gdb/amd64fbsd-nat.c

   1 /* Native-dependent code for FreeBSD/amd64.
   2
   3    Copyright 2003, 2004 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 2 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, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "inferior.h"
  24 #include "regcache.h"
  25 #include "target.h"
  26
  27 #include "gdb_assert.h"
  28 #include <signal.h>
  29 #include <stddef.h>
  30 #include <sys/types.h>
  31 #include <sys/ptrace.h>
  32 #include <sys/sysctl.h>
  33 #include <machine/reg.h>
  34
  35 #include "fbsd-nat.h"
  36 #include "amd64-tdep.h"
  37 #include "amd64-nat.h"
  38 \f
  39
  40 /* Offset in `struct reg' where MEMBER is stored.  */
  41 #define REG_OFFSET(member) offsetof (struct reg, member)
  42
  43 /* At amd64fbsd64_r_reg_offset[REGNUM] you'll find the offset in
  44    `struct reg' location where the GDB register REGNUM is stored.
  45    Unsupported registers are marked with `-1'.  */
  46 static int amd64fbsd64_r_reg_offset[] =
  47 {
  48   REG_OFFSET (r_rax),
  49   REG_OFFSET (r_rbx),
  50   REG_OFFSET (r_rcx),
  51   REG_OFFSET (r_rdx),
  52   REG_OFFSET (r_rsi),
  53   REG_OFFSET (r_rdi),
  54   REG_OFFSET (r_rbp),
  55   REG_OFFSET (r_rsp),
  56   REG_OFFSET (r_r8),
  57   REG_OFFSET (r_r9),
  58   REG_OFFSET (r_r10),
  59   REG_OFFSET (r_r11),
  60   REG_OFFSET (r_r12),
  61   REG_OFFSET (r_r13),
  62   REG_OFFSET (r_r14),
  63   REG_OFFSET (r_r15),
  64   REG_OFFSET (r_rip),
  65   REG_OFFSET (r_rflags),
  66   REG_OFFSET (r_cs),
  67   REG_OFFSET (r_ss),
  68   -1,
  69   -1,
  70   -1,
  71   -1
  72 };
  73 \f
  74
  75 /* Mapping between the general-purpose registers in FreeBSD/amd64
  76    `struct reg' format and GDB's register cache layout for
  77    FreeBSD/i386.
  78
  79    Note that most FreeBSD/amd64 registers are 64-bit, while the
  80    FreeBSD/i386 registers are all 32-bit, but since we're
  81    little-endian we get away with that.  */
  82
  83 /* From <machine/reg.h>.  */
  84 static int amd64fbsd32_r_reg_offset[I386_NUM_GREGS] =
  85 {
  86   14 * 8, 13 * 8,               /* %eax, %ecx */
  87   12 * 8, 11 * 8,               /* %edx, %ebx */
  88   20 * 8, 10 * 8,               /* %esp, %ebp */
  89   9 * 8, 8 * 8,                 /* %esi, %edi */
  90   17 * 8, 19 * 8,               /* %eip, %eflags */
  91   18 * 8, 21 * 8,               /* %cs, %ss */
  92   -1, -1, -1, -1                /* %ds, %es, %fs, %gs */
  93 };
  94 \f
  95
  96 /* Support for debugging kernel virtual memory images.  */
  97
  98 #include <sys/types.h>
  99 #include <machine/pcb.h>
 100
 101 #include "bsd-kvm.h"
 102
 103 static int
 104 amd64fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 105 {
 106   /* The following is true for FreeBSD 5.2:
 107
 108      The pcb contains %rip, %rbx, %rsp, %rbp, %r12, %r13, %r14, %r15,
 109      %ds, %es, %fs and %gs.  This accounts for all callee-saved
 110      registers specified by the psABI and then some.  Here %esp
 111      contains the stack pointer at the point just after the call to
 112      cpu_switch().  From this information we reconstruct the register
 113      state as it would like when we just returned from cpu_switch().  */
 114
 115   /* The stack pointer shouldn't be zero.  */
 116   if (pcb->pcb_rsp == 0)
 117     return 0;
 118
 119   pcb->pcb_rsp += 8;
 120   regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &pcb->pcb_rip);
 121   regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &pcb->pcb_rbx);
 122   regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp);
 123   regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp);
 124   regcache_raw_supply (regcache, 12, &pcb->pcb_r12);
 125   regcache_raw_supply (regcache, 13, &pcb->pcb_r13);
 126   regcache_raw_supply (regcache, 14, &pcb->pcb_r14);
 127   regcache_raw_supply (regcache, 15, &pcb->pcb_r15);
 128   regcache_raw_supply (regcache, AMD64_DS_REGNUM, &pcb->pcb_ds);
 129   regcache_raw_supply (regcache, AMD64_ES_REGNUM, &pcb->pcb_es);
 130   regcache_raw_supply (regcache, AMD64_FS_REGNUM, &pcb->pcb_fs);
 131   regcache_raw_supply (regcache, AMD64_GS_REGNUM, &pcb->pcb_gs);
 132
 133   return 1;
 134 }
 135 \f
 136
 137 /* Provide a prototype to silence -Wmissing-prototypes.  */
 138 void _initialize_amd64fbsd_nat (void);
 139
 140 void
 141 _initialize_amd64fbsd_nat (void)
 142 {
 143   struct target_ops *t;
 144   int offset;
 145
 146   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 147   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 148
 149   /* Add some extra features to the common *BSD/i386 target.  */
 150   t = amd64bsd_target ();
 151   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
 152   t->to_find_memory_regions = fbsd_find_memory_regions;
 153   t->to_make_corefile_notes = fbsd_make_corefile_notes;
 154   add_target (t);
 155
 156   /* Support debugging kernel virtual memory images.  */
 157   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 158
 159   /* To support the recognition of signal handlers, i386bsd-tdep.c
 160      hardcodes some constants.  Inclusion of this file means that we
 161      are compiling a native debugger, which means that we can use the
 162      system header files and sysctl(3) to get at the relevant
 163      information.  */
 164
 165 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 166
 167   /* We only check the program counter, stack pointer and frame
 168      pointer since these members of `struct sigcontext' are essential
 169      for providing backtraces.  */
 170
 171 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 172 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 173 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 174
 175   /* Override the default value for the offset of the program counter
 176      in the sigcontext structure.  */
 177   offset = offsetof (struct sigcontext, sc_rip);
 178
 179   if (SC_RIP_OFFSET != offset)
 180     {
 181       warning (_("\
 182 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 183 Please report this to <bug-gdb@gnu.org>."),
 184                offset, SC_RIP_OFFSET);
 185     }
 186
 187   SC_RIP_OFFSET = offset;
 188
 189   /* Likewise for the stack pointer.  */
 190   offset = offsetof (struct sigcontext, sc_rsp);
 191
 192   if (SC_RSP_OFFSET != offset)
 193     {
 194       warning (_("\
 195 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 196 Please report this to <bug-gdb@gnu.org>."),
 197                offset, SC_RSP_OFFSET);
 198     }
 199
 200   SC_RSP_OFFSET = offset;
 201
 202   /* And the frame pointer.  */
 203   offset = offsetof (struct sigcontext, sc_rbp);
 204
 205   if (SC_RBP_OFFSET != offset)
 206     {
 207       warning (_("\
 208 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 209 Please report this to <bug-gdb@gnu.org>."),
 210                offset, SC_RBP_OFFSET);
 211     }
 212
 213   SC_RBP_OFFSET = offset;
 214
 215   /* FreeBSD provides a kern.ps_strings sysctl that we can use to
 216      locate the sigtramp.  That way we can still recognize a sigtramp
 217      if its location is changed in a new kernel.  Of course this is
 218      still based on the assumption that the sigtramp is placed
 219      directly under the location where the program arguments and
 220      environment can be found.  */
 221   {
 222     int mib[2];
 223     long ps_strings;
 224     size_t len;
 225
 226     mib[0] = CTL_KERN;
 227     mib[1] = KERN_PS_STRINGS;
 228     len = sizeof (ps_strings);
 229     if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
 230       {
 231         amd64fbsd_sigtramp_start_addr = ps_strings - 32;
 232         amd64fbsd_sigtramp_end_addr = ps_strings;
 233       }
 234   }
 235 }