1 /* Target-dependent code for GNU/Linux on RISC-V processors. 2 Copyright (C) 2018-2020 Free Software Foundation, Inc. 3 4 This file is part of GDB. 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 18 19 #include "defs.h" 20 #include "riscv-tdep.h" 21 #include "osabi.h" 22 #include "glibc-tdep.h" 23 #include "linux-tdep.h" 24 #include "solib-svr4.h" 25 #include "regset.h" 26 #include "tramp-frame.h" 27 #include "trad-frame.h" 28 #include "gdbarch.h" 29 30 /* Define the general register mapping. The kernel puts the PC at offset 0, 31 gdb puts it at offset 32. Register x0 is always 0 and can be ignored. 32 Registers x1 to x31 are in the same place. */ 33 34 static const struct regcache_map_entry riscv_linux_gregmap[] = 35 { 36 { 1, RISCV_PC_REGNUM, 0 }, 37 { 31, RISCV_RA_REGNUM, 0 }, /* x1 to x31 */ 38 { 0 } 39 }; 40 41 /* Define the FP register mapping. The kernel puts the 32 FP regs first, and 42 then FCSR. */ 43 44 static const struct regcache_map_entry riscv_linux_fregmap[] = 45 { 46 { 32, RISCV_FIRST_FP_REGNUM, 0 }, 47 { 1, RISCV_CSR_FCSR_REGNUM, 0 }, 48 { 0 } 49 }; 50 51 /* Define the general register regset. */ 52 53 static const struct regset riscv_linux_gregset = 54 { 55 riscv_linux_gregmap, regcache_supply_regset, regcache_collect_regset 56 }; 57 58 /* Define the FP register regset. */ 59 60 static const struct regset riscv_linux_fregset = 61 { 62 riscv_linux_fregmap, regcache_supply_regset, regcache_collect_regset 63 }; 64 65 /* Define hook for core file support. */ 66 67 static void 68 riscv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, 69 iterate_over_regset_sections_cb *cb, 70 void *cb_data, 71 const struct regcache *regcache) 72 { 73 cb (".reg", (32 * riscv_isa_xlen (gdbarch)), (32 * riscv_isa_xlen (gdbarch)), 74 &riscv_linux_gregset, NULL, cb_data); 75 /* The kernel is adding 8 bytes for FCSR. */ 76 cb (".reg2", (32 * riscv_isa_flen (gdbarch)) + 8, 77 (32 * riscv_isa_flen (gdbarch)) + 8, 78 &riscv_linux_fregset, NULL, cb_data); 79 } 80 81 /* Signal trampoline support. */ 82 83 static void riscv_linux_sigframe_init (const struct tramp_frame *self, 84 struct frame_info *this_frame, 85 struct trad_frame_cache *this_cache, 86 CORE_ADDR func); 87 88 #define RISCV_INST_LI_A7_SIGRETURN 0x08b00893 89 #define RISCV_INST_ECALL 0x00000073 90 91 static const struct tramp_frame riscv_linux_sigframe = { 92 SIGTRAMP_FRAME, 93 4, 94 { 95 { RISCV_INST_LI_A7_SIGRETURN, ULONGEST_MAX }, 96 { RISCV_INST_ECALL, ULONGEST_MAX }, 97 { TRAMP_SENTINEL_INSN } 98 }, 99 riscv_linux_sigframe_init, 100 NULL 101 }; 102 103 /* Runtime signal frames look like this: 104 struct rt_sigframe { 105 struct siginfo info; 106 struct ucontext uc; 107 }; 108 109 struct ucontext { 110 unsigned long __uc_flags; 111 struct ucontext *uclink; 112 stack_t uc_stack; 113 sigset_t uc_sigmask; 114 char __glibc_reserved[1024 / 8 - sizeof (sigset_t)]; 115 mcontext_t uc_mcontext; 116 }; */ 117 118 #define SIGFRAME_SIGINFO_SIZE 128 119 #define UCONTEXT_MCONTEXT_OFFSET 176 120 121 static void 122 riscv_linux_sigframe_init (const struct tramp_frame *self, 123 struct frame_info *this_frame, 124 struct trad_frame_cache *this_cache, 125 CORE_ADDR func) 126 { 127 struct gdbarch *gdbarch = get_frame_arch (this_frame); 128 int xlen = riscv_isa_xlen (gdbarch); 129 int flen = riscv_isa_flen (gdbarch); 130 CORE_ADDR frame_sp = get_frame_sp (this_frame); 131 CORE_ADDR mcontext_base; 132 CORE_ADDR regs_base; 133 134 mcontext_base = frame_sp + SIGFRAME_SIGINFO_SIZE + UCONTEXT_MCONTEXT_OFFSET; 135 136 /* Handle the integer registers. The first one is PC, followed by x1 137 through x31. */ 138 regs_base = mcontext_base; 139 trad_frame_set_reg_addr (this_cache, RISCV_PC_REGNUM, regs_base); 140 for (int i = 1; i < 32; i++) 141 trad_frame_set_reg_addr (this_cache, RISCV_ZERO_REGNUM + i, 142 regs_base + (i * xlen)); 143 144 /* Handle the FP registers. First comes the 32 FP registers, followed by 145 fcsr. */ 146 regs_base += 32 * xlen; 147 for (int i = 0; i < 32; i++) 148 trad_frame_set_reg_addr (this_cache, RISCV_FIRST_FP_REGNUM + i, 149 regs_base + (i * flen)); 150 regs_base += 32 * flen; 151 trad_frame_set_reg_addr (this_cache, RISCV_CSR_FCSR_REGNUM, regs_base); 152 153 /* Choice of the bottom of the sigframe is somewhat arbitrary. */ 154 trad_frame_set_id (this_cache, frame_id_build (frame_sp, func)); 155 } 156 157 /* Initialize RISC-V Linux ABI info. */ 158 159 static void 160 riscv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 161 { 162 linux_init_abi (info, gdbarch); 163 164 set_gdbarch_software_single_step (gdbarch, riscv_software_single_step); 165 166 set_solib_svr4_fetch_link_map_offsets (gdbarch, 167 (riscv_isa_xlen (gdbarch) == 4 168 ? svr4_ilp32_fetch_link_map_offsets 169 : svr4_lp64_fetch_link_map_offsets)); 170 171 /* GNU/Linux uses SVR4-style shared libraries. */ 172 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); 173 174 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ 175 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); 176 177 /* Enable TLS support. */ 178 set_gdbarch_fetch_tls_load_module_address (gdbarch, 179 svr4_fetch_objfile_link_map); 180 181 set_gdbarch_iterate_over_regset_sections 182 (gdbarch, riscv_linux_iterate_over_regset_sections); 183 184 tramp_frame_prepend_unwinder (gdbarch, &riscv_linux_sigframe); 185 } 186 187 /* Initialize RISC-V Linux target support. */ 188 189 void _initialize_riscv_linux_tdep (); 190 void 191 _initialize_riscv_linux_tdep () 192 { 193 gdbarch_register_osabi (bfd_arch_riscv, 0, GDB_OSABI_LINUX, 194 riscv_linux_init_abi); 195 } 196