gdb/arm-fbsd-tdep.c

   1 /* Target-dependent code for FreeBSD/arm.
   2
   3    Copyright (C) 2017-2022 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
  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 /* In a signal frame, sp points to a 'struct sigframe' which is
  56    defined as:
  57
  58    struct sigframe {
  59            siginfo_t    sf_si;
  60            ucontext_t   sf_uc;
  61            mcontext_vfp_t sf_vfp;
  62    };
  63
  64    ucontext_t is defined as:
  65
  66    struct __ucontext {
  67            sigset_t     uc_sigmask;
  68            mcontext_t   uc_mcontext;
  69            ...
  70    };
  71
  72    mcontext_t is defined as:
  73
  74    struct {
  75            unsigned int __gregs[17];
  76            size_t       mc_vfp_size;
  77            void         *mc_vfp_ptr;
  78            ...
  79    };
  80
  81    mcontext_vfp_t is defined as:
  82
  83    struct {
  84           uint64_t      mcv_reg[32];
  85           uint32_t      mcv_fpscr;
  86    };
  87
  88    If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
  89    the sigframe, otherwise it is NULL.  There is no non-VFP floating
  90    point register state saved in the signal frame.  */
  91
  92 #define ARM_SIGFRAME_UCONTEXT_OFFSET    64
  93 #define ARM_UCONTEXT_MCONTEXT_OFFSET    16
  94 #define ARM_MCONTEXT_VFP_PTR_OFFSET     72
  95
  96 /* Implement the "init" method of struct tramp_frame.  */
  97
  98 static void
  99 arm_fbsd_sigframe_init (const struct tramp_frame *self,
 100                         struct frame_info *this_frame,
 101                         struct trad_frame_cache *this_cache,
 102                         CORE_ADDR func)
 103 {
 104   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 105   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 106   CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
 107   CORE_ADDR mcontext_addr = (sp
 108                              + ARM_SIGFRAME_UCONTEXT_OFFSET
 109                              + ARM_UCONTEXT_MCONTEXT_OFFSET);
 110   ULONGEST mcontext_vfp_addr;
 111
 112   trad_frame_set_reg_regmap (this_cache, arm_fbsd_gregmap, mcontext_addr,
 113                              regcache_map_entry_size (arm_fbsd_gregmap));
 114
 115   if (safe_read_memory_unsigned_integer (mcontext_addr
 116                                          + ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
 117                                          byte_order,
 118                                          &mcontext_vfp_addr)
 119       && mcontext_vfp_addr != 0)
 120     trad_frame_set_reg_regmap (this_cache, arm_fbsd_vfpregmap, mcontext_vfp_addr,
 121                                regcache_map_entry_size (arm_fbsd_vfpregmap));
 122
 123   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 124 }
 125
 126 static const struct tramp_frame arm_fbsd_sigframe =
 127 {
 128   SIGTRAMP_FRAME,
 129   4,
 130   {
 131     {0xe1a0000d, ULONGEST_MAX},         /* mov  r0, sp  */
 132     {0xe2800040, ULONGEST_MAX},         /* add  r0, r0, #SIGF_UC  */
 133     {0xe59f700c, ULONGEST_MAX},         /* ldr  r7, [pc, #12]  */
 134     {0xef0001a1, ULONGEST_MAX},         /* swi  SYS_sigreturn  */
 135     {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
 136   },
 137   arm_fbsd_sigframe_init
 138 };
 139
 140 /* Register set definitions.  */
 141
 142 const struct regset arm_fbsd_gregset =
 143   {
 144     arm_fbsd_gregmap,
 145     regcache_supply_regset, regcache_collect_regset
 146   };
 147
 148 const struct regset arm_fbsd_vfpregset =
 149   {
 150     arm_fbsd_vfpregmap,
 151     regcache_supply_regset, regcache_collect_regset
 152   };
 153
 154 /* Implement the "iterate_over_regset_sections" gdbarch method.  */
 155
 156 static void
 157 arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 158                                        iterate_over_regset_sections_cb *cb,
 159                                        void *cb_data,
 160                                        const struct regcache *regcache)
 161 {
 162   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 163
 164   cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
 165       &arm_fbsd_gregset, NULL, cb_data);
 166
 167   if (tdep->tls_regnum > 0)
 168     {
 169       const struct regcache_map_entry arm_fbsd_tlsregmap[] =
 170         {
 171           { 1, tdep->tls_regnum, 4 },
 172           { 0 }
 173         };
 174
 175       const struct regset arm_fbsd_tlsregset =
 176         {
 177           arm_fbsd_tlsregmap,
 178           regcache_supply_regset, regcache_collect_regset
 179         };
 180
 181       cb (".reg-aarch-tls", ARM_FBSD_SIZEOF_TLSREGSET, ARM_FBSD_SIZEOF_TLSREGSET,
 182           &arm_fbsd_tlsregset, NULL, cb_data);
 183     }
 184
 185   /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
 186      register set, it is not populated with register values by the
 187      kernel but just contains all zeroes.  */
 188   if (tdep->vfp_register_count > 0)
 189     cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, ARM_FBSD_SIZEOF_VFPREGSET,
 190         &arm_fbsd_vfpregset, "VFP floating-point", cb_data);
 191 }
 192
 193 /* Lookup a target description from a target's AT_HWCAP auxiliary
 194    vector.  */
 195
 196 const struct target_desc *
 197 arm_fbsd_read_description_auxv (struct target_ops *target, bool tls)
 198 {
 199   CORE_ADDR arm_hwcap = 0;
 200
 201   if (target_auxv_search (target, AT_FREEBSD_HWCAP, &arm_hwcap) != 1)
 202     return arm_read_description (ARM_FP_TYPE_NONE, tls);
 203
 204   if (arm_hwcap & HWCAP_VFP)
 205     {
 206       if (arm_hwcap & HWCAP_NEON)
 207         return aarch32_read_description ();
 208       else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
 209                == (HWCAP_VFPv3 | HWCAP_VFPD32))
 210         return arm_read_description (ARM_FP_TYPE_VFPV3, tls);
 211       else
 212         return arm_read_description (ARM_FP_TYPE_VFPV2, tls);
 213     }
 214
 215   return arm_read_description (ARM_FP_TYPE_NONE, tls);
 216 }
 217
 218 /* Implement the "core_read_description" gdbarch method.  */
 219
 220 static const struct target_desc *
 221 arm_fbsd_core_read_description (struct gdbarch *gdbarch,
 222                                 struct target_ops *target,
 223                                 bfd *abfd)
 224 {
 225   asection *tls = bfd_get_section_by_name (abfd, ".reg-aarch-tls");
 226
 227   return arm_fbsd_read_description_auxv (target, tls != nullptr);
 228 }
 229
 230 /* Implement the get_thread_local_address gdbarch method.  */
 231
 232 static CORE_ADDR
 233 arm_fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
 234                                    CORE_ADDR lm_addr, CORE_ADDR offset)
 235 {
 236   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 237   struct regcache *regcache;
 238
 239   regcache = get_thread_arch_regcache (current_inferior ()->process_target (),
 240                                        ptid, gdbarch);
 241
 242   target_fetch_registers (regcache, tdep->tls_regnum);
 243
 244   ULONGEST tpidruro;
 245   if (regcache->cooked_read (tdep->tls_regnum, &tpidruro) != REG_VALID)
 246     error (_("Unable to fetch %%tpidruro"));
 247
 248   /* %tpidruro points to the TCB whose first member is the dtv
 249       pointer.  */
 250   CORE_ADDR dtv_addr = tpidruro;
 251   return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
 252 }
 253
 254 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
 255
 256 static void
 257 arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 258 {
 259   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 260
 261   /* Generic FreeBSD support.  */
 262   fbsd_init_abi (info, gdbarch);
 263
 264   if (tdep->fp_model == ARM_FLOAT_AUTO)
 265     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 266
 267   tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
 268
 269   set_solib_svr4_fetch_link_map_offsets
 270     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 271
 272   tdep->jb_pc = 24;
 273   tdep->jb_elt_size = 4;
 274
 275   set_gdbarch_iterate_over_regset_sections
 276     (gdbarch, arm_fbsd_iterate_over_regset_sections);
 277   set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
 278
 279   if (tdep->tls_regnum > 0)
 280     {
 281       set_gdbarch_fetch_tls_load_module_address (gdbarch,
 282                                                  svr4_fetch_objfile_link_map);
 283       set_gdbarch_get_thread_local_address (gdbarch,
 284                                             arm_fbsd_get_thread_local_address);
 285     }
 286
 287   /* Single stepping.  */
 288   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 289 }
 290
 291 void _initialize_arm_fbsd_tdep ();
 292 void
 293 _initialize_arm_fbsd_tdep ()
 294 {
 295   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
 296                           arm_fbsd_init_abi);
 297 }