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 } 212