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