gdb/tic6x-linux-tdep.c

   1 /* GNU/Linux on  TI C6x target support.
   2    Copyright (C) 2011-2022 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 #include "solib-dsbt.h"
  31
  32 /* The offset from rt_sigframe pointer to SP register.  */
  33 #define TIC6X_SP_RT_SIGFRAME 8
  34 /* Size of struct siginfo info.  */
  35 #define TIC6X_SIGINFO_SIZE 128
  36 /* Size of type stack_t, which contains three fields of type void*, int, and
  37    size_t respectively.  */
  38 #define TIC6X_STACK_T_SIZE (3 * 4)
  39
  40 static const gdb_byte tic6x_bkpt_bnop_be[] = { 0x00, 0x00, 0xa1, 0x22 };
  41 static const gdb_byte tic6x_bkpt_bnop_le[] = { 0x22, 0xa1, 0x00, 0x00 };
  42
  43 /* Return the offset of register REGNUM in struct sigcontext.  Return 0 if no
  44    such register in sigcontext.  */
  45
  46 static unsigned int
  47 tic6x_register_sigcontext_offset (unsigned int regnum, struct gdbarch *gdbarch)
  48 {
  49   tic6x_gdbarch_tdep *tdep = gdbarch_tdep<tic6x_gdbarch_tdep> (gdbarch);
  50
  51   if (regnum == TIC6X_A4_REGNUM || regnum == TIC6X_A4_REGNUM + 2
  52       || regnum == TIC6X_A4_REGNUM + 4)
  53     return 4 * (regnum - TIC6X_A4_REGNUM + 2);  /* A4, A6, A8 */
  54   else if (regnum == TIC6X_A5_REGNUM || regnum == TIC6X_A5_REGNUM + 2
  55            || regnum == TIC6X_A5_REGNUM + 4)
  56     return 4 * (regnum - TIC6X_A5_REGNUM + 12); /* A5, A7, A9 */
  57   else if (regnum == TIC6X_B4_REGNUM || regnum == TIC6X_B4_REGNUM + 2
  58            || regnum == TIC6X_B4_REGNUM + 4)
  59     return 4 * (regnum - TIC6X_B4_REGNUM + 3);  /* B4, B6, B8 */
  60   else if (regnum == TIC6X_B5_REGNUM || regnum == TIC6X_B5_REGNUM + 2
  61            || regnum == TIC6X_B5_REGNUM + 4)
  62     return 4 * (regnum - TIC6X_B5_REGNUM + 19); /* B5, B7, B9 */
  63   else if (regnum < TIC6X_A4_REGNUM)
  64     return 4 * (regnum - 0 + 8);        /* A0 - A3 */
  65   else if (regnum >= TIC6X_B0_REGNUM && regnum < TIC6X_B4_REGNUM)
  66     return 4 * (regnum - TIC6X_B0_REGNUM + 15); /* B0 - B3 */
  67   else if (regnum >= 34 && regnum < 34 + 32)
  68     return 4 * (regnum - 34 + 23);      /* A16 - A31, B16 - B31 */
  69   else if (regnum == TIC6X_PC_REGNUM)
  70     return 4 * (tdep->has_gp ? 55 : 23);
  71   else if (regnum == TIC6X_SP_REGNUM)
  72     return 4;
  73
  74   return 0;
  75 }
  76
  77 /* Support unwinding frame in signal trampoline.  We don't check sigreturn,
  78    since it is not used in kernel.  */
  79
  80 static void
  81 tic6x_linux_rt_sigreturn_init (const struct tramp_frame *self,
  82                                struct frame_info *this_frame,
  83                                struct trad_frame_cache *this_cache,
  84                                CORE_ADDR func)
  85 {
  86   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  87   CORE_ADDR sp = get_frame_register_unsigned (this_frame, TIC6X_SP_REGNUM);
  88   /* The base of struct sigcontext is computed by examining the definition of
  89      struct rt_sigframe in linux kernel source arch/c6x/kernel/signal.c.  */
  90   CORE_ADDR base = (sp + TIC6X_SP_RT_SIGFRAME
  91                     /* Pointer type *pinfo and *puc in struct rt_sigframe.  */
  92                     + 4 + 4
  93                     + TIC6X_SIGINFO_SIZE
  94                     + 4 + 4 /* uc_flags and *uc_link in struct ucontext.  */
  95                     + TIC6X_STACK_T_SIZE);
  96   tic6x_gdbarch_tdep *tdep = gdbarch_tdep<tic6x_gdbarch_tdep> (gdbarch);
  97   unsigned int reg_offset;
  98   unsigned int i;
  99
 100   for (i = 0; i < 10; i++)      /* A0 - A9 */
 101     {
 102       reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 103       gdb_assert (reg_offset != 0);
 104
 105       trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 106     }
 107
 108   for (i = TIC6X_B0_REGNUM; i < TIC6X_B0_REGNUM + 10; i++)      /* B0 - B9 */
 109     {
 110       reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 111       gdb_assert (reg_offset != 0);
 112
 113       trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 114     }
 115
 116   if (tdep->has_gp)
 117     for (i = 34; i < 34 + 32; i++)      /* A16 - A31, B16 - B31 */
 118       {
 119         reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
 120         gdb_assert (reg_offset != 0);
 121
 122         trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
 123       }
 124
 125   trad_frame_set_reg_addr (this_cache, TIC6X_PC_REGNUM,
 126                            base + tic6x_register_sigcontext_offset (TIC6X_PC_REGNUM,
 127                                                                     gdbarch));
 128   trad_frame_set_reg_addr (this_cache, TIC6X_SP_REGNUM,
 129                            base + tic6x_register_sigcontext_offset (TIC6X_SP_REGNUM,
 130                                                                     gdbarch));
 131
 132   /* Save a frame ID.  */
 133   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 134 }
 135
 136 static struct tramp_frame tic6x_linux_rt_sigreturn_tramp_frame =
 137 {
 138   SIGTRAMP_FRAME,
 139   4,
 140   {
 141     {0x000045aa, 0x0fffffff},   /* mvk .S2 139,b0 */
 142     {0x10000000, ULONGEST_MAX},         /* swe */
 143     {TRAMP_SENTINEL_INSN}
 144   },
 145   tic6x_linux_rt_sigreturn_init
 146 };
 147
 148 /* When FRAME is at a syscall instruction, return the PC of the next
 149    instruction to be executed.  */
 150
 151 static CORE_ADDR
 152 tic6x_linux_syscall_next_pc (struct frame_info *frame)
 153 {
 154   ULONGEST syscall_number = get_frame_register_unsigned (frame,
 155                                                          TIC6X_B0_REGNUM);
 156   CORE_ADDR pc = get_frame_pc (frame);
 157
 158   if (syscall_number == 139 /* rt_sigreturn */)
 159     return frame_unwind_caller_pc (frame);
 160
 161   return pc + 4;
 162 }
 163
 164
 165 static void
 166 tic6x_uclinux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 167 {
 168   tic6x_gdbarch_tdep *tdep = gdbarch_tdep<tic6x_gdbarch_tdep> (gdbarch);
 169
 170   linux_init_abi (info, gdbarch, 0);
 171
 172   /* Shared library handling.  */
 173   set_gdbarch_so_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 _initialize_tic6x_linux_tdep ();
 208 void
 209 _initialize_tic6x_linux_tdep ()
 210 {
 211   gdbarch_register_osabi (bfd_arch_tic6x, 0, GDB_OSABI_LINUX,
 212                           tic6x_uclinux_init_abi);
 213 }