gdb/amd64fbsd-nat.c

   1 /* Native-dependent code for FreeBSD/amd64.
   2
   3    Copyright (C) 2003-2015 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 "x86-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   x86_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   x86_use_watchpoints (t);
 171
 172   x86_dr_low.set_control = amd64bsd_dr_set_control;
 173   x86_dr_low.set_addr = amd64bsd_dr_set_addr;
 174   x86_dr_low.get_addr = amd64bsd_dr_get_addr;
 175   x86_dr_low.get_status = amd64bsd_dr_get_status;
 176   x86_dr_low.get_control = amd64bsd_dr_get_control;
 177   x86_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   add_target (t);
 187
 188   /* Support debugging kernel virtual memory images.  */
 189   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 190
 191   /* To support the recognition of signal handlers, i386bsd-tdep.c
 192      hardcodes some constants.  Inclusion of this file means that we
 193      are compiling a native debugger, which means that we can use the
 194      system header files and sysctl(3) to get at the relevant
 195      information.  */
 196
 197 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 198
 199   /* We only check the program counter, stack pointer and frame
 200      pointer since these members of `struct sigcontext' are essential
 201      for providing backtraces.  */
 202
 203 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 204 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 205 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 206
 207   /* Override the default value for the offset of the program counter
 208      in the sigcontext structure.  */
 209   offset = offsetof (struct sigcontext, sc_rip);
 210
 211   if (SC_RIP_OFFSET != offset)
 212     {
 213       warning (_("\
 214 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 215 Please report this to <bug-gdb@gnu.org>."),
 216                offset, SC_RIP_OFFSET);
 217     }
 218
 219   SC_RIP_OFFSET = offset;
 220
 221   /* Likewise for the stack pointer.  */
 222   offset = offsetof (struct sigcontext, sc_rsp);
 223
 224   if (SC_RSP_OFFSET != offset)
 225     {
 226       warning (_("\
 227 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 228 Please report this to <bug-gdb@gnu.org>."),
 229                offset, SC_RSP_OFFSET);
 230     }
 231
 232   SC_RSP_OFFSET = offset;
 233
 234   /* And the frame pointer.  */
 235   offset = offsetof (struct sigcontext, sc_rbp);
 236
 237   if (SC_RBP_OFFSET != offset)
 238     {
 239       warning (_("\
 240 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 241 Please report this to <bug-gdb@gnu.org>."),
 242                offset, SC_RBP_OFFSET);
 243     }
 244
 245   SC_RBP_OFFSET = offset;
 246
 247   /* FreeBSD provides a kern.ps_strings sysctl that we can use to
 248      locate the sigtramp.  That way we can still recognize a sigtramp
 249      if its location is changed in a new kernel.  Of course this is
 250      still based on the assumption that the sigtramp is placed
 251      directly under the location where the program arguments and
 252      environment can be found.  */
 253   {
 254     int mib[2];
 255     long ps_strings;
 256     size_t len;
 257
 258     mib[0] = CTL_KERN;
 259     mib[1] = KERN_PS_STRINGS;
 260     len = sizeof (ps_strings);
 261     if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
 262       {
 263         amd64fbsd_sigtramp_start_addr = ps_strings - 32;
 264         amd64fbsd_sigtramp_end_addr = ps_strings;
 265       }
 266   }
 267 }