gdb/amd64fbsd-nat.c

   1 /* Native-dependent code for FreeBSD/amd64.
   2
   3    Copyright (C) 2003-2004, 2007-2012 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 #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 /* Provide a prototype to silence -Wmissing-prototypes.  */
 144 void _initialize_amd64fbsd_nat (void);
 145
 146 void
 147 _initialize_amd64fbsd_nat (void)
 148 {
 149   struct target_ops *t;
 150   int offset;
 151
 152   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 153   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 154
 155   /* Add some extra features to the common *BSD/i386 target.  */
 156   t = amd64bsd_target ();
 157   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
 158   t->to_find_memory_regions = fbsd_find_memory_regions;
 159   t->to_make_corefile_notes = fbsd_make_corefile_notes;
 160   add_target (t);
 161
 162   /* Support debugging kernel virtual memory images.  */
 163   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 164
 165   /* To support the recognition of signal handlers, i386bsd-tdep.c
 166      hardcodes some constants.  Inclusion of this file means that we
 167      are compiling a native debugger, which means that we can use the
 168      system header files and sysctl(3) to get at the relevant
 169      information.  */
 170
 171 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 172
 173   /* We only check the program counter, stack pointer and frame
 174      pointer since these members of `struct sigcontext' are essential
 175      for providing backtraces.  */
 176
 177 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 178 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 179 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 180
 181   /* Override the default value for the offset of the program counter
 182      in the sigcontext structure.  */
 183   offset = offsetof (struct sigcontext, sc_rip);
 184
 185   if (SC_RIP_OFFSET != offset)
 186     {
 187       warning (_("\
 188 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 189 Please report this to <bug-gdb@gnu.org>."),
 190                offset, SC_RIP_OFFSET);
 191     }
 192
 193   SC_RIP_OFFSET = offset;
 194
 195   /* Likewise for the stack pointer.  */
 196   offset = offsetof (struct sigcontext, sc_rsp);
 197
 198   if (SC_RSP_OFFSET != offset)
 199     {
 200       warning (_("\
 201 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 202 Please report this to <bug-gdb@gnu.org>."),
 203                offset, SC_RSP_OFFSET);
 204     }
 205
 206   SC_RSP_OFFSET = offset;
 207
 208   /* And the frame pointer.  */
 209   offset = offsetof (struct sigcontext, sc_rbp);
 210
 211   if (SC_RBP_OFFSET != offset)
 212     {
 213       warning (_("\
 214 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 215 Please report this to <bug-gdb@gnu.org>."),
 216                offset, SC_RBP_OFFSET);
 217     }
 218
 219   SC_RBP_OFFSET = offset;
 220
 221   /* FreeBSD provides a kern.ps_strings sysctl that we can use to
 222      locate the sigtramp.  That way we can still recognize a sigtramp
 223      if its location is changed in a new kernel.  Of course this is
 224      still based on the assumption that the sigtramp is placed
 225      directly under the location where the program arguments and
 226      environment can be found.  */
 227   {
 228     int mib[2];
 229     long ps_strings;
 230     size_t len;
 231
 232     mib[0] = CTL_KERN;
 233     mib[1] = KERN_PS_STRINGS;
 234     len = sizeof (ps_strings);
 235     if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
 236       {
 237         amd64fbsd_sigtramp_start_addr = ps_strings - 32;
 238         amd64fbsd_sigtramp_end_addr = ps_strings;
 239       }
 240   }
 241 }