gdb/tic6x-linux-tdep.c

   1 /* GNU/Linux on  TI C6x target support.
   2    Copyright (C) 2011-2019 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 "elf-bfd.h"
  28 #include "elf/tic6x.h"
  29
  30 /* The offset from rt_sigframe pointer to SP register.  */
  31 #define TIC6X_SP_RT_SIGFRAME 8
  32 /* Size of struct siginfo info.  */
  33 #define TIC6X_SIGINFO_SIZE 128
  34 /* Size of type stack_t, which contains three fields of type void*, int, and
  35    size_t respectively.  */
  36 #define TIC6X_STACK_T_SIZE (3 * 4)
  37
  38 static const gdb_byte tic6x_bkpt_bnop_be[] = { 0x00, 0x00, 0xa1, 0x22 };
  39 static const gdb_byte tic6x_bkpt_bnop_le[] = { 0x22, 0xa1, 0x00, 0x00 };
  40
  41 /* Return the offset of register REGNUM in struct sigcontext.  Return 0 if no
  42    such register in sigcontext.  */
  43
  44 static unsigned int
  45 tic6x_register_sigcontext_offset (unsigned int regnum, struct gdbarch *gdbarch)
  46 {
  47   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  48
  49   if (regnum == TIC6X_A4_REGNUM || regnum == TIC6X_A4_REGNUM + 2
  50       || regnum == TIC6X_A4_REGNUM + 4)
  51     return 4 * (regnum - TIC6X_A4_REGNUM + 2);  /* A4, A6, A8 */
  52   else if (regnum == TIC6X_A5_REGNUM || regnum == TIC6X_A5_REGNUM + 2
  53            || regnum == TIC6X_A5_REGNUM + 4)
  54     return 4 * (regnum - TIC6X_A5_REGNUM + 12); /* A5, A7, A9 */
  55   else if (regnum == TIC6X_B4_REGNUM || regnum == TIC6X_B4_REGNUM + 2
  56            || regnum == TIC6X_B4_REGNUM + 4)
  57     return 4 * (regnum - TIC6X_B4_REGNUM + 3);  /* B4, B6, B8 */
  58   else if (regnum == TIC6X_B5_REGNUM || regnum == TIC6X_B5_REGNUM + 2
  59            || regnum == TIC6X_B5_REGNUM + 4)
  60     return 4 * (regnum - TIC6X_B5_REGNUM + 19); /* B5, B7, B9 */
  61   else if (regnum < TIC6X_A4_REGNUM)
  62     return 4 * (regnum - 0 + 8);        /* A0 - A3 */
  63   else if (regnum >= TIC6X_B0_REGNUM && regnum < TIC6X_B4_REGNUM)
  64     return 4 * (regnum - TIC6X_B0_REGNUM + 15); /* B0 - B3 */
  65   else if (regnum >= 34 && regnum < 34 + 32)
  66     return 4 * (regnum - 34 + 23);      /* A16 - A31, B16 - B31 */
  67   else if (regnum == TIC6X_PC_REGNUM)
  68     return 4 * (tdep->has_gp ? 55 : 23);
  69   else if (regnum == TIC6X_SP_REGNUM)
  70     return 4;
  71
  72   return 0;
  73 }
  74
  75 /* Support unwinding frame in signal trampoline.  We don't check sigreturn,
  76    since it is not used in kernel.  */
  77
  78 static void
  79 tic6x_linux_rt_sigreturn_init (const struct tramp_frame *self,
  80                                struct frame_info *this_frame,
  81                                struct trad_frame_cache *this_cache,
  82                                CORE_ADDR func)
  83 {
  84   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  85   CORE_ADDR sp = get_frame_register_unsigned (this_frame, TIC6X_SP_REGNUM);
  86   /* The base of struct sigcontext is computed by examining the definition of
  87      struct rt_sigframe in linux kernel source arch/c6x/kernel/signal.c.  */
  88   CORE_ADDR base = (sp + TIC6X_SP_RT_SIGFRAME
  89                     /* Pointer type *pinfo and *puc in struct rt_sigframe.  */
  90                     + 4 + 4
  91                     + TIC6X_SIGINFO_SIZE
  92                     + 4 + 4 /* uc_flags and *uc_link in struct ucontext.  */
  93                     + TIC6X_STACK_T_SIZE);
  94   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  95   unsigned int reg_offset;
  96   unsigned int i;
  97
  98   for (i = 0; i < 10; i++)      /* A0 - A9 */
  99     {
 100       reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 101       gdb_assert (reg_offset != 0);
 102
 103       trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 104     }
 105
 106   for (i = TIC6X_B0_REGNUM; i < TIC6X_B0_REGNUM + 10; i++)      /* B0 - B9 */
 107     {
 108       reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 109       gdb_assert (reg_offset != 0);
 110
 111       trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 112     }
 113
 114   if (tdep->has_gp)
 115     for (i = 34; i < 34 + 32; i++)      /* A16 - A31, B16 - B31 */
 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   trad_frame_set_reg_addr (this_cache, TIC6X_PC_REGNUM,
 124                            base + tic6x_register_sigcontext_offset (TIC6X_PC_REGNUM,
 125                                                                     gdbarch));
 126   trad_frame_set_reg_addr (this_cache, TIC6X_SP_REGNUM,
 127                            base + tic6x_register_sigcontext_offset (TIC6X_SP_REGNUM,
 128                                                                     gdbarch));
 129
 130   /* Save a frame ID.  */
 131   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 132 }
 133
 134 static struct tramp_frame tic6x_linux_rt_sigreturn_tramp_frame =
 135 {
 136   SIGTRAMP_FRAME,
 137   4,
 138   {
 139     {0x000045aa, 0x0fffffff},   /* mvk .S2 139,b0 */
 140     {0x10000000, ULONGEST_MAX},         /* swe */
 141     {TRAMP_SENTINEL_INSN}
 142   },
 143   tic6x_linux_rt_sigreturn_init
 144 };
 145
 146 /* When FRAME is at a syscall instruction, return the PC of the next
 147    instruction to be executed.  */
 148
 149 static CORE_ADDR
 150 tic6x_linux_syscall_next_pc (struct frame_info *frame)
 151 {
 152   ULONGEST syscall_number = get_frame_register_unsigned (frame,
 153                                                          TIC6X_B0_REGNUM);
 154   CORE_ADDR pc = get_frame_pc (frame);
 155
 156   if (syscall_number == 139 /* rt_sigreturn */)
 157     return frame_unwind_caller_pc (frame);
 158
 159   return pc + 4;
 160 }
 161
 162
 163 extern struct target_so_ops dsbt_so_ops;
 164 static void
 165 tic6x_uclinux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 166 {
 167   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 168
 169   linux_init_abi (info, gdbarch);
 170
 171   /* Shared library handling.  */
 172   set_solib_ops (gdbarch, &dsbt_so_ops);
 173
 174   tdep->syscall_next_pc = tic6x_linux_syscall_next_pc;
 175
 176 #ifdef HAVE_ELF
 177   /* In tic6x Linux kernel, breakpoint instructions varies on different archs.
 178      On C64x+ and C67x+, breakpoint instruction is 0x56454314, which is an
 179      illegal opcode.  On other arch, breakpoint instruction is 0x0000a122
 180      (BNOP .S2 0,5).  */
 181   if (info.abfd)
 182     switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_PROC, Tag_ISA))
 183       {
 184       case C6XABI_Tag_ISA_C64XP:
 185       case C6XABI_Tag_ISA_C67XP:
 186         if (info.byte_order == BFD_ENDIAN_BIG)
 187           tdep->breakpoint = tic6x_bkpt_illegal_opcode_be;
 188         else
 189           tdep->breakpoint = tic6x_bkpt_illegal_opcode_le;
 190         break;
 191       default:
 192         {
 193           if (info.byte_order == BFD_ENDIAN_BIG)
 194             tdep->breakpoint = tic6x_bkpt_bnop_be;
 195           else
 196             tdep->breakpoint = tic6x_bkpt_bnop_le;
 197         }
 198       }
 199 #endif
 200
 201   /* Signal trampoline support.  */
 202   tramp_frame_prepend_unwinder (gdbarch,
 203                                 &tic6x_linux_rt_sigreturn_tramp_frame);
 204 }
 205
 206 void
 207 _initialize_tic6x_linux_tdep (void)
 208 {
 209   gdbarch_register_osabi (bfd_arch_tic6x, 0, GDB_OSABI_LINUX,
 210                           tic6x_uclinux_init_abi);
 211 }