sys/platform/pc64/x86_64/db_interface.c

   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 #include <sys/kerneldump.h>
  69
  70 #include <machine/cpu.h>
  71 #include <machine/smp.h>
  72 #include <machine/globaldata.h>
  73 #include <machine/md_var.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 #include <machine/setjmp.h>
  83
  84 static jmp_buf *db_nofault = NULL;
  85 extern jmp_buf  db_jmpbuf;
  86
  87 extern void     gdb_handle_exception (db_regs_t *, int, int);
  88
  89 int     db_active;
  90 db_regs_t ddb_regs;
  91
  92 static jmp_buf  db_global_jmpbuf;
  93 static int      db_global_jmpbuf_valid;
  94
  95 #ifdef __GNUC__
  96 #define rss() ({u_short ss; __asm __volatile("mov %%ss,%0" : "=r" (ss)); ss;})
  97 #endif
  98
  99 /*
 100  *  kdb_trap - field a TRACE or BPT trap
 101  */
 102 int
 103 kdb_trap(int type, int code, struct x86_64_saved_state *regs)
 104 {
 105         volatile int ddb_mode = !(boothowto & RB_GDB);
 106
 107         /*
 108          * XXX try to do nothing if the console is in graphics mode.
 109          * Handle trace traps (and hardware breakpoints...) by ignoring
 110          * them except for forgetting about them.  Return 0 for other
 111          * traps to say that we haven't done anything.  The trap handler
 112          * will usually panic.  We should handle breakpoint traps for
 113          * our breakpoints by disarming our breakpoints and fixing up
 114          * %eip.
 115          */
 116         if (cons_unavail && ddb_mode) {
 117             if (type == T_TRCTRAP) {
 118                 regs->tf_rflags &= ~PSL_T;
 119                 return (1);
 120             }
 121             return (0);
 122         }
 123
 124         switch (type) {
 125             case T_BPTFLT:      /* breakpoint */
 126             case T_TRCTRAP:     /* debug exception */
 127                 break;
 128
 129             default:
 130                 /*
 131                  * XXX this is almost useless now.  In most cases,
 132                  * trap_fatal() has already printed a much more verbose
 133                  * message.  However, it is dangerous to print things in
 134                  * trap_fatal() - kprintf() might be reentered and trap.
 135                  * The debugger should be given control first.
 136                  */
 137                 if (ddb_mode)
 138                     db_printf("kernel: type %d trap, code=%x\n", type, code);
 139
 140                 if (db_nofault) {
 141                     jmp_buf *no_fault = db_nofault;
 142                     db_nofault = NULL;
 143                     longjmp(*no_fault, 1);
 144                 }
 145         }
 146
 147         /*
 148          * This handles unexpected traps in ddb commands, including calls to
 149          * non-ddb functions.  db_nofault only applies to memory accesses by
 150          * internal ddb commands.
 151          */
 152         if (db_global_jmpbuf_valid)
 153             longjmp(db_global_jmpbuf, 1);
 154
 155         /*
 156          * XXX We really should switch to a local stack here.
 157          */
 158         ddb_regs = *regs;
 159
 160         crit_enter();
 161         db_printf("\nCPU%d stopping CPUs: 0x%08jx\n",
 162                   mycpu->gd_cpuid,
 163                   (uintmax_t)CPUMASK_LOWMASK(mycpu->gd_other_cpus));
 164
 165         /* We stop all CPUs except ourselves (obviously) */
 166         stop_cpus(mycpu->gd_other_cpus);
 167
 168         db_printf(" stopped\n");
 169
 170         setjmp(db_global_jmpbuf);
 171         db_global_jmpbuf_valid = TRUE;
 172         db_active++;
 173         /* vcons_set_mode(1); */
 174         if (ddb_mode) {
 175             cndbctl(TRUE);
 176             db_trap(type, code);
 177             cndbctl(FALSE);
 178         } else
 179             gdb_handle_exception(&ddb_regs, type, code);
 180         db_active--;
 181         /* vcons_set_mode(0); */
 182         db_global_jmpbuf_valid = FALSE;
 183
 184         if (panicstr == NULL) {
 185                 db_printf("\nCPU%d restarting CPUs: 0x%016jx\n",
 186                           mycpu->gd_cpuid,
 187                           (uintmax_t)CPUMASK_LOWMASK(stopped_cpus));
 188
 189                 /* Restart all the CPUs we previously stopped */
 190                 if (CPUMASK_CMPMASKNEQ(stopped_cpus, mycpu->gd_other_cpus)) {
 191                         db_printf("whoa, other_cpus: 0x%016jx, "
 192                                   "stopped_cpus: 0x%016jx\n",
 193                                   (uintmax_t)CPUMASK_LOWMASK(mycpu->gd_other_cpus),
 194                                   (uintmax_t)CPUMASK_LOWMASK(stopped_cpus));
 195                         panic("stop_cpus() failed");
 196                 }
 197                 restart_cpus(stopped_cpus);
 198         }
 199
 200         db_printf(" restarted\n");
 201         crit_exit();
 202
 203         regs->tf_rip    = ddb_regs.tf_rip;
 204         regs->tf_rflags = ddb_regs.tf_rflags;
 205         regs->tf_rax    = ddb_regs.tf_rax;
 206         regs->tf_rcx    = ddb_regs.tf_rcx;
 207         regs->tf_rdx    = ddb_regs.tf_rdx;
 208         regs->tf_rbx    = ddb_regs.tf_rbx;
 209
 210         regs->tf_rsp    = ddb_regs.tf_rsp;
 211         regs->tf_ss     = ddb_regs.tf_ss & 0xffff;
 212
 213         regs->tf_rbp    = ddb_regs.tf_rbp;
 214         regs->tf_rsi    = ddb_regs.tf_rsi;
 215         regs->tf_rdi    = ddb_regs.tf_rdi;
 216
 217         regs->tf_r8     = ddb_regs.tf_r8;
 218         regs->tf_r9     = ddb_regs.tf_r9;
 219         regs->tf_r10    = ddb_regs.tf_r10;
 220         regs->tf_r11    = ddb_regs.tf_r11;
 221         regs->tf_r12    = ddb_regs.tf_r12;
 222         regs->tf_r13    = ddb_regs.tf_r13;
 223         regs->tf_r14    = ddb_regs.tf_r14;
 224         regs->tf_r15    = ddb_regs.tf_r15;
 225
 226         /* regs->tf_es     = ddb_regs.tf_es & 0xffff; */
 227         /* regs->tf_fs     = ddb_regs.tf_fs & 0xffff; */
 228         /* regs->tf_gs     = ddb_regs.tf_gs & 0xffff; */
 229         regs->tf_cs     = ddb_regs.tf_cs & 0xffff;
 230         /* regs->tf_ds     = ddb_regs.tf_ds & 0xffff; */
 231         return (1);
 232 }
 233
 234 /*
 235  * Read bytes from kernel address space for debugger.
 236  */
 237 void
 238 db_read_bytes(vm_offset_t addr, size_t size, char *data)
 239 {
 240         char    *src;
 241
 242         db_nofault = &db_jmpbuf;
 243
 244         src = (char *)addr;
 245         while (size-- > 0)
 246             *data++ = *src++;
 247
 248         db_nofault = NULL;
 249 }
 250
 251 /*
 252  * Write bytes to kernel address space for debugger.
 253  */
 254 void
 255 db_write_bytes(vm_offset_t addr, size_t size, char *data)
 256 {
 257         char    *dst;
 258 #if 0
 259         vpte_t  *ptep0 = NULL;
 260         vpte_t  oldmap0 = 0;
 261         vm_offset_t     addr1;
 262         vpte_t  *ptep1 = NULL;
 263         vpte_t  oldmap1 = 0;
 264 #endif
 265
 266         db_nofault = &db_jmpbuf;
 267 #if 0
 268         if (addr > trunc_page((vm_offset_t)btext) - size &&
 269             addr < round_page((vm_offset_t)etext)) {
 270
 271             ptep0 = pmap_kpte(addr);
 272             oldmap0 = *ptep0;
 273             *ptep0 |= VPTE_RW;
 274
 275             /* Map another page if the data crosses a page boundary. */
 276             if ((*ptep0 & PG_PS) == 0) {
 277                 addr1 = trunc_page(addr + size - 1);
 278                 if (trunc_page(addr) != addr1) {
 279                     ptep1 = pmap_kpte(addr1);
 280                     oldmap1 = *ptep1;
 281                     *ptep1 |= VPTE_RW;
 282                 }
 283             } else {
 284                 addr1 = trunc_4mpage(addr + size - 1);
 285                 if (trunc_4mpage(addr) != addr1) {
 286                     ptep1 = pmap_kpte(addr1);
 287                     oldmap1 = *ptep1;
 288                     *ptep1 |= VPTE_RW;
 289                 }
 290             }
 291
 292             cpu_invltlb();
 293         }
 294 #endif
 295
 296         dst = (char *)addr;
 297
 298         while (size-- > 0)
 299             *dst++ = *data++;
 300
 301         db_nofault = NULL;
 302
 303 #if 0
 304         if (ptep0) {
 305             *ptep0 = oldmap0;
 306
 307             if (ptep1)
 308                 *ptep1 = oldmap1;
 309
 310             cpu_invltlb();
 311         }
 312 #endif
 313 }
 314
 315 /*
 316  * The debugger sometimes needs to know the actual KVM address represented
 317  * by the instruction pointer, stack pointer, or base pointer.  Normally
 318  * the actual KVM address is simply the contents of the register.  However,
 319  * if the debugger is entered from the BIOS or VM86 we need to figure out
 320  * the offset from the segment register.
 321  */
 322 db_addr_t
 323 PC_REGS(db_regs_t *regs)
 324 {
 325     return(regs->tf_rip);
 326 }
 327
 328 db_addr_t
 329 SP_REGS(db_regs_t *regs)
 330 {
 331     return(regs->tf_rsp);
 332 }
 333
 334 db_addr_t
 335 BP_REGS(db_regs_t *regs)
 336 {
 337     return(regs->tf_rbp);
 338 }
 339
 340 /*
 341  * XXX
 342  * Move this to machdep.c and allow it to be called if any debugger is
 343  * installed.
 344  */
 345 void
 346 Debugger(const char *msg)
 347 {
 348         static volatile u_char in_Debugger;
 349
 350         /*
 351          * XXX
 352          * Do nothing if the console is in graphics mode.  This is
 353          * OK if the call is for the debugger hotkey but not if the call
 354          * is a weak form of panicing.
 355          */
 356         if (cons_unavail && !(boothowto & RB_GDB)) {
 357                 /*
 358                  * If we are panicing, panic() expects cpus to be stopped
 359                  * when Debugger() returns.
 360                  */
 361                 if (panicstr != NULL)
 362                         stop_cpus(mycpu->gd_other_cpus);
 363                 return;
 364         }
 365
 366         if (!in_Debugger) {
 367             in_Debugger = 1;
 368             db_printf("Debugger(\"%s\")\n", msg);
 369
 370             /*
 371              * Save the pcb just in case the sysop entered the debugger
 372              * manually and called dumpsys,
 373              */
 374             if (dumpthread == NULL) {
 375                     savectx(&dumppcb);
 376                     dumpthread = curthread;
 377             }
 378
 379             breakpoint();
 380             in_Debugger = 0;
 381
 382             /*
 383              * Clear before returning from the debugger so a later panic
 384              * saves the correct context.
 385              */
 386             dumpthread = NULL;
 387         }
 388 }