gdb/nios2-linux-tdep.c

   1 /* Target-dependent code for GNU/Linux on Nios II.
   2    Copyright (C) 2012-2014 Free Software Foundation, Inc.
   3    Contributed by Mentor Graphics, 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 #include "frame.h"
  22 #include "osabi.h"
  23 #include "solib-svr4.h"
  24 #include "trad-frame.h"
  25 #include "tramp-frame.h"
  26 #include "symtab.h"
  27 #include "regset.h"
  28 #include "regcache.h"
  29 #include "linux-tdep.h"
  30 #include "glibc-tdep.h"
  31 #include "nios2-tdep.h"
  32
  33 #include "features/nios2-linux.c"
  34
  35 /* Core file and register set support.  */
  36
  37 /* Map from the normal register enumeration order to the order that
  38    registers appear in core files, which corresponds to the order
  39    of the register slots in the kernel's struct pt_regs.  */
  40
  41 static const int reg_offsets[NIOS2_NUM_REGS] =
  42 {
  43   -1,  8,  9, 10, 11, 12, 13, 14,       /* r0 - r7 */
  44   0,  1,  2,  3,  4,  5,  6,  7,        /* r8 - r15 */
  45   23, 24, 25, 26, 27, 28, 29, 30,       /* r16 - r23 */
  46   -1, -1, 19, 18, 17, 21, -1, 16,       /* et bt gp sp fp ea sstatus ra */
  47   21,                                   /* pc */
  48   -1, 20, -1, -1, -1, -1, -1, -1,       /* status estatus ...  */
  49   -1, -1, -1, -1, -1, -1, -1, -1
  50 };
  51
  52 /* Implement the supply_regset hook for core files.  */
  53
  54 static void
  55 nios2_supply_gregset (const struct regset *regset,
  56                       struct regcache *regcache,
  57                       int regnum, const void *gregs_buf, size_t len)
  58 {
  59   const gdb_byte *gregs = gregs_buf;
  60   int regno;
  61   static const gdb_byte zero_buf[4] = {0, 0, 0, 0};
  62
  63   for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++)
  64     if (regnum == -1 || regnum == regno)
  65       {
  66         if (reg_offsets[regno] != -1)
  67           regcache_raw_supply (regcache, regno,
  68                                gregs + 4 * reg_offsets[regno]);
  69         else
  70           regcache_raw_supply (regcache, regno, zero_buf);
  71       }
  72 }
  73
  74 static const struct regset nios2_core_regset =
  75 {
  76   NULL,
  77   nios2_supply_gregset,
  78   NULL,
  79 };
  80
  81 /* Implement the regset_from_core_section gdbarch method.  */
  82
  83 static const struct regset *
  84 nios2_regset_from_core_section (struct gdbarch *gdbarch,
  85                                 const char *sect_name, size_t sect_size)
  86 {
  87   if (strcmp (sect_name, ".reg") == 0)
  88     return &nios2_core_regset;
  89
  90   return NULL;
  91 }
  92
  93 /* Initialize a trad-frame cache corresponding to the tramp-frame.
  94    FUNC is the address of the instruction TRAMP[0] in memory.  */
  95
  96 static void
  97 nios2_linux_rt_sigreturn_init (const struct tramp_frame *self,
  98                                struct frame_info *next_frame,
  99                                struct trad_frame_cache *this_cache,
 100                                CORE_ADDR func)
 101 {
 102   CORE_ADDR base = func + 41 * 4;
 103   int i;
 104
 105   for (i = 0; i < 23; i++)
 106     trad_frame_set_reg_addr (this_cache, i + 1, base + i * 4);
 107   trad_frame_set_reg_addr (this_cache, NIOS2_RA_REGNUM, base + 23 * 4);
 108   trad_frame_set_reg_addr (this_cache, NIOS2_FP_REGNUM, base + 24 * 4);
 109   trad_frame_set_reg_addr (this_cache, NIOS2_GP_REGNUM, base + 25 * 4);
 110   trad_frame_set_reg_addr (this_cache, NIOS2_PC_REGNUM, base + 27 * 4);
 111   trad_frame_set_reg_addr (this_cache, NIOS2_SP_REGNUM, base + 28 * 4);
 112
 113   /* Save a frame ID.  */
 114   trad_frame_set_id (this_cache, frame_id_build (base, func));
 115 }
 116
 117 static struct tramp_frame nios2_linux_rt_sigreturn_tramp_frame =
 118 {
 119   SIGTRAMP_FRAME,
 120   4,
 121   {
 122     { 0x00800004 | (139 << 6), -1 },  /* movi r2,__NR_rt_sigreturn */
 123     { 0x003b683a, -1 },               /* trap */
 124     { TRAMP_SENTINEL_INSN }
 125   },
 126   nios2_linux_rt_sigreturn_init
 127 };
 128
 129 /* When FRAME is at a syscall instruction, return the PC of the next
 130    instruction to be executed.  */
 131
 132 static CORE_ADDR
 133 nios2_linux_syscall_next_pc (struct frame_info *frame)
 134 {
 135   CORE_ADDR pc = get_frame_pc (frame);
 136   ULONGEST syscall_nr = get_frame_register_unsigned (frame, NIOS2_R2_REGNUM);
 137
 138   /* If we are about to make a sigreturn syscall, use the unwinder to
 139      decode the signal frame.  */
 140   if (syscall_nr == 139 /* rt_sigreturn */)
 141     return frame_unwind_caller_pc (frame);
 142
 143   return pc + NIOS2_OPCODE_SIZE;
 144 }
 145
 146 /* Hook function for gdbarch_register_osabi.  */
 147
 148 static void
 149 nios2_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 150 {
 151   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 152
 153   linux_init_abi (info, gdbarch);
 154
 155   /* Shared library handling.  */
 156   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 157   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 158
 159   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 160                                          svr4_ilp32_fetch_link_map_offsets);
 161   /* Enable TLS support.  */
 162   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 163                                              svr4_fetch_objfile_link_map);
 164   /* Core file support.  */
 165   set_gdbarch_regset_from_core_section (gdbarch,
 166                                         nios2_regset_from_core_section);
 167   /* Linux signal frame unwinders.  */
 168   tramp_frame_prepend_unwinder (gdbarch,
 169                                 &nios2_linux_rt_sigreturn_tramp_frame);
 170
 171   tdep->syscall_next_pc = nios2_linux_syscall_next_pc;
 172
 173   /* Index of target address word in glibc jmp_buf.  */
 174   tdep->jb_pc = 10;
 175 }
 176
 177 /* Provide a prototype to silence -Wmissing-prototypes.  */
 178
 179 extern initialize_file_ftype _initialize_nios2_linux_tdep;
 180
 181 void
 182 _initialize_nios2_linux_tdep (void)
 183 {
 184   gdbarch_register_osabi (bfd_arch_nios2, 0, GDB_OSABI_LINUX,
 185                           nios2_linux_init_abi);
 186
 187   initialize_tdesc_nios2_linux ();
 188 }