sys/platform/vkernel/i386/db_interface.c

   1 /*
   2  * Mach Operating System
   3  * Copyright (c) 1991,1990 Carnegie Mellon University
   4  * All Rights Reserved.
   5  *
   6  * Permission to use, copy, modify and distribute this software and its
   7  * documentation is hereby granted, provided that both the copyright
   8  * notice and this permission notice appear in all copies of the
   9  * software, derivative works or modified versions, and any portions
  10  * thereof, and that both notices appear in supporting documentation.
  11  *
  12  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
  13  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  14  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  15  *
  16  * Carnegie Mellon requests users of this software to return to
  17  *
  18  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  19  *  School of Computer Science
  20  *  Carnegie Mellon University
  21  *  Pittsburgh PA 15213-3890
  22  *
  23  * any improvements or extensions that they make and grant Carnegie the
  24  * rights to redistribute these changes.
  25  *
  26  * $FreeBSD: src/sys/i386/i386/db_interface.c,v 1.48.2.1 2000/07/07 00:38:46 obrien Exp $
  27  * $DragonFly: src/sys/platform/vkernel/i386/db_interface.c,v 1.3 2007/01/09 01:20:17 dillon Exp $
  28  */
  29
  30 /*
  31  * Interface to new debugger.
  32  */
  33 #include <sys/param.h>
  34 #include <sys/systm.h>
  35 #include <sys/reboot.h>
  36 #include <sys/cons.h>
  37 #include <sys/vkernel.h>
  38
  39 #include <machine/cpu.h>
  40 #include <machine/smp.h>
  41 #include <machine/globaldata.h>
  42 #include <machine/md_var.h>
  43
  44 #include <vm/vm.h>
  45 #include <vm/pmap.h>
  46
  47 #include <ddb/ddb.h>
  48
  49 #include <setjmp.h>
  50
  51 static jmp_buf *db_nofault = 0;
  52 extern jmp_buf  db_jmpbuf;
  53
  54 extern void     gdb_handle_exception (db_regs_t *, int, int);
  55
  56 int     db_active;
  57 db_regs_t ddb_regs;
  58
  59 static jmp_buf  db_global_jmpbuf;
  60 static int      db_global_jmpbuf_valid;
  61
  62 #ifdef __GNUC__
  63 #define rss() ({u_short ss; __asm __volatile("mov %%ss,%0" : "=r" (ss)); ss;})
  64 #endif
  65
  66 /*
  67  *  kdb_trap - field a TRACE or BPT trap
  68  */
  69 int
  70 kdb_trap(int type, int code, struct i386_saved_state *regs)
  71 {
  72         volatile int ddb_mode = !(boothowto & RB_GDB);
  73
  74         /*
  75          * XXX try to do nothing if the console is in graphics mode.
  76          * Handle trace traps (and hardware breakpoints...) by ignoring
  77          * them except for forgetting about them.  Return 0 for other
  78          * traps to say that we haven't done anything.  The trap handler
  79          * will usually panic.  We should handle breakpoint traps for
  80          * our breakpoints by disarming our breakpoints and fixing up
  81          * %eip.
  82          */
  83         if (cons_unavail && ddb_mode) {
  84             if (type == T_TRCTRAP) {
  85                 regs->tf_eflags &= ~PSL_T;
  86                 return (1);
  87             }
  88             return (0);
  89         }
  90
  91         switch (type) {
  92             case T_BPTFLT:      /* breakpoint */
  93             case T_TRCTRAP:     /* debug exception */
  94                 break;
  95
  96             default:
  97                 /*
  98                  * XXX this is almost useless now.  In most cases,
  99                  * trap_fatal() has already printed a much more verbose
 100                  * message.  However, it is dangerous to print things in
 101                  * trap_fatal() - kprintf() might be reentered and trap.
 102                  * The debugger should be given control first.
 103                  */
 104                 if (ddb_mode)
 105                     db_printf("kernel: type %d trap, code=%x\n", type, code);
 106
 107                 if (db_nofault) {
 108                     jmp_buf *no_fault = db_nofault;
 109                     db_nofault = 0;
 110                     longjmp(*no_fault, 1);
 111                 }
 112         }
 113
 114         /*
 115          * This handles unexpected traps in ddb commands, including calls to
 116          * non-ddb functions.  db_nofault only applies to memory accesses by
 117          * internal ddb commands.
 118          */
 119         if (db_global_jmpbuf_valid)
 120             longjmp(db_global_jmpbuf, 1);
 121
 122         /*
 123          * XXX We really should switch to a local stack here.
 124          */
 125         ddb_regs = *regs;
 126
 127         /*
 128          * If in kernel mode, esp and ss are not saved, so dummy them up.
 129          */
 130         if (ISPL(regs->tf_cs) == 0) {
 131             ddb_regs.tf_esp = (int)&regs->tf_esp;
 132             ddb_regs.tf_ss = rss();
 133         }
 134
 135 #ifdef SMP
 136         db_printf("\nCPU%d stopping CPUs: 0x%08x\n",
 137             mycpu->gd_cpuid, mycpu->gd_other_cpus);
 138
 139         /* We stop all CPUs except ourselves (obviously) */
 140         stop_cpus(mycpu->gd_other_cpus);
 141
 142         db_printf(" stopped\n");
 143 #endif /* SMP */
 144
 145         setjmp(db_global_jmpbuf);
 146         db_global_jmpbuf_valid = TRUE;
 147         db_active++;
 148         vcons_set_mode(1);
 149         if (ddb_mode) {
 150             cndbctl(TRUE);
 151             db_trap(type, code);
 152             cndbctl(FALSE);
 153         } else
 154             gdb_handle_exception(&ddb_regs, type, code);
 155         db_active--;
 156         vcons_set_mode(0);
 157         db_global_jmpbuf_valid = FALSE;
 158
 159 #ifdef SMP
 160         db_printf("\nCPU%d restarting CPUs: 0x%08x\n",
 161             mycpu->gd_cpuid, stopped_cpus);
 162
 163         /* Restart all the CPUs we previously stopped */
 164         if (stopped_cpus != mycpu->gd_other_cpus) {
 165                 db_printf("whoa, other_cpus: 0x%08x, stopped_cpus: 0x%08x\n",
 166                           mycpu->gd_other_cpus, stopped_cpus);
 167                 panic("stop_cpus() failed");
 168         }
 169         restart_cpus(stopped_cpus);
 170
 171         db_printf(" restarted\n");
 172 #endif /* SMP */
 173
 174         regs->tf_eip    = ddb_regs.tf_eip;
 175         regs->tf_eflags = ddb_regs.tf_eflags;
 176         regs->tf_eax    = ddb_regs.tf_eax;
 177         regs->tf_ecx    = ddb_regs.tf_ecx;
 178         regs->tf_edx    = ddb_regs.tf_edx;
 179         regs->tf_ebx    = ddb_regs.tf_ebx;
 180
 181         /*
 182          * If in user mode, the saved ESP and SS were valid, restore them.
 183          */
 184         if (ISPL(regs->tf_cs)) {
 185             regs->tf_esp = ddb_regs.tf_esp;
 186             regs->tf_ss  = ddb_regs.tf_ss & 0xffff;
 187         }
 188
 189         regs->tf_ebp    = ddb_regs.tf_ebp;
 190         regs->tf_esi    = ddb_regs.tf_esi;
 191         regs->tf_edi    = ddb_regs.tf_edi;
 192         regs->tf_es     = ddb_regs.tf_es & 0xffff;
 193         regs->tf_fs     = ddb_regs.tf_fs & 0xffff;
 194         regs->tf_gs     = ddb_regs.tf_gs & 0xffff;
 195         regs->tf_cs     = ddb_regs.tf_cs & 0xffff;
 196         regs->tf_ds     = ddb_regs.tf_ds & 0xffff;
 197         return (1);
 198 }
 199
 200 /*
 201  * Read bytes from kernel address space for debugger.
 202  */
 203 void
 204 db_read_bytes(vm_offset_t addr, size_t size, char *data)
 205 {
 206         char    *src;
 207
 208         db_nofault = &db_jmpbuf;
 209
 210         src = (char *)addr;
 211         while (size-- > 0)
 212             *data++ = *src++;
 213
 214         db_nofault = 0;
 215 }
 216
 217 /*
 218  * Write bytes to kernel address space for debugger.
 219  */
 220 void
 221 db_write_bytes(vm_offset_t addr, size_t size, char *data)
 222 {
 223         char    *dst;
 224 #if 0
 225         vpte_t  *ptep0 = NULL;
 226         vpte_t  oldmap0 = 0;
 227         vm_offset_t     addr1;
 228         vpte_t  *ptep1 = NULL;
 229         vpte_t  oldmap1 = 0;
 230 #endif
 231
 232         db_nofault = &db_jmpbuf;
 233 #if 0
 234         if (addr > trunc_page((vm_offset_t)btext) - size &&
 235             addr < round_page((vm_offset_t)etext)) {
 236
 237             ptep0 = pmap_kpte(addr);
 238             oldmap0 = *ptep0;
 239             *ptep0 |= VPTE_W;
 240
 241             /* Map another page if the data crosses a page boundary. */
 242             if ((*ptep0 & PG_PS) == 0) {
 243                 addr1 = trunc_page(addr + size - 1);
 244                 if (trunc_page(addr) != addr1) {
 245                     ptep1 = pmap_kpte(addr1);
 246                     oldmap1 = *ptep1;
 247                     *ptep1 |= VPTE_W;
 248                 }
 249             } else {
 250                 addr1 = trunc_4mpage(addr + size - 1);
 251                 if (trunc_4mpage(addr) != addr1) {
 252                     ptep1 = pmap_kpte(addr1);
 253                     oldmap1 = *ptep1;
 254                     *ptep1 |= VPTE_W;
 255                 }
 256             }
 257
 258             cpu_invltlb();
 259         }
 260 #endif
 261
 262         dst = (char *)addr;
 263
 264         while (size-- > 0)
 265             *dst++ = *data++;
 266
 267         db_nofault = 0;
 268
 269 #if 0
 270         if (ptep0) {
 271             *ptep0 = oldmap0;
 272
 273             if (ptep1)
 274                 *ptep1 = oldmap1;
 275
 276             cpu_invltlb();
 277         }
 278 #endif
 279 }
 280
 281 /*
 282  * The debugger sometimes needs to know the actual KVM address represented
 283  * by the instruction pointer, stack pointer, or base pointer.  Normally
 284  * the actual KVM address is simply the contents of the register.  However,
 285  * if the debugger is entered from the BIOS or VM86 we need to figure out
 286  * the offset from the segment register.
 287  */
 288 db_addr_t
 289 PC_REGS(db_regs_t *regs)
 290 {
 291     return(regs->tf_eip);
 292 }
 293
 294 db_addr_t
 295 SP_REGS(db_regs_t *regs)
 296 {
 297     return(regs->tf_esp);
 298 }
 299
 300 db_addr_t
 301 BP_REGS(db_regs_t *regs)
 302 {
 303     return(regs->tf_ebp);
 304 }
 305
 306 /*
 307  * XXX
 308  * Move this to machdep.c and allow it to be called if any debugger is
 309  * installed.
 310  */
 311 void
 312 Debugger(const char *msg)
 313 {
 314         static volatile u_char in_Debugger;
 315
 316         /*
 317          * XXX
 318          * Do nothing if the console is in graphics mode.  This is
 319          * OK if the call is for the debugger hotkey but not if the call
 320          * is a weak form of panicing.
 321          */
 322         if (cons_unavail && !(boothowto & RB_GDB))
 323             return;
 324
 325         if (!in_Debugger) {
 326             in_Debugger = 1;
 327             db_printf("Debugger(\"%s\")\n", msg);
 328             breakpoint();
 329             in_Debugger = 0;
 330         }
 331 }