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 "amd64-tdep.h"
  33 #include "amd64-fbsd-tdep.h"
  34 #include "amd64-nat.h"
  35 #include "x86-nat.h"
  36 #include "gdbsupport/x86-xstate.h"
  37 #include "x86-fbsd-nat.h"
  38
  39 class amd64_fbsd_nat_target final : public x86_fbsd_nat_target
  40 {
  41 public:
  42   void fetch_registers (struct regcache *, int) override;
  43   void store_registers (struct regcache *, int) override;
  44
  45   const struct target_desc *read_description () override;
  46 };
  47
  48 static amd64_fbsd_nat_target the_amd64_fbsd_nat_target;
  49
  50 #ifdef PT_GETXSTATE_INFO
  51 static size_t xsave_len;
  52 #endif
  53
  54 /* This is a layout of the amd64 'struct reg' but with i386
  55    registers.  */
  56
  57 static const struct regcache_map_entry amd64_fbsd32_gregmap[] =
  58 {
  59   { 8, REGCACHE_MAP_SKIP, 8 },
  60   { 1, I386_EDI_REGNUM, 8 },
  61   { 1, I386_ESI_REGNUM, 8 },
  62   { 1, I386_EBP_REGNUM, 8 },
  63   { 1, I386_EBX_REGNUM, 8 },
  64   { 1, I386_EDX_REGNUM, 8 },
  65   { 1, I386_ECX_REGNUM, 8 },
  66   { 1, I386_EAX_REGNUM, 8 },
  67   { 1, REGCACHE_MAP_SKIP, 4 },  /* trapno */
  68   { 1, I386_FS_REGNUM, 2 },
  69   { 1, I386_GS_REGNUM, 2 },
  70   { 1, REGCACHE_MAP_SKIP, 4 },  /* err */
  71   { 1, I386_ES_REGNUM, 2 },
  72   { 1, I386_DS_REGNUM, 2 },
  73   { 1, I386_EIP_REGNUM, 8 },
  74   { 1, I386_CS_REGNUM, 8 },
  75   { 1, I386_EFLAGS_REGNUM, 8 },
  76   { 1, I386_ESP_REGNUM, 0 },
  77   { 1, I386_SS_REGNUM, 8 },
  78   { 0 }
  79 };
  80
  81 static const struct regset amd64_fbsd32_gregset =
  82 {
  83   amd64_fbsd32_gregmap, regcache_supply_regset, regcache_collect_regset
  84 };
  85
  86 /* Return the regset to use for 'struct reg' for the GDBARCH.  */
  87
  88 static const struct regset *
  89 find_gregset (struct gdbarch *gdbarch)
  90 {
  91   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
  92     return &amd64_fbsd32_gregset;
  93   else
  94     return &amd64_fbsd_gregset;
  95 }
  96
  97 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  98    for all registers.  */
  99
 100 void
 101 amd64_fbsd_nat_target::fetch_registers (struct regcache *regcache, int regnum)
 102 {
 103   struct gdbarch *gdbarch = regcache->arch ();
 104 #if defined(PT_GETFSBASE) || defined(PT_GETGSBASE)
 105   const i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
 106 #endif
 107   pid_t pid = get_ptrace_pid (regcache->ptid ());
 108   const struct regset *gregset = find_gregset (gdbarch);
 109
 110   if (fetch_register_set<struct reg> (regcache, regnum, PT_GETREGS, gregset))
 111     {
 112       if (regnum != -1)
 113         return;
 114     }
 115
 116 #ifdef PT_GETFSBASE
 117   if (regnum == -1 || regnum == tdep->fsbase_regnum)
 118     {
 119       register_t base;
 120
 121       if (ptrace (PT_GETFSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
 122         perror_with_name (_("Couldn't get segment register fs_base"));
 123
 124       regcache->raw_supply (tdep->fsbase_regnum, &base);
 125       if (regnum != -1)
 126         return;
 127     }
 128 #endif
 129 #ifdef PT_GETGSBASE
 130   if (regnum == -1 || regnum == tdep->fsbase_regnum + 1)
 131     {
 132       register_t base;
 133
 134       if (ptrace (PT_GETGSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
 135         perror_with_name (_("Couldn't get segment register gs_base"));
 136
 137       regcache->raw_supply (tdep->fsbase_regnum + 1, &base);
 138       if (regnum != -1)
 139         return;
 140     }
 141 #endif
 142
 143   /* There is no amd64_fxsave_supplies or amd64_xsave_supplies.
 144      Instead, the earlier register sets return early if the request
 145      was for a specific register that was already satisified to avoid
 146      fetching the FPU/XSAVE state unnecessarily.  */
 147
 148 #ifdef PT_GETXSTATE_INFO
 149   if (xsave_len != 0)
 150     {
 151       void *xstateregs = alloca (xsave_len);
 152
 153       if (ptrace (PT_GETXSTATE, pid, (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 154         perror_with_name (_("Couldn't get extended state status"));
 155
 156       amd64_supply_xsave (regcache, regnum, xstateregs);
 157       return;
 158     }
 159 #endif
 160
 161   struct fpreg fpregs;
 162
 163   if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 164     perror_with_name (_("Couldn't get floating point status"));
 165
 166   amd64_supply_fxsave (regcache, regnum, &fpregs);
 167 }
 168
 169 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 170    this for all registers.  */
 171
 172 void
 173 amd64_fbsd_nat_target::store_registers (struct regcache *regcache, int regnum)
 174 {
 175   struct gdbarch *gdbarch = regcache->arch ();
 176 #if defined(PT_GETFSBASE) || defined(PT_GETGSBASE)
 177   const i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
 178 #endif
 179   pid_t pid = get_ptrace_pid (regcache->ptid ());
 180   const struct regset *gregset = find_gregset (gdbarch);
 181
 182   if (store_register_set<struct reg> (regcache, regnum, PT_GETREGS, PT_SETREGS,
 183                                       gregset))
 184     {
 185       if (regnum != -1)
 186         return;
 187     }
 188
 189 #ifdef PT_SETFSBASE
 190   if (regnum == -1 || regnum == tdep->fsbase_regnum)
 191     {
 192       register_t base;
 193
 194       /* Clear the full base value to support 32-bit targets.  */
 195       base = 0;
 196       regcache->raw_collect (tdep->fsbase_regnum, &base);
 197
 198       if (ptrace (PT_SETFSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
 199         perror_with_name (_("Couldn't write segment register fs_base"));
 200       if (regnum != -1)
 201         return;
 202     }
 203 #endif
 204 #ifdef PT_SETGSBASE
 205   if (regnum == -1 || regnum == tdep->fsbase_regnum + 1)
 206     {
 207       register_t base;
 208
 209       /* Clear the full base value to support 32-bit targets.  */
 210       base = 0;
 211       regcache->raw_collect (tdep->fsbase_regnum + 1, &base);
 212
 213       if (ptrace (PT_SETGSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
 214         perror_with_name (_("Couldn't write segment register gs_base"));
 215       if (regnum != -1)
 216         return;
 217     }
 218 #endif
 219
 220   /* There is no amd64_fxsave_supplies or amd64_xsave_supplies.
 221      Instead, the earlier register sets return early if the request
 222      was for a specific register that was already satisified to avoid
 223      fetching the FPU/XSAVE state unnecessarily.  */
 224
 225 #ifdef PT_GETXSTATE_INFO
 226   if (xsave_len != 0)
 227     {
 228       void *xstateregs = alloca (xsave_len);
 229
 230       if (ptrace (PT_GETXSTATE, pid, (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 231         perror_with_name (_("Couldn't get extended state status"));
 232
 233       amd64_collect_xsave (regcache, regnum, xstateregs, 0);
 234
 235       if (ptrace (PT_SETXSTATE, pid, (PTRACE_TYPE_ARG3) xstateregs,
 236                   xsave_len) == -1)
 237         perror_with_name (_("Couldn't write extended state status"));
 238       return;
 239     }
 240 #endif
 241
 242   struct fpreg fpregs;
 243
 244   if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 245     perror_with_name (_("Couldn't get floating point status"));
 246
 247   amd64_collect_fxsave (regcache, regnum, &fpregs);
 248
 249   if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 250     perror_with_name (_("Couldn't write floating point status"));
 251 }
 252
 253 /* Support for debugging kernel virtual memory images.  */
 254
 255 #include <machine/pcb.h>
 256 #include <osreldate.h>
 257
 258 #include "bsd-kvm.h"
 259
 260 static int
 261 amd64fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 262 {
 263   /* The following is true for FreeBSD 5.2:
 264
 265      The pcb contains %rip, %rbx, %rsp, %rbp, %r12, %r13, %r14, %r15,
 266      %ds, %es, %fs and %gs.  This accounts for all callee-saved
 267      registers specified by the psABI and then some.  Here %esp
 268      contains the stack pointer at the point just after the call to
 269      cpu_switch().  From this information we reconstruct the register
 270      state as it would like when we just returned from cpu_switch().  */
 271
 272   /* The stack pointer shouldn't be zero.  */
 273   if (pcb->pcb_rsp == 0)
 274     return 0;
 275
 276   pcb->pcb_rsp += 8;
 277   regcache->raw_supply (AMD64_RIP_REGNUM, &pcb->pcb_rip);
 278   regcache->raw_supply (AMD64_RBX_REGNUM, &pcb->pcb_rbx);
 279   regcache->raw_supply (AMD64_RSP_REGNUM, &pcb->pcb_rsp);
 280   regcache->raw_supply (AMD64_RBP_REGNUM, &pcb->pcb_rbp);
 281   regcache->raw_supply (12, &pcb->pcb_r12);
 282   regcache->raw_supply (13, &pcb->pcb_r13);
 283   regcache->raw_supply (14, &pcb->pcb_r14);
 284   regcache->raw_supply (15, &pcb->pcb_r15);
 285 #if (__FreeBSD_version < 800075) && (__FreeBSD_kernel_version < 800075)
 286   /* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only
 287      up until __FreeBSD_version 800074: The removal of these fields
 288      occurred on 2009-04-01 while the __FreeBSD_version number was
 289      bumped to 800075 on 2009-04-06.  So 800075 is the closest version
 290      number where we should not try to access these fields.  */
 291   regcache->raw_supply (AMD64_DS_REGNUM, &pcb->pcb_ds);
 292   regcache->raw_supply (AMD64_ES_REGNUM, &pcb->pcb_es);
 293   regcache->raw_supply (AMD64_FS_REGNUM, &pcb->pcb_fs);
 294   regcache->raw_supply (AMD64_GS_REGNUM, &pcb->pcb_gs);
 295 #endif
 296
 297   return 1;
 298 }
 299 \f
 300
 301 /* Implement the read_description method.  */
 302
 303 const struct target_desc *
 304 amd64_fbsd_nat_target::read_description ()
 305 {
 306 #ifdef PT_GETXSTATE_INFO
 307   static int xsave_probed;
 308   static uint64_t xcr0;
 309 #endif
 310   struct reg regs;
 311   int is64;
 312
 313   if (ptrace (PT_GETREGS, inferior_ptid.pid (),
 314               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 315     perror_with_name (_("Couldn't get registers"));
 316   is64 = (regs.r_cs == GSEL (GUCODE_SEL, SEL_UPL));
 317 #ifdef PT_GETXSTATE_INFO
 318   if (!xsave_probed)
 319     {
 320       struct ptrace_xstate_info info;
 321
 322       if (ptrace (PT_GETXSTATE_INFO, inferior_ptid.pid (),
 323                   (PTRACE_TYPE_ARG3) &info, sizeof (info)) == 0)
 324         {
 325           xsave_len = info.xsave_len;
 326           xcr0 = info.xsave_mask;
 327         }
 328       xsave_probed = 1;
 329     }
 330
 331   if (xsave_len != 0)
 332     {
 333       if (is64)
 334         return amd64_target_description (xcr0, true);
 335       else
 336         return i386_target_description (xcr0, true);
 337     }
 338 #endif
 339   if (is64)
 340     return amd64_target_description (X86_XSTATE_SSE_MASK, true);
 341   else
 342     return i386_target_description (X86_XSTATE_SSE_MASK, true);
 343 }
 344
 345 void _initialize_amd64fbsd_nat ();
 346 void
 347 _initialize_amd64fbsd_nat ()
 348 {
 349   add_inf_child_target (&the_amd64_fbsd_nat_target);
 350
 351   /* Support debugging kernel virtual memory images.  */
 352   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 353 }