gdb/arm-fbsd-tdep.c

   1 /* Target-dependent code for FreeBSD/arm.
   2
   3    Copyright (C) 2017-2019 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 "arm-tdep.h"
  24 #include "arm-fbsd-tdep.h"
  25 #include "auxv.h"
  26 #include "fbsd-tdep.h"
  27 #include "gdbcore.h"
  28 #include "osabi.h"
  29 #include "solib-svr4.h"
  30 #include "trad-frame.h"
  31 #include "tramp-frame.h"
  32
  33 /* Register maps.  */
  34
  35 static const struct regcache_map_entry arm_fbsd_gregmap[] =
  36   {
  37     { 13, ARM_A1_REGNUM, 4 }, /* r0 ... r12 */
  38     { 1, ARM_SP_REGNUM, 4 },
  39     { 1, ARM_LR_REGNUM, 4 },
  40     { 1, ARM_PC_REGNUM, 4 },
  41     { 1, ARM_PS_REGNUM, 4 },
  42     { 0 }
  43   };
  44
  45 static const struct regcache_map_entry arm_fbsd_vfpregmap[] =
  46   {
  47     { 32, ARM_D0_REGNUM, 8 }, /* d0 ... d31 */
  48     { 1, ARM_FPSCR_REGNUM, 4 },
  49     { 0 }
  50   };
  51
  52 /* In a signal frame, sp points to a 'struct sigframe' which is
  53    defined as:
  54
  55    struct sigframe {
  56            siginfo_t    sf_si;
  57            ucontext_t   sf_uc;
  58            mcontext_vfp_t sf_vfp;
  59    };
  60
  61    ucontext_t is defined as:
  62
  63    struct __ucontext {
  64            sigset_t     uc_sigmask;
  65            mcontext_t   uc_mcontext;
  66            ...
  67    };
  68
  69    mcontext_t is defined as:
  70
  71    struct {
  72            unsigned int __gregs[17];
  73            size_t       mc_vfp_size;
  74            void         *mc_vfp_ptr;
  75            ...
  76    };
  77
  78    mcontext_vfp_t is defined as:
  79
  80    struct {
  81           uint64_t      mcv_reg[32];
  82           uint32_t      mcv_fpscr;
  83    };
  84
  85    If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
  86    the sigframe, otherwise it is NULL.  There is no non-VFP floating
  87    point register state saved in the signal frame.  */
  88
  89 #define ARM_SIGFRAME_UCONTEXT_OFFSET    64
  90 #define ARM_UCONTEXT_MCONTEXT_OFFSET    16
  91 #define ARM_MCONTEXT_VFP_PTR_OFFSET     72
  92
  93 /* Implement the "init" method of struct tramp_frame.  */
  94
  95 static void
  96 arm_fbsd_sigframe_init (const struct tramp_frame *self,
  97                         struct frame_info *this_frame,
  98                         struct trad_frame_cache *this_cache,
  99                         CORE_ADDR func)
 100 {
 101   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 102   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 103   CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
 104   CORE_ADDR mcontext_addr = (sp
 105                              + ARM_SIGFRAME_UCONTEXT_OFFSET
 106                              + ARM_UCONTEXT_MCONTEXT_OFFSET);
 107   ULONGEST mcontext_vfp_addr;
 108
 109   trad_frame_set_reg_regmap (this_cache, arm_fbsd_gregmap, mcontext_addr,
 110                              regcache_map_entry_size (arm_fbsd_gregmap));
 111
 112   if (safe_read_memory_unsigned_integer (mcontext_addr
 113                                          + ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
 114                                          byte_order,
 115                                          &mcontext_vfp_addr)
 116       && mcontext_vfp_addr != 0)
 117     trad_frame_set_reg_regmap (this_cache, arm_fbsd_vfpregmap, mcontext_vfp_addr,
 118                                regcache_map_entry_size (arm_fbsd_vfpregmap));
 119
 120   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 121 }
 122
 123 static const struct tramp_frame arm_fbsd_sigframe =
 124 {
 125   SIGTRAMP_FRAME,
 126   4,
 127   {
 128     {0xe1a0000d, ULONGEST_MAX},         /* mov  r0, sp  */
 129     {0xe2800040, ULONGEST_MAX},         /* add  r0, r0, #SIGF_UC  */
 130     {0xe59f700c, ULONGEST_MAX},         /* ldr  r7, [pc, #12]  */
 131     {0xef0001a1, ULONGEST_MAX},         /* swi  SYS_sigreturn  */
 132     {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
 133   },
 134   arm_fbsd_sigframe_init
 135 };
 136
 137 /* Register set definitions.  */
 138
 139 const struct regset arm_fbsd_gregset =
 140   {
 141     arm_fbsd_gregmap,
 142     regcache_supply_regset, regcache_collect_regset
 143   };
 144
 145 const struct regset arm_fbsd_vfpregset =
 146   {
 147     arm_fbsd_vfpregmap,
 148     regcache_supply_regset, regcache_collect_regset
 149   };
 150
 151 /* Implement the "regset_from_core_section" gdbarch method.  */
 152
 153 static void
 154 arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 155                                        iterate_over_regset_sections_cb *cb,
 156                                        void *cb_data,
 157                                        const struct regcache *regcache)
 158 {
 159   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 160
 161   cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
 162       &arm_fbsd_gregset, NULL, cb_data);
 163
 164   /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
 165      register set, it is not populated with register values by the
 166      kernel but just contains all zeroes.  */
 167   if (tdep->vfp_register_count > 0)
 168     cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, ARM_FBSD_SIZEOF_VFPREGSET,
 169         &arm_fbsd_vfpregset, "VFP floating-point", cb_data);
 170 }
 171
 172 /* Lookup a target description from a target's AT_HWCAP auxiliary
 173    vector.  */
 174
 175 const struct target_desc *
 176 arm_fbsd_read_description_auxv (struct target_ops *target)
 177 {
 178   CORE_ADDR arm_hwcap = 0;
 179
 180   if (target_auxv_search (target, AT_FREEBSD_HWCAP, &arm_hwcap) != 1)
 181     return NULL;
 182
 183   if (arm_hwcap & HWCAP_VFP)
 184     {
 185       if (arm_hwcap & HWCAP_NEON)
 186         return tdesc_arm_with_neon;
 187       else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
 188           == (HWCAP_VFPv3 | HWCAP_VFPD32))
 189         return tdesc_arm_with_vfpv3;
 190       else
 191         return tdesc_arm_with_vfpv2;
 192     }
 193
 194   return NULL;
 195 }
 196
 197 /* Implement the "core_read_description" gdbarch method.  */
 198
 199 static const struct target_desc *
 200 arm_fbsd_core_read_description (struct gdbarch *gdbarch,
 201                                 struct target_ops *target,
 202                                 bfd *abfd)
 203 {
 204   return arm_fbsd_read_description_auxv (target);
 205 }
 206
 207 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
 208
 209 static void
 210 arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 211 {
 212   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 213
 214   /* Generic FreeBSD support.  */
 215   fbsd_init_abi (info, gdbarch);
 216
 217   if (tdep->fp_model == ARM_FLOAT_AUTO)
 218     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 219
 220   tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
 221
 222   set_solib_svr4_fetch_link_map_offsets
 223     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 224
 225   tdep->jb_pc = 24;
 226   tdep->jb_elt_size = 4;
 227
 228   set_gdbarch_iterate_over_regset_sections
 229     (gdbarch, arm_fbsd_iterate_over_regset_sections);
 230   set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
 231
 232   /* Single stepping.  */
 233   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 234 }
 235
 236 void
 237 _initialize_arm_fbsd_tdep (void)
 238 {
 239   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
 240                           arm_fbsd_init_abi);
 241 }