gdb/amd64fbsd-nat.c

   1 /* Native-dependent code for FreeBSD/amd64.
   2
   3    Copyright (C) 2003-2014 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 <signal.h>
  26 #include <sys/types.h>
  27 #include <sys/ptrace.h>
  28 #include <sys/sysctl.h>
  29 #include <machine/reg.h>
  30
  31 #include "fbsd-nat.h"
  32 #include "amd64-tdep.h"
  33 #include "amd64-nat.h"
  34 #include "amd64bsd-nat.h"
  35 #include "i386-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 <machine/pcb.h>
  97 #include <osreldate.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 #if (__FreeBSD_version < 800075) && (__FreeBSD_kernel_version < 800075)
 127   /* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only
 128      up until __FreeBSD_version 800074: The removal of these fields
 129      occurred on 2009-04-01 while the __FreeBSD_version number was
 130      bumped to 800075 on 2009-04-06.  So 800075 is the closest version
 131      number where we should not try to access these fields.  */
 132   regcache_raw_supply (regcache, AMD64_DS_REGNUM, &pcb->pcb_ds);
 133   regcache_raw_supply (regcache, AMD64_ES_REGNUM, &pcb->pcb_es);
 134   regcache_raw_supply (regcache, AMD64_FS_REGNUM, &pcb->pcb_fs);
 135   regcache_raw_supply (regcache, AMD64_GS_REGNUM, &pcb->pcb_gs);
 136 #endif
 137
 138   return 1;
 139 }
 140 \f
 141
 142 static void (*super_mourn_inferior) (struct target_ops *ops);
 143
 144 static void
 145 amd64fbsd_mourn_inferior (struct target_ops *ops)
 146 {
 147 #ifdef HAVE_PT_GETDBREGS
 148   i386_cleanup_dregs ();
 149 #endif
 150   super_mourn_inferior (ops);
 151 }
 152
 153 /* Provide a prototype to silence -Wmissing-prototypes.  */
 154 void _initialize_amd64fbsd_nat (void);
 155
 156 void
 157 _initialize_amd64fbsd_nat (void)
 158 {
 159   struct target_ops *t;
 160   int offset;
 161
 162   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 163   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 164
 165   /* Add some extra features to the common *BSD/i386 target.  */
 166   t = amd64bsd_target ();
 167
 168 #ifdef HAVE_PT_GETDBREGS
 169
 170   i386_use_watchpoints (t);
 171
 172   i386_dr_low.set_control = amd64bsd_dr_set_control;
 173   i386_dr_low.set_addr = amd64bsd_dr_set_addr;
 174   i386_dr_low.get_addr = amd64bsd_dr_get_addr;
 175   i386_dr_low.get_status = amd64bsd_dr_get_status;
 176   i386_dr_low.get_control = amd64bsd_dr_get_control;
 177   i386_set_debug_register_length (8);
 178
 179 #endif /* HAVE_PT_GETDBREGS */
 180
 181   super_mourn_inferior = t->to_mourn_inferior;
 182   t->to_mourn_inferior = amd64fbsd_mourn_inferior;
 183
 184   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
 185   t->to_find_memory_regions = fbsd_find_memory_regions;
 186   t->to_make_corefile_notes = fbsd_make_corefile_notes;
 187   add_target (t);
 188
 189   /* Support debugging kernel virtual memory images.  */
 190   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 191
 192   /* To support the recognition of signal handlers, i386bsd-tdep.c
 193      hardcodes some constants.  Inclusion of this file means that we
 194      are compiling a native debugger, which means that we can use the
 195      system header files and sysctl(3) to get at the relevant
 196      information.  */
 197
 198 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 199
 200   /* We only check the program counter, stack pointer and frame
 201      pointer since these members of `struct sigcontext' are essential
 202      for providing backtraces.  */
 203
 204 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 205 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 206 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 207
 208   /* Override the default value for the offset of the program counter
 209      in the sigcontext structure.  */
 210   offset = offsetof (struct sigcontext, sc_rip);
 211
 212   if (SC_RIP_OFFSET != offset)
 213     {
 214       warning (_("\
 215 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 216 Please report this to <bug-gdb@gnu.org>."),
 217                offset, SC_RIP_OFFSET);
 218     }
 219
 220   SC_RIP_OFFSET = offset;
 221
 222   /* Likewise for the stack pointer.  */
 223   offset = offsetof (struct sigcontext, sc_rsp);
 224
 225   if (SC_RSP_OFFSET != offset)
 226     {
 227       warning (_("\
 228 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 229 Please report this to <bug-gdb@gnu.org>."),
 230                offset, SC_RSP_OFFSET);
 231     }
 232
 233   SC_RSP_OFFSET = offset;
 234
 235   /* And the frame pointer.  */
 236   offset = offsetof (struct sigcontext, sc_rbp);
 237
 238   if (SC_RBP_OFFSET != offset)
 239     {
 240       warning (_("\
 241 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 242 Please report this to <bug-gdb@gnu.org>."),
 243                offset, SC_RBP_OFFSET);
 244     }
 245
 246   SC_RBP_OFFSET = offset;
 247
 248   /* FreeBSD provides a kern.ps_strings sysctl that we can use to
 249      locate the sigtramp.  That way we can still recognize a sigtramp
 250      if its location is changed in a new kernel.  Of course this is
 251      still based on the assumption that the sigtramp is placed
 252      directly under the location where the program arguments and
 253      environment can be found.  */
 254   {
 255     int mib[2];
 256     long ps_strings;
 257     size_t len;
 258
 259     mib[0] = CTL_KERN;
 260     mib[1] = KERN_PS_STRINGS;
 261     len = sizeof (ps_strings);
 262     if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
 263       {
 264         amd64fbsd_sigtramp_start_addr = ps_strings - 32;
 265         amd64fbsd_sigtramp_end_addr = ps_strings;
 266       }
 267   }
 268 }