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 #include "defs.h"
  21
  22 #include "elf/common.h"
  23 #include "target-descriptions.h"
  24 #include "aarch32-tdep.h"
  25 #include "arm-tdep.h"
  26 #include "arm-fbsd-tdep.h"
  27 #include "auxv.h"
  28 #include "fbsd-tdep.h"
  29 #include "gdbcore.h"
  30 #include "inferior.h"
  31 #include "osabi.h"
  32 #include "solib-svr4.h"
  33 #include "trad-frame.h"
  34 #include "tramp-frame.h"
  35
  36 /* Register maps.  */
  37
  38 static const struct regcache_map_entry arm_fbsd_gregmap[] =
  39   {
  40     { 13, ARM_A1_REGNUM, 4 }, /* r0 ... r12 */
  41     { 1, ARM_SP_REGNUM, 4 },
  42     { 1, ARM_LR_REGNUM, 4 },
  43     { 1, ARM_PC_REGNUM, 4 },
  44     { 1, ARM_PS_REGNUM, 4 },
  45     { 0 }
  46   };
  47
  48 static const struct regcache_map_entry arm_fbsd_vfpregmap[] =
  49   {
  50     { 32, ARM_D0_REGNUM, 8 }, /* d0 ... d31 */
  51     { 1, ARM_FPSCR_REGNUM, 4 },
  52     { 0 }
  53   };
  54
  55 /* Register numbers are relative to tdep->tls_regnum.  */
  56
  57 static const struct regcache_map_entry arm_fbsd_tls_regmap[] =
  58   {
  59     { 1, 0, 4 },        /* tpidruro  */
  60     { 0 }
  61   };
  62
  63 /* In a signal frame, sp points to a 'struct sigframe' which is
  64    defined as:
  65
  66    struct sigframe {
  67            siginfo_t    sf_si;
  68            ucontext_t   sf_uc;
  69            mcontext_vfp_t sf_vfp;
  70    };
  71
  72    ucontext_t is defined as:
  73
  74    struct __ucontext {
  75            sigset_t     uc_sigmask;
  76            mcontext_t   uc_mcontext;
  77            ...
  78    };
  79
  80    mcontext_t is defined as:
  81
  82    struct {
  83            unsigned int __gregs[17];
  84            size_t       mc_vfp_size;
  85            void         *mc_vfp_ptr;
  86            ...
  87    };
  88
  89    mcontext_vfp_t is defined as:
  90
  91    struct {
  92           uint64_t      mcv_reg[32];
  93           uint32_t      mcv_fpscr;
  94    };
  95
  96    If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
  97    the sigframe, otherwise it is NULL.  There is no non-VFP floating
  98    point register state saved in the signal frame.  */
  99
 100 #define ARM_SIGFRAME_UCONTEXT_OFFSET    64
 101 #define ARM_UCONTEXT_MCONTEXT_OFFSET    16
 102 #define ARM_MCONTEXT_VFP_PTR_OFFSET     72
 103
 104 /* Implement the "init" method of struct tramp_frame.  */
 105
 106 static void
 107 arm_fbsd_sigframe_init (const struct tramp_frame *self,
 108                         frame_info_ptr this_frame,
 109                         struct trad_frame_cache *this_cache,
 110                         CORE_ADDR func)
 111 {
 112   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 113   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 114   CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
 115   CORE_ADDR mcontext_addr = (sp
 116                              + ARM_SIGFRAME_UCONTEXT_OFFSET
 117                              + ARM_UCONTEXT_MCONTEXT_OFFSET);
 118   ULONGEST mcontext_vfp_addr;
 119
 120   trad_frame_set_reg_regmap (this_cache, arm_fbsd_gregmap, mcontext_addr,
 121                              regcache_map_entry_size (arm_fbsd_gregmap));
 122
 123   if (safe_read_memory_unsigned_integer (mcontext_addr
 124                                          + ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
 125                                          byte_order,
 126                                          &mcontext_vfp_addr)
 127       && mcontext_vfp_addr != 0)
 128     trad_frame_set_reg_regmap (this_cache, arm_fbsd_vfpregmap, mcontext_vfp_addr,
 129                                regcache_map_entry_size (arm_fbsd_vfpregmap));
 130
 131   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 132 }
 133
 134 static const struct tramp_frame arm_fbsd_sigframe =
 135 {
 136   SIGTRAMP_FRAME,
 137   4,
 138   {
 139     {0xe1a0000d, ULONGEST_MAX},         /* mov  r0, sp  */
 140     {0xe2800040, ULONGEST_MAX},         /* add  r0, r0, #SIGF_UC  */
 141     {0xe59f700c, ULONGEST_MAX},         /* ldr  r7, [pc, #12]  */
 142     {0xef0001a1, ULONGEST_MAX},         /* swi  SYS_sigreturn  */
 143     {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
 144   },
 145   arm_fbsd_sigframe_init
 146 };
 147
 148 /* Register set definitions.  */
 149
 150 const struct regset arm_fbsd_gregset =
 151   {
 152     arm_fbsd_gregmap,
 153     regcache_supply_regset, regcache_collect_regset
 154   };
 155
 156 const struct regset arm_fbsd_vfpregset =
 157   {
 158     arm_fbsd_vfpregmap,
 159     regcache_supply_regset, regcache_collect_regset
 160   };
 161
 162 static void
 163 arm_fbsd_supply_tls_regset (const struct regset *regset,
 164                             struct regcache *regcache,
 165                             int regnum, const void *buf, size_t size)
 166 {
 167   struct gdbarch *gdbarch = regcache->arch ();
 168   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 169
 170   regcache->supply_regset (regset, tdep->tls_regnum, regnum, buf, size);
 171 }
 172
 173 static void
 174 arm_fbsd_collect_tls_regset (const struct regset *regset,
 175                              const struct regcache *regcache,
 176                              int regnum, void *buf, size_t size)
 177 {
 178   struct gdbarch *gdbarch = regcache->arch ();
 179   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 180
 181   regcache->collect_regset (regset, tdep->tls_regnum, regnum, buf, size);
 182 }
 183
 184 const struct regset arm_fbsd_tls_regset =
 185   {
 186     arm_fbsd_tls_regmap,
 187     arm_fbsd_supply_tls_regset, arm_fbsd_collect_tls_regset
 188   };
 189
 190 /* Implement the "iterate_over_regset_sections" gdbarch method.  */
 191
 192 static void
 193 arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 194                                        iterate_over_regset_sections_cb *cb,
 195                                        void *cb_data,
 196                                        const struct regcache *regcache)
 197 {
 198   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 199
 200   cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
 201       &arm_fbsd_gregset, NULL, cb_data);
 202
 203   if (tdep->tls_regnum > 0)
 204     cb (".reg-aarch-tls", ARM_FBSD_SIZEOF_TLSREGSET, ARM_FBSD_SIZEOF_TLSREGSET,
 205         &arm_fbsd_tls_regset, NULL, cb_data);
 206
 207   /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
 208      register set, it is not populated with register values by the
 209      kernel but just contains all zeroes.  */
 210   if (tdep->vfp_register_count > 0)
 211     cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, ARM_FBSD_SIZEOF_VFPREGSET,
 212         &arm_fbsd_vfpregset, "VFP floating-point", cb_data);
 213 }
 214
 215 /* See arm-fbsd-tdep.h.  */
 216
 217 const struct target_desc *
 218 arm_fbsd_read_description_auxv (const std::optional<gdb::byte_vector> &auxv,
 219                                 target_ops *target, gdbarch *gdbarch, bool tls)
 220 {
 221   CORE_ADDR arm_hwcap = 0;
 222
 223   if (!auxv.has_value ()
 224       || target_auxv_search (*auxv, target, gdbarch, AT_FREEBSD_HWCAP,
 225                              &arm_hwcap) != 1)
 226     return arm_read_description (ARM_FP_TYPE_NONE, tls);
 227
 228   if (arm_hwcap & HWCAP_VFP)
 229     {
 230       if (arm_hwcap & HWCAP_NEON)
 231         return aarch32_read_description ();
 232       else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
 233                == (HWCAP_VFPv3 | HWCAP_VFPD32))
 234         return arm_read_description (ARM_FP_TYPE_VFPV3, tls);
 235       else
 236         return arm_read_description (ARM_FP_TYPE_VFPV2, tls);
 237     }
 238
 239   return arm_read_description (ARM_FP_TYPE_NONE, tls);
 240 }
 241
 242 /* See arm-fbsd-tdep.h.  */
 243
 244 const struct target_desc *
 245 arm_fbsd_read_description_auxv (bool tls)
 246 {
 247   const std::optional<gdb::byte_vector> &auxv = target_read_auxv ();
 248   return arm_fbsd_read_description_auxv (auxv,
 249                                          current_inferior ()->top_target (),
 250                                          current_inferior ()->arch (),
 251                                          tls);
 252 }
 253
 254 /* Implement the "core_read_description" gdbarch method.  */
 255
 256 static const struct target_desc *
 257 arm_fbsd_core_read_description (struct gdbarch *gdbarch,
 258                                 struct target_ops *target,
 259                                 bfd *abfd)
 260 {
 261   asection *tls = bfd_get_section_by_name (abfd, ".reg-aarch-tls");
 262
 263   std::optional<gdb::byte_vector> auxv = target_read_auxv_raw (target);
 264   return arm_fbsd_read_description_auxv (auxv, target, gdbarch, tls != nullptr);
 265 }
 266
 267 /* Implement the get_thread_local_address gdbarch method.  */
 268
 269 static CORE_ADDR
 270 arm_fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
 271                                    CORE_ADDR lm_addr, CORE_ADDR offset)
 272 {
 273   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 274   regcache *regcache
 275     = get_thread_arch_regcache (current_inferior (), ptid, gdbarch);
 276
 277   target_fetch_registers (regcache, tdep->tls_regnum);
 278
 279   ULONGEST tpidruro;
 280   if (regcache->cooked_read (tdep->tls_regnum, &tpidruro) != REG_VALID)
 281     error (_("Unable to fetch %%tpidruro"));
 282
 283   /* %tpidruro points to the TCB whose first member is the dtv
 284       pointer.  */
 285   CORE_ADDR dtv_addr = tpidruro;
 286   return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
 287 }
 288
 289 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
 290
 291 static void
 292 arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 293 {
 294   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 295
 296   /* Generic FreeBSD support.  */
 297   fbsd_init_abi (info, gdbarch);
 298
 299   if (tdep->fp_model == ARM_FLOAT_AUTO)
 300     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 301
 302   tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
 303
 304   set_solib_svr4_fetch_link_map_offsets
 305     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 306
 307   tdep->jb_pc = 24;
 308   tdep->jb_elt_size = 4;
 309
 310   set_gdbarch_iterate_over_regset_sections
 311     (gdbarch, arm_fbsd_iterate_over_regset_sections);
 312   set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
 313
 314   if (tdep->tls_regnum > 0)
 315     {
 316       set_gdbarch_fetch_tls_load_module_address (gdbarch,
 317                                                  svr4_fetch_objfile_link_map);
 318       set_gdbarch_get_thread_local_address (gdbarch,
 319                                             arm_fbsd_get_thread_local_address);
 320     }
 321
 322   /* Single stepping.  */
 323   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 324 }
 325
 326 void _initialize_arm_fbsd_tdep ();
 327 void
 328 _initialize_arm_fbsd_tdep ()
 329 {
 330   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
 331                           arm_fbsd_init_abi);
 332 }