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 "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 #include "amd64bsd-nat.h"
  37 #include "i386-nat.h"
  38 \f
  39
  40 /* Offset in `struct reg' where MEMBER is stored.  */
  41 #define REG_OFFSET(member) offsetof (struct reg, member)
  42
  43 /* At amd64fbsd64_r_reg_offset[REGNUM] you'll find the offset in
  44    `struct reg' location where the GDB register REGNUM is stored.
  45    Unsupported registers are marked with `-1'.  */
  46 static int amd64fbsd64_r_reg_offset[] =
  47 {
  48   REG_OFFSET (r_rax),
  49   REG_OFFSET (r_rbx),
  50   REG_OFFSET (r_rcx),
  51   REG_OFFSET (r_rdx),
  52   REG_OFFSET (r_rsi),
  53   REG_OFFSET (r_rdi),
  54   REG_OFFSET (r_rbp),
  55   REG_OFFSET (r_rsp),
  56   REG_OFFSET (r_r8),
  57   REG_OFFSET (r_r9),
  58   REG_OFFSET (r_r10),
  59   REG_OFFSET (r_r11),
  60   REG_OFFSET (r_r12),
  61   REG_OFFSET (r_r13),
  62   REG_OFFSET (r_r14),
  63   REG_OFFSET (r_r15),
  64   REG_OFFSET (r_rip),
  65   REG_OFFSET (r_rflags),
  66   REG_OFFSET (r_cs),
  67   REG_OFFSET (r_ss),
  68   -1,
  69   -1,
  70   -1,
  71   -1
  72 };
  73 \f
  74
  75 /* Mapping between the general-purpose registers in FreeBSD/amd64
  76    `struct reg' format and GDB's register cache layout for
  77    FreeBSD/i386.
  78
  79    Note that most FreeBSD/amd64 registers are 64-bit, while the
  80    FreeBSD/i386 registers are all 32-bit, but since we're
  81    little-endian we get away with that.  */
  82
  83 /* From <machine/reg.h>.  */
  84 static int amd64fbsd32_r_reg_offset[I386_NUM_GREGS] =
  85 {
  86   14 * 8, 13 * 8,               /* %eax, %ecx */
  87   12 * 8, 11 * 8,               /* %edx, %ebx */
  88   20 * 8, 10 * 8,               /* %esp, %ebp */
  89   9 * 8, 8 * 8,                 /* %esi, %edi */
  90   17 * 8, 19 * 8,               /* %eip, %eflags */
  91   18 * 8, 21 * 8,               /* %cs, %ss */
  92   -1, -1, -1, -1                /* %ds, %es, %fs, %gs */
  93 };
  94 \f
  95
  96 /* Support for debugging kernel virtual memory images.  */
  97
  98 #include <sys/types.h>
  99 #include <machine/pcb.h>
 100 #include <osreldate.h>
 101
 102 #include "bsd-kvm.h"
 103
 104 static int
 105 amd64fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 106 {
 107   /* The following is true for FreeBSD 5.2:
 108
 109      The pcb contains %rip, %rbx, %rsp, %rbp, %r12, %r13, %r14, %r15,
 110      %ds, %es, %fs and %gs.  This accounts for all callee-saved
 111      registers specified by the psABI and then some.  Here %esp
 112      contains the stack pointer at the point just after the call to
 113      cpu_switch().  From this information we reconstruct the register
 114      state as it would like when we just returned from cpu_switch().  */
 115
 116   /* The stack pointer shouldn't be zero.  */
 117   if (pcb->pcb_rsp == 0)
 118     return 0;
 119
 120   pcb->pcb_rsp += 8;
 121   regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &pcb->pcb_rip);
 122   regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &pcb->pcb_rbx);
 123   regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp);
 124   regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp);
 125   regcache_raw_supply (regcache, 12, &pcb->pcb_r12);
 126   regcache_raw_supply (regcache, 13, &pcb->pcb_r13);
 127   regcache_raw_supply (regcache, 14, &pcb->pcb_r14);
 128   regcache_raw_supply (regcache, 15, &pcb->pcb_r15);
 129 #if (__FreeBSD_version < 800075) && (__FreeBSD_kernel_version < 800075)
 130   /* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only
 131      up until __FreeBSD_version 800074: The removal of these fields
 132      occurred on 2009-04-01 while the __FreeBSD_version number was
 133      bumped to 800075 on 2009-04-06.  So 800075 is the closest version
 134      number where we should not try to access these fields.  */
 135   regcache_raw_supply (regcache, AMD64_DS_REGNUM, &pcb->pcb_ds);
 136   regcache_raw_supply (regcache, AMD64_ES_REGNUM, &pcb->pcb_es);
 137   regcache_raw_supply (regcache, AMD64_FS_REGNUM, &pcb->pcb_fs);
 138   regcache_raw_supply (regcache, AMD64_GS_REGNUM, &pcb->pcb_gs);
 139 #endif
 140
 141   return 1;
 142 }
 143 \f
 144
 145 static void (*super_mourn_inferior) (struct target_ops *ops);
 146
 147 static void
 148 amd64fbsd_mourn_inferior (struct target_ops *ops)
 149 {
 150 #ifdef HAVE_PT_GETDBREGS
 151   i386_cleanup_dregs ();
 152 #endif
 153   super_mourn_inferior (ops);
 154 }
 155
 156 /* Provide a prototype to silence -Wmissing-prototypes.  */
 157 void _initialize_amd64fbsd_nat (void);
 158
 159 void
 160 _initialize_amd64fbsd_nat (void)
 161 {
 162   struct target_ops *t;
 163   int offset;
 164
 165   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 166   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 167
 168   /* Add some extra features to the common *BSD/i386 target.  */
 169   t = amd64bsd_target ();
 170
 171 #ifdef HAVE_PT_GETDBREGS
 172
 173   i386_use_watchpoints (t);
 174
 175   i386_dr_low.set_control = amd64bsd_dr_set_control;
 176   i386_dr_low.set_addr = amd64bsd_dr_set_addr;
 177   i386_dr_low.get_addr = amd64bsd_dr_get_addr;
 178   i386_dr_low.get_status = amd64bsd_dr_get_status;
 179   i386_dr_low.get_control = amd64bsd_dr_get_control;
 180   i386_set_debug_register_length (8);
 181
 182 #endif /* HAVE_PT_GETDBREGS */
 183
 184   super_mourn_inferior = t->to_mourn_inferior;
 185   t->to_mourn_inferior = amd64fbsd_mourn_inferior;
 186
 187   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
 188   t->to_find_memory_regions = fbsd_find_memory_regions;
 189   t->to_make_corefile_notes = fbsd_make_corefile_notes;
 190   add_target (t);
 191
 192   /* Support debugging kernel virtual memory images.  */
 193   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 194
 195   /* To support the recognition of signal handlers, i386bsd-tdep.c
 196      hardcodes some constants.  Inclusion of this file means that we
 197      are compiling a native debugger, which means that we can use the
 198      system header files and sysctl(3) to get at the relevant
 199      information.  */
 200
 201 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 202
 203   /* We only check the program counter, stack pointer and frame
 204      pointer since these members of `struct sigcontext' are essential
 205      for providing backtraces.  */
 206
 207 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 208 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 209 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 210
 211   /* Override the default value for the offset of the program counter
 212      in the sigcontext structure.  */
 213   offset = offsetof (struct sigcontext, sc_rip);
 214
 215   if (SC_RIP_OFFSET != offset)
 216     {
 217       warning (_("\
 218 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 219 Please report this to <bug-gdb@gnu.org>."),
 220                offset, SC_RIP_OFFSET);
 221     }
 222
 223   SC_RIP_OFFSET = offset;
 224
 225   /* Likewise for the stack pointer.  */
 226   offset = offsetof (struct sigcontext, sc_rsp);
 227
 228   if (SC_RSP_OFFSET != offset)
 229     {
 230       warning (_("\
 231 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 232 Please report this to <bug-gdb@gnu.org>."),
 233                offset, SC_RSP_OFFSET);
 234     }
 235
 236   SC_RSP_OFFSET = offset;
 237
 238   /* And the frame pointer.  */
 239   offset = offsetof (struct sigcontext, sc_rbp);
 240
 241   if (SC_RBP_OFFSET != offset)
 242     {
 243       warning (_("\
 244 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 245 Please report this to <bug-gdb@gnu.org>."),
 246                offset, SC_RBP_OFFSET);
 247     }
 248
 249   SC_RBP_OFFSET = offset;
 250
 251   /* FreeBSD provides a kern.ps_strings sysctl that we can use to
 252      locate the sigtramp.  That way we can still recognize a sigtramp
 253      if its location is changed in a new kernel.  Of course this is
 254      still based on the assumption that the sigtramp is placed
 255      directly under the location where the program arguments and
 256      environment can be found.  */
 257   {
 258     int mib[2];
 259     long ps_strings;
 260     size_t len;
 261
 262     mib[0] = CTL_KERN;
 263     mib[1] = KERN_PS_STRINGS;
 264     len = sizeof (ps_strings);
 265     if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
 266       {
 267         amd64fbsd_sigtramp_start_addr = ps_strings - 32;
 268         amd64fbsd_sigtramp_end_addr = ps_strings;
 269       }
 270   }
 271 }