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 "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 "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 /* In a signal frame, sp points to a 'struct sigframe' which is
  55    defined as:
  56
  57    struct sigframe {
  58            siginfo_t    sf_si;
  59            ucontext_t   sf_uc;
  60            mcontext_vfp_t sf_vfp;
  61    };
  62
  63    ucontext_t is defined as:
  64
  65    struct __ucontext {
  66            sigset_t     uc_sigmask;
  67            mcontext_t   uc_mcontext;
  68            ...
  69    };
  70
  71    mcontext_t is defined as:
  72
  73    struct {
  74            unsigned int __gregs[17];
  75            size_t       mc_vfp_size;
  76            void         *mc_vfp_ptr;
  77            ...
  78    };
  79
  80    mcontext_vfp_t is defined as:
  81
  82    struct {
  83           uint64_t      mcv_reg[32];
  84           uint32_t      mcv_fpscr;
  85    };
  86
  87    If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
  88    the sigframe, otherwise it is NULL.  There is no non-VFP floating
  89    point register state saved in the signal frame.  */
  90
  91 #define ARM_SIGFRAME_UCONTEXT_OFFSET    64
  92 #define ARM_UCONTEXT_MCONTEXT_OFFSET    16
  93 #define ARM_MCONTEXT_VFP_PTR_OFFSET     72
  94
  95 /* Implement the "init" method of struct tramp_frame.  */
  96
  97 static void
  98 arm_fbsd_sigframe_init (const struct tramp_frame *self,
  99                         struct frame_info *this_frame,
 100                         struct trad_frame_cache *this_cache,
 101                         CORE_ADDR func)
 102 {
 103   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 104   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 105   CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
 106   CORE_ADDR mcontext_addr = (sp
 107                              + ARM_SIGFRAME_UCONTEXT_OFFSET
 108                              + ARM_UCONTEXT_MCONTEXT_OFFSET);
 109   ULONGEST mcontext_vfp_addr;
 110
 111   trad_frame_set_reg_regmap (this_cache, arm_fbsd_gregmap, mcontext_addr,
 112                              regcache_map_entry_size (arm_fbsd_gregmap));
 113
 114   if (safe_read_memory_unsigned_integer (mcontext_addr
 115                                          + ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
 116                                          byte_order,
 117                                          &mcontext_vfp_addr)
 118       && mcontext_vfp_addr != 0)
 119     trad_frame_set_reg_regmap (this_cache, arm_fbsd_vfpregmap, mcontext_vfp_addr,
 120                                regcache_map_entry_size (arm_fbsd_vfpregmap));
 121
 122   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 123 }
 124
 125 static const struct tramp_frame arm_fbsd_sigframe =
 126 {
 127   SIGTRAMP_FRAME,
 128   4,
 129   {
 130     {0xe1a0000d, ULONGEST_MAX},         /* mov  r0, sp  */
 131     {0xe2800040, ULONGEST_MAX},         /* add  r0, r0, #SIGF_UC  */
 132     {0xe59f700c, ULONGEST_MAX},         /* ldr  r7, [pc, #12]  */
 133     {0xef0001a1, ULONGEST_MAX},         /* swi  SYS_sigreturn  */
 134     {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
 135   },
 136   arm_fbsd_sigframe_init
 137 };
 138
 139 /* Register set definitions.  */
 140
 141 const struct regset arm_fbsd_gregset =
 142   {
 143     arm_fbsd_gregmap,
 144     regcache_supply_regset, regcache_collect_regset
 145   };
 146
 147 const struct regset arm_fbsd_vfpregset =
 148   {
 149     arm_fbsd_vfpregmap,
 150     regcache_supply_regset, regcache_collect_regset
 151   };
 152
 153 /* Implement the "regset_from_core_section" gdbarch method.  */
 154
 155 static void
 156 arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 157                                        iterate_over_regset_sections_cb *cb,
 158                                        void *cb_data,
 159                                        const struct regcache *regcache)
 160 {
 161   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 162
 163   cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
 164       &arm_fbsd_gregset, NULL, cb_data);
 165
 166   /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
 167      register set, it is not populated with register values by the
 168      kernel but just contains all zeroes.  */
 169   if (tdep->vfp_register_count > 0)
 170     cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, ARM_FBSD_SIZEOF_VFPREGSET,
 171         &arm_fbsd_vfpregset, "VFP floating-point", cb_data);
 172 }
 173
 174 /* Lookup a target description from a target's AT_HWCAP auxiliary
 175    vector.  */
 176
 177 const struct target_desc *
 178 arm_fbsd_read_description_auxv (struct target_ops *target)
 179 {
 180   CORE_ADDR arm_hwcap = 0;
 181
 182   if (target_auxv_search (target, AT_FREEBSD_HWCAP, &arm_hwcap) != 1)
 183     return nullptr;
 184
 185   if (arm_hwcap & HWCAP_VFP)
 186     {
 187       if (arm_hwcap & HWCAP_NEON)
 188         return aarch32_read_description ();
 189       else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
 190           == (HWCAP_VFPv3 | HWCAP_VFPD32))
 191         return arm_read_description (ARM_FP_TYPE_VFPV3);
 192       else
 193       return arm_read_description (ARM_FP_TYPE_VFPV2);
 194     }
 195
 196   return nullptr;
 197 }
 198
 199 /* Implement the "core_read_description" gdbarch method.  */
 200
 201 static const struct target_desc *
 202 arm_fbsd_core_read_description (struct gdbarch *gdbarch,
 203                                 struct target_ops *target,
 204                                 bfd *abfd)
 205 {
 206   return arm_fbsd_read_description_auxv (target);
 207 }
 208
 209 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
 210
 211 static void
 212 arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 213 {
 214   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 215
 216   /* Generic FreeBSD support.  */
 217   fbsd_init_abi (info, gdbarch);
 218
 219   if (tdep->fp_model == ARM_FLOAT_AUTO)
 220     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 221
 222   tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
 223
 224   set_solib_svr4_fetch_link_map_offsets
 225     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 226
 227   tdep->jb_pc = 24;
 228   tdep->jb_elt_size = 4;
 229
 230   set_gdbarch_iterate_over_regset_sections
 231     (gdbarch, arm_fbsd_iterate_over_regset_sections);
 232   set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
 233
 234   /* Single stepping.  */
 235   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 236 }
 237
 238 void
 239 _initialize_arm_fbsd_tdep (void)
 240 {
 241   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
 242                           arm_fbsd_init_abi);
 243 }