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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include <sys/types.h> 30 #include <sys/reg.h> 31 #include <sys/privregs.h> 32 #include <sys/stack.h> 33 #include <sys/frame.h> 34 35 #include <mdb/mdb_ia32util.h> 36 #include <mdb/mdb_target_impl.h> 37 #include <mdb/mdb_kreg_impl.h> 38 #include <mdb/mdb_debug.h> 39 #include <mdb/mdb_modapi.h> 40 #include <mdb/mdb_err.h> 41 #include <mdb/mdb.h> 42 43 /* 44 * We also define an array of register names and their corresponding 45 * array indices. This is used by the getareg and putareg entry points, 46 * and also by our register variable discipline. 47 */ 48 const mdb_tgt_regdesc_t mdb_ia32_kregs[] = { 49 { "savfp", KREG_SAVFP, MDB_TGT_R_EXPORT }, 50 { "savpc", KREG_SAVPC, MDB_TGT_R_EXPORT }, 51 { "eax", KREG_EAX, MDB_TGT_R_EXPORT }, 52 { "ebx", KREG_EBX, MDB_TGT_R_EXPORT }, 53 { "ecx", KREG_ECX, MDB_TGT_R_EXPORT }, 54 { "edx", KREG_EDX, MDB_TGT_R_EXPORT }, 55 { "esi", KREG_ESI, MDB_TGT_R_EXPORT }, 56 { "edi", KREG_EDI, MDB_TGT_R_EXPORT }, 57 { "ebp", KREG_EBP, MDB_TGT_R_EXPORT }, 58 { "esp", KREG_ESP, MDB_TGT_R_EXPORT }, 59 { "cs", KREG_CS, MDB_TGT_R_EXPORT }, 60 { "ds", KREG_DS, MDB_TGT_R_EXPORT }, 61 { "ss", KREG_SS, MDB_TGT_R_EXPORT }, 62 { "es", KREG_ES, MDB_TGT_R_EXPORT }, 63 { "fs", KREG_FS, MDB_TGT_R_EXPORT }, 64 { "gs", KREG_GS, MDB_TGT_R_EXPORT }, 65 { "eflags", KREG_EFLAGS, MDB_TGT_R_EXPORT }, 66 { "eip", KREG_EIP, MDB_TGT_R_EXPORT }, 67 { "uesp", KREG_UESP, MDB_TGT_R_EXPORT | MDB_TGT_R_PRIV }, 68 { "trapno", KREG_TRAPNO, MDB_TGT_R_EXPORT | MDB_TGT_R_PRIV }, 69 { "err", KREG_ERR, MDB_TGT_R_EXPORT | MDB_TGT_R_PRIV }, 70 { NULL, 0, 0 } 71 }; 72 73 void 74 mdb_ia32_printregs(const mdb_tgt_gregset_t *gregs) 75 { 76 const kreg_t *kregs = &gregs->kregs[0]; 77 kreg_t eflags = kregs[KREG_EFLAGS]; 78 79 mdb_printf("%%cs = 0x%04x\t\t%%eax = 0x%0?p %A\n", 80 kregs[KREG_CS], kregs[KREG_EAX], kregs[KREG_EAX]); 81 82 mdb_printf("%%ds = 0x%04x\t\t%%ebx = 0x%0?p %A\n", 83 kregs[KREG_DS], kregs[KREG_EBX], kregs[KREG_EBX]); 84 85 mdb_printf("%%ss = 0x%04x\t\t%%ecx = 0x%0?p %A\n", 86 kregs[KREG_SS], kregs[KREG_ECX], kregs[KREG_ECX]); 87 88 mdb_printf("%%es = 0x%04x\t\t%%edx = 0x%0?p %A\n", 89 kregs[KREG_ES], kregs[KREG_EDX], kregs[KREG_EDX]); 90 91 mdb_printf("%%fs = 0x%04x\t\t%%esi = 0x%0?p %A\n", 92 kregs[KREG_FS], kregs[KREG_ESI], kregs[KREG_ESI]); 93 94 mdb_printf("%%gs = 0x%04x\t\t%%edi = 0x%0?p %A\n\n", 95 kregs[KREG_GS], kregs[KREG_EDI], kregs[KREG_EDI]); 96 97 mdb_printf("%%eip = 0x%0?p %A\n", kregs[KREG_EIP], kregs[KREG_EIP]); 98 mdb_printf("%%ebp = 0x%0?p\n", kregs[KREG_EBP]); 99 mdb_printf("%%esp = 0x%0?p\n\n", kregs[KREG_ESP]); 100 mdb_printf("%%eflags = 0x%08x\n", eflags); 101 102 mdb_printf(" id=%u vip=%u vif=%u ac=%u vm=%u rf=%u nt=%u iopl=0x%x\n", 103 (eflags & KREG_EFLAGS_ID_MASK) >> KREG_EFLAGS_ID_SHIFT, 104 (eflags & KREG_EFLAGS_VIP_MASK) >> KREG_EFLAGS_VIP_SHIFT, 105 (eflags & KREG_EFLAGS_VIF_MASK) >> KREG_EFLAGS_VIF_SHIFT, 106 (eflags & KREG_EFLAGS_AC_MASK) >> KREG_EFLAGS_AC_SHIFT, 107 (eflags & KREG_EFLAGS_VM_MASK) >> KREG_EFLAGS_VM_SHIFT, 108 (eflags & KREG_EFLAGS_RF_MASK) >> KREG_EFLAGS_RF_SHIFT, 109 (eflags & KREG_EFLAGS_NT_MASK) >> KREG_EFLAGS_NT_SHIFT, 110 (eflags & KREG_EFLAGS_IOPL_MASK) >> KREG_EFLAGS_IOPL_SHIFT); 111 112 mdb_printf(" status=<%s,%s,%s,%s,%s,%s,%s,%s,%s>\n\n", 113 (eflags & KREG_EFLAGS_OF_MASK) ? "OF" : "of", 114 (eflags & KREG_EFLAGS_DF_MASK) ? "DF" : "df", 115 (eflags & KREG_EFLAGS_IF_MASK) ? "IF" : "if", 116 (eflags & KREG_EFLAGS_TF_MASK) ? "TF" : "tf", 117 (eflags & KREG_EFLAGS_SF_MASK) ? "SF" : "sf", 118 (eflags & KREG_EFLAGS_ZF_MASK) ? "ZF" : "zf", 119 (eflags & KREG_EFLAGS_AF_MASK) ? "AF" : "af", 120 (eflags & KREG_EFLAGS_PF_MASK) ? "PF" : "pf", 121 (eflags & KREG_EFLAGS_CF_MASK) ? "CF" : "cf"); 122 123 #ifndef _KMDB 124 mdb_printf(" %%uesp = 0x%0?x\n", kregs[KREG_UESP]); 125 #endif 126 mdb_printf("%%trapno = 0x%x\n", kregs[KREG_TRAPNO]); 127 mdb_printf(" %%err = 0x%x\n", kregs[KREG_ERR]); 128 } 129 130 /* 131 * Given a return address (%eip), determine the likely number of arguments 132 * that were pushed on the stack prior to its execution. We do this by 133 * expecting that a typical call sequence consists of pushing arguments on 134 * the stack, executing a call instruction, and then performing an add 135 * on %esp to restore it to the value prior to pushing the arguments for 136 * the call. We attempt to detect such an add, and divide the addend 137 * by the size of a word to determine the number of pushed arguments. 138 */ 139 static uint_t 140 kvm_argcount(mdb_tgt_t *t, uintptr_t eip, ssize_t size) 141 { 142 uint8_t ins[6]; 143 ulong_t n; 144 145 enum { 146 M_MODRM_ESP = 0xc4, /* Mod/RM byte indicates %esp */ 147 M_ADD_IMM32 = 0x81, /* ADD imm32 to r/m32 */ 148 M_ADD_IMM8 = 0x83 /* ADD imm8 to r/m32 */ 149 }; 150 151 if (mdb_tgt_vread(t, ins, sizeof (ins), eip) != sizeof (ins)) 152 return (0); 153 154 if (ins[1] != M_MODRM_ESP) 155 return (0); 156 157 switch (ins[0]) { 158 case M_ADD_IMM32: 159 n = ins[2] + (ins[3] << 8) + (ins[4] << 16) + (ins[5] << 24); 160 break; 161 162 case M_ADD_IMM8: 163 n = ins[2]; 164 break; 165 166 default: 167 n = 0; 168 } 169 170 return (MIN((ssize_t)n, size) / sizeof (long)); 171 } 172 173 int 174 mdb_ia32_kvm_stack_iter(mdb_tgt_t *t, const mdb_tgt_gregset_t *gsp, 175 mdb_tgt_stack_f *func, void *arg) 176 { 177 mdb_tgt_gregset_t gregs; 178 kreg_t *kregs = &gregs.kregs[0]; 179 int got_pc = (gsp->kregs[KREG_EIP] != 0); 180 181 struct { 182 uintptr_t fr_savfp; 183 uintptr_t fr_savpc; 184 long fr_argv[32]; 185 } fr; 186 187 uintptr_t fp = gsp->kregs[KREG_EBP]; 188 uintptr_t pc = gsp->kregs[KREG_EIP]; 189 190 ssize_t size; 191 uint_t argc; 192 193 bcopy(gsp, &gregs, sizeof (gregs)); 194 195 while (fp != 0) { 196 197 if (fp & (STACK_ALIGN - 1)) 198 return (set_errno(EMDB_STKALIGN)); 199 200 if ((size = mdb_tgt_vread(t, &fr, sizeof (fr), fp)) >= 201 (ssize_t)(2 * sizeof (uintptr_t))) { 202 size -= (ssize_t)(2 * sizeof (uintptr_t)); 203 argc = kvm_argcount(t, fr.fr_savpc, size); 204 } else { 205 bzero(&fr, sizeof (fr)); 206 argc = 0; 207 } 208 209 if (got_pc && func(arg, pc, argc, fr.fr_argv, &gregs) != 0) 210 break; 211 212 kregs[KREG_ESP] = kregs[KREG_EBP]; 213 214 kregs[KREG_EBP] = fp = fr.fr_savfp; 215 kregs[KREG_EIP] = pc = fr.fr_savpc; 216 217 got_pc = (pc != 0); 218 } 219 220 return (0); 221 } 222 223 /* 224 * Determine the return address for the current frame. Typically this is the 225 * fr_savpc value from the current frame, but we also perform some special 226 * handling to see if we are stopped on one of the first two instructions of a 227 * typical function prologue, in which case %ebp will not be set up yet. 228 */ 229 int 230 mdb_ia32_step_out(mdb_tgt_t *t, uintptr_t *p, kreg_t pc, kreg_t fp, kreg_t sp, 231 mdb_instr_t curinstr) 232 { 233 struct frame fr; 234 GElf_Sym s; 235 char buf[1]; 236 237 enum { 238 M_PUSHL_EBP = 0x55, /* pushl %ebp */ 239 M_MOVL_EBP = 0x8b /* movl %esp, %ebp */ 240 }; 241 242 if (mdb_tgt_lookup_by_addr(t, pc, MDB_TGT_SYM_FUZZY, 243 buf, 0, &s, NULL) == 0) { 244 if (pc == s.st_value && curinstr == M_PUSHL_EBP) 245 fp = sp - 4; 246 else if (pc == s.st_value + 1 && curinstr == M_MOVL_EBP) 247 fp = sp; 248 } 249 250 if (mdb_tgt_vread(t, &fr, sizeof (fr), fp) == sizeof (fr)) { 251 *p = fr.fr_savpc; 252 return (0); 253 } 254 255 return (-1); /* errno is set for us */ 256 } 257 258 /* 259 * Return the address of the next instruction following a call, or return -1 260 * and set errno to EAGAIN if the target should just single-step. We perform 261 * a bit of disassembly on the current instruction in order to determine if it 262 * is a call and how many bytes should be skipped, depending on the exact form 263 * of the call instruction that is being used. 264 */ 265 int 266 mdb_ia32_next(mdb_tgt_t *t, uintptr_t *p, kreg_t pc, mdb_instr_t curinstr) 267 { 268 uint8_t m; 269 270 enum { 271 M_CALL_REL = 0xe8, /* call near with relative displacement */ 272 M_CALL_REG = 0xff, /* call near indirect or call far register */ 273 274 M_MODRM_MD = 0xc0, /* mask for Mod/RM byte Mod field */ 275 M_MODRM_OP = 0x38, /* mask for Mod/RM byte opcode field */ 276 M_MODRM_RM = 0x07, /* mask for Mod/RM byte R/M field */ 277 278 M_MD_IND = 0x00, /* Mod code for [REG] */ 279 M_MD_DSP8 = 0x40, /* Mod code for disp8[REG] */ 280 M_MD_DSP32 = 0x80, /* Mod code for disp32[REG] */ 281 M_MD_REG = 0xc0, /* Mod code for REG */ 282 283 M_OP_IND = 0x10, /* Opcode for call near indirect */ 284 M_RM_DSP32 = 0x05 /* R/M code for disp32 */ 285 }; 286 287 /* 288 * If the opcode is a near call with relative displacement, assume the 289 * displacement is a rel32 from the next instruction. 290 */ 291 if (curinstr == M_CALL_REL) { 292 *p = pc + sizeof (mdb_instr_t) + sizeof (uint32_t); 293 return (0); 294 } 295 296 /* 297 * If the opcode is a call near indirect or call far register opcode, 298 * read the subsequent Mod/RM byte to perform additional decoding. 299 */ 300 if (curinstr == M_CALL_REG) { 301 if (mdb_tgt_vread(t, &m, sizeof (m), pc + 1) != sizeof (m)) 302 return (-1); /* errno is set for us */ 303 304 /* 305 * If the Mod/RM opcode extension indicates a near indirect 306 * call, then skip the appropriate number of additional 307 * bytes depending on the addressing form that is used. 308 */ 309 if ((m & M_MODRM_OP) == M_OP_IND) { 310 switch (m & M_MODRM_MD) { 311 case M_MD_DSP8: 312 *p = pc + 3; /* skip pr_instr, m, disp8 */ 313 break; 314 case M_MD_DSP32: 315 *p = pc + 6; /* skip pr_instr, m, disp32 */ 316 break; 317 case M_MD_IND: 318 if ((m & M_MODRM_RM) == M_RM_DSP32) { 319 *p = pc + 6; 320 break; /* skip pr_instr, m, disp32 */ 321 } 322 /* FALLTHRU */ 323 case M_MD_REG: 324 *p = pc + 2; /* skip pr_instr, m */ 325 break; 326 } 327 return (0); 328 } 329 } 330 331 return (set_errno(EAGAIN)); 332 } 333 334 /*ARGSUSED*/ 335 int 336 mdb_ia32_kvm_frame(void *arglim, uintptr_t pc, uint_t argc, const long *argv, 337 const mdb_tgt_gregset_t *gregs) 338 { 339 argc = MIN(argc, (uint_t)arglim); 340 mdb_printf("%a(", pc); 341 342 if (argc != 0) { 343 mdb_printf("%lr", *argv++); 344 for (argc--; argc != 0; argc--) 345 mdb_printf(", %lr", *argv++); 346 } 347 348 mdb_printf(")\n"); 349 return (0); 350 } 351 352 int 353 mdb_ia32_kvm_framev(void *arglim, uintptr_t pc, uint_t argc, const long *argv, 354 const mdb_tgt_gregset_t *gregs) 355 { 356 argc = MIN(argc, (uint_t)arglim); 357 mdb_printf("%0?lr %a(", gregs->kregs[KREG_EBP], pc); 358 359 if (argc != 0) { 360 mdb_printf("%lr", *argv++); 361 for (argc--; argc != 0; argc--) 362 mdb_printf(", %lr", *argv++); 363 } 364 365 mdb_printf(")\n"); 366 return (0); 367 } 368