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-fbsd-tdep.h"
  35 #include "amd64-nat.h"
  36 #include "x86-nat.h"
  37 #include "gdbsupport/x86-xstate.h"
  38 #include "x86-bsd-nat.h"
  39
  40 class amd64_fbsd_nat_target final
  41   : public x86bsd_nat_target<fbsd_nat_target>
  42 {
  43 public:
  44   void fetch_registers (struct regcache *, int) override;
  45   void store_registers (struct regcache *, int) override;
  46
  47   const struct target_desc *read_description () override;
  48
  49 #if defined(HAVE_PT_GETDBREGS) && defined(USE_SIGTRAP_SIGINFO)
  50   bool supports_stopped_by_hw_breakpoint () override;
  51 #endif
  52 };
  53
  54 static amd64_fbsd_nat_target the_amd64_fbsd_nat_target;
  55
  56 #ifdef PT_GETXSTATE_INFO
  57 static size_t xsave_len;
  58 #endif
  59
  60 /* This is a layout of the amd64 'struct reg' but with i386
  61    registers.  */
  62
  63 static const struct regcache_map_entry amd64_fbsd32_gregmap[] =
  64 {
  65   { 8, REGCACHE_MAP_SKIP, 8 },
  66   { 1, I386_EDI_REGNUM, 8 },
  67   { 1, I386_ESI_REGNUM, 8 },
  68   { 1, I386_EBP_REGNUM, 8 },
  69   { 1, I386_EBX_REGNUM, 8 },
  70   { 1, I386_EDX_REGNUM, 8 },
  71   { 1, I386_ECX_REGNUM, 8 },
  72   { 1, I386_EAX_REGNUM, 8 },
  73   { 1, REGCACHE_MAP_SKIP, 4 },  /* trapno */
  74   { 1, I386_FS_REGNUM, 2 },
  75   { 1, I386_GS_REGNUM, 2 },
  76   { 1, REGCACHE_MAP_SKIP, 4 },  /* err */
  77   { 1, I386_ES_REGNUM, 2 },
  78   { 1, I386_DS_REGNUM, 2 },
  79   { 1, I386_EIP_REGNUM, 8 },
  80   { 1, I386_CS_REGNUM, 8 },
  81   { 1, I386_EFLAGS_REGNUM, 8 },
  82   { 1, I386_ESP_REGNUM, 0 },
  83   { 1, I386_SS_REGNUM, 8 },
  84   { 0 }
  85 };
  86
  87 static const struct regset amd64_fbsd32_gregset =
  88 {
  89   amd64_fbsd32_gregmap, regcache_supply_regset, regcache_collect_regset
  90 };
  91
  92 /* Return the regset to use for 'struct reg' for the GDBARCH.  */
  93
  94 static const struct regset *
  95 find_gregset (struct gdbarch *gdbarch)
  96 {
  97   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
  98     return &amd64_fbsd32_gregset;
  99   else
 100     return &amd64_fbsd_gregset;
 101 }
 102
 103 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
 104    for all registers.  */
 105
 106 void
 107 amd64_fbsd_nat_target::fetch_registers (struct regcache *regcache, int regnum)
 108 {
 109   struct gdbarch *gdbarch = regcache->arch ();
 110 #if defined(PT_GETFSBASE) || defined(PT_GETGSBASE)
 111   const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 112 #endif
 113   pid_t pid = get_ptrace_pid (regcache->ptid ());
 114   const struct regset *gregset = find_gregset (gdbarch);
 115
 116   if (fetch_register_set<struct reg> (regcache, regnum, PT_GETREGS, gregset))
 117     {
 118       if (regnum != -1)
 119         return;
 120     }
 121
 122 #ifdef PT_GETFSBASE
 123   if (regnum == -1 || regnum == tdep->fsbase_regnum)
 124     {
 125       register_t base;
 126
 127       if (ptrace (PT_GETFSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
 128         perror_with_name (_("Couldn't get segment register fs_base"));
 129
 130       regcache->raw_supply (tdep->fsbase_regnum, &base);
 131       if (regnum != -1)
 132         return;
 133     }
 134 #endif
 135 #ifdef PT_GETGSBASE
 136   if (regnum == -1 || regnum == tdep->fsbase_regnum + 1)
 137     {
 138       register_t base;
 139
 140       if (ptrace (PT_GETGSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
 141         perror_with_name (_("Couldn't get segment register gs_base"));
 142
 143       regcache->raw_supply (tdep->fsbase_regnum + 1, &base);
 144       if (regnum != -1)
 145         return;
 146     }
 147 #endif
 148
 149   /* There is no amd64_fxsave_supplies or amd64_xsave_supplies.
 150      Instead, the earlier register sets return early if the request
 151      was for a specific register that was already satisified to avoid
 152      fetching the FPU/XSAVE state unnecessarily.  */
 153
 154 #ifdef PT_GETXSTATE_INFO
 155   if (xsave_len != 0)
 156     {
 157       void *xstateregs = alloca (xsave_len);
 158
 159       if (ptrace (PT_GETXSTATE, pid, (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 160         perror_with_name (_("Couldn't get extended state status"));
 161
 162       amd64_supply_xsave (regcache, regnum, xstateregs);
 163       return;
 164     }
 165 #endif
 166
 167   struct fpreg fpregs;
 168
 169   if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 170     perror_with_name (_("Couldn't get floating point status"));
 171
 172   amd64_supply_fxsave (regcache, regnum, &fpregs);
 173 }
 174
 175 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 176    this for all registers.  */
 177
 178 void
 179 amd64_fbsd_nat_target::store_registers (struct regcache *regcache, int regnum)
 180 {
 181   struct gdbarch *gdbarch = regcache->arch ();
 182 #if defined(PT_GETFSBASE) || defined(PT_GETGSBASE)
 183   const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 184 #endif
 185   pid_t pid = get_ptrace_pid (regcache->ptid ());
 186   const struct regset *gregset = find_gregset (gdbarch);
 187
 188   if (store_register_set<struct reg> (regcache, regnum, PT_GETREGS, PT_SETREGS,
 189                                       gregset))
 190     {
 191       if (regnum != -1)
 192         return;
 193     }
 194
 195 #ifdef PT_SETFSBASE
 196   if (regnum == -1 || regnum == tdep->fsbase_regnum)
 197     {
 198       register_t base;
 199
 200       /* Clear the full base value to support 32-bit targets.  */
 201       base = 0;
 202       regcache->raw_collect (tdep->fsbase_regnum, &base);
 203
 204       if (ptrace (PT_SETFSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
 205         perror_with_name (_("Couldn't write segment register fs_base"));
 206       if (regnum != -1)
 207         return;
 208     }
 209 #endif
 210 #ifdef PT_SETGSBASE
 211   if (regnum == -1 || regnum == tdep->fsbase_regnum + 1)
 212     {
 213       register_t base;
 214
 215       /* Clear the full base value to support 32-bit targets.  */
 216       base = 0;
 217       regcache->raw_collect (tdep->fsbase_regnum + 1, &base);
 218
 219       if (ptrace (PT_SETGSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
 220         perror_with_name (_("Couldn't write segment register gs_base"));
 221       if (regnum != -1)
 222         return;
 223     }
 224 #endif
 225
 226   /* There is no amd64_fxsave_supplies or amd64_xsave_supplies.
 227      Instead, the earlier register sets return early if the request
 228      was for a specific register that was already satisified to avoid
 229      fetching the FPU/XSAVE state unnecessarily.  */
 230
 231 #ifdef PT_GETXSTATE_INFO
 232   if (xsave_len != 0)
 233     {
 234       void *xstateregs = alloca (xsave_len);
 235
 236       if (ptrace (PT_GETXSTATE, pid, (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 237         perror_with_name (_("Couldn't get extended state status"));
 238
 239       amd64_collect_xsave (regcache, regnum, xstateregs, 0);
 240
 241       if (ptrace (PT_SETXSTATE, pid, (PTRACE_TYPE_ARG3) xstateregs,
 242                   xsave_len) == -1)
 243         perror_with_name (_("Couldn't write extended state status"));
 244       return;
 245     }
 246 #endif
 247
 248   struct fpreg fpregs;
 249
 250   if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 251     perror_with_name (_("Couldn't get floating point status"));
 252
 253   amd64_collect_fxsave (regcache, regnum, &fpregs);
 254
 255   if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 256     perror_with_name (_("Couldn't write floating point status"));
 257 }
 258
 259 /* Support for debugging kernel virtual memory images.  */
 260
 261 #include <machine/pcb.h>
 262 #include <osreldate.h>
 263
 264 #include "bsd-kvm.h"
 265
 266 static int
 267 amd64fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 268 {
 269   /* The following is true for FreeBSD 5.2:
 270
 271      The pcb contains %rip, %rbx, %rsp, %rbp, %r12, %r13, %r14, %r15,
 272      %ds, %es, %fs and %gs.  This accounts for all callee-saved
 273      registers specified by the psABI and then some.  Here %esp
 274      contains the stack pointer at the point just after the call to
 275      cpu_switch().  From this information we reconstruct the register
 276      state as it would like when we just returned from cpu_switch().  */
 277
 278   /* The stack pointer shouldn't be zero.  */
 279   if (pcb->pcb_rsp == 0)
 280     return 0;
 281
 282   pcb->pcb_rsp += 8;
 283   regcache->raw_supply (AMD64_RIP_REGNUM, &pcb->pcb_rip);
 284   regcache->raw_supply (AMD64_RBX_REGNUM, &pcb->pcb_rbx);
 285   regcache->raw_supply (AMD64_RSP_REGNUM, &pcb->pcb_rsp);
 286   regcache->raw_supply (AMD64_RBP_REGNUM, &pcb->pcb_rbp);
 287   regcache->raw_supply (12, &pcb->pcb_r12);
 288   regcache->raw_supply (13, &pcb->pcb_r13);
 289   regcache->raw_supply (14, &pcb->pcb_r14);
 290   regcache->raw_supply (15, &pcb->pcb_r15);
 291 #if (__FreeBSD_version < 800075) && (__FreeBSD_kernel_version < 800075)
 292   /* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only
 293      up until __FreeBSD_version 800074: The removal of these fields
 294      occurred on 2009-04-01 while the __FreeBSD_version number was
 295      bumped to 800075 on 2009-04-06.  So 800075 is the closest version
 296      number where we should not try to access these fields.  */
 297   regcache->raw_supply (AMD64_DS_REGNUM, &pcb->pcb_ds);
 298   regcache->raw_supply (AMD64_ES_REGNUM, &pcb->pcb_es);
 299   regcache->raw_supply (AMD64_FS_REGNUM, &pcb->pcb_fs);
 300   regcache->raw_supply (AMD64_GS_REGNUM, &pcb->pcb_gs);
 301 #endif
 302
 303   return 1;
 304 }
 305 \f
 306
 307 /* Implement the read_description method.  */
 308
 309 const struct target_desc *
 310 amd64_fbsd_nat_target::read_description ()
 311 {
 312 #ifdef PT_GETXSTATE_INFO
 313   static int xsave_probed;
 314   static uint64_t xcr0;
 315 #endif
 316   struct reg regs;
 317   int is64;
 318
 319   if (ptrace (PT_GETREGS, inferior_ptid.pid (),
 320               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 321     perror_with_name (_("Couldn't get registers"));
 322   is64 = (regs.r_cs == GSEL (GUCODE_SEL, SEL_UPL));
 323 #ifdef PT_GETXSTATE_INFO
 324   if (!xsave_probed)
 325     {
 326       struct ptrace_xstate_info info;
 327
 328       if (ptrace (PT_GETXSTATE_INFO, inferior_ptid.pid (),
 329                   (PTRACE_TYPE_ARG3) &info, sizeof (info)) == 0)
 330         {
 331           xsave_len = info.xsave_len;
 332           xcr0 = info.xsave_mask;
 333         }
 334       xsave_probed = 1;
 335     }
 336
 337   if (xsave_len != 0)
 338     {
 339       if (is64)
 340         return amd64_target_description (xcr0, true);
 341       else
 342         return i386_target_description (xcr0, true);
 343     }
 344 #endif
 345   if (is64)
 346     return amd64_target_description (X86_XSTATE_SSE_MASK, true);
 347   else
 348     return i386_target_description (X86_XSTATE_SSE_MASK, true);
 349 }
 350
 351 #if defined(HAVE_PT_GETDBREGS) && defined(USE_SIGTRAP_SIGINFO)
 352 /* Implement the supports_stopped_by_hw_breakpoints method.  */
 353
 354 bool
 355 amd64_fbsd_nat_target::supports_stopped_by_hw_breakpoint ()
 356 {
 357   return true;
 358 }
 359 #endif
 360
 361 void _initialize_amd64fbsd_nat ();
 362 void
 363 _initialize_amd64fbsd_nat ()
 364 {
 365   add_inf_child_target (&the_amd64_fbsd_nat_target);
 366
 367   /* Support debugging kernel virtual memory images.  */
 368   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 369 }