gdb/nios2-linux-tdep.c

   1 /* Target-dependent code for GNU/Linux on Nios II.
   2    Copyright (C) 2012-2015 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 /* General register set size.  Should match sizeof (struct pt_regs) +
  53    sizeof (struct switch_stack) from the NIOS2 Linux kernel patch.  */
  54
  55 #define NIOS2_GREGS_SIZE (4 * 34)
  56
  57 /* Implement the supply_regset hook for core files.  */
  58
  59 static void
  60 nios2_supply_gregset (const struct regset *regset,
  61                       struct regcache *regcache,
  62                       int regnum, const void *gregs_buf, size_t len)
  63 {
  64   const gdb_byte *gregs = gregs_buf;
  65   int regno;
  66   static const gdb_byte zero_buf[4] = {0, 0, 0, 0};
  67
  68   for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++)
  69     if (regnum == -1 || regnum == regno)
  70       {
  71         if (reg_offsets[regno] != -1)
  72           regcache_raw_supply (regcache, regno,
  73                                gregs + 4 * reg_offsets[regno]);
  74         else
  75           regcache_raw_supply (regcache, regno, zero_buf);
  76       }
  77 }
  78
  79 /* Implement the collect_regset hook for core files.  */
  80
  81 static void
  82 nios2_collect_gregset (const struct regset *regset,
  83                        const struct regcache *regcache,
  84                        int regnum, void *gregs_buf, size_t len)
  85 {
  86   gdb_byte *gregs = gregs_buf;
  87   int regno;
  88
  89   for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++)
  90     if (regnum == -1 || regnum == regno)
  91       {
  92         if (reg_offsets[regno] != -1)
  93           regcache_raw_collect (regcache, regno,
  94                                 gregs + 4 * reg_offsets[regno]);
  95       }
  96 }
  97
  98 static const struct regset nios2_core_regset =
  99 {
 100   NULL,
 101   nios2_supply_gregset,
 102   nios2_collect_gregset
 103 };
 104
 105 /* Iterate over core file register note sections.  */
 106
 107 static void
 108 nios2_iterate_over_regset_sections (struct gdbarch *gdbarch,
 109                                     iterate_over_regset_sections_cb *cb,
 110                                     void *cb_data,
 111                                     const struct regcache *regcache)
 112 {
 113   cb (".reg", NIOS2_GREGS_SIZE, &nios2_core_regset, NULL, cb_data);
 114 }
 115
 116 /* Initialize a trad-frame cache corresponding to the tramp-frame.
 117    FUNC is the address of the instruction TRAMP[0] in memory.  */
 118
 119 static void
 120 nios2_linux_rt_sigreturn_init (const struct tramp_frame *self,
 121                                struct frame_info *next_frame,
 122                                struct trad_frame_cache *this_cache,
 123                                CORE_ADDR func)
 124 {
 125   CORE_ADDR base = func + 41 * 4;
 126   int i;
 127
 128   for (i = 0; i < 23; i++)
 129     trad_frame_set_reg_addr (this_cache, i + 1, base + i * 4);
 130   trad_frame_set_reg_addr (this_cache, NIOS2_RA_REGNUM, base + 23 * 4);
 131   trad_frame_set_reg_addr (this_cache, NIOS2_FP_REGNUM, base + 24 * 4);
 132   trad_frame_set_reg_addr (this_cache, NIOS2_GP_REGNUM, base + 25 * 4);
 133   trad_frame_set_reg_addr (this_cache, NIOS2_PC_REGNUM, base + 27 * 4);
 134   trad_frame_set_reg_addr (this_cache, NIOS2_SP_REGNUM, base + 28 * 4);
 135
 136   /* Save a frame ID.  */
 137   trad_frame_set_id (this_cache, frame_id_build (base, func));
 138 }
 139
 140 static struct tramp_frame nios2_linux_rt_sigreturn_tramp_frame =
 141 {
 142   SIGTRAMP_FRAME,
 143   4,
 144   {
 145     { 0x00800004 | (139 << 6), -1 },  /* movi r2,__NR_rt_sigreturn */
 146     { 0x003b683a, -1 },               /* trap */
 147     { TRAMP_SENTINEL_INSN }
 148   },
 149   nios2_linux_rt_sigreturn_init
 150 };
 151
 152 /* When FRAME is at a syscall instruction, return the PC of the next
 153    instruction to be executed.  */
 154
 155 static CORE_ADDR
 156 nios2_linux_syscall_next_pc (struct frame_info *frame)
 157 {
 158   CORE_ADDR pc = get_frame_pc (frame);
 159   ULONGEST syscall_nr = get_frame_register_unsigned (frame, NIOS2_R2_REGNUM);
 160
 161   /* If we are about to make a sigreturn syscall, use the unwinder to
 162      decode the signal frame.  */
 163   if (syscall_nr == 139 /* rt_sigreturn */)
 164     return frame_unwind_caller_pc (frame);
 165
 166   return pc + NIOS2_OPCODE_SIZE;
 167 }
 168
 169 /* Hook function for gdbarch_register_osabi.  */
 170
 171 static void
 172 nios2_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 173 {
 174   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 175
 176   linux_init_abi (info, gdbarch);
 177
 178   /* Shared library handling.  */
 179   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 180   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 181
 182   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 183                                          svr4_ilp32_fetch_link_map_offsets);
 184   /* Enable TLS support.  */
 185   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 186                                              svr4_fetch_objfile_link_map);
 187   /* Core file support.  */
 188   set_gdbarch_iterate_over_regset_sections
 189     (gdbarch, nios2_iterate_over_regset_sections);
 190   /* Linux signal frame unwinders.  */
 191   tramp_frame_prepend_unwinder (gdbarch,
 192                                 &nios2_linux_rt_sigreturn_tramp_frame);
 193
 194   tdep->syscall_next_pc = nios2_linux_syscall_next_pc;
 195
 196   /* Index of target address word in glibc jmp_buf.  */
 197   tdep->jb_pc = 10;
 198 }
 199
 200 /* Provide a prototype to silence -Wmissing-prototypes.  */
 201
 202 extern initialize_file_ftype _initialize_nios2_linux_tdep;
 203
 204 void
 205 _initialize_nios2_linux_tdep (void)
 206 {
 207   gdbarch_register_osabi (bfd_arch_nios2, 0, GDB_OSABI_LINUX,
 208                           nios2_linux_init_abi);
 209
 210   initialize_tdesc_nios2_linux ();
 211 }