gdb/arm-fbsd-tdep.c

   1 /* Target-dependent code for FreeBSD/arm.
   2
   3    Copyright (C) 2017-2024 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
  21 #include "elf/common.h"
  22 #include "target-descriptions.h"
  23 #include "aarch32-tdep.h"
  24 #include "arm-tdep.h"
  25 #include "arm-fbsd-tdep.h"
  26 #include "auxv.h"
  27 #include "fbsd-tdep.h"
  28 #include "gdbcore.h"
  29 #include "inferior.h"
  30 #include "osabi.h"
  31 #include "solib-svr4.h"
  32 #include "trad-frame.h"
  33 #include "tramp-frame.h"
  34
  35 /* Register maps.  */
  36
  37 static const struct regcache_map_entry arm_fbsd_gregmap[] =
  38   {
  39     { 13, ARM_A1_REGNUM, 4 }, /* r0 ... r12 */
  40     { 1, ARM_SP_REGNUM, 4 },
  41     { 1, ARM_LR_REGNUM, 4 },
  42     { 1, ARM_PC_REGNUM, 4 },
  43     { 1, ARM_PS_REGNUM, 4 },
  44     { 0 }
  45   };
  46
  47 static const struct regcache_map_entry arm_fbsd_vfpregmap[] =
  48   {
  49     { 32, ARM_D0_REGNUM, 8 }, /* d0 ... d31 */
  50     { 1, ARM_FPSCR_REGNUM, 4 },
  51     { 0 }
  52   };
  53
  54 /* Register numbers are relative to tdep->tls_regnum.  */
  55
  56 static const struct regcache_map_entry arm_fbsd_tls_regmap[] =
  57   {
  58     { 1, 0, 4 },        /* tpidruro  */
  59     { 0 }
  60   };
  61
  62 /* In a signal frame, sp points to a 'struct sigframe' which is
  63    defined as:
  64
  65    struct sigframe {
  66            siginfo_t    sf_si;
  67            ucontext_t   sf_uc;
  68            mcontext_vfp_t sf_vfp;
  69    };
  70
  71    ucontext_t is defined as:
  72
  73    struct __ucontext {
  74            sigset_t     uc_sigmask;
  75            mcontext_t   uc_mcontext;
  76            ...
  77    };
  78
  79    mcontext_t is defined as:
  80
  81    struct {
  82            unsigned int __gregs[17];
  83            size_t       mc_vfp_size;
  84            void         *mc_vfp_ptr;
  85            ...
  86    };
  87
  88    mcontext_vfp_t is defined as:
  89
  90    struct {
  91           uint64_t      mcv_reg[32];
  92           uint32_t      mcv_fpscr;
  93    };
  94
  95    If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
  96    the sigframe, otherwise it is NULL.  There is no non-VFP floating
  97    point register state saved in the signal frame.  */
  98
  99 #define ARM_SIGFRAME_UCONTEXT_OFFSET    64
 100 #define ARM_UCONTEXT_MCONTEXT_OFFSET    16
 101 #define ARM_MCONTEXT_VFP_PTR_OFFSET     72
 102
 103 /* Implement the "init" method of struct tramp_frame.  */
 104
 105 static void
 106 arm_fbsd_sigframe_init (const struct tramp_frame *self,
 107                         const frame_info_ptr &this_frame,
 108                         struct trad_frame_cache *this_cache,
 109                         CORE_ADDR func)
 110 {
 111   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 112   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 113   CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
 114   CORE_ADDR mcontext_addr = (sp
 115                              + ARM_SIGFRAME_UCONTEXT_OFFSET
 116                              + ARM_UCONTEXT_MCONTEXT_OFFSET);
 117   ULONGEST mcontext_vfp_addr;
 118
 119   trad_frame_set_reg_regmap (this_cache, arm_fbsd_gregmap, mcontext_addr,
 120                              regcache_map_entry_size (arm_fbsd_gregmap));
 121
 122   if (safe_read_memory_unsigned_integer (mcontext_addr
 123                                          + ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
 124                                          byte_order,
 125                                          &mcontext_vfp_addr)
 126       && mcontext_vfp_addr != 0)
 127     trad_frame_set_reg_regmap (this_cache, arm_fbsd_vfpregmap, mcontext_vfp_addr,
 128                                regcache_map_entry_size (arm_fbsd_vfpregmap));
 129
 130   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 131 }
 132
 133 static const struct tramp_frame arm_fbsd_sigframe =
 134 {
 135   SIGTRAMP_FRAME,
 136   4,
 137   {
 138     {0xe1a0000d, ULONGEST_MAX},         /* mov  r0, sp  */
 139     {0xe2800040, ULONGEST_MAX},         /* add  r0, r0, #SIGF_UC  */
 140     {0xe59f700c, ULONGEST_MAX},         /* ldr  r7, [pc, #12]  */
 141     {0xef0001a1, ULONGEST_MAX},         /* swi  SYS_sigreturn  */
 142     {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
 143   },
 144   arm_fbsd_sigframe_init
 145 };
 146
 147 /* Register set definitions.  */
 148
 149 const struct regset arm_fbsd_gregset =
 150   {
 151     arm_fbsd_gregmap,
 152     regcache_supply_regset, regcache_collect_regset
 153   };
 154
 155 const struct regset arm_fbsd_vfpregset =
 156   {
 157     arm_fbsd_vfpregmap,
 158     regcache_supply_regset, regcache_collect_regset
 159   };
 160
 161 static void
 162 arm_fbsd_supply_tls_regset (const struct regset *regset,
 163                             struct regcache *regcache,
 164                             int regnum, const void *buf, size_t size)
 165 {
 166   struct gdbarch *gdbarch = regcache->arch ();
 167   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 168
 169   regcache->supply_regset (regset, tdep->tls_regnum, regnum, buf, size);
 170 }
 171
 172 static void
 173 arm_fbsd_collect_tls_regset (const struct regset *regset,
 174                              const struct regcache *regcache,
 175                              int regnum, void *buf, size_t size)
 176 {
 177   struct gdbarch *gdbarch = regcache->arch ();
 178   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 179
 180   regcache->collect_regset (regset, tdep->tls_regnum, regnum, buf, size);
 181 }
 182
 183 const struct regset arm_fbsd_tls_regset =
 184   {
 185     arm_fbsd_tls_regmap,
 186     arm_fbsd_supply_tls_regset, arm_fbsd_collect_tls_regset
 187   };
 188
 189 /* Implement the "iterate_over_regset_sections" gdbarch method.  */
 190
 191 static void
 192 arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 193                                        iterate_over_regset_sections_cb *cb,
 194                                        void *cb_data,
 195                                        const struct regcache *regcache)
 196 {
 197   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 198
 199   cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
 200       &arm_fbsd_gregset, NULL, cb_data);
 201
 202   if (tdep->tls_regnum > 0)
 203     cb (".reg-aarch-tls", ARM_FBSD_SIZEOF_TLSREGSET, ARM_FBSD_SIZEOF_TLSREGSET,
 204         &arm_fbsd_tls_regset, NULL, cb_data);
 205
 206   /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
 207      register set, it is not populated with register values by the
 208      kernel but just contains all zeroes.  */
 209   if (tdep->vfp_register_count > 0)
 210     cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, ARM_FBSD_SIZEOF_VFPREGSET,
 211         &arm_fbsd_vfpregset, "VFP floating-point", cb_data);
 212 }
 213
 214 /* See arm-fbsd-tdep.h.  */
 215
 216 const struct target_desc *
 217 arm_fbsd_read_description_auxv (const std::optional<gdb::byte_vector> &auxv,
 218                                 target_ops *target, gdbarch *gdbarch, bool tls)
 219 {
 220   CORE_ADDR arm_hwcap = 0;
 221
 222   if (!auxv.has_value ()
 223       || target_auxv_search (*auxv, target, gdbarch, AT_FREEBSD_HWCAP,
 224                              &arm_hwcap) != 1)
 225     return arm_read_description (ARM_FP_TYPE_NONE, tls);
 226
 227   if (arm_hwcap & HWCAP_VFP)
 228     {
 229       if (arm_hwcap & HWCAP_NEON)
 230         return aarch32_read_description (tls);
 231       else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
 232                == (HWCAP_VFPv3 | HWCAP_VFPD32))
 233         return arm_read_description (ARM_FP_TYPE_VFPV3, tls);
 234       else
 235         return arm_read_description (ARM_FP_TYPE_VFPV2, tls);
 236     }
 237
 238   return arm_read_description (ARM_FP_TYPE_NONE, tls);
 239 }
 240
 241 /* See arm-fbsd-tdep.h.  */
 242
 243 const struct target_desc *
 244 arm_fbsd_read_description_auxv (bool tls)
 245 {
 246   const std::optional<gdb::byte_vector> &auxv = target_read_auxv ();
 247   return arm_fbsd_read_description_auxv (auxv,
 248                                          current_inferior ()->top_target (),
 249                                          current_inferior ()->arch (),
 250                                          tls);
 251 }
 252
 253 /* Implement the "core_read_description" gdbarch method.  */
 254
 255 static const struct target_desc *
 256 arm_fbsd_core_read_description (struct gdbarch *gdbarch,
 257                                 struct target_ops *target,
 258                                 bfd *abfd)
 259 {
 260   asection *tls = bfd_get_section_by_name (abfd, ".reg-aarch-tls");
 261
 262   std::optional<gdb::byte_vector> auxv = target_read_auxv_raw (target);
 263   return arm_fbsd_read_description_auxv (auxv, target, gdbarch, tls != nullptr);
 264 }
 265
 266 /* Implement the get_thread_local_address gdbarch method.  */
 267
 268 static CORE_ADDR
 269 arm_fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
 270                                    CORE_ADDR lm_addr, CORE_ADDR offset)
 271 {
 272   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 273   regcache *regcache
 274     = get_thread_arch_regcache (current_inferior (), ptid, gdbarch);
 275
 276   target_fetch_registers (regcache, tdep->tls_regnum);
 277
 278   ULONGEST tpidruro;
 279   if (regcache->cooked_read (tdep->tls_regnum, &tpidruro) != REG_VALID)
 280     error (_("Unable to fetch %%tpidruro"));
 281
 282   /* %tpidruro points to the TCB whose first member is the dtv
 283       pointer.  */
 284   CORE_ADDR dtv_addr = tpidruro;
 285   return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
 286 }
 287
 288 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
 289
 290 static void
 291 arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 292 {
 293   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 294
 295   /* Generic FreeBSD support.  */
 296   fbsd_init_abi (info, gdbarch);
 297
 298   if (tdep->fp_model == ARM_FLOAT_AUTO)
 299     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 300
 301   tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
 302
 303   set_solib_svr4_fetch_link_map_offsets
 304     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 305
 306   tdep->jb_pc = 24;
 307   tdep->jb_elt_size = 4;
 308
 309   set_gdbarch_iterate_over_regset_sections
 310     (gdbarch, arm_fbsd_iterate_over_regset_sections);
 311   set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
 312
 313   if (tdep->tls_regnum > 0)
 314     {
 315       set_gdbarch_fetch_tls_load_module_address (gdbarch,
 316                                                  svr4_fetch_objfile_link_map);
 317       set_gdbarch_get_thread_local_address (gdbarch,
 318                                             arm_fbsd_get_thread_local_address);
 319     }
 320
 321   /* Single stepping.  */
 322   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 323 }
 324
 325 void _initialize_arm_fbsd_tdep ();
 326 void
 327 _initialize_arm_fbsd_tdep ()
 328 {
 329   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
 330                           arm_fbsd_init_abi);
 331 }