gdb/tic6x-linux-tdep.c

   1 /* GNU/Linux on  TI C6x target support.
   2    Copyright (C) 2011-2020 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 #include "gdbarch.h"
  30
  31 /* The offset from rt_sigframe pointer to SP register.  */
  32 #define TIC6X_SP_RT_SIGFRAME 8
  33 /* Size of struct siginfo info.  */
  34 #define TIC6X_SIGINFO_SIZE 128
  35 /* Size of type stack_t, which contains three fields of type void*, int, and
  36    size_t respectively.  */
  37 #define TIC6X_STACK_T_SIZE (3 * 4)
  38
  39 static const gdb_byte tic6x_bkpt_bnop_be[] = { 0x00, 0x00, 0xa1, 0x22 };
  40 static const gdb_byte tic6x_bkpt_bnop_le[] = { 0x22, 0xa1, 0x00, 0x00 };
  41
  42 /* Return the offset of register REGNUM in struct sigcontext.  Return 0 if no
  43    such register in sigcontext.  */
  44
  45 static unsigned int
  46 tic6x_register_sigcontext_offset (unsigned int regnum, struct gdbarch *gdbarch)
  47 {
  48   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  49
  50   if (regnum == TIC6X_A4_REGNUM || regnum == TIC6X_A4_REGNUM + 2
  51       || regnum == TIC6X_A4_REGNUM + 4)
  52     return 4 * (regnum - TIC6X_A4_REGNUM + 2);  /* A4, A6, A8 */
  53   else if (regnum == TIC6X_A5_REGNUM || regnum == TIC6X_A5_REGNUM + 2
  54            || regnum == TIC6X_A5_REGNUM + 4)
  55     return 4 * (regnum - TIC6X_A5_REGNUM + 12); /* A5, A7, A9 */
  56   else if (regnum == TIC6X_B4_REGNUM || regnum == TIC6X_B4_REGNUM + 2
  57            || regnum == TIC6X_B4_REGNUM + 4)
  58     return 4 * (regnum - TIC6X_B4_REGNUM + 3);  /* B4, B6, B8 */
  59   else if (regnum == TIC6X_B5_REGNUM || regnum == TIC6X_B5_REGNUM + 2
  60            || regnum == TIC6X_B5_REGNUM + 4)
  61     return 4 * (regnum - TIC6X_B5_REGNUM + 19); /* B5, B7, B9 */
  62   else if (regnum < TIC6X_A4_REGNUM)
  63     return 4 * (regnum - 0 + 8);        /* A0 - A3 */
  64   else if (regnum >= TIC6X_B0_REGNUM && regnum < TIC6X_B4_REGNUM)
  65     return 4 * (regnum - TIC6X_B0_REGNUM + 15); /* B0 - B3 */
  66   else if (regnum >= 34 && regnum < 34 + 32)
  67     return 4 * (regnum - 34 + 23);      /* A16 - A31, B16 - B31 */
  68   else if (regnum == TIC6X_PC_REGNUM)
  69     return 4 * (tdep->has_gp ? 55 : 23);
  70   else if (regnum == TIC6X_SP_REGNUM)
  71     return 4;
  72
  73   return 0;
  74 }
  75
  76 /* Support unwinding frame in signal trampoline.  We don't check sigreturn,
  77    since it is not used in kernel.  */
  78
  79 static void
  80 tic6x_linux_rt_sigreturn_init (const struct tramp_frame *self,
  81                                struct frame_info *this_frame,
  82                                struct trad_frame_cache *this_cache,
  83                                CORE_ADDR func)
  84 {
  85   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  86   CORE_ADDR sp = get_frame_register_unsigned (this_frame, TIC6X_SP_REGNUM);
  87   /* The base of struct sigcontext is computed by examining the definition of
  88      struct rt_sigframe in linux kernel source arch/c6x/kernel/signal.c.  */
  89   CORE_ADDR base = (sp + TIC6X_SP_RT_SIGFRAME
  90                     /* Pointer type *pinfo and *puc in struct rt_sigframe.  */
  91                     + 4 + 4
  92                     + TIC6X_SIGINFO_SIZE
  93                     + 4 + 4 /* uc_flags and *uc_link in struct ucontext.  */
  94                     + TIC6X_STACK_T_SIZE);
  95   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  96   unsigned int reg_offset;
  97   unsigned int i;
  98
  99   for (i = 0; i < 10; i++)      /* A0 - A9 */
 100     {
 101       reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 102       gdb_assert (reg_offset != 0);
 103
 104       trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 105     }
 106
 107   for (i = TIC6X_B0_REGNUM; i < TIC6X_B0_REGNUM + 10; i++)      /* B0 - B9 */
 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   if (tdep->has_gp)
 116     for (i = 34; i < 34 + 32; i++)      /* A16 - A31, B16 - B31 */
 117       {
 118         reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 119         gdb_assert (reg_offset != 0);
 120
 121         trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 122       }
 123
 124   trad_frame_set_reg_addr (this_cache, TIC6X_PC_REGNUM,
 125                            base + tic6x_register_sigcontext_offset (TIC6X_PC_REGNUM,
 126                                                                     gdbarch));
 127   trad_frame_set_reg_addr (this_cache, TIC6X_SP_REGNUM,
 128                            base + tic6x_register_sigcontext_offset (TIC6X_SP_REGNUM,
 129                                                                     gdbarch));
 130
 131   /* Save a frame ID.  */
 132   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 133 }
 134
 135 static struct tramp_frame tic6x_linux_rt_sigreturn_tramp_frame =
 136 {
 137   SIGTRAMP_FRAME,
 138   4,
 139   {
 140     {0x000045aa, 0x0fffffff},   /* mvk .S2 139,b0 */
 141     {0x10000000, ULONGEST_MAX},         /* swe */
 142     {TRAMP_SENTINEL_INSN}
 143   },
 144   tic6x_linux_rt_sigreturn_init
 145 };
 146
 147 /* When FRAME is at a syscall instruction, return the PC of the next
 148    instruction to be executed.  */
 149
 150 static CORE_ADDR
 151 tic6x_linux_syscall_next_pc (struct frame_info *frame)
 152 {
 153   ULONGEST syscall_number = get_frame_register_unsigned (frame,
 154                                                          TIC6X_B0_REGNUM);
 155   CORE_ADDR pc = get_frame_pc (frame);
 156
 157   if (syscall_number == 139 /* rt_sigreturn */)
 158     return frame_unwind_caller_pc (frame);
 159
 160   return pc + 4;
 161 }
 162
 163
 164 extern struct target_so_ops dsbt_so_ops;
 165 static void
 166 tic6x_uclinux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 167 {
 168   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 169
 170   linux_init_abi (info, gdbarch);
 171
 172   /* Shared library handling.  */
 173   set_solib_ops (gdbarch, &dsbt_so_ops);
 174
 175   tdep->syscall_next_pc = tic6x_linux_syscall_next_pc;
 176
 177 #ifdef HAVE_ELF
 178   /* In tic6x Linux kernel, breakpoint instructions varies on different archs.
 179      On C64x+ and C67x+, breakpoint instruction is 0x56454314, which is an
 180      illegal opcode.  On other arch, breakpoint instruction is 0x0000a122
 181      (BNOP .S2 0,5).  */
 182   if (info.abfd)
 183     switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_PROC, Tag_ISA))
 184       {
 185       case C6XABI_Tag_ISA_C64XP:
 186       case C6XABI_Tag_ISA_C67XP:
 187         if (info.byte_order == BFD_ENDIAN_BIG)
 188           tdep->breakpoint = tic6x_bkpt_illegal_opcode_be;
 189         else
 190           tdep->breakpoint = tic6x_bkpt_illegal_opcode_le;
 191         break;
 192       default:
 193         {
 194           if (info.byte_order == BFD_ENDIAN_BIG)
 195             tdep->breakpoint = tic6x_bkpt_bnop_be;
 196           else
 197             tdep->breakpoint = tic6x_bkpt_bnop_le;
 198         }
 199       }
 200 #endif
 201
 202   /* Signal trampoline support.  */
 203   tramp_frame_prepend_unwinder (gdbarch,
 204                                 &tic6x_linux_rt_sigreturn_tramp_frame);
 205 }
 206
 207 void
 208 _initialize_tic6x_linux_tdep (void)
 209 {
 210   gdbarch_register_osabi (bfd_arch_tic6x, 0, GDB_OSABI_LINUX,
 211                           tic6x_uclinux_init_abi);
 212 }