gdb/amd64fbsd-nat.c

   1 /* Native-dependent code for FreeBSD/amd64.
   2
   3    Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "inferior.h"
  23 #include "regcache.h"
  24 #include "target.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 "fbsd-nat.h"
  35 #include "amd64-tdep.h"
  36 #include "amd64-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 <sys/types.h>
  98 #include <machine/pcb.h>
  99 #include <osreldate.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 #if (__FreeBSD_version <  800075)
 129   /* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only
 130      up until __FreeBSD_version 800074: The removal of these fields
 131      occurred on 2009-04-01 while the __FreeBSD_version number was
 132      bumped to 800075 on 2009-04-06.  So 800075 is the closest version
 133      number where we should not try to access these fields.  */
 134   regcache_raw_supply (regcache, AMD64_DS_REGNUM, &pcb->pcb_ds);
 135   regcache_raw_supply (regcache, AMD64_ES_REGNUM, &pcb->pcb_es);
 136   regcache_raw_supply (regcache, AMD64_FS_REGNUM, &pcb->pcb_fs);
 137   regcache_raw_supply (regcache, AMD64_GS_REGNUM, &pcb->pcb_gs);
 138 #endif
 139
 140   return 1;
 141 }
 142 \f
 143
 144 /* Provide a prototype to silence -Wmissing-prototypes.  */
 145 void _initialize_amd64fbsd_nat (void);
 146
 147 void
 148 _initialize_amd64fbsd_nat (void)
 149 {
 150   struct target_ops *t;
 151   int offset;
 152
 153   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 154   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 155
 156   /* Add some extra features to the common *BSD/i386 target.  */
 157   t = amd64bsd_target ();
 158   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
 159   t->to_find_memory_regions = fbsd_find_memory_regions;
 160   t->to_make_corefile_notes = fbsd_make_corefile_notes;
 161   add_target (t);
 162
 163   /* Support debugging kernel virtual memory images.  */
 164   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 165
 166   /* To support the recognition of signal handlers, i386bsd-tdep.c
 167      hardcodes some constants.  Inclusion of this file means that we
 168      are compiling a native debugger, which means that we can use the
 169      system header files and sysctl(3) to get at the relevant
 170      information.  */
 171
 172 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 173
 174   /* We only check the program counter, stack pointer and frame
 175      pointer since these members of `struct sigcontext' are essential
 176      for providing backtraces.  */
 177
 178 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 179 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 180 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 181
 182   /* Override the default value for the offset of the program counter
 183      in the sigcontext structure.  */
 184   offset = offsetof (struct sigcontext, sc_rip);
 185
 186   if (SC_RIP_OFFSET != offset)
 187     {
 188       warning (_("\
 189 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 190 Please report this to <bug-gdb@gnu.org>."),
 191                offset, SC_RIP_OFFSET);
 192     }
 193
 194   SC_RIP_OFFSET = offset;
 195
 196   /* Likewise for the stack pointer.  */
 197   offset = offsetof (struct sigcontext, sc_rsp);
 198
 199   if (SC_RSP_OFFSET != offset)
 200     {
 201       warning (_("\
 202 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 203 Please report this to <bug-gdb@gnu.org>."),
 204                offset, SC_RSP_OFFSET);
 205     }
 206
 207   SC_RSP_OFFSET = offset;
 208
 209   /* And the frame pointer.  */
 210   offset = offsetof (struct sigcontext, sc_rbp);
 211
 212   if (SC_RBP_OFFSET != offset)
 213     {
 214       warning (_("\
 215 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 216 Please report this to <bug-gdb@gnu.org>."),
 217                offset, SC_RBP_OFFSET);
 218     }
 219
 220   SC_RBP_OFFSET = offset;
 221
 222   /* FreeBSD provides a kern.ps_strings sysctl that we can use to
 223      locate the sigtramp.  That way we can still recognize a sigtramp
 224      if its location is changed in a new kernel.  Of course this is
 225      still based on the assumption that the sigtramp is placed
 226      directly under the location where the program arguments and
 227      environment can be found.  */
 228   {
 229     int mib[2];
 230     long ps_strings;
 231     size_t len;
 232
 233     mib[0] = CTL_KERN;
 234     mib[1] = KERN_PS_STRINGS;
 235     len = sizeof (ps_strings);
 236     if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
 237       {
 238         amd64fbsd_sigtramp_start_addr = ps_strings - 32;
 239         amd64fbsd_sigtramp_end_addr = ps_strings;
 240       }
 241   }
 242 }