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 _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 } 214