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 "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 const struct regset nios2_core_regset =
  77 {
  78   NULL,
  79   nios2_supply_gregset,
  80   NULL,
  81 };
  82
  83 /* Implement the regset_from_core_section gdbarch method.  */
  84
  85 static const struct regset *
  86 nios2_regset_from_core_section (struct gdbarch *gdbarch,
  87                                 const char *sect_name, size_t sect_size)
  88 {
  89   if (strcmp (sect_name, ".reg") == 0)
  90     return &nios2_core_regset;
  91
  92   return NULL;
  93 }
  94
  95 /* Initialize a trad-frame cache corresponding to the tramp-frame.
  96    FUNC is the address of the instruction TRAMP[0] in memory.  */
  97
  98 static void
  99 nios2_linux_rt_sigreturn_init (const struct tramp_frame *self,
 100                                struct frame_info *next_frame,
 101                                struct trad_frame_cache *this_cache,
 102                                CORE_ADDR func)
 103 {
 104   CORE_ADDR base = func + 41 * 4;
 105   int i;
 106
 107   for (i = 0; i < 23; i++)
 108     trad_frame_set_reg_addr (this_cache, i + 1, base + i * 4);
 109   trad_frame_set_reg_addr (this_cache, NIOS2_RA_REGNUM, base + 23 * 4);
 110   trad_frame_set_reg_addr (this_cache, NIOS2_FP_REGNUM, base + 24 * 4);
 111   trad_frame_set_reg_addr (this_cache, NIOS2_GP_REGNUM, base + 25 * 4);
 112   trad_frame_set_reg_addr (this_cache, NIOS2_PC_REGNUM, base + 27 * 4);
 113   trad_frame_set_reg_addr (this_cache, NIOS2_SP_REGNUM, base + 28 * 4);
 114
 115   /* Save a frame ID.  */
 116   trad_frame_set_id (this_cache, frame_id_build (base, func));
 117 }
 118
 119 static struct tramp_frame nios2_linux_rt_sigreturn_tramp_frame =
 120 {
 121   SIGTRAMP_FRAME,
 122   4,
 123   {
 124     { 0x00800004 | (139 << 6), -1 },  /* movi r2,__NR_rt_sigreturn */
 125     { 0x003b683a, -1 },               /* trap */
 126     { TRAMP_SENTINEL_INSN }
 127   },
 128   nios2_linux_rt_sigreturn_init
 129 };
 130
 131 /* When FRAME is at a syscall instruction, return the PC of the next
 132    instruction to be executed.  */
 133
 134 static CORE_ADDR
 135 nios2_linux_syscall_next_pc (struct frame_info *frame)
 136 {
 137   CORE_ADDR pc = get_frame_pc (frame);
 138   ULONGEST syscall_nr = get_frame_register_unsigned (frame, NIOS2_R2_REGNUM);
 139
 140   /* If we are about to make a sigreturn syscall, use the unwinder to
 141      decode the signal frame.  */
 142   if (syscall_nr == 139 /* rt_sigreturn */)
 143     return frame_unwind_caller_pc (frame);
 144
 145   return pc + NIOS2_OPCODE_SIZE;
 146 }
 147
 148 /* Hook function for gdbarch_register_osabi.  */
 149
 150 static void
 151 nios2_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 152 {
 153   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 154
 155   linux_init_abi (info, gdbarch);
 156
 157   /* Shared library handling.  */
 158   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 159   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 160
 161   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 162                                          svr4_ilp32_fetch_link_map_offsets);
 163   /* Enable TLS support.  */
 164   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 165                                              svr4_fetch_objfile_link_map);
 166   /* Core file support.  */
 167   set_gdbarch_regset_from_core_section (gdbarch,
 168                                         nios2_regset_from_core_section);
 169   /* Linux signal frame unwinders.  */
 170   tramp_frame_prepend_unwinder (gdbarch,
 171                                 &nios2_linux_rt_sigreturn_tramp_frame);
 172
 173   tdep->syscall_next_pc = nios2_linux_syscall_next_pc;
 174
 175   /* Index of target address word in glibc jmp_buf.  */
 176   tdep->jb_pc = 10;
 177 }
 178
 179 /* Provide a prototype to silence -Wmissing-prototypes.  */
 180
 181 extern initialize_file_ftype _initialize_nios2_linux_tdep;
 182
 183 void
 184 _initialize_nios2_linux_tdep (void)
 185 {
 186   gdbarch_register_osabi (bfd_arch_nios2, 0, GDB_OSABI_LINUX,
 187                           nios2_linux_init_abi);
 188
 189   initialize_tdesc_nios2_linux ();
 190 }