gdb/tic6x-linux-tdep.c

   1 /* GNU/Linux on  TI C6x target support.
   2    Copyright (C) 2011
   3    Free Software Foundation, Inc.
   4    Contributed by Yao Qi <yao@codesourcery.com>
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "solib.h"
  23 #include "osabi.h"
  24 #include "linux-tdep.h"
  25 #include "tic6x-tdep.h"
  26 #include "trad-frame.h"
  27 #include "tramp-frame.h"
  28 #include "gdb_assert.h"
  29 #include "elf-bfd.h"
  30 #include "elf/tic6x.h"
  31
  32 #include "features/tic6x-c64xp-linux.c"
  33 #include "features/tic6x-c64x-linux.c"
  34 #include "features/tic6x-c62x-linux.c"
  35
  36 /* The offset from rt_sigframe pointer to SP register.  */
  37 #define TIC6X_SP_RT_SIGFRAME 8
  38 /* Size of struct siginfo info.  */
  39 #define TIC6X_SIGINFO_SIZE 128
  40 /* Size of type stack_t, which contains three fields of type void*, int, and
  41    size_t respectively.  */
  42 #define TIC6X_STACK_T_SIZE (3 * 4)
  43
  44 const gdb_byte tic6x_bkpt_illegal_opcode_be[] = { 0x56, 0x45, 0x43, 0x14 };
  45 const gdb_byte tic6x_bkpt_illegal_opcode_le[] = { 0x14, 0x43, 0x45, 0x56 };
  46
  47 static const gdb_byte tic6x_bkpt_bnop_be[] = { 0x00, 0x00, 0xa1, 0x22 };
  48 static const gdb_byte tic6x_bkpt_bnop_le[] = { 0x22, 0xa1, 0x00, 0x00 };
  49
  50 /* Return the offset of register REGNUM in struct sigcontext.  Return 0 if no
  51    such register in sigcontext.  */
  52
  53 static unsigned int
  54 tic6x_register_sigcontext_offset (unsigned int regnum, struct gdbarch *gdbarch)
  55 {
  56   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  57
  58   if (regnum == TIC6X_A4_REGNUM || regnum == TIC6X_A4_REGNUM + 2
  59       || regnum == TIC6X_A4_REGNUM + 4)
  60     return 4 * (regnum - TIC6X_A4_REGNUM + 2);  /* A4, A6, A8 */
  61   else if (regnum == TIC6X_A5_REGNUM || regnum == TIC6X_A5_REGNUM + 2
  62            || regnum == TIC6X_A5_REGNUM + 4)
  63     return 4 * (regnum - TIC6X_A5_REGNUM + 12); /* A5, A7, A9 */
  64   else if (regnum == TIC6X_B4_REGNUM || regnum == TIC6X_B4_REGNUM + 2
  65            || regnum == TIC6X_B4_REGNUM + 4)
  66     return 4 * (regnum - TIC6X_B4_REGNUM + 3);  /* B4, B6, B8 */
  67   else if (regnum == TIC6X_B5_REGNUM || regnum == TIC6X_B5_REGNUM + 2
  68            || regnum == TIC6X_B5_REGNUM + 4)
  69     return 4 * (regnum - TIC6X_B5_REGNUM + 19); /* B5, B7, B9 */
  70   else if (regnum >= 0 && regnum < TIC6X_A4_REGNUM)
  71     return 4 * (regnum - 0 + 8);        /* A0 - A3 */
  72   else if (regnum >= TIC6X_B0_REGNUM && regnum < TIC6X_B4_REGNUM)
  73     return 4 * (regnum - TIC6X_B0_REGNUM + 15); /* B0 - B3 */
  74   else if (regnum >= 34 && regnum < 34 + 32)
  75     return 4 * (regnum - 34 + 23);      /* A16 - A31, B16 - B31 */
  76   else if (regnum == TIC6X_PC_REGNUM)
  77     return 4 * (tdep->has_gp ? 55 : 23);
  78   else if (regnum == TIC6X_SP_REGNUM)
  79     return 4;
  80
  81   return 0;
  82 }
  83
  84 /* Support unwinding frame in signal trampoline.  We don't check sigreturn,
  85    since it is not used in kernel.  */
  86
  87 static void
  88 tic6x_linux_rt_sigreturn_init (const struct tramp_frame *self,
  89                                struct frame_info *this_frame,
  90                                struct trad_frame_cache *this_cache,
  91                                CORE_ADDR func)
  92 {
  93   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  94   CORE_ADDR sp = get_frame_register_unsigned (this_frame, TIC6X_SP_REGNUM);
  95   /* The base of struct sigcontext is computed by examining the definition of
  96      struct rt_sigframe in linux kernel source arch/c6x/kernel/signal.c.  */
  97   CORE_ADDR base = (sp + TIC6X_SP_RT_SIGFRAME
  98                     /* Pointer type *pinfo and *puc in struct rt_sigframe.  */
  99                     + 4 + 4
 100                     + TIC6X_SIGINFO_SIZE
 101                     + 4 + 4 /* uc_flags and *uc_link in struct ucontext.  */
 102                     + TIC6X_STACK_T_SIZE);
 103   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 104   unsigned int reg_offset;
 105   unsigned int i;
 106
 107   for (i = 0; i < 10; i++)      /* A0 - A9 */
 108     {
 109       reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 110       gdb_assert (reg_offset != 0);
 111
 112       trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 113     }
 114
 115   for (i = TIC6X_B0_REGNUM; i < TIC6X_B0_REGNUM + 10; i++)      /* B0 - B9 */
 116     {
 117       reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 118       gdb_assert (reg_offset != 0);
 119
 120       trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 121     }
 122
 123   if (tdep->has_gp)
 124     for (i = 34; i < 34 + 32; i++)      /* A16 - A31, B16 - B31 */
 125       {
 126         reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 127         gdb_assert (reg_offset != 0);
 128
 129         trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 130       }
 131
 132   trad_frame_set_reg_addr (this_cache, TIC6X_PC_REGNUM,
 133                            base + tic6x_register_sigcontext_offset (TIC6X_PC_REGNUM,
 134                                                                     gdbarch));
 135   trad_frame_set_reg_addr (this_cache, TIC6X_SP_REGNUM,
 136                            base + tic6x_register_sigcontext_offset (TIC6X_SP_REGNUM,
 137                                                                     gdbarch));
 138
 139   /* Save a frame ID.  */
 140   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 141 }
 142
 143 static struct tramp_frame tic6x_linux_rt_sigreturn_tramp_frame =
 144 {
 145   SIGTRAMP_FRAME,
 146   4,
 147   {
 148     {0x000045aa, 0x0fffffff},   /* mvk .S2 139,b0 */
 149     {0x10000000, -1},           /* swe */
 150     {TRAMP_SENTINEL_INSN}
 151   },
 152   tic6x_linux_rt_sigreturn_init
 153 };
 154
 155 /* When FRAME is at a syscall instruction, return the PC of the next
 156    instruction to be executed.  */
 157
 158 static CORE_ADDR
 159 tic6x_linux_syscall_next_pc (struct frame_info *frame)
 160 {
 161   ULONGEST syscall_number = get_frame_register_unsigned (frame,
 162                                                          TIC6X_B0_REGNUM);
 163   CORE_ADDR pc = get_frame_pc (frame);
 164
 165   if (syscall_number == 139 /* rt_sigreturn */)
 166     return frame_unwind_caller_pc (frame);
 167
 168   return pc + 4;
 169 }
 170
 171
 172 extern struct target_so_ops dsbt_so_ops;
 173 static void
 174 tic6x_uclinux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 175 {
 176   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 177
 178   linux_init_abi (info, gdbarch);
 179
 180   /* Shared library handling.  */
 181   set_solib_ops (gdbarch, &dsbt_so_ops);
 182
 183   tdep->syscall_next_pc = tic6x_linux_syscall_next_pc;
 184
 185 #ifdef HAVE_ELF
 186   /* In tic6x Linux kernel, breakpoint instructions varies on different archs.
 187      On C64x+ and C67x+, breakpoint instruction is 0x56454314, which is an
 188      illegal opcode.  On other arch, breakpoint instruction is 0x0000a122
 189      (BNOP .S2 0,5).  */
 190   if (info.abfd)
 191     switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_PROC, Tag_ISA))
 192       {
 193       case C6XABI_Tag_ISA_C64XP:
 194       case C6XABI_Tag_ISA_C67XP:
 195         if (info.byte_order == BFD_ENDIAN_BIG)
 196           tdep->breakpoint = tic6x_bkpt_illegal_opcode_be;
 197         else
 198           tdep->breakpoint = tic6x_bkpt_illegal_opcode_le;
 199         break;
 200       default:
 201         {
 202           if (info.byte_order == BFD_ENDIAN_BIG)
 203             tdep->breakpoint = tic6x_bkpt_bnop_be;
 204           else
 205             tdep->breakpoint = tic6x_bkpt_bnop_le;
 206         }
 207       }
 208 #endif
 209
 210   /* Signal trampoline support.  */
 211   tramp_frame_prepend_unwinder (gdbarch,
 212                                 &tic6x_linux_rt_sigreturn_tramp_frame);
 213 }
 214
 215 /* Provide a prototype to silence -Wmissing-prototypes.  */
 216 extern initialize_file_ftype _initialize_tic6x_linux_tdep;
 217
 218 void
 219 _initialize_tic6x_linux_tdep (void)
 220 {
 221   gdbarch_register_osabi (bfd_arch_tic6x, 0, GDB_OSABI_LINUX,
 222                           tic6x_uclinux_init_abi);
 223
 224   initialize_tdesc_tic6x_c64xp_linux ();
 225   initialize_tdesc_tic6x_c64x_linux ();
 226   initialize_tdesc_tic6x_c62x_linux ();
 227 }