }, 56 { "ebp", KREG_EBP, MDB_TGT_R_EXPORT }, 57 { "esp", KREG_ESP, MDB_TGT_R_EXPORT }, 58 { "cs", KREG_CS, MDB_TGT_R_EXPORT }, 59 { "ds", KREG_DS, MDB_TGT_R_EXPORT }, 60 { "ss", KREG_SS, MDB_TGT_R_EXPORT }, 61 { "es", KREG_ES, MDB_TGT_R_EXPORT }, 62 { "fs", KREG_FS, MDB_TGT_R_EXPORT }, 63 { "gs", KREG_GS, MDB_TGT_R_EXPORT }, 64 { "eflags", KREG_EFLAGS, MDB_TGT_R_EXPORT }, 65 { "eip", KREG_EIP, MDB_TGT_R_EXPORT }, 66 { "uesp", KREG_UESP, MDB_TGT_R_EXPORT | MDB_TGT_R_PRIV }, 67 { "trapno", KREG_TRAPNO, MDB_TGT_R_EXPORT | MDB_TGT_R_PRIV }, 68 { "err", KREG_ERR, MDB_TGT_R_EXPORT | MDB_TGT_R_PRIV }, 69 { NULL, 0, 0 } 70 }; 71 72 void 73 mdb_ia32_printregs(const mdb_tgt_gregset_t *gregs) 74 { 75 const kreg_t *kregs = &gregs->kregs[0]; 76 kreg_t eflags = kregs[KREG_EFLAGS]; 77 78 mdb_printf("%%cs = 0x%04x\t\t%%eax = 0x%0?p %A\n", 79 kregs[KREG_CS], kregs[KREG_EAX], kregs[KREG_EAX]); 80 81 mdb_printf("%%ds = 0x%04x\t\t%%ebx = 0x%0?p %A\n", 82 kregs[KREG_DS], kregs[KREG_EBX], kregs[KREG_EBX]); 83 84 mdb_printf("%%ss = 0x%04x\t\t%%ecx = 0x%0?p %A\n", 85 kregs[KREG_SS], kregs[KREG_ECX], kregs[KREG_ECX]); 86 87 mdb_printf("%%es = 0x%04x\t\t%%edx = 0x%0?p %A\n", 88 kregs[KREG_ES], kregs[KREG_EDX], kregs[KREG_EDX]); 89 90 mdb_printf("%%fs = 0x%04x\t\t%%esi = 0x%0?p %A\n", 91 kregs[KREG_FS], kregs[KREG_ESI], kregs[KREG_ESI]); 92 93 mdb_printf("%%gs = 0x%04x\t\t%%edi = 0x%0?p %A\n\n", 94 kregs[KREG_GS], kregs[KREG_EDI], kregs[KREG_EDI]); 95 96 mdb_printf("%%eip = 0x%0?p %A\n", kregs[KREG_EIP], kregs[KREG_EIP]); 97 mdb_printf("%%ebp = 0x%0?p\n", kregs[KREG_EBP]); 98 mdb_printf("%%esp = 0x%0?p\n\n", kregs[KREG_ESP]); 99 mdb_printf("%%eflags = 0x%08x\n", eflags); 100 101 mdb_printf(" id=%u vip=%u vif=%u ac=%u vm=%u rf=%u nt=%u iopl=0x%x\n", 102 (eflags & KREG_EFLAGS_ID_MASK) >> KREG_EFLAGS_ID_SHIFT, 103 (eflags & KREG_EFLAGS_VIP_MASK) >> KREG_EFLAGS_VIP_SHIFT, 104 (eflags & KREG_EFLAGS_VIF_MASK) >> KREG_EFLAGS_VIF_SHIFT, 105 (eflags & KREG_EFLAGS_AC_MASK) >> KREG_EFLAGS_AC_SHIFT, 106 (eflags & KREG_EFLAGS_VM_MASK) >> KREG_EFLAGS_VM_SHIFT, 107 (eflags & KREG_EFLAGS_RF_MASK) >> KREG_EFLAGS_RF_SHIFT, 108 (eflags & KREG_EFLAGS_NT_MASK) >> KREG_EFLAGS_NT_SHIFT, 109 (eflags & KREG_EFLAGS_IOPL_MASK) >> KREG_EFLAGS_IOPL_SHIFT); 110 111 mdb_printf(" status=<%s,%s,%s,%s,%s,%s,%s,%s,%s>\n\n", 112 (eflags & KREG_EFLAGS_OF_MASK) ? "OF" : "of", 113 (eflags & KREG_EFLAGS_DF_MASK) ? "DF" : "df", 114 (eflags & KREG_EFLAGS_IF_MASK) ? "IF" : "if", 115 (eflags & KREG_EFLAGS_TF_MASK) ? "TF" : "tf", 116 (eflags & KREG_EFLAGS_SF_MASK) ? "SF" : "sf", 117 (eflags & KREG_EFLAGS_ZF_MASK) ? "ZF" : "zf", 118 (eflags & KREG_EFLAGS_AF_MASK) ? "AF" : "af", 119 (eflags & KREG_EFLAGS_PF_MASK) ? "PF" : "pf", 120 (eflags & KREG_EFLAGS_CF_MASK) ? "CF" : "cf"); 121 122 #ifndef _KMDB 123 mdb_printf(" %%uesp = 0x%0?x\n", kregs[KREG_UESP]); 124 #endif 125 mdb_printf("%%trapno = 0x%x\n", kregs[KREG_TRAPNO]); 126 mdb_printf(" %%err = 0x%x\n", kregs[KREG_ERR]); 127 } 128 129 /* 130 * Given a return address (%eip), determine the likely number of arguments 131 * that were pushed on the stack prior to its execution. We do this by 132 * expecting that a typical call sequence consists of pushing arguments on 133 * the stack, executing a call instruction, and then performing an add 134 * on %esp to restore it to the value prior to pushing the arguments for 135 * the call. We attempt to detect such an add, and divide the addend 136 * by the size of a word to determine the number of pushed arguments. 137 */ 138 static uint_t 139 kvm_argcount(mdb_tgt_t *t, uintptr_t eip, ssize_t size) 140 { 141 uint8_t ins[6]; 142 ulong_t n; 143 144 enum { 145 M_MODRM_ESP = 0xc4, /* Mod/RM byte indicates %esp */ 146 M_ADD_IMM32 = 0x81, /* ADD imm32 to r/m32 */ 147 M_ADD_IMM8 = 0x83 /* ADD imm8 to r/m32 */ 148 }; 149 150 if (mdb_tgt_vread(t, ins, sizeof (ins), eip) != sizeof (ins)) 151 return (0); 152 153 if (ins[1] != M_MODRM_ESP) 154 return (0); 155 156 switch (ins[0]) { 157 case M_ADD_IMM32: 158 n = ins[2] + (ins[3] << 8) + (ins[4] << 16) + (ins[5] << 24); 159 break; 160 161 case M_ADD_IMM8: 162 n = ins[2]; 163 break; 164 165 default: 166 n = 0; 167 } 168 169 return (MIN((ssize_t)n, size) / sizeof (long)); 170 } 171 172 int 173 mdb_ia32_kvm_stack_iter(mdb_tgt_t *t, const mdb_tgt_gregset_t *gsp, 174 mdb_tgt_stack_f *func, void *arg) 175 { 176 mdb_tgt_gregset_t gregs; 177 kreg_t *kregs = &gregs.kregs[0]; 178 int got_pc = (gsp->kregs[KREG_EIP] != 0); 179 180 struct { 181 uintptr_t fr_savfp; 182 uintptr_t fr_savpc; 183 long fr_argv[32]; 184 } fr; 185 186 uintptr_t fp = gsp->kregs[KREG_EBP]; 187 uintptr_t pc = gsp->kregs[KREG_EIP]; 188 uintptr_t lastfp; 189 190 ssize_t size; 191 uint_t argc; 192 int detect_exception_frames = 0; 193 #ifndef _KMDB 194 int xp; 195 196 if ((mdb_readsym(&xp, sizeof (xp), "xpv_panicking") != -1) && (xp > 0)) 197 detect_exception_frames = 1; 198 #endif 199 200 bcopy(gsp, &gregs, sizeof (gregs)); 201 202 while (fp != 0) { 203 204 if (fp & (STACK_ALIGN - 1)) 205 return (set_errno(EMDB_STKALIGN)); 206 207 if ((size = mdb_tgt_vread(t, &fr, sizeof (fr), fp)) >= 208 (ssize_t)(2 * sizeof (uintptr_t))) { 209 size -= (ssize_t)(2 * sizeof (uintptr_t)); 210 argc = kvm_argcount(t, fr.fr_savpc, size); 211 } else { 212 bzero(&fr, sizeof (fr)); 213 argc = 0; 214 } 215 216 if (got_pc && func(arg, pc, argc, fr.fr_argv, &gregs) != 0) 217 break; 218 219 kregs[KREG_ESP] = kregs[KREG_EBP]; 220 221 lastfp = fp; 222 fp = fr.fr_savfp; 223 /* 224 * The Xen hypervisor marks a stack frame as belonging to 225 * an exception by inverting the bits of the pointer to 226 * that frame. We attempt to identify these frames by 227 * inverting the pointer and seeing if it is within 0xfff 228 * bytes of the last frame. 229 */ 230 if (detect_exception_frames) 231 if ((fp != 0) && (fp < lastfp) && 232 ((lastfp ^ ~fp) < 0xfff)) 233 fp = ~fp; 234 235 kregs[KREG_EBP] = fp; 236 kregs[KREG_EIP] = pc = fr.fr_savpc; 237 238 got_pc = (pc != 0); 239 } 240 241 return (0); 242 } 243 244 /* 245 * Determine the return address for the current frame. Typically this is the 246 * fr_savpc value from the current frame, but we also perform some special 247 * handling to see if we are stopped on one of the first two instructions of a 248 * typical function prologue, in which case %ebp will not be set up yet. 249 */ 250 int 251 mdb_ia32_step_out(mdb_tgt_t *t, uintptr_t *p, kreg_t pc, kreg_t fp, kreg_t sp, 252 mdb_instr_t curinstr) 253 { 254 struct frame fr; 255 GElf_Sym s; 256 char buf[1]; 257 258 enum { 259 M_PUSHL_EBP = 0x55, /* pushl %ebp */ 260 M_MOVL_EBP = 0x8b /* movl %esp, %ebp */ 261 }; 262 263 if (mdb_tgt_lookup_by_addr(t, pc, MDB_TGT_SYM_FUZZY, 264 buf, 0, &s, NULL) == 0) { 265 if (pc == s.st_value && curinstr == M_PUSHL_EBP) 266 fp = sp - 4; 267 else if (pc == s.st_value + 1 && curinstr == M_MOVL_EBP) 268 fp = sp; 269 } 270 271 if (mdb_tgt_vread(t, &fr, sizeof (fr), fp) == sizeof (fr)) { 272 *p = fr.fr_savpc; 273 return (0); 274 } 275 276 return (-1); /* errno is set for us */ 277 } 278 279 /* 280 * Return the address of the next instruction following a call, or return -1 281 * and set errno to EAGAIN if the target should just single-step. We perform 282 * a bit of disassembly on the current instruction in order to determine if it 283 * is a call and how many bytes should be skipped, depending on the exact form 284 * of the call instruction that is being used. 285 */ 286 int 287 mdb_ia32_next(mdb_tgt_t *t, uintptr_t *p, kreg_t pc, mdb_instr_t curinstr) 288 { 289 uint8_t m; 290 291 enum { 292 M_CALL_REL = 0xe8, /* call near with relative displacement */ 293 M_CALL_REG = 0xff, /* call near indirect or call far register */ 294 295 M_MODRM_MD = 0xc0, /* mask for Mod/RM byte Mod field */ 296 M_MODRM_OP = 0x38, /* mask for Mod/RM byte opcode field */ 297 M_MODRM_RM = 0x07, /* mask for Mod/RM byte R/M field */ 298 299 M_MD_IND = 0x00, /* Mod code for [REG] */ 300 M_MD_DSP8 = 0x40, /* Mod code for disp8[REG] */ 301 M_MD_DSP32 = 0x80, /* Mod code for disp32[REG] */ 302 M_MD_REG = 0xc0, /* Mod code for REG */ 303 304 M_OP_IND = 0x10, /* Opcode for call near indirect */ 305 M_RM_DSP32 = 0x05 /* R/M code for disp32 */ 306 }; 307 308 /* 309 * If the opcode is a near call with relative displacement, assume the 310 * displacement is a rel32 from the next instruction. 311 */ 312 if (curinstr == M_CALL_REL) { 313 *p = pc + sizeof (mdb_instr_t) + sizeof (uint32_t); 314 return (0); 315 } 316 317 /* 318 * If the opcode is a call near indirect or call far register opcode, 319 * read the subsequent Mod/RM byte to perform additional decoding. 320 */ 321 if (curinstr == M_CALL_REG) { 322 if (mdb_tgt_vread(t, &m, sizeof (m), pc + 1) != sizeof (m)) 323 return (-1); /* errno is set for us */ 324 325 /* 326 * If the Mod/RM opcode extension indicates a near indirect 327 * call, then skip the appropriate number of additional 328 * bytes depending on the addressing form that is used. 329 */ 330 if ((m & M_MODRM_OP) == M_OP_IND) { 331 switch (m & M_MODRM_MD) { 332 case M_MD_DSP8: 333 *p = pc + 3; /* skip pr_instr, m, disp8 */ 334 break; 335 case M_MD_DSP32: 336 *p = pc + 6; /* skip pr_instr, m, disp32 */ 337 break; 338 case M_MD_IND: 339 if ((m & M_MODRM_RM) == M_RM_DSP32) { 340 *p = pc + 6; 341 break; /* skip pr_instr, m, disp32 */ 342 } 343 /* FALLTHRU */ 344 case M_MD_REG: 345 *p = pc + 2; /* skip pr_instr, m */ 346 break; 347 } 348 return (0); 349 } 350 } 351 352 return (set_errno(EAGAIN)); 353 } 354 355 /*ARGSUSED*/ 356 int 357 mdb_ia32_kvm_frame(void *arglim, uintptr_t pc, uint_t argc, const long *argv, 358 const mdb_tgt_gregset_t *gregs) 359 { 360 argc = MIN(argc, (uint_t)arglim); 361 mdb_printf("%a(", pc); 362 363 if (argc != 0) { 364 mdb_printf("%lr", *argv++); 365 for (argc--; argc != 0; argc--) 366 mdb_printf(", %lr", *argv++); 367 } 368 369 mdb_printf(")\n"); 370 return (0); 371 } 372 373 int 374 mdb_ia32_kvm_framev(void *arglim, uintptr_t pc, uint_t argc, const long *argv, 375 const mdb_tgt_gregset_t *gregs) 376 { 377 argc = MIN(argc, (uint_t)arglim); 378 mdb_printf("%0?lr %a(", gregs->kregs[KREG_EBP], pc); 379 380 if (argc != 0) { 381 mdb_printf("%lr", *argv++); 382 for (argc--; argc != 0; argc--) 383 mdb_printf(", %lr", *argv++); 384 } 385 386 mdb_printf(")\n"); 387 return (0); 388 } 389