gdb/amd64fbsd-nat.c

   1 /* Native-dependent code for FreeBSD/amd64.
   2
   3    Copyright (C) 2003-2015 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "inferior.h"
  22 #include "regcache.h"
  23 #include "target.h"
  24
  25 #include <signal.h>
  26 #include <sys/types.h>
  27 #include <sys/ptrace.h>
  28 #include <sys/sysctl.h>
  29 #include <sys/user.h>
  30 #include <machine/reg.h>
  31
  32 #include "fbsd-nat.h"
  33 #include "amd64-tdep.h"
  34 #include "amd64-nat.h"
  35 #include "amd64bsd-nat.h"
  36 #include "x86-nat.h"
  37 \f
  38
  39 /* Offset in `struct reg' where MEMBER is stored.  */
  40 #define REG_OFFSET(member) offsetof (struct reg, member)
  41
  42 /* At amd64fbsd64_r_reg_offset[REGNUM] you'll find the offset in
  43    `struct reg' location where the GDB register REGNUM is stored.
  44    Unsupported registers are marked with `-1'.  */
  45 static int amd64fbsd64_r_reg_offset[] =
  46 {
  47   REG_OFFSET (r_rax),
  48   REG_OFFSET (r_rbx),
  49   REG_OFFSET (r_rcx),
  50   REG_OFFSET (r_rdx),
  51   REG_OFFSET (r_rsi),
  52   REG_OFFSET (r_rdi),
  53   REG_OFFSET (r_rbp),
  54   REG_OFFSET (r_rsp),
  55   REG_OFFSET (r_r8),
  56   REG_OFFSET (r_r9),
  57   REG_OFFSET (r_r10),
  58   REG_OFFSET (r_r11),
  59   REG_OFFSET (r_r12),
  60   REG_OFFSET (r_r13),
  61   REG_OFFSET (r_r14),
  62   REG_OFFSET (r_r15),
  63   REG_OFFSET (r_rip),
  64   REG_OFFSET (r_rflags),
  65   REG_OFFSET (r_cs),
  66   REG_OFFSET (r_ss),
  67   -1,
  68   -1,
  69   -1,
  70   -1
  71 };
  72 \f
  73
  74 /* Mapping between the general-purpose registers in FreeBSD/amd64
  75    `struct reg' format and GDB's register cache layout for
  76    FreeBSD/i386.
  77
  78    Note that most FreeBSD/amd64 registers are 64-bit, while the
  79    FreeBSD/i386 registers are all 32-bit, but since we're
  80    little-endian we get away with that.  */
  81
  82 /* From <machine/reg.h>.  */
  83 static int amd64fbsd32_r_reg_offset[I386_NUM_GREGS] =
  84 {
  85   14 * 8, 13 * 8,               /* %eax, %ecx */
  86   12 * 8, 11 * 8,               /* %edx, %ebx */
  87   20 * 8, 10 * 8,               /* %esp, %ebp */
  88   9 * 8, 8 * 8,                 /* %esi, %edi */
  89   17 * 8, 19 * 8,               /* %eip, %eflags */
  90   18 * 8, 21 * 8,               /* %cs, %ss */
  91   -1, -1, -1, -1                /* %ds, %es, %fs, %gs */
  92 };
  93 \f
  94
  95 /* Support for debugging kernel virtual memory images.  */
  96
  97 #include <machine/pcb.h>
  98 #include <osreldate.h>
  99
 100 #include "bsd-kvm.h"
 101
 102 static int
 103 amd64fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 104 {
 105   /* The following is true for FreeBSD 5.2:
 106
 107      The pcb contains %rip, %rbx, %rsp, %rbp, %r12, %r13, %r14, %r15,
 108      %ds, %es, %fs and %gs.  This accounts for all callee-saved
 109      registers specified by the psABI and then some.  Here %esp
 110      contains the stack pointer at the point just after the call to
 111      cpu_switch().  From this information we reconstruct the register
 112      state as it would like when we just returned from cpu_switch().  */
 113
 114   /* The stack pointer shouldn't be zero.  */
 115   if (pcb->pcb_rsp == 0)
 116     return 0;
 117
 118   pcb->pcb_rsp += 8;
 119   regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &pcb->pcb_rip);
 120   regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &pcb->pcb_rbx);
 121   regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp);
 122   regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp);
 123   regcache_raw_supply (regcache, 12, &pcb->pcb_r12);
 124   regcache_raw_supply (regcache, 13, &pcb->pcb_r13);
 125   regcache_raw_supply (regcache, 14, &pcb->pcb_r14);
 126   regcache_raw_supply (regcache, 15, &pcb->pcb_r15);
 127 #if (__FreeBSD_version < 800075) && (__FreeBSD_kernel_version < 800075)
 128   /* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only
 129      up until __FreeBSD_version 800074: The removal of these fields
 130      occurred on 2009-04-01 while the __FreeBSD_version number was
 131      bumped to 800075 on 2009-04-06.  So 800075 is the closest version
 132      number where we should not try to access these fields.  */
 133   regcache_raw_supply (regcache, AMD64_DS_REGNUM, &pcb->pcb_ds);
 134   regcache_raw_supply (regcache, AMD64_ES_REGNUM, &pcb->pcb_es);
 135   regcache_raw_supply (regcache, AMD64_FS_REGNUM, &pcb->pcb_fs);
 136   regcache_raw_supply (regcache, AMD64_GS_REGNUM, &pcb->pcb_gs);
 137 #endif
 138
 139   return 1;
 140 }
 141 \f
 142
 143 static void (*super_mourn_inferior) (struct target_ops *ops);
 144
 145 static void
 146 amd64fbsd_mourn_inferior (struct target_ops *ops)
 147 {
 148 #ifdef HAVE_PT_GETDBREGS
 149   x86_cleanup_dregs ();
 150 #endif
 151   super_mourn_inferior (ops);
 152 }
 153
 154 /* Provide a prototype to silence -Wmissing-prototypes.  */
 155 void _initialize_amd64fbsd_nat (void);
 156
 157 void
 158 _initialize_amd64fbsd_nat (void)
 159 {
 160   struct target_ops *t;
 161   int offset;
 162
 163   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 164   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 165
 166   /* Add some extra features to the common *BSD/i386 target.  */
 167   t = amd64bsd_target ();
 168
 169 #ifdef HAVE_PT_GETDBREGS
 170
 171   x86_use_watchpoints (t);
 172
 173   x86_dr_low.set_control = amd64bsd_dr_set_control;
 174   x86_dr_low.set_addr = amd64bsd_dr_set_addr;
 175   x86_dr_low.get_addr = amd64bsd_dr_get_addr;
 176   x86_dr_low.get_status = amd64bsd_dr_get_status;
 177   x86_dr_low.get_control = amd64bsd_dr_get_control;
 178   x86_set_debug_register_length (8);
 179
 180 #endif /* HAVE_PT_GETDBREGS */
 181
 182   super_mourn_inferior = t->to_mourn_inferior;
 183   t->to_mourn_inferior = amd64fbsd_mourn_inferior;
 184
 185   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
 186   t->to_find_memory_regions = fbsd_find_memory_regions;
 187   add_target (t);
 188
 189   /* Support debugging kernel virtual memory images.  */
 190   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 191
 192   /* To support the recognition of signal handlers, i386bsd-tdep.c
 193      hardcodes some constants.  Inclusion of this file means that we
 194      are compiling a native debugger, which means that we can use the
 195      system header files and sysctl(3) to get at the relevant
 196      information.  */
 197
 198 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 199
 200   /* We only check the program counter, stack pointer and frame
 201      pointer since these members of `struct sigcontext' are essential
 202      for providing backtraces.  */
 203
 204 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 205 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 206 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 207
 208   /* Override the default value for the offset of the program counter
 209      in the sigcontext structure.  */
 210   offset = offsetof (struct sigcontext, sc_rip);
 211
 212   if (SC_RIP_OFFSET != offset)
 213     {
 214       warning (_("\
 215 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 216 Please report this to <bug-gdb@gnu.org>."),
 217                offset, SC_RIP_OFFSET);
 218     }
 219
 220   SC_RIP_OFFSET = offset;
 221
 222   /* Likewise for the stack pointer.  */
 223   offset = offsetof (struct sigcontext, sc_rsp);
 224
 225   if (SC_RSP_OFFSET != offset)
 226     {
 227       warning (_("\
 228 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 229 Please report this to <bug-gdb@gnu.org>."),
 230                offset, SC_RSP_OFFSET);
 231     }
 232
 233   SC_RSP_OFFSET = offset;
 234
 235   /* And the frame pointer.  */
 236   offset = offsetof (struct sigcontext, sc_rbp);
 237
 238   if (SC_RBP_OFFSET != offset)
 239     {
 240       warning (_("\
 241 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 242 Please report this to <bug-gdb@gnu.org>."),
 243                offset, SC_RBP_OFFSET);
 244     }
 245
 246   SC_RBP_OFFSET = offset;
 247
 248 #ifdef KERN_PROC_SIGTRAMP
 249   /* Normally signal frames are detected via amd64fbsd_sigtramp_p.
 250      However, FreeBSD 9.2 through 10.1 do not include the page holding
 251      the signal code in core dumps.  These releases do provide a
 252      kern.proc.sigtramp.<pid> sysctl that returns the location of the
 253      signal trampoline for a running process.  We fetch the location
 254      of the current (gdb) process and use this to identify signal
 255      frames in core dumps from these releases.  Note that this only
 256      works for core dumps of 64-bit (FreeBSD/amd64) processes and does
 257      not handle core dumps of 32-bit (FreeBSD/i386) processes.  */
 258   {
 259     int mib[4];
 260     struct kinfo_sigtramp kst;
 261     size_t len;
 262
 263     mib[0] = CTL_KERN;
 264     mib[1] = KERN_PROC;
 265     mib[2] = KERN_PROC_SIGTRAMP;
 266     mib[3] = getpid ();
 267     len = sizeof (kst);
 268     if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
 269       {
 270         amd64fbsd_sigtramp_start_addr = (uintptr_t) kst.ksigtramp_start;
 271         amd64fbsd_sigtramp_end_addr = (uintptr_t) kst.ksigtramp_end;
 272       }
 273   }
 274 #endif
 275 }