nios2-linux-tdep.c revision 1.3
1/* Target-dependent code for GNU/Linux on Nios II. 2 Copyright (C) 2012-2015 Free Software Foundation, Inc. 3 Contributed by Mentor Graphics, Inc. 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 "frame.h" 22#include "osabi.h" 23#include "solib-svr4.h" 24#include "trad-frame.h" 25#include "tramp-frame.h" 26#include "symtab.h" 27#include "regset.h" 28#include "regcache.h" 29#include "linux-tdep.h" 30#include "glibc-tdep.h" 31#include "nios2-tdep.h" 32 33#include "features/nios2-linux.c" 34 35/* Core file and register set support. */ 36 37/* Map from the normal register enumeration order to the order that 38 registers appear in core files, which corresponds to the order 39 of the register slots in the kernel's struct pt_regs. */ 40 41static const int reg_offsets[NIOS2_NUM_REGS] = 42{ 43 -1, 8, 9, 10, 11, 12, 13, 14, /* r0 - r7 */ 44 0, 1, 2, 3, 4, 5, 6, 7, /* r8 - r15 */ 45 23, 24, 25, 26, 27, 28, 29, 30, /* r16 - r23 */ 46 -1, -1, 19, 18, 17, 21, -1, 16, /* et bt gp sp fp ea sstatus ra */ 47 21, /* pc */ 48 -1, 20, -1, -1, -1, -1, -1, -1, /* status estatus ... */ 49 -1, -1, -1, -1, -1, -1, -1, -1 50}; 51 52/* General register set size. Should match sizeof (struct pt_regs) + 53 sizeof (struct switch_stack) from the NIOS2 Linux kernel patch. */ 54 55#define NIOS2_GREGS_SIZE (4 * 34) 56 57/* Implement the supply_regset hook for core files. */ 58 59static void 60nios2_supply_gregset (const struct regset *regset, 61 struct regcache *regcache, 62 int regnum, const void *gregs_buf, size_t len) 63{ 64 const gdb_byte *gregs = gregs_buf; 65 int regno; 66 static const gdb_byte zero_buf[4] = {0, 0, 0, 0}; 67 68 for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++) 69 if (regnum == -1 || regnum == regno) 70 { 71 if (reg_offsets[regno] != -1) 72 regcache_raw_supply (regcache, regno, 73 gregs + 4 * reg_offsets[regno]); 74 else 75 regcache_raw_supply (regcache, regno, zero_buf); 76 } 77} 78 79/* Implement the collect_regset hook for core files. */ 80 81static void 82nios2_collect_gregset (const struct regset *regset, 83 const struct regcache *regcache, 84 int regnum, void *gregs_buf, size_t len) 85{ 86 gdb_byte *gregs = gregs_buf; 87 int regno; 88 89 for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++) 90 if (regnum == -1 || regnum == regno) 91 { 92 if (reg_offsets[regno] != -1) 93 regcache_raw_collect (regcache, regno, 94 gregs + 4 * reg_offsets[regno]); 95 } 96} 97 98static const struct regset nios2_core_regset = 99{ 100 NULL, 101 nios2_supply_gregset, 102 nios2_collect_gregset 103}; 104 105/* Iterate over core file register note sections. */ 106 107static void 108nios2_iterate_over_regset_sections (struct gdbarch *gdbarch, 109 iterate_over_regset_sections_cb *cb, 110 void *cb_data, 111 const struct regcache *regcache) 112{ 113 cb (".reg", NIOS2_GREGS_SIZE, &nios2_core_regset, NULL, cb_data); 114} 115 116/* Initialize a trad-frame cache corresponding to the tramp-frame. 117 FUNC is the address of the instruction TRAMP[0] in memory. */ 118 119static void 120nios2_linux_rt_sigreturn_init (const struct tramp_frame *self, 121 struct frame_info *next_frame, 122 struct trad_frame_cache *this_cache, 123 CORE_ADDR func) 124{ 125 CORE_ADDR base = func + 41 * 4; 126 int i; 127 128 for (i = 0; i < 23; i++) 129 trad_frame_set_reg_addr (this_cache, i + 1, base + i * 4); 130 trad_frame_set_reg_addr (this_cache, NIOS2_RA_REGNUM, base + 23 * 4); 131 trad_frame_set_reg_addr (this_cache, NIOS2_FP_REGNUM, base + 24 * 4); 132 trad_frame_set_reg_addr (this_cache, NIOS2_GP_REGNUM, base + 25 * 4); 133 trad_frame_set_reg_addr (this_cache, NIOS2_PC_REGNUM, base + 27 * 4); 134 trad_frame_set_reg_addr (this_cache, NIOS2_SP_REGNUM, base + 28 * 4); 135 136 /* Save a frame ID. */ 137 trad_frame_set_id (this_cache, frame_id_build (base, func)); 138} 139 140static struct tramp_frame nios2_linux_rt_sigreturn_tramp_frame = 141{ 142 SIGTRAMP_FRAME, 143 4, 144 { 145 { 0x00800004 | (139 << 6), -1 }, /* movi r2,__NR_rt_sigreturn */ 146 { 0x003b683a, -1 }, /* trap */ 147 { TRAMP_SENTINEL_INSN } 148 }, 149 nios2_linux_rt_sigreturn_init 150}; 151 152/* When FRAME is at a syscall instruction, return the PC of the next 153 instruction to be executed. */ 154 155static CORE_ADDR 156nios2_linux_syscall_next_pc (struct frame_info *frame) 157{ 158 CORE_ADDR pc = get_frame_pc (frame); 159 ULONGEST syscall_nr = get_frame_register_unsigned (frame, NIOS2_R2_REGNUM); 160 161 /* If we are about to make a sigreturn syscall, use the unwinder to 162 decode the signal frame. */ 163 if (syscall_nr == 139 /* rt_sigreturn */) 164 return frame_unwind_caller_pc (frame); 165 166 return pc + NIOS2_OPCODE_SIZE; 167} 168 169/* Hook function for gdbarch_register_osabi. */ 170 171static void 172nios2_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 173{ 174 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 175 176 linux_init_abi (info, gdbarch); 177 178 /* Shared library handling. */ 179 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); 180 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); 181 182 set_solib_svr4_fetch_link_map_offsets (gdbarch, 183 svr4_ilp32_fetch_link_map_offsets); 184 /* Enable TLS support. */ 185 set_gdbarch_fetch_tls_load_module_address (gdbarch, 186 svr4_fetch_objfile_link_map); 187 /* Core file support. */ 188 set_gdbarch_iterate_over_regset_sections 189 (gdbarch, nios2_iterate_over_regset_sections); 190 /* Linux signal frame unwinders. */ 191 tramp_frame_prepend_unwinder (gdbarch, 192 &nios2_linux_rt_sigreturn_tramp_frame); 193 194 tdep->syscall_next_pc = nios2_linux_syscall_next_pc; 195 196 /* Index of target address word in glibc jmp_buf. */ 197 tdep->jb_pc = 10; 198} 199 200/* Provide a prototype to silence -Wmissing-prototypes. */ 201 202extern initialize_file_ftype _initialize_nios2_linux_tdep; 203 204void 205_initialize_nios2_linux_tdep (void) 206{ 207 gdbarch_register_osabi (bfd_arch_nios2, 0, GDB_OSABI_LINUX, 208 nios2_linux_init_abi); 209 210 initialize_tdesc_nios2_linux (); 211} 212