gdb/tic6x-linux-tdep.c

   1 /* GNU/Linux on  TI C6x target support.
   2    Copyright (C) 2011-2014 Free Software Foundation, Inc.
   3    Contributed by Yao Qi <yao@codesourcery.com>
   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 "solib.h"
  22 #include "osabi.h"
  23 #include "linux-tdep.h"
  24 #include "tic6x-tdep.h"
  25 #include "trad-frame.h"
  26 #include "tramp-frame.h"
  27 #include "gdb_assert.h"
  28 #include "elf-bfd.h"
  29 #include "elf/tic6x.h"
  30
  31 #include "features/tic6x-c64xp-linux.c"
  32 #include "features/tic6x-c64x-linux.c"
  33 #include "features/tic6x-c62x-linux.c"
  34
  35 /* The offset from rt_sigframe pointer to SP register.  */
  36 #define TIC6X_SP_RT_SIGFRAME 8
  37 /* Size of struct siginfo info.  */
  38 #define TIC6X_SIGINFO_SIZE 128
  39 /* Size of type stack_t, which contains three fields of type void*, int, and
  40    size_t respectively.  */
  41 #define TIC6X_STACK_T_SIZE (3 * 4)
  42
  43 static const gdb_byte tic6x_bkpt_bnop_be[] = { 0x00, 0x00, 0xa1, 0x22 };
  44 static const gdb_byte tic6x_bkpt_bnop_le[] = { 0x22, 0xa1, 0x00, 0x00 };
  45
  46 /* Return the offset of register REGNUM in struct sigcontext.  Return 0 if no
  47    such register in sigcontext.  */
  48
  49 static unsigned int
  50 tic6x_register_sigcontext_offset (unsigned int regnum, struct gdbarch *gdbarch)
  51 {
  52   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  53
  54   if (regnum == TIC6X_A4_REGNUM || regnum == TIC6X_A4_REGNUM + 2
  55       || regnum == TIC6X_A4_REGNUM + 4)
  56     return 4 * (regnum - TIC6X_A4_REGNUM + 2);  /* A4, A6, A8 */
  57   else if (regnum == TIC6X_A5_REGNUM || regnum == TIC6X_A5_REGNUM + 2
  58            || regnum == TIC6X_A5_REGNUM + 4)
  59     return 4 * (regnum - TIC6X_A5_REGNUM + 12); /* A5, A7, A9 */
  60   else if (regnum == TIC6X_B4_REGNUM || regnum == TIC6X_B4_REGNUM + 2
  61            || regnum == TIC6X_B4_REGNUM + 4)
  62     return 4 * (regnum - TIC6X_B4_REGNUM + 3);  /* B4, B6, B8 */
  63   else if (regnum == TIC6X_B5_REGNUM || regnum == TIC6X_B5_REGNUM + 2
  64            || regnum == TIC6X_B5_REGNUM + 4)
  65     return 4 * (regnum - TIC6X_B5_REGNUM + 19); /* B5, B7, B9 */
  66   else if (regnum < TIC6X_A4_REGNUM)
  67     return 4 * (regnum - 0 + 8);        /* A0 - A3 */
  68   else if (regnum >= TIC6X_B0_REGNUM && regnum < TIC6X_B4_REGNUM)
  69     return 4 * (regnum - TIC6X_B0_REGNUM + 15); /* B0 - B3 */
  70   else if (regnum >= 34 && regnum < 34 + 32)
  71     return 4 * (regnum - 34 + 23);      /* A16 - A31, B16 - B31 */
  72   else if (regnum == TIC6X_PC_REGNUM)
  73     return 4 * (tdep->has_gp ? 55 : 23);
  74   else if (regnum == TIC6X_SP_REGNUM)
  75     return 4;
  76
  77   return 0;
  78 }
  79
  80 /* Support unwinding frame in signal trampoline.  We don't check sigreturn,
  81    since it is not used in kernel.  */
  82
  83 static void
  84 tic6x_linux_rt_sigreturn_init (const struct tramp_frame *self,
  85                                struct frame_info *this_frame,
  86                                struct trad_frame_cache *this_cache,
  87                                CORE_ADDR func)
  88 {
  89   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  90   CORE_ADDR sp = get_frame_register_unsigned (this_frame, TIC6X_SP_REGNUM);
  91   /* The base of struct sigcontext is computed by examining the definition of
  92      struct rt_sigframe in linux kernel source arch/c6x/kernel/signal.c.  */
  93   CORE_ADDR base = (sp + TIC6X_SP_RT_SIGFRAME
  94                     /* Pointer type *pinfo and *puc in struct rt_sigframe.  */
  95                     + 4 + 4
  96                     + TIC6X_SIGINFO_SIZE
  97                     + 4 + 4 /* uc_flags and *uc_link in struct ucontext.  */
  98                     + TIC6X_STACK_T_SIZE);
  99   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 100   unsigned int reg_offset;
 101   unsigned int i;
 102
 103   for (i = 0; i < 10; i++)      /* A0 - A9 */
 104     {
 105       reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 106       gdb_assert (reg_offset != 0);
 107
 108       trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 109     }
 110
 111   for (i = TIC6X_B0_REGNUM; i < TIC6X_B0_REGNUM + 10; i++)      /* B0 - B9 */
 112     {
 113       reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 114       gdb_assert (reg_offset != 0);
 115
 116       trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 117     }
 118
 119   if (tdep->has_gp)
 120     for (i = 34; i < 34 + 32; i++)      /* A16 - A31, B16 - B31 */
 121       {
 122         reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 123         gdb_assert (reg_offset != 0);
 124
 125         trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 126       }
 127
 128   trad_frame_set_reg_addr (this_cache, TIC6X_PC_REGNUM,
 129                            base + tic6x_register_sigcontext_offset (TIC6X_PC_REGNUM,
 130                                                                     gdbarch));
 131   trad_frame_set_reg_addr (this_cache, TIC6X_SP_REGNUM,
 132                            base + tic6x_register_sigcontext_offset (TIC6X_SP_REGNUM,
 133                                                                     gdbarch));
 134
 135   /* Save a frame ID.  */
 136   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 137 }
 138
 139 static struct tramp_frame tic6x_linux_rt_sigreturn_tramp_frame =
 140 {
 141   SIGTRAMP_FRAME,
 142   4,
 143   {
 144     {0x000045aa, 0x0fffffff},   /* mvk .S2 139,b0 */
 145     {0x10000000, -1},           /* swe */
 146     {TRAMP_SENTINEL_INSN}
 147   },
 148   tic6x_linux_rt_sigreturn_init
 149 };
 150
 151 /* When FRAME is at a syscall instruction, return the PC of the next
 152    instruction to be executed.  */
 153
 154 static CORE_ADDR
 155 tic6x_linux_syscall_next_pc (struct frame_info *frame)
 156 {
 157   ULONGEST syscall_number = get_frame_register_unsigned (frame,
 158                                                          TIC6X_B0_REGNUM);
 159   CORE_ADDR pc = get_frame_pc (frame);
 160
 161   if (syscall_number == 139 /* rt_sigreturn */)
 162     return frame_unwind_caller_pc (frame);
 163
 164   return pc + 4;
 165 }
 166
 167
 168 extern struct target_so_ops dsbt_so_ops;
 169 static void
 170 tic6x_uclinux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 171 {
 172   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 173
 174   linux_init_abi (info, gdbarch);
 175
 176   /* Shared library handling.  */
 177   set_solib_ops (gdbarch, &dsbt_so_ops);
 178
 179   tdep->syscall_next_pc = tic6x_linux_syscall_next_pc;
 180
 181 #ifdef HAVE_ELF
 182   /* In tic6x Linux kernel, breakpoint instructions varies on different archs.
 183      On C64x+ and C67x+, breakpoint instruction is 0x56454314, which is an
 184      illegal opcode.  On other arch, breakpoint instruction is 0x0000a122
 185      (BNOP .S2 0,5).  */
 186   if (info.abfd)
 187     switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_PROC, Tag_ISA))
 188       {
 189       case C6XABI_Tag_ISA_C64XP:
 190       case C6XABI_Tag_ISA_C67XP:
 191         if (info.byte_order == BFD_ENDIAN_BIG)
 192           tdep->breakpoint = tic6x_bkpt_illegal_opcode_be;
 193         else
 194           tdep->breakpoint = tic6x_bkpt_illegal_opcode_le;
 195         break;
 196       default:
 197         {
 198           if (info.byte_order == BFD_ENDIAN_BIG)
 199             tdep->breakpoint = tic6x_bkpt_bnop_be;
 200           else
 201             tdep->breakpoint = tic6x_bkpt_bnop_le;
 202         }
 203       }
 204 #endif
 205
 206   /* Signal trampoline support.  */
 207   tramp_frame_prepend_unwinder (gdbarch,
 208                                 &tic6x_linux_rt_sigreturn_tramp_frame);
 209 }
 210
 211 /* Provide a prototype to silence -Wmissing-prototypes.  */
 212 extern initialize_file_ftype _initialize_tic6x_linux_tdep;
 213
 214 void
 215 _initialize_tic6x_linux_tdep (void)
 216 {
 217   gdbarch_register_osabi (bfd_arch_tic6x, 0, GDB_OSABI_LINUX,
 218                           tic6x_uclinux_init_abi);
 219
 220   initialize_tdesc_tic6x_c64xp_linux ();
 221   initialize_tdesc_tic6x_c64x_linux ();
 222   initialize_tdesc_tic6x_c62x_linux ();
 223 }