gdb/amd64-fbsd-nat.c

   1 /* Native-dependent code for FreeBSD/amd64.
   2
   3    Copyright (C) 2003-2022 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 "amd64-bsd-nat.h"
  36 #include "x86-nat.h"
  37 #include "gdbsupport/x86-xstate.h"
  38 \f
  39
  40 class amd64_fbsd_nat_target final
  41   : public amd64_bsd_nat_target<fbsd_nat_target>
  42 {
  43 public:
  44   /* Add some extra features to the common *BSD/amd64 target.  */
  45   const struct target_desc *read_description () override;
  46
  47 #if defined(HAVE_PT_GETDBREGS) && defined(USE_SIGTRAP_SIGINFO)
  48   bool supports_stopped_by_hw_breakpoint () override;
  49 #endif
  50 };
  51
  52 static amd64_fbsd_nat_target the_amd64_fbsd_nat_target;
  53
  54 /* Offset in `struct reg' where MEMBER is stored.  */
  55 #define REG_OFFSET(member) offsetof (struct reg, member)
  56
  57 /* At amd64fbsd64_r_reg_offset[REGNUM] you'll find the offset in
  58    `struct reg' location where the GDB register REGNUM is stored.
  59    Unsupported registers are marked with `-1'.  */
  60 static int amd64fbsd64_r_reg_offset[] =
  61 {
  62   REG_OFFSET (r_rax),
  63   REG_OFFSET (r_rbx),
  64   REG_OFFSET (r_rcx),
  65   REG_OFFSET (r_rdx),
  66   REG_OFFSET (r_rsi),
  67   REG_OFFSET (r_rdi),
  68   REG_OFFSET (r_rbp),
  69   REG_OFFSET (r_rsp),
  70   REG_OFFSET (r_r8),
  71   REG_OFFSET (r_r9),
  72   REG_OFFSET (r_r10),
  73   REG_OFFSET (r_r11),
  74   REG_OFFSET (r_r12),
  75   REG_OFFSET (r_r13),
  76   REG_OFFSET (r_r14),
  77   REG_OFFSET (r_r15),
  78   REG_OFFSET (r_rip),
  79   REG_OFFSET (r_rflags),
  80   REG_OFFSET (r_cs),
  81   REG_OFFSET (r_ss),
  82   -1,
  83   -1,
  84   -1,
  85   -1
  86 };
  87 \f
  88
  89 /* Mapping between the general-purpose registers in FreeBSD/amd64
  90    `struct reg' format and GDB's register cache layout for
  91    FreeBSD/i386.
  92
  93    Note that most FreeBSD/amd64 registers are 64-bit, while the
  94    FreeBSD/i386 registers are all 32-bit, but since we're
  95    little-endian we get away with that.  */
  96
  97 /* From <machine/reg.h>.  */
  98 static int amd64fbsd32_r_reg_offset[I386_NUM_GREGS] =
  99 {
 100   14 * 8, 13 * 8,               /* %eax, %ecx */
 101   12 * 8, 11 * 8,               /* %edx, %ebx */
 102   20 * 8, 10 * 8,               /* %esp, %ebp */
 103   9 * 8, 8 * 8,                 /* %esi, %edi */
 104   17 * 8, 19 * 8,               /* %eip, %eflags */
 105   18 * 8, 21 * 8,               /* %cs, %ss */
 106   -1, -1, -1, -1                /* %ds, %es, %fs, %gs */
 107 };
 108 \f
 109
 110 /* Support for debugging kernel virtual memory images.  */
 111
 112 #include <machine/pcb.h>
 113 #include <osreldate.h>
 114
 115 #include "bsd-kvm.h"
 116
 117 static int
 118 amd64fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 119 {
 120   /* The following is true for FreeBSD 5.2:
 121
 122      The pcb contains %rip, %rbx, %rsp, %rbp, %r12, %r13, %r14, %r15,
 123      %ds, %es, %fs and %gs.  This accounts for all callee-saved
 124      registers specified by the psABI and then some.  Here %esp
 125      contains the stack pointer at the point just after the call to
 126      cpu_switch().  From this information we reconstruct the register
 127      state as it would like when we just returned from cpu_switch().  */
 128
 129   /* The stack pointer shouldn't be zero.  */
 130   if (pcb->pcb_rsp == 0)
 131     return 0;
 132
 133   pcb->pcb_rsp += 8;
 134   regcache->raw_supply (AMD64_RIP_REGNUM, &pcb->pcb_rip);
 135   regcache->raw_supply (AMD64_RBX_REGNUM, &pcb->pcb_rbx);
 136   regcache->raw_supply (AMD64_RSP_REGNUM, &pcb->pcb_rsp);
 137   regcache->raw_supply (AMD64_RBP_REGNUM, &pcb->pcb_rbp);
 138   regcache->raw_supply (12, &pcb->pcb_r12);
 139   regcache->raw_supply (13, &pcb->pcb_r13);
 140   regcache->raw_supply (14, &pcb->pcb_r14);
 141   regcache->raw_supply (15, &pcb->pcb_r15);
 142 #if (__FreeBSD_version < 800075) && (__FreeBSD_kernel_version < 800075)
 143   /* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only
 144      up until __FreeBSD_version 800074: The removal of these fields
 145      occurred on 2009-04-01 while the __FreeBSD_version number was
 146      bumped to 800075 on 2009-04-06.  So 800075 is the closest version
 147      number where we should not try to access these fields.  */
 148   regcache->raw_supply (AMD64_DS_REGNUM, &pcb->pcb_ds);
 149   regcache->raw_supply (AMD64_ES_REGNUM, &pcb->pcb_es);
 150   regcache->raw_supply (AMD64_FS_REGNUM, &pcb->pcb_fs);
 151   regcache->raw_supply (AMD64_GS_REGNUM, &pcb->pcb_gs);
 152 #endif
 153
 154   return 1;
 155 }
 156 \f
 157
 158 /* Implement the read_description method.  */
 159
 160 const struct target_desc *
 161 amd64_fbsd_nat_target::read_description ()
 162 {
 163 #ifdef PT_GETXSTATE_INFO
 164   static int xsave_probed;
 165   static uint64_t xcr0;
 166 #endif
 167   struct reg regs;
 168   int is64;
 169
 170   if (ptrace (PT_GETREGS, inferior_ptid.pid (),
 171               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 172     perror_with_name (_("Couldn't get registers"));
 173   is64 = (regs.r_cs == GSEL (GUCODE_SEL, SEL_UPL));
 174 #ifdef PT_GETXSTATE_INFO
 175   if (!xsave_probed)
 176     {
 177       struct ptrace_xstate_info info;
 178
 179       if (ptrace (PT_GETXSTATE_INFO, inferior_ptid.pid (),
 180                   (PTRACE_TYPE_ARG3) &info, sizeof (info)) == 0)
 181         {
 182           x86bsd_xsave_len = info.xsave_len;
 183           xcr0 = info.xsave_mask;
 184         }
 185       xsave_probed = 1;
 186     }
 187
 188   if (x86bsd_xsave_len != 0)
 189     {
 190       if (is64)
 191         return amd64_target_description (xcr0, true);
 192       else
 193         return i386_target_description (xcr0, true);
 194     }
 195 #endif
 196   if (is64)
 197     return amd64_target_description (X86_XSTATE_SSE_MASK, true);
 198   else
 199     return i386_target_description (X86_XSTATE_SSE_MASK, true);
 200 }
 201
 202 #if defined(HAVE_PT_GETDBREGS) && defined(USE_SIGTRAP_SIGINFO)
 203 /* Implement the supports_stopped_by_hw_breakpoints method.  */
 204
 205 bool
 206 amd64_fbsd_nat_target::supports_stopped_by_hw_breakpoint ()
 207 {
 208   return true;
 209 }
 210 #endif
 211
 212 void _initialize_amd64fbsd_nat ();
 213 void
 214 _initialize_amd64fbsd_nat ()
 215 {
 216   int offset;
 217
 218   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 219   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 220
 221   add_inf_child_target (&the_amd64_fbsd_nat_target);
 222
 223   /* Support debugging kernel virtual memory images.  */
 224   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 225
 226   /* To support the recognition of signal handlers, i386-bsd-tdep.c
 227      hardcodes some constants.  Inclusion of this file means that we
 228      are compiling a native debugger, which means that we can use the
 229      system header files and sysctl(3) to get at the relevant
 230      information.  */
 231
 232 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 233
 234   /* We only check the program counter, stack pointer and frame
 235      pointer since these members of `struct sigcontext' are essential
 236      for providing backtraces.  */
 237
 238 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 239 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 240 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 241
 242   /* Override the default value for the offset of the program counter
 243      in the sigcontext structure.  */
 244   offset = offsetof (struct sigcontext, sc_rip);
 245
 246   if (SC_RIP_OFFSET != offset)
 247     {
 248       warning (_("\
 249 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 250 Please report this to <bug-gdb@gnu.org>."),
 251                offset, SC_RIP_OFFSET);
 252     }
 253
 254   SC_RIP_OFFSET = offset;
 255
 256   /* Likewise for the stack pointer.  */
 257   offset = offsetof (struct sigcontext, sc_rsp);
 258
 259   if (SC_RSP_OFFSET != offset)
 260     {
 261       warning (_("\
 262 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 263 Please report this to <bug-gdb@gnu.org>."),
 264                offset, SC_RSP_OFFSET);
 265     }
 266
 267   SC_RSP_OFFSET = offset;
 268
 269   /* And the frame pointer.  */
 270   offset = offsetof (struct sigcontext, sc_rbp);
 271
 272   if (SC_RBP_OFFSET != offset)
 273     {
 274       warning (_("\
 275 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 276 Please report this to <bug-gdb@gnu.org>."),
 277                offset, SC_RBP_OFFSET);
 278     }
 279
 280   SC_RBP_OFFSET = offset;
 281 }