1 /* Target-dependent code for GNU/Linux on RISC-V processors. 2 Copyright (C) 2018-2019 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 29 /* Define the general register mapping. The kernel puts the PC at offset 0, 30 gdb puts it at offset 32. Register x0 is always 0 and can be ignored. 31 Registers x1 to x31 are in the same place. */ 32 33 static const struct regcache_map_entry riscv_linux_gregmap[] = 34 { 35 { 1, RISCV_PC_REGNUM, 0 }, 36 { 31, RISCV_RA_REGNUM, 0 }, /* x1 to x31 */ 37 { 0 } 38 }; 39 40 /* Define the FP register mapping. The kernel puts the 32 FP regs first, and 41 then FCSR. */ 42 43 static const struct regcache_map_entry riscv_linux_fregmap[] = 44 { 45 { 32, RISCV_FIRST_FP_REGNUM, 0 }, 46 { 1, RISCV_CSR_FCSR_REGNUM, 0 }, 47 { 0 } 48 }; 49 50 /* Define the general register regset. */ 51 52 static const struct regset riscv_linux_gregset = 53 { 54 riscv_linux_gregmap, regcache_supply_regset, regcache_collect_regset 55 }; 56 57 /* Define the FP register regset. */ 58 59 static const struct regset riscv_linux_fregset = 60 { 61 riscv_linux_fregmap, regcache_supply_regset, regcache_collect_regset 62 }; 63 64 /* Define hook for core file support. */ 65 66 static void 67 riscv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, 68 iterate_over_regset_sections_cb *cb, 69 void *cb_data, 70 const struct regcache *regcache) 71 { 72 cb (".reg", (32 * riscv_isa_xlen (gdbarch)), (32 * riscv_isa_xlen (gdbarch)), 73 &riscv_linux_gregset, NULL, cb_data); 74 /* The kernel is adding 8 bytes for FCSR. */ 75 cb (".reg2", (32 * riscv_isa_flen (gdbarch)) + 8, 76 (32 * riscv_isa_flen (gdbarch)) + 8, 77 &riscv_linux_fregset, NULL, cb_data); 78 } 79 80 /* Signal trampoline support. */ 81 82 static void riscv_linux_sigframe_init (const struct tramp_frame *self, 83 struct frame_info *this_frame, 84 struct trad_frame_cache *this_cache, 85 CORE_ADDR func); 86 87 #define RISCV_INST_LI_A7_SIGRETURN 0x08b00893 88 #define RISCV_INST_ECALL 0x00000073 89 90 static const struct tramp_frame riscv_linux_sigframe = { 91 SIGTRAMP_FRAME, 92 4, 93 { 94 { RISCV_INST_LI_A7_SIGRETURN, ULONGEST_MAX }, 95 { RISCV_INST_ECALL, ULONGEST_MAX }, 96 { TRAMP_SENTINEL_INSN } 97 }, 98 riscv_linux_sigframe_init, 99 NULL 100 }; 101 102 /* Runtime signal frames look like this: 103 struct rt_sigframe { 104 struct siginfo info; 105 struct ucontext uc; 106 }; 107 108 struct ucontext { 109 unsigned long __uc_flags; 110 struct ucontext *uclink; 111 stack_t uc_stack; 112 sigset_t uc_sigmask; 113 char __glibc_reserved[1024 / 8 - sizeof (sigset_t)]; 114 mcontext_t uc_mcontext; 115 }; */ 116 117 #define SIGFRAME_SIGINFO_SIZE 128 118 #define UCONTEXT_MCONTEXT_OFFSET 176 119 120 static void 121 riscv_linux_sigframe_init (const struct tramp_frame *self, 122 struct frame_info *this_frame, 123 struct trad_frame_cache *this_cache, 124 CORE_ADDR func) 125 { 126 struct gdbarch *gdbarch = get_frame_arch (this_frame); 127 int xlen = riscv_isa_xlen (gdbarch); 128 int flen = riscv_isa_flen (gdbarch); 129 CORE_ADDR frame_sp = get_frame_sp (this_frame); 130 CORE_ADDR mcontext_base; 131 CORE_ADDR regs_base; 132 133 mcontext_base = frame_sp + SIGFRAME_SIGINFO_SIZE + UCONTEXT_MCONTEXT_OFFSET; 134 135 /* Handle the integer registers. The first one is PC, followed by x1 136 through x31. */ 137 regs_base = mcontext_base; 138 trad_frame_set_reg_addr (this_cache, RISCV_PC_REGNUM, regs_base); 139 for (int i = 1; i < 32; i++) 140 trad_frame_set_reg_addr (this_cache, RISCV_ZERO_REGNUM + i, 141 regs_base + (i * xlen)); 142 143 /* Handle the FP registers. First comes the 32 FP registers, followed by 144 fcsr. */ 145 regs_base += 32 * xlen; 146 for (int i = 0; i < 32; i++) 147 trad_frame_set_reg_addr (this_cache, RISCV_FIRST_FP_REGNUM + i, 148 regs_base + (i * flen)); 149 regs_base += 32 * flen; 150 trad_frame_set_reg_addr (this_cache, RISCV_CSR_FCSR_REGNUM, regs_base); 151 152 /* Choice of the bottom of the sigframe is somewhat arbitrary. */ 153 trad_frame_set_id (this_cache, frame_id_build (frame_sp, func)); 154 } 155 156 /* Initialize RISC-V Linux ABI info. */ 157 158 static void 159 riscv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 160 { 161 linux_init_abi (info, gdbarch); 162 163 set_gdbarch_software_single_step (gdbarch, riscv_software_single_step); 164 165 set_solib_svr4_fetch_link_map_offsets (gdbarch, 166 (riscv_isa_xlen (gdbarch) == 4 167 ? svr4_ilp32_fetch_link_map_offsets 168 : svr4_lp64_fetch_link_map_offsets)); 169 170 /* GNU/Linux uses SVR4-style shared libraries. */ 171 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); 172 173 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ 174 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); 175 176 /* Enable TLS support. */ 177 set_gdbarch_fetch_tls_load_module_address (gdbarch, 178 svr4_fetch_objfile_link_map); 179 180 set_gdbarch_iterate_over_regset_sections 181 (gdbarch, riscv_linux_iterate_over_regset_sections); 182 183 tramp_frame_prepend_unwinder (gdbarch, &riscv_linux_sigframe); 184 } 185 186 /* Initialize RISC-V Linux target support. */ 187 188 void 189 _initialize_riscv_linux_tdep (void) 190 { 191 gdbarch_register_osabi (bfd_arch_riscv, 0, GDB_OSABI_LINUX, 192 riscv_linux_init_abi); 193 } 194