| 1 | /* Target-dependent code for FreeBSD 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 "fbsd-tdep.h" |
| 21 | #include "osabi.h" |
| 22 | #include "riscv-tdep.h" |
| 23 | #include "riscv-fbsd-tdep.h" |
| 24 | #include "solib-svr4.h" |
| 25 | #include "target.h" |
| 26 | #include "trad-frame.h" |
| 27 | #include "tramp-frame.h" |
| 28 | #include "gdbarch.h" |
| 29 | |
| 30 | /* Register maps. */ |
| 31 | |
| 32 | static const struct regcache_map_entry riscv_fbsd_gregmap[] = |
| 33 | { |
| 34 | { 1, RISCV_RA_REGNUM, 0 }, |
| 35 | { 1, RISCV_SP_REGNUM, 0 }, |
| 36 | { 1, RISCV_GP_REGNUM, 0 }, |
| 37 | { 1, RISCV_TP_REGNUM, 0 }, |
| 38 | { 3, 5, 0 }, /* t0 - t2 */ |
| 39 | { 4, 28, 0 }, /* t3 - t6 */ |
| 40 | { 2, RISCV_FP_REGNUM, 0 }, /* s0 - s1 */ |
| 41 | { 10, 18, 0 }, /* s2 - s11 */ |
| 42 | { 8, RISCV_A0_REGNUM, 0 }, /* a0 - a7 */ |
| 43 | { 1, RISCV_PC_REGNUM, 0 }, |
| 44 | { 1, RISCV_CSR_SSTATUS_REGNUM, 0 }, |
| 45 | { 0 } |
| 46 | }; |
| 47 | |
| 48 | static const struct regcache_map_entry riscv_fbsd_fpregmap[] = |
| 49 | { |
| 50 | { 32, RISCV_FIRST_FP_REGNUM, 16 }, |
| 51 | { 1, RISCV_CSR_FCSR_REGNUM, 8 }, |
| 52 | { 0 } |
| 53 | }; |
| 54 | |
| 55 | /* Supply the general-purpose registers stored in GREGS to REGCACHE. |
| 56 | This function only exists to supply the always-zero x0 in addition |
| 57 | to the registers in GREGS. */ |
| 58 | |
| 59 | static void |
| 60 | riscv_fbsd_supply_gregset (const struct regset *regset, |
| 61 | struct regcache *regcache, int regnum, |
| 62 | const void *gregs, size_t len) |
| 63 | { |
| 64 | regcache->supply_regset (&riscv_fbsd_gregset, regnum, gregs, len); |
| 65 | if (regnum == -1 || regnum == RISCV_ZERO_REGNUM) |
| 66 | regcache->raw_supply_zeroed (RISCV_ZERO_REGNUM); |
| 67 | } |
| 68 | |
| 69 | /* Register set definitions. */ |
| 70 | |
| 71 | const struct regset riscv_fbsd_gregset = |
| 72 | { |
| 73 | riscv_fbsd_gregmap, |
| 74 | riscv_fbsd_supply_gregset, regcache_collect_regset |
| 75 | }; |
| 76 | |
| 77 | const struct regset riscv_fbsd_fpregset = |
| 78 | { |
| 79 | riscv_fbsd_fpregmap, |
| 80 | regcache_supply_regset, regcache_collect_regset |
| 81 | }; |
| 82 | |
| 83 | /* Implement the "regset_from_core_section" gdbarch method. */ |
| 84 | |
| 85 | static void |
| 86 | riscv_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch, |
| 87 | iterate_over_regset_sections_cb *cb, |
| 88 | void *cb_data, |
| 89 | const struct regcache *regcache) |
| 90 | { |
| 91 | cb (".reg", RISCV_FBSD_NUM_GREGS * riscv_isa_xlen (gdbarch), |
| 92 | RISCV_FBSD_NUM_GREGS * riscv_isa_xlen (gdbarch), |
| 93 | &riscv_fbsd_gregset, NULL, cb_data); |
| 94 | cb (".reg2", RISCV_FBSD_SIZEOF_FPREGSET, RISCV_FBSD_SIZEOF_FPREGSET, |
| 95 | &riscv_fbsd_fpregset, NULL, cb_data); |
| 96 | } |
| 97 | |
| 98 | /* In a signal frame, sp points to a 'struct sigframe' which is |
| 99 | defined as: |
| 100 | |
| 101 | struct sigframe { |
| 102 | siginfo_t sf_si; |
| 103 | ucontext_t sf_uc; |
| 104 | }; |
| 105 | |
| 106 | ucontext_t is defined as: |
| 107 | |
| 108 | struct __ucontext { |
| 109 | sigset_t uc_sigmask; |
| 110 | mcontext_t uc_mcontext; |
| 111 | ... |
| 112 | }; |
| 113 | |
| 114 | The mcontext_t contains the general purpose register set followed |
| 115 | by the floating point register set. The floating point register |
| 116 | set is only valid if the _MC_FP_VALID flag is set in mc_flags. */ |
| 117 | |
| 118 | #define RISCV_SIGFRAME_UCONTEXT_OFFSET 80 |
| 119 | #define RISCV_UCONTEXT_MCONTEXT_OFFSET 16 |
| 120 | #define RISCV_MCONTEXT_FLAG_FP_VALID 0x1 |
| 121 | |
| 122 | /* Implement the "init" method of struct tramp_frame. */ |
| 123 | |
| 124 | static void |
| 125 | riscv_fbsd_sigframe_init (const struct tramp_frame *self, |
| 126 | struct frame_info *this_frame, |
| 127 | struct trad_frame_cache *this_cache, |
| 128 | CORE_ADDR func) |
| 129 | { |
| 130 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 131 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 132 | CORE_ADDR sp = get_frame_register_unsigned (this_frame, RISCV_SP_REGNUM); |
| 133 | CORE_ADDR mcontext_addr |
| 134 | = (sp |
| 135 | + RISCV_SIGFRAME_UCONTEXT_OFFSET |
| 136 | + RISCV_UCONTEXT_MCONTEXT_OFFSET); |
| 137 | gdb_byte buf[4]; |
| 138 | |
| 139 | trad_frame_set_reg_regmap (this_cache, riscv_fbsd_gregmap, mcontext_addr, |
| 140 | RISCV_FBSD_NUM_GREGS * riscv_isa_xlen (gdbarch)); |
| 141 | |
| 142 | CORE_ADDR fpregs_addr |
| 143 | = mcontext_addr + RISCV_FBSD_NUM_GREGS * riscv_isa_xlen (gdbarch); |
| 144 | CORE_ADDR fp_flags_addr |
| 145 | = fpregs_addr + RISCV_FBSD_SIZEOF_FPREGSET; |
| 146 | if (target_read_memory (fp_flags_addr, buf, 4) == 0 |
| 147 | && (extract_unsigned_integer (buf, 4, byte_order) |
| 148 | & RISCV_MCONTEXT_FLAG_FP_VALID)) |
| 149 | trad_frame_set_reg_regmap (this_cache, riscv_fbsd_fpregmap, fpregs_addr, |
| 150 | RISCV_FBSD_SIZEOF_FPREGSET); |
| 151 | |
| 152 | trad_frame_set_id (this_cache, frame_id_build (sp, func)); |
| 153 | } |
| 154 | |
| 155 | /* RISC-V supports 16-bit instructions ("C") as well as 32-bit |
| 156 | instructions. The signal trampoline on FreeBSD uses a mix of |
| 157 | these, but tramp_frame assumes a fixed instruction size. To cope, |
| 158 | claim that all instructions are 16 bits and use two "slots" for |
| 159 | 32-bit instructions. */ |
| 160 | |
| 161 | static const struct tramp_frame riscv_fbsd_sigframe = |
| 162 | { |
| 163 | SIGTRAMP_FRAME, |
| 164 | 2, |
| 165 | { |
| 166 | {0x850a, ULONGEST_MAX}, /* mov a0, sp */ |
| 167 | {0x0513, ULONGEST_MAX}, /* addi a0, a0, #SF_UC */ |
| 168 | {0x0505, ULONGEST_MAX}, |
| 169 | {0x0293, ULONGEST_MAX}, /* li t0, #SYS_sigreturn */ |
| 170 | {0x1a10, ULONGEST_MAX}, |
| 171 | {0x0073, ULONGEST_MAX}, /* ecall */ |
| 172 | {0x0000, ULONGEST_MAX}, |
| 173 | {TRAMP_SENTINEL_INSN, ULONGEST_MAX} |
| 174 | }, |
| 175 | riscv_fbsd_sigframe_init |
| 176 | }; |
| 177 | |
| 178 | /* Implement the "get_thread_local_address" gdbarch method. */ |
| 179 | |
| 180 | static CORE_ADDR |
| 181 | riscv_fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid, |
| 182 | CORE_ADDR lm_addr, CORE_ADDR offset) |
| 183 | { |
| 184 | struct regcache *regcache; |
| 185 | |
| 186 | regcache = get_thread_arch_regcache (ptid, gdbarch); |
| 187 | |
| 188 | target_fetch_registers (regcache, RISCV_TP_REGNUM); |
| 189 | |
| 190 | ULONGEST tp; |
| 191 | if (regcache->cooked_read (RISCV_TP_REGNUM, &tp) != REG_VALID) |
| 192 | error (_("Unable to fetch %%tp")); |
| 193 | |
| 194 | /* %tp points to the end of the TCB which contains two pointers. |
| 195 | The first pointer in the TCB points to the DTV array. */ |
| 196 | CORE_ADDR dtv_addr = tp - (gdbarch_ptr_bit (gdbarch) / 8) * 2; |
| 197 | return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset); |
| 198 | } |
| 199 | |
| 200 | /* Implement the 'init_osabi' method of struct gdb_osabi_handler. */ |
| 201 | |
| 202 | static void |
| 203 | riscv_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 204 | { |
| 205 | /* Generic FreeBSD support. */ |
| 206 | fbsd_init_abi (info, gdbarch); |
| 207 | |
| 208 | set_gdbarch_software_single_step (gdbarch, riscv_software_single_step); |
| 209 | |
| 210 | set_solib_svr4_fetch_link_map_offsets (gdbarch, |
| 211 | (riscv_isa_xlen (gdbarch) == 4 |
| 212 | ? svr4_ilp32_fetch_link_map_offsets |
| 213 | : svr4_lp64_fetch_link_map_offsets)); |
| 214 | |
| 215 | tramp_frame_prepend_unwinder (gdbarch, &riscv_fbsd_sigframe); |
| 216 | |
| 217 | set_gdbarch_iterate_over_regset_sections |
| 218 | (gdbarch, riscv_fbsd_iterate_over_regset_sections); |
| 219 | |
| 220 | set_gdbarch_fetch_tls_load_module_address (gdbarch, |
| 221 | svr4_fetch_objfile_link_map); |
| 222 | set_gdbarch_get_thread_local_address (gdbarch, |
| 223 | riscv_fbsd_get_thread_local_address); |
| 224 | } |
| 225 | |
| 226 | void |
| 227 | _initialize_riscv_fbsd_tdep (void) |
| 228 | { |
| 229 | gdbarch_register_osabi (bfd_arch_riscv, 0, GDB_OSABI_FREEBSD, |
| 230 | riscv_fbsd_init_abi); |
| 231 | } |