gdb/amd64fbsd-nat.c

   1 /* Native-dependent code for FreeBSD/amd64.
   2
   3    Copyright (C) 2003, 2004, 2007, 2008 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 "gdb_assert.h"
  26 #include <signal.h>
  27 #include <stddef.h>
  28 #include <sys/types.h>
  29 #include <sys/ptrace.h>
  30 #include <sys/sysctl.h>
  31 #include <machine/reg.h>
  32
  33 #include "fbsd-nat.h"
  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   struct target_ops *t;
 142   int offset;
 143
 144   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 145   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 146
 147   /* Add some extra features to the common *BSD/i386 target.  */
 148   t = amd64bsd_target ();
 149   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
 150   t->to_find_memory_regions = fbsd_find_memory_regions;
 151   t->to_make_corefile_notes = fbsd_make_corefile_notes;
 152   add_target (t);
 153
 154   /* Support debugging kernel virtual memory images.  */
 155   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 156
 157   /* To support the recognition of signal handlers, i386bsd-tdep.c
 158      hardcodes some constants.  Inclusion of this file means that we
 159      are compiling a native debugger, which means that we can use the
 160      system header files and sysctl(3) to get at the relevant
 161      information.  */
 162
 163 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 164
 165   /* We only check the program counter, stack pointer and frame
 166      pointer since these members of `struct sigcontext' are essential
 167      for providing backtraces.  */
 168
 169 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 170 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 171 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 172
 173   /* Override the default value for the offset of the program counter
 174      in the sigcontext structure.  */
 175   offset = offsetof (struct sigcontext, sc_rip);
 176
 177   if (SC_RIP_OFFSET != offset)
 178     {
 179       warning (_("\
 180 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 181 Please report this to <bug-gdb@gnu.org>."),
 182                offset, SC_RIP_OFFSET);
 183     }
 184
 185   SC_RIP_OFFSET = offset;
 186
 187   /* Likewise for the stack pointer.  */
 188   offset = offsetof (struct sigcontext, sc_rsp);
 189
 190   if (SC_RSP_OFFSET != offset)
 191     {
 192       warning (_("\
 193 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 194 Please report this to <bug-gdb@gnu.org>."),
 195                offset, SC_RSP_OFFSET);
 196     }
 197
 198   SC_RSP_OFFSET = offset;
 199
 200   /* And the frame pointer.  */
 201   offset = offsetof (struct sigcontext, sc_rbp);
 202
 203   if (SC_RBP_OFFSET != offset)
 204     {
 205       warning (_("\
 206 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 207 Please report this to <bug-gdb@gnu.org>."),
 208                offset, SC_RBP_OFFSET);
 209     }
 210
 211   SC_RBP_OFFSET = offset;
 212
 213   /* FreeBSD provides a kern.ps_strings sysctl that we can use to
 214      locate the sigtramp.  That way we can still recognize a sigtramp
 215      if its location is changed in a new kernel.  Of course this is
 216      still based on the assumption that the sigtramp is placed
 217      directly under the location where the program arguments and
 218      environment can be found.  */
 219   {
 220     int mib[2];
 221     long ps_strings;
 222     size_t len;
 223
 224     mib[0] = CTL_KERN;
 225     mib[1] = KERN_PS_STRINGS;
 226     len = sizeof (ps_strings);
 227     if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
 228       {
 229         amd64fbsd_sigtramp_start_addr = ps_strings - 32;
 230         amd64fbsd_sigtramp_end_addr = ps_strings;
 231       }
 232   }
 233 }