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 /* Local non-gdb includes.  */
  23 #include "arm-fbsd-tdep.h"
  24 #include "arm-tdep.h"
  25 #include "auxv.h"
  26 #include "elf/common.h"
  27 #include "fbsd-tdep.h"
  28 #include "gdbcore.h"
  29 #include "osabi.h"
  30 #include "solib-svr4.h"
  31 #include "trad-frame.h"
  32 #include "tramp-frame.h"
  33
  34 /* Register maps.  */
  35
  36 static const struct regcache_map_entry arm_fbsd_gregmap[] =
  37   {
  38     { 13, ARM_A1_REGNUM, 4 }, /* r0 ... r12 */
  39     { 1, ARM_SP_REGNUM, 4 },
  40     { 1, ARM_LR_REGNUM, 4 },
  41     { 1, ARM_PC_REGNUM, 4 },
  42     { 1, ARM_PS_REGNUM, 4 },
  43     { 0 }
  44   };
  45
  46 static const struct regcache_map_entry arm_fbsd_vfpregmap[] =
  47   {
  48     { 32, ARM_D0_REGNUM, 8 }, /* d0 ... d31 */
  49     { 1, ARM_FPSCR_REGNUM, 4 },
  50     { 0 }
  51   };
  52
  53 /* In a signal frame, sp points to a 'struct sigframe' which is
  54    defined as:
  55
  56    struct sigframe {
  57            siginfo_t    sf_si;
  58            ucontext_t   sf_uc;
  59            mcontext_vfp_t sf_vfp;
  60    };
  61
  62    ucontext_t is defined as:
  63
  64    struct __ucontext {
  65            sigset_t     uc_sigmask;
  66            mcontext_t   uc_mcontext;
  67            ...
  68    };
  69
  70    mcontext_t is defined as:
  71
  72    struct {
  73            unsigned int __gregs[17];
  74            size_t       mc_vfp_size;
  75            void         *mc_vfp_ptr;
  76            ...
  77    };
  78
  79    mcontext_vfp_t is defined as:
  80
  81    struct {
  82           uint64_t      mcv_reg[32];
  83           uint32_t      mcv_fpscr;
  84    };
  85
  86    If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
  87    the sigframe, otherwise it is NULL.  There is no non-VFP floating
  88    point register state saved in the signal frame.  */
  89
  90 #define ARM_SIGFRAME_UCONTEXT_OFFSET    64
  91 #define ARM_UCONTEXT_MCONTEXT_OFFSET    16
  92 #define ARM_MCONTEXT_VFP_PTR_OFFSET     72
  93
  94 /* Implement the "init" method of struct tramp_frame.  */
  95
  96 static void
  97 arm_fbsd_sigframe_init (const struct tramp_frame *self,
  98                         struct frame_info *this_frame,
  99                         struct trad_frame_cache *this_cache,
 100                         CORE_ADDR func)
 101 {
 102   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 103   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 104   CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
 105   CORE_ADDR mcontext_addr = (sp
 106                              + ARM_SIGFRAME_UCONTEXT_OFFSET
 107                              + ARM_UCONTEXT_MCONTEXT_OFFSET);
 108   ULONGEST mcontext_vfp_addr;
 109
 110   trad_frame_set_reg_regmap (this_cache, arm_fbsd_gregmap, mcontext_addr,
 111                              regcache_map_entry_size (arm_fbsd_gregmap));
 112
 113   if (safe_read_memory_unsigned_integer (mcontext_addr
 114                                          + ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
 115                                          byte_order,
 116                                          &mcontext_vfp_addr)
 117       && mcontext_vfp_addr != 0)
 118     trad_frame_set_reg_regmap (this_cache, arm_fbsd_vfpregmap, mcontext_vfp_addr,
 119                                regcache_map_entry_size (arm_fbsd_vfpregmap));
 120
 121   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 122 }
 123
 124 static const struct tramp_frame arm_fbsd_sigframe =
 125 {
 126   SIGTRAMP_FRAME,
 127   4,
 128   {
 129     {0xe1a0000d, ULONGEST_MAX},         /* mov  r0, sp  */
 130     {0xe2800040, ULONGEST_MAX},         /* add  r0, r0, #SIGF_UC  */
 131     {0xe59f700c, ULONGEST_MAX},         /* ldr  r7, [pc, #12]  */
 132     {0xef0001a1, ULONGEST_MAX},         /* swi  SYS_sigreturn  */
 133     {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
 134   },
 135   arm_fbsd_sigframe_init
 136 };
 137
 138 /* Register set definitions.  */
 139
 140 const struct regset arm_fbsd_gregset =
 141   {
 142     arm_fbsd_gregmap,
 143     regcache_supply_regset, regcache_collect_regset
 144   };
 145
 146 const struct regset arm_fbsd_vfpregset =
 147   {
 148     arm_fbsd_vfpregmap,
 149     regcache_supply_regset, regcache_collect_regset
 150   };
 151
 152 /* Implement the "regset_from_core_section" gdbarch method.  */
 153
 154 static void
 155 arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 156                                        iterate_over_regset_sections_cb *cb,
 157                                        void *cb_data,
 158                                        const struct regcache *regcache)
 159 {
 160   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 161
 162   cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
 163       &arm_fbsd_gregset, NULL, cb_data);
 164
 165   /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
 166      register set, it is not populated with register values by the
 167      kernel but just contains all zeroes.  */
 168   if (tdep->vfp_register_count > 0)
 169     cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, ARM_FBSD_SIZEOF_VFPREGSET,
 170         &arm_fbsd_vfpregset, "VFP floating-point", cb_data);
 171 }
 172
 173 /* Lookup a target description from a target's AT_HWCAP auxiliary
 174    vector.  */
 175
 176 const struct target_desc *
 177 arm_fbsd_read_description_auxv (struct target_ops *target)
 178 {
 179   CORE_ADDR arm_hwcap = 0;
 180
 181   if (target_auxv_search (target, AT_FREEBSD_HWCAP, &arm_hwcap) != 1)
 182     return NULL;
 183
 184   if (arm_hwcap & HWCAP_VFP)
 185     {
 186       if (arm_hwcap & HWCAP_NEON)
 187         return tdesc_arm_with_neon;
 188       else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
 189           == (HWCAP_VFPv3 | HWCAP_VFPD32))
 190         return tdesc_arm_with_vfpv3;
 191       else
 192         return tdesc_arm_with_vfpv2;
 193     }
 194
 195   return NULL;
 196 }
 197
 198 /* Implement the "core_read_description" gdbarch method.  */
 199
 200 static const struct target_desc *
 201 arm_fbsd_core_read_description (struct gdbarch *gdbarch,
 202                                 struct target_ops *target,
 203                                 bfd *abfd)
 204 {
 205   return arm_fbsd_read_description_auxv (target);
 206 }
 207
 208 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
 209
 210 static void
 211 arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 212 {
 213   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 214
 215   /* Generic FreeBSD support.  */
 216   fbsd_init_abi (info, gdbarch);
 217
 218   if (tdep->fp_model == ARM_FLOAT_AUTO)
 219     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 220
 221   tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
 222
 223   set_solib_svr4_fetch_link_map_offsets
 224     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 225
 226   tdep->jb_pc = 24;
 227   tdep->jb_elt_size = 4;
 228
 229   set_gdbarch_iterate_over_regset_sections
 230     (gdbarch, arm_fbsd_iterate_over_regset_sections);
 231   set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
 232
 233   /* Single stepping.  */
 234   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 235 }
 236
 237 void
 238 _initialize_arm_fbsd_tdep (void)
 239 {
 240   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
 241                           arm_fbsd_init_abi);
 242 }