gdb/nios2-linux-tdep.c

   1 /* Target-dependent code for GNU/Linux on Nios II.
   2    Copyright (C) 2012-2013 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 "gdb_assert.h"
  23 #include <string.h>
  24 #include "osabi.h"
  25 #include "solib-svr4.h"
  26 #include "trad-frame.h"
  27 #include "tramp-frame.h"
  28 #include "symtab.h"
  29 #include "regset.h"
  30 #include "regcache.h"
  31 #include "linux-tdep.h"
  32 #include "glibc-tdep.h"
  33 #include "nios2-tdep.h"
  34
  35 #include "features/nios2-linux.c"
  36
  37 /* Core file and register set support.  */
  38
  39 /* Map from the normal register enumeration order to the order that
  40    registers appear in core files, which corresponds to the order
  41    of the register slots in the kernel's struct pt_regs.  */
  42
  43 static const int reg_offsets[NIOS2_NUM_REGS] =
  44 {
  45   -1,  8,  9, 10, 11, 12, 13, 14,       /* r0 - r7 */
  46   0,  1,  2,  3,  4,  5,  6,  7,        /* r8 - r15 */
  47   23, 24, 25, 26, 27, 28, 29, 30,       /* r16 - r23 */
  48   -1, -1, 19, 18, 17, 21, -1, 16,       /* et bt gp sp fp ea sstatus ra */
  49   21,                                   /* pc */
  50   -1, 20, -1, -1, -1, -1, -1, -1,       /* status estatus ...  */
  51   -1, -1, -1, -1, -1, -1, -1, -1
  52 };
  53
  54 /* Implement the supply_regset hook for core files.  */
  55
  56 static void
  57 nios2_supply_gregset (const struct regset *regset,
  58                       struct regcache *regcache,
  59                       int regnum, const void *gregs_buf, size_t len)
  60 {
  61   const gdb_byte *gregs = gregs_buf;
  62   int regno;
  63   static const gdb_byte zero_buf[4] = {0, 0, 0, 0};
  64
  65   for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++)
  66     if (regnum == -1 || regnum == regno)
  67       {
  68         if (reg_offsets[regno] != -1)
  69           regcache_raw_supply (regcache, regno,
  70                                gregs + 4 * reg_offsets[regno]);
  71         else
  72           regcache_raw_supply (regcache, regno, zero_buf);
  73       }
  74 }
  75
  76 static struct regset nios2_core_regset =
  77 {
  78   NULL,
  79   nios2_supply_gregset,
  80   NULL,
  81   NULL
  82 };
  83
  84 /* Implement the regset_from_core_section gdbarch method.  */
  85
  86 static const struct regset *
  87 nios2_regset_from_core_section (struct gdbarch *gdbarch,
  88                                 const char *sect_name, size_t sect_size)
  89 {
  90   if (strcmp (sect_name, ".reg") == 0)
  91     return &nios2_core_regset;
  92
  93   return NULL;
  94 }
  95
  96 /* Initialize a trad-frame cache corresponding to the tramp-frame.
  97    FUNC is the address of the instruction TRAMP[0] in memory.  */
  98
  99 static void
 100 nios2_linux_rt_sigreturn_init (const struct tramp_frame *self,
 101                                struct frame_info *next_frame,
 102                                struct trad_frame_cache *this_cache,
 103                                CORE_ADDR func)
 104 {
 105   CORE_ADDR base = func + 41 * 4;
 106   int i;
 107
 108   for (i = 0; i < 23; i++)
 109     trad_frame_set_reg_addr (this_cache, i + 1, base + i * 4);
 110   trad_frame_set_reg_addr (this_cache, NIOS2_RA_REGNUM, base + 23 * 4);
 111   trad_frame_set_reg_addr (this_cache, NIOS2_FP_REGNUM, base + 24 * 4);
 112   trad_frame_set_reg_addr (this_cache, NIOS2_GP_REGNUM, base + 25 * 4);
 113   trad_frame_set_reg_addr (this_cache, NIOS2_PC_REGNUM, base + 27 * 4);
 114   trad_frame_set_reg_addr (this_cache, NIOS2_SP_REGNUM, base + 28 * 4);
 115
 116   /* Save a frame ID.  */
 117   trad_frame_set_id (this_cache, frame_id_build (base, func));
 118 }
 119
 120 static struct tramp_frame nios2_linux_rt_sigreturn_tramp_frame =
 121 {
 122   SIGTRAMP_FRAME,
 123   4,
 124   {
 125     { 0x00800004 | (139 << 6), -1 },  /* movi r2,__NR_rt_sigreturn */
 126     { 0x003b683a, -1 },               /* trap */
 127     { TRAMP_SENTINEL_INSN }
 128   },
 129   nios2_linux_rt_sigreturn_init
 130 };
 131
 132 /* When FRAME is at a syscall instruction, return the PC of the next
 133    instruction to be executed.  */
 134
 135 static CORE_ADDR
 136 nios2_linux_syscall_next_pc (struct frame_info *frame)
 137 {
 138   CORE_ADDR pc = get_frame_pc (frame);
 139   ULONGEST syscall_nr = get_frame_register_unsigned (frame, NIOS2_R2_REGNUM);
 140
 141   /* If we are about to make a sigreturn syscall, use the unwinder to
 142      decode the signal frame.  */
 143   if (syscall_nr == 139 /* rt_sigreturn */)
 144     return frame_unwind_caller_pc (frame);
 145
 146   return pc + NIOS2_OPCODE_SIZE;
 147 }
 148
 149 /* Hook function for gdbarch_register_osabi.  */
 150
 151 static void
 152 nios2_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 153 {
 154   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 155
 156   linux_init_abi (info, gdbarch);
 157
 158   /* Shared library handling.  */
 159   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 160   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 161
 162   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 163                                          svr4_ilp32_fetch_link_map_offsets);
 164   /* Enable TLS support.  */
 165   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 166                                              svr4_fetch_objfile_link_map);
 167   /* Core file support.  */
 168   set_gdbarch_regset_from_core_section (gdbarch,
 169                                         nios2_regset_from_core_section);
 170   /* Linux signal frame unwinders.  */
 171   tramp_frame_prepend_unwinder (gdbarch,
 172                                 &nios2_linux_rt_sigreturn_tramp_frame);
 173
 174   tdep->syscall_next_pc = nios2_linux_syscall_next_pc;
 175
 176   /* Index of target address word in glibc jmp_buf.  */
 177   tdep->jb_pc = 10;
 178 }
 179
 180 /* Provide a prototype to silence -Wmissing-prototypes.  */
 181
 182 extern initialize_file_ftype _initialize_nios2_linux_tdep;
 183
 184 void
 185 _initialize_nios2_linux_tdep (void)
 186 {
 187   gdbarch_register_osabi (bfd_arch_nios2, 0, GDB_OSABI_LINUX,
 188                           nios2_linux_init_abi);
 189
 190   initialize_tdesc_nios2_linux ();
 191 }