gdb/arm-fbsd-tdep.c

   1 /* Target-dependent code for FreeBSD/arm.
   2
   3    Copyright (C) 2017-2018 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 /* In a signal frame, sp points to a 'struct sigframe' which is
  34    defined as:
  35
  36    struct sigframe {
  37            siginfo_t    sf_si;
  38            ucontext_t   sf_uc;
  39            mcontext_vfp_t sf_vfp;
  40    };
  41
  42    ucontext_t is defined as:
  43
  44    struct __ucontext {
  45            sigset_t     uc_sigmask;
  46            mcontext_t   uc_mcontext;
  47            ...
  48    };
  49
  50    mcontext_t is defined as:
  51
  52    struct {
  53            unsigned int __gregs[17];
  54            size_t       mc_vfp_size;
  55            void         *mc_vfp_ptr;
  56            ...
  57    };
  58
  59    mcontext_vfp_t is defined as:
  60
  61    struct {
  62           uint64_t      mcv_reg[32];
  63           uint32_t      mcv_fpscr;
  64    };
  65
  66    If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
  67    the sigframe, otherwise it is NULL.  There is no non-VFP floating
  68    point register state saved in the signal frame.  */
  69
  70 #define ARM_MCONTEXT_REG_SIZE           4
  71 #define ARM_MCONTEXT_VFP_REG_SIZE       8
  72 #define ARM_SIGFRAME_UCONTEXT_OFFSET    64
  73 #define ARM_UCONTEXT_MCONTEXT_OFFSET    16
  74 #define ARM_MCONTEXT_VFP_PTR_OFFSET     72
  75
  76 /* Implement the "init" method of struct tramp_frame.  */
  77
  78 static void
  79 arm_fbsd_sigframe_init (const struct tramp_frame *self,
  80                         struct frame_info *this_frame,
  81                         struct trad_frame_cache *this_cache,
  82                         CORE_ADDR func)
  83 {
  84   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  85   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  86   CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
  87   CORE_ADDR mcontext_addr = (sp
  88                              + ARM_SIGFRAME_UCONTEXT_OFFSET
  89                              + ARM_UCONTEXT_MCONTEXT_OFFSET);
  90   ULONGEST mcontext_vfp_addr;
  91
  92   for (int i = 0; i < 16; i++)
  93     {
  94       trad_frame_set_reg_addr (this_cache,
  95                                ARM_A1_REGNUM + i,
  96                                mcontext_addr + i * ARM_MCONTEXT_REG_SIZE);
  97     }
  98   trad_frame_set_reg_addr (this_cache, ARM_PS_REGNUM,
  99                            mcontext_addr + 16 * ARM_MCONTEXT_REG_SIZE);
 100
 101   if (safe_read_memory_unsigned_integer (mcontext_addr
 102                                          + ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
 103                                          byte_order,
 104                                          &mcontext_vfp_addr)
 105       && mcontext_vfp_addr != 0)
 106     {
 107       for (int i = 0; i < 32; i++)
 108         {
 109           trad_frame_set_reg_addr (this_cache, ARM_D0_REGNUM + i,
 110                                    mcontext_vfp_addr
 111                                    + i * ARM_MCONTEXT_VFP_REG_SIZE);
 112         }
 113       trad_frame_set_reg_addr (this_cache, ARM_FPSCR_REGNUM,
 114                                mcontext_vfp_addr
 115                                + 32 * ARM_MCONTEXT_VFP_REG_SIZE);
 116     }
 117
 118   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 119 }
 120
 121 static const struct tramp_frame arm_fbsd_sigframe =
 122 {
 123   SIGTRAMP_FRAME,
 124   4,
 125   {
 126     {0xe1a0000d, ULONGEST_MAX},         /* mov  r0, sp  */
 127     {0xe2800040, ULONGEST_MAX},         /* add  r0, r0, #SIGF_UC  */
 128     {0xe59f700c, ULONGEST_MAX},         /* ldr  r7, [pc, #12]  */
 129     {0xef0001a1, ULONGEST_MAX},         /* swi  SYS_sigreturn  */
 130     {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
 131   },
 132   arm_fbsd_sigframe_init
 133 };
 134
 135 /* Register maps.  */
 136
 137 static const struct regcache_map_entry arm_fbsd_gregmap[] =
 138   {
 139     { 13, ARM_A1_REGNUM, 4 }, /* r0 ... r12 */
 140     { 1, ARM_SP_REGNUM, 4 },
 141     { 1, ARM_LR_REGNUM, 4 },
 142     { 1, ARM_PC_REGNUM, 4 },
 143     { 1, ARM_PS_REGNUM, 4 },
 144     { 0 }
 145   };
 146
 147 static const struct regcache_map_entry arm_fbsd_vfpregmap[] =
 148   {
 149     { 32, ARM_D0_REGNUM, 8 }, /* d0 ... d31 */
 150     { 1, ARM_FPSCR_REGNUM, 4 },
 151     { 0 }
 152   };
 153
 154 /* Register set definitions.  */
 155
 156 const struct regset arm_fbsd_gregset =
 157   {
 158     arm_fbsd_gregmap,
 159     regcache_supply_regset, regcache_collect_regset
 160   };
 161
 162 const struct regset arm_fbsd_vfpregset =
 163   {
 164     arm_fbsd_vfpregmap,
 165     regcache_supply_regset, regcache_collect_regset
 166   };
 167
 168 /* Implement the "regset_from_core_section" gdbarch method.  */
 169
 170 static void
 171 arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 172                                        iterate_over_regset_sections_cb *cb,
 173                                        void *cb_data,
 174                                        const struct regcache *regcache)
 175 {
 176   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 177
 178   cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
 179       &arm_fbsd_gregset, NULL, cb_data);
 180
 181   /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
 182      register set, it is not populated with register values by the
 183      kernel but just contains all zeroes.  */
 184   if (tdep->vfp_register_count > 0)
 185     cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, ARM_FBSD_SIZEOF_VFPREGSET,
 186         &arm_fbsd_vfpregset, "VFP floating-point", cb_data);
 187 }
 188
 189 /* Lookup a target description from a target's AT_HWCAP auxiliary
 190    vector.  */
 191
 192 const struct target_desc *
 193 arm_fbsd_read_description_auxv (struct target_ops *target)
 194 {
 195   CORE_ADDR arm_hwcap = 0;
 196
 197   if (target_auxv_search (target, AT_FREEBSD_HWCAP, &arm_hwcap) != 1)
 198     return NULL;
 199
 200   if (arm_hwcap & HWCAP_VFP)
 201     {
 202       if (arm_hwcap & HWCAP_NEON)
 203         return tdesc_arm_with_neon;
 204       else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
 205           == (HWCAP_VFPv3 | HWCAP_VFPD32))
 206         return tdesc_arm_with_vfpv3;
 207       else
 208         return tdesc_arm_with_vfpv2;
 209     }
 210
 211   return NULL;
 212 }
 213
 214 /* Implement the "core_read_description" gdbarch method.  */
 215
 216 static const struct target_desc *
 217 arm_fbsd_core_read_description (struct gdbarch *gdbarch,
 218                                 struct target_ops *target,
 219                                 bfd *abfd)
 220 {
 221   return arm_fbsd_read_description_auxv (target);
 222 }
 223
 224 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
 225
 226 static void
 227 arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 228 {
 229   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 230
 231   /* Generic FreeBSD support.  */
 232   fbsd_init_abi (info, gdbarch);
 233
 234   if (tdep->fp_model == ARM_FLOAT_AUTO)
 235     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 236
 237   tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
 238
 239   set_solib_svr4_fetch_link_map_offsets
 240     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 241
 242   tdep->jb_pc = 24;
 243   tdep->jb_elt_size = 4;
 244
 245   set_gdbarch_iterate_over_regset_sections
 246     (gdbarch, arm_fbsd_iterate_over_regset_sections);
 247   set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
 248
 249   /* Single stepping.  */
 250   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 251 }
 252
 253 void
 254 _initialize_arm_fbsd_tdep (void)
 255 {
 256   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
 257                           arm_fbsd_init_abi);
 258 }