| 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 | #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 | } |