1 /* 2 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 3. Neither the name of The DragonFly Project nor the names of its 15 * contributors may be used to endorse or promote products derived 16 * from this software without specific, prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 21 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 22 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 24 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 26 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 27 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 28 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * -- 32 * 33 * Mach Operating System 34 * Copyright (c) 1991,1990 Carnegie Mellon University 35 * All Rights Reserved. 36 * 37 * Permission to use, copy, modify and distribute this software and its 38 * documentation is hereby granted, provided that both the copyright 39 * notice and this permission notice appear in all copies of the 40 * software, derivative works or modified versions, and any portions 41 * thereof, and that both notices appear in supporting documentation. 42 * 43 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 44 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 45 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 46 * 47 * Carnegie Mellon requests users of this software to return to 48 * 49 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 50 * School of Computer Science 51 * Carnegie Mellon University 52 * Pittsburgh PA 15213-3890 53 * 54 * any improvements or extensions that they make and grant Carnegie the 55 * rights to redistribute these changes. 56 * 57 * $FreeBSD: src/sys/i386/i386/db_interface.c,v 1.48.2.1 2000/07/07 00:38:46 obrien Exp $ 58 */ 59 60 /* 61 * Interface to new debugger. 62 */ 63 #include <sys/param.h> 64 #include <sys/systm.h> 65 #include <sys/reboot.h> 66 #include <sys/cons.h> 67 #include <sys/thread.h> 68 69 #include <machine/cpu.h> 70 #include <machine/smp.h> 71 #include <machine/globaldata.h> 72 #include <machine/md_var.h> 73 #include <machine/setjmp.h> 74 75 #include <vm/vm.h> 76 #include <vm/pmap.h> 77 78 #include <ddb/ddb.h> 79 80 #include <sys/thread2.h> 81 82 static jmp_buf *db_nofault = NULL; 83 extern jmp_buf db_jmpbuf; 84 85 extern void gdb_handle_exception (db_regs_t *, int, int); 86 87 int db_active; 88 db_regs_t ddb_regs; 89 90 static jmp_buf db_global_jmpbuf; 91 static int db_global_jmpbuf_valid; 92 93 #ifdef __GNUC__ 94 #define rss() ({u_short ss; __asm __volatile("mov %%ss,%0" : "=r" (ss)); ss;}) 95 #endif 96 97 /* 98 * kdb_trap - field a TRACE or BPT trap 99 */ 100 int 101 kdb_trap(int type, int code, struct x86_64_saved_state *regs) 102 { 103 volatile int ddb_mode = !(boothowto & RB_GDB); 104 105 /* 106 * XXX try to do nothing if the console is in graphics mode. 107 * Handle trace traps (and hardware breakpoints...) by ignoring 108 * them except for forgetting about them. Return 0 for other 109 * traps to say that we haven't done anything. The trap handler 110 * will usually panic. We should handle breakpoint traps for 111 * our breakpoints by disarming our breakpoints and fixing up 112 * %eip. 113 */ 114 if (cons_unavail && ddb_mode) { 115 if (type == T_TRCTRAP) { 116 regs->tf_rflags &= ~PSL_T; 117 return (1); 118 } 119 return (0); 120 } 121 122 switch (type) { 123 case T_BPTFLT: /* breakpoint */ 124 case T_TRCTRAP: /* debug exception */ 125 break; 126 127 default: 128 /* 129 * XXX this is almost useless now. In most cases, 130 * trap_fatal() has already printed a much more verbose 131 * message. However, it is dangerous to print things in 132 * trap_fatal() - kprintf() might be reentered and trap. 133 * The debugger should be given control first. 134 */ 135 if (ddb_mode) 136 db_printf("kernel: type %d trap, code=%x\n", type, code); 137 138 if (db_nofault) { 139 jmp_buf *no_fault = db_nofault; 140 db_nofault = NULL; 141 longjmp(*no_fault, 1); 142 } 143 } 144 145 /* 146 * This handles unexpected traps in ddb commands, including calls to 147 * non-ddb functions. db_nofault only applies to memory accesses by 148 * internal ddb commands. 149 */ 150 if (db_global_jmpbuf_valid) 151 longjmp(db_global_jmpbuf, 1); 152 153 /* 154 * XXX We really should switch to a local stack here. 155 */ 156 ddb_regs = *regs; 157 158 crit_enter(); 159 db_printf("\nCPU%d stopping CPUs: 0x%016jx\n", 160 mycpu->gd_cpuid, (uintmax_t)CPUMASK_LOWMASK(mycpu->gd_other_cpus)); 161 162 /* We stop all CPUs except ourselves (obviously) */ 163 stop_cpus(mycpu->gd_other_cpus); 164 165 db_printf(" stopped\n"); 166 167 setjmp(db_global_jmpbuf); 168 db_global_jmpbuf_valid = TRUE; 169 db_active++; 170 vcons_set_mode(1); 171 if (ddb_mode) { 172 cndbctl(TRUE); 173 db_trap(type, code); 174 cndbctl(FALSE); 175 } else 176 gdb_handle_exception(&ddb_regs, type, code); 177 db_active--; 178 vcons_set_mode(0); 179 db_global_jmpbuf_valid = FALSE; 180 181 db_printf("\nCPU%d restarting CPUs: 0x%016jx\n", 182 mycpu->gd_cpuid, (uintmax_t)CPUMASK_LOWMASK(stopped_cpus)); 183 184 /* Restart all the CPUs we previously stopped */ 185 if (CPUMASK_CMPMASKNEQ(stopped_cpus, mycpu->gd_other_cpus)) { 186 db_printf("whoa, other_cpus: 0x%016jx, " 187 "stopped_cpus: 0x%016jx\n", 188 (uintmax_t)CPUMASK_LOWMASK(mycpu->gd_other_cpus), 189 (uintmax_t)CPUMASK_LOWMASK(stopped_cpus)); 190 panic("stop_cpus() failed"); 191 } 192 restart_cpus(stopped_cpus); 193 194 db_printf(" restarted\n"); 195 crit_exit(); 196 197 regs->tf_rip = ddb_regs.tf_rip; 198 regs->tf_rflags = ddb_regs.tf_rflags; 199 regs->tf_rax = ddb_regs.tf_rax; 200 regs->tf_rcx = ddb_regs.tf_rcx; 201 regs->tf_rdx = ddb_regs.tf_rdx; 202 regs->tf_rbx = ddb_regs.tf_rbx; 203 204 regs->tf_rsp = ddb_regs.tf_rsp; 205 regs->tf_ss = ddb_regs.tf_ss & 0xffff; 206 207 regs->tf_rbp = ddb_regs.tf_rbp; 208 regs->tf_rsi = ddb_regs.tf_rsi; 209 regs->tf_rdi = ddb_regs.tf_rdi; 210 211 regs->tf_r8 = ddb_regs.tf_r8; 212 regs->tf_r9 = ddb_regs.tf_r9; 213 regs->tf_r10 = ddb_regs.tf_r10; 214 regs->tf_r11 = ddb_regs.tf_r11; 215 regs->tf_r12 = ddb_regs.tf_r12; 216 regs->tf_r13 = ddb_regs.tf_r13; 217 regs->tf_r14 = ddb_regs.tf_r14; 218 regs->tf_r15 = ddb_regs.tf_r15; 219 220 /* regs->tf_es = ddb_regs.tf_es & 0xffff; */ 221 /* regs->tf_fs = ddb_regs.tf_fs & 0xffff; */ 222 /* regs->tf_gs = ddb_regs.tf_gs & 0xffff; */ 223 regs->tf_cs = ddb_regs.tf_cs & 0xffff; 224 /* regs->tf_ds = ddb_regs.tf_ds & 0xffff; */ 225 return (1); 226 } 227 228 /* 229 * Read bytes from kernel address space for debugger. 230 */ 231 void 232 db_read_bytes(vm_offset_t addr, size_t size, char *data) 233 { 234 char *src; 235 236 db_nofault = &db_jmpbuf; 237 238 src = (char *)addr; 239 while (size-- > 0) 240 *data++ = *src++; 241 242 db_nofault = NULL; 243 } 244 245 /* 246 * Write bytes to kernel address space for debugger. 247 */ 248 void 249 db_write_bytes(vm_offset_t addr, size_t size, char *data) 250 { 251 char *dst; 252 #if 0 253 vpte_t *ptep0 = NULL; 254 vpte_t oldmap0 = 0; 255 vm_offset_t addr1; 256 vpte_t *ptep1 = NULL; 257 vpte_t oldmap1 = 0; 258 #endif 259 260 db_nofault = &db_jmpbuf; 261 #if 0 262 if (addr > trunc_page((vm_offset_t)btext) - size && 263 addr < round_page((vm_offset_t)etext)) { 264 265 ptep0 = pmap_kpte(addr); 266 oldmap0 = *ptep0; 267 *ptep0 |= VPTE_RW; 268 269 /* Map another page if the data crosses a page boundary. */ 270 if ((*ptep0 & PG_PS) == 0) { 271 addr1 = trunc_page(addr + size - 1); 272 if (trunc_page(addr) != addr1) { 273 ptep1 = pmap_kpte(addr1); 274 oldmap1 = *ptep1; 275 *ptep1 |= VPTE_RW; 276 } 277 } else { 278 addr1 = trunc_4mpage(addr + size - 1); 279 if (trunc_4mpage(addr) != addr1) { 280 ptep1 = pmap_kpte(addr1); 281 oldmap1 = *ptep1; 282 *ptep1 |= VPTE_RW; 283 } 284 } 285 286 cpu_invltlb(); 287 } 288 #endif 289 290 dst = (char *)addr; 291 292 while (size-- > 0) 293 *dst++ = *data++; 294 295 db_nofault = NULL; 296 297 #if 0 298 if (ptep0) { 299 *ptep0 = oldmap0; 300 301 if (ptep1) 302 *ptep1 = oldmap1; 303 304 cpu_invltlb(); 305 } 306 #endif 307 } 308 309 /* 310 * The debugger sometimes needs to know the actual KVM address represented 311 * by the instruction pointer, stack pointer, or base pointer. Normally 312 * the actual KVM address is simply the contents of the register. However, 313 * if the debugger is entered from the BIOS or VM86 we need to figure out 314 * the offset from the segment register. 315 */ 316 db_addr_t 317 PC_REGS(db_regs_t *regs) 318 { 319 return(regs->tf_rip); 320 } 321 322 db_addr_t 323 SP_REGS(db_regs_t *regs) 324 { 325 return(regs->tf_rsp); 326 } 327 328 db_addr_t 329 BP_REGS(db_regs_t *regs) 330 { 331 return(regs->tf_rbp); 332 } 333 334 /* 335 * XXX 336 * Move this to machdep.c and allow it to be called if any debugger is 337 * installed. 338 */ 339 void 340 Debugger(const char *msg) 341 { 342 static volatile u_char in_Debugger; 343 344 /* 345 * XXX 346 * Do nothing if the console is in graphics mode. This is 347 * OK if the call is for the debugger hotkey but not if the call 348 * is a weak form of panicing. 349 */ 350 if (cons_unavail && !(boothowto & RB_GDB)) 351 return; 352 353 if (!in_Debugger) { 354 in_Debugger = 1; 355 db_printf("Debugger(\"%s\")\n", msg); 356 breakpoint(); 357 in_Debugger = 0; 358 } 359 } 360