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 <sys/user.h>
  30 #include <machine/reg.h>
  31
  32 #include "fbsd-nat.h"
  33 #include "amd64-tdep.h"
  34 #include "amd64-nat.h"
  35 #include "amd64bsd-nat.h"
  36 #include "x86-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 <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 static void (*super_mourn_inferior) (struct target_ops *ops);
 144
 145 static void
 146 amd64fbsd_mourn_inferior (struct target_ops *ops)
 147 {
 148 #ifdef HAVE_PT_GETDBREGS
 149   x86_cleanup_dregs ();
 150 #endif
 151   super_mourn_inferior (ops);
 152 }
 153
 154 /* Implement the to_read_description method.  */
 155
 156 static const struct target_desc *
 157 amd64fbsd_read_description (struct target_ops *ops)
 158 {
 159 #ifdef PT_GETXSTATE_INFO
 160   static int xsave_probed;
 161   static uint64_t xcr0;
 162 #endif
 163   struct reg regs;
 164   int is64;
 165
 166   if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
 167               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 168     perror_with_name (_("Couldn't get registers"));
 169   is64 = (regs.r_cs == GSEL (GUCODE_SEL, SEL_UPL));
 170 #ifdef PT_GETXSTATE_INFO
 171   if (!xsave_probed)
 172     {
 173       struct ptrace_xstate_info info;
 174
 175       if (ptrace (PT_GETXSTATE_INFO, ptid_get_pid (inferior_ptid),
 176                   (PTRACE_TYPE_ARG3) &info, sizeof (info)) == 0)
 177         {
 178           amd64bsd_xsave_len = info.xsave_len;
 179           xcr0 = info.xsave_mask;
 180         }
 181       xsave_probed = 1;
 182     }
 183
 184   if (amd64bsd_xsave_len != 0)
 185     {
 186       if (is64)
 187         return amd64_target_description (xcr0);
 188       else
 189         return i386_target_description (xcr0);
 190     }
 191 #endif
 192   if (is64)
 193     return tdesc_amd64;
 194   else
 195     return tdesc_i386;
 196 }
 197
 198 /* Provide a prototype to silence -Wmissing-prototypes.  */
 199 void _initialize_amd64fbsd_nat (void);
 200
 201 void
 202 _initialize_amd64fbsd_nat (void)
 203 {
 204   struct target_ops *t;
 205   int offset;
 206
 207   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 208   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 209
 210   /* Add some extra features to the common *BSD/i386 target.  */
 211   t = amd64bsd_target ();
 212
 213 #ifdef HAVE_PT_GETDBREGS
 214
 215   x86_use_watchpoints (t);
 216
 217   x86_dr_low.set_control = amd64bsd_dr_set_control;
 218   x86_dr_low.set_addr = amd64bsd_dr_set_addr;
 219   x86_dr_low.get_addr = amd64bsd_dr_get_addr;
 220   x86_dr_low.get_status = amd64bsd_dr_get_status;
 221   x86_dr_low.get_control = amd64bsd_dr_get_control;
 222   x86_set_debug_register_length (8);
 223
 224 #endif /* HAVE_PT_GETDBREGS */
 225
 226   super_mourn_inferior = t->to_mourn_inferior;
 227   t->to_mourn_inferior = amd64fbsd_mourn_inferior;
 228   t->to_read_description = amd64fbsd_read_description;
 229
 230   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
 231   t->to_find_memory_regions = fbsd_find_memory_regions;
 232   add_target (t);
 233
 234   /* Support debugging kernel virtual memory images.  */
 235   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 236
 237   /* To support the recognition of signal handlers, i386bsd-tdep.c
 238      hardcodes some constants.  Inclusion of this file means that we
 239      are compiling a native debugger, which means that we can use the
 240      system header files and sysctl(3) to get at the relevant
 241      information.  */
 242
 243 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 244
 245   /* We only check the program counter, stack pointer and frame
 246      pointer since these members of `struct sigcontext' are essential
 247      for providing backtraces.  */
 248
 249 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 250 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 251 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 252
 253   /* Override the default value for the offset of the program counter
 254      in the sigcontext structure.  */
 255   offset = offsetof (struct sigcontext, sc_rip);
 256
 257   if (SC_RIP_OFFSET != offset)
 258     {
 259       warning (_("\
 260 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 261 Please report this to <bug-gdb@gnu.org>."),
 262                offset, SC_RIP_OFFSET);
 263     }
 264
 265   SC_RIP_OFFSET = offset;
 266
 267   /* Likewise for the stack pointer.  */
 268   offset = offsetof (struct sigcontext, sc_rsp);
 269
 270   if (SC_RSP_OFFSET != offset)
 271     {
 272       warning (_("\
 273 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 274 Please report this to <bug-gdb@gnu.org>."),
 275                offset, SC_RSP_OFFSET);
 276     }
 277
 278   SC_RSP_OFFSET = offset;
 279
 280   /* And the frame pointer.  */
 281   offset = offsetof (struct sigcontext, sc_rbp);
 282
 283   if (SC_RBP_OFFSET != offset)
 284     {
 285       warning (_("\
 286 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 287 Please report this to <bug-gdb@gnu.org>."),
 288                offset, SC_RBP_OFFSET);
 289     }
 290
 291   SC_RBP_OFFSET = offset;
 292
 293 #ifdef KERN_PROC_SIGTRAMP
 294   /* Normally signal frames are detected via amd64fbsd_sigtramp_p.
 295      However, FreeBSD 9.2 through 10.1 do not include the page holding
 296      the signal code in core dumps.  These releases do provide a
 297      kern.proc.sigtramp.<pid> sysctl that returns the location of the
 298      signal trampoline for a running process.  We fetch the location
 299      of the current (gdb) process and use this to identify signal
 300      frames in core dumps from these releases.  Note that this only
 301      works for core dumps of 64-bit (FreeBSD/amd64) processes and does
 302      not handle core dumps of 32-bit (FreeBSD/i386) processes.  */
 303   {
 304     int mib[4];
 305     struct kinfo_sigtramp kst;
 306     size_t len;
 307
 308     mib[0] = CTL_KERN;
 309     mib[1] = KERN_PROC;
 310     mib[2] = KERN_PROC_SIGTRAMP;
 311     mib[3] = getpid ();
 312     len = sizeof (kst);
 313     if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
 314       {
 315         amd64fbsd_sigtramp_start_addr = (uintptr_t) kst.ksigtramp_start;
 316         amd64fbsd_sigtramp_end_addr = (uintptr_t) kst.ksigtramp_end;
 317       }
 318   }
 319 #endif
 320 }