nios2-linux-tdep.c revision 1.8
1/* Target-dependent code for GNU/Linux on Nios II. 2 Copyright (C) 2012-2019 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/* Core file and register set support. */ 34 35/* Map from the normal register enumeration order to the order that 36 registers appear in core files, which corresponds to the order 37 of the register slots in the kernel's struct pt_regs. */ 38 39static const int reg_offsets[NIOS2_NUM_REGS] = 40{ 41 -1, 8, 9, 10, 11, 12, 13, 14, /* r0 - r7 */ 42 0, 1, 2, 3, 4, 5, 6, 7, /* r8 - r15 */ 43 23, 24, 25, 26, 27, 28, 29, 30, /* r16 - r23 */ 44 -1, -1, 19, 18, 17, 21, -1, 16, /* et bt gp sp fp ea sstatus ra */ 45 21, /* pc */ 46 -1, 20, -1, -1, -1, -1, -1, -1, /* status estatus ... */ 47 -1, -1, -1, -1, -1, -1, -1, -1 48}; 49 50/* General register set size. Should match sizeof (struct pt_regs) + 51 sizeof (struct switch_stack) from the NIOS2 Linux kernel patch. */ 52 53#define NIOS2_GREGS_SIZE (4 * 34) 54 55/* Implement the supply_regset hook for core files. */ 56 57static void 58nios2_supply_gregset (const struct regset *regset, 59 struct regcache *regcache, 60 int regnum, const void *gregs_buf, size_t len) 61{ 62 const gdb_byte *gregs = (const gdb_byte *) gregs_buf; 63 int regno; 64 static const gdb_byte zero_buf[4] = {0, 0, 0, 0}; 65 66 for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++) 67 if (regnum == -1 || regnum == regno) 68 { 69 if (reg_offsets[regno] != -1) 70 regcache->raw_supply (regno, gregs + 4 * reg_offsets[regno]); 71 else 72 regcache->raw_supply (regno, zero_buf); 73 } 74} 75 76/* Implement the collect_regset hook for core files. */ 77 78static void 79nios2_collect_gregset (const struct regset *regset, 80 const struct regcache *regcache, 81 int regnum, void *gregs_buf, size_t len) 82{ 83 gdb_byte *gregs = (gdb_byte *) gregs_buf; 84 int regno; 85 86 for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++) 87 if (regnum == -1 || regnum == regno) 88 { 89 if (reg_offsets[regno] != -1) 90 regcache->raw_collect (regno, gregs + 4 * reg_offsets[regno]); 91 } 92} 93 94static const struct regset nios2_core_regset = 95{ 96 NULL, 97 nios2_supply_gregset, 98 nios2_collect_gregset 99}; 100 101/* Iterate over core file register note sections. */ 102 103static void 104nios2_iterate_over_regset_sections (struct gdbarch *gdbarch, 105 iterate_over_regset_sections_cb *cb, 106 void *cb_data, 107 const struct regcache *regcache) 108{ 109 cb (".reg", NIOS2_GREGS_SIZE, NIOS2_GREGS_SIZE, &nios2_core_regset, NULL, 110 cb_data); 111} 112 113/* Initialize a trad-frame cache corresponding to the tramp-frame. 114 FUNC is the address of the instruction TRAMP[0] in memory. 115 116 This ABI is not documented. It corresponds to rt_setup_ucontext in 117 the kernel arch/nios2/kernel/signal.c file. 118 119 The key points are: 120 - The kernel creates a trampoline at the hard-wired address 0x1044. 121 - The stack pointer points to an object of type struct rt_sigframe. 122 The definition of this structure is not exported from the kernel. 123 The register save area is located at offset 152 bytes (as determined 124 by inspection of the stack contents in the debugger), and the 125 registers are saved as r1-r23, ra, fp, gp, ea, sp. 126 127 This interface was implemented with kernel version 3.19 (the first 128 official mainline kernel). Older unofficial kernel versions used 129 incompatible conventions; we do not support those here. */ 130 131#define NIOS2_SIGRETURN_TRAMP_ADDR 0x1044 132#define NIOS2_SIGRETURN_REGSAVE_OFFSET 152 133 134static void 135nios2_linux_rt_sigreturn_init (const struct tramp_frame *self, 136 struct frame_info *next_frame, 137 struct trad_frame_cache *this_cache, 138 CORE_ADDR func) 139{ 140 CORE_ADDR sp = get_frame_register_unsigned (next_frame, NIOS2_SP_REGNUM); 141 CORE_ADDR base = sp + NIOS2_SIGRETURN_REGSAVE_OFFSET; 142 int i; 143 144 for (i = 0; i < 23; i++) 145 trad_frame_set_reg_addr (this_cache, i + 1, base + i * 4); 146 trad_frame_set_reg_addr (this_cache, NIOS2_RA_REGNUM, base + 23 * 4); 147 trad_frame_set_reg_addr (this_cache, NIOS2_FP_REGNUM, base + 24 * 4); 148 trad_frame_set_reg_addr (this_cache, NIOS2_GP_REGNUM, base + 25 * 4); 149 trad_frame_set_reg_addr (this_cache, NIOS2_PC_REGNUM, base + 27 * 4); 150 trad_frame_set_reg_addr (this_cache, NIOS2_SP_REGNUM, base + 28 * 4); 151 152 /* Save a frame ID. */ 153 trad_frame_set_id (this_cache, frame_id_build (base, func)); 154} 155 156/* Trampoline for sigreturn. This has the form 157 movi r2, __NR_rt_sigreturn 158 trap 0 159 appropriately encoded for R1 or R2. */ 160 161static struct tramp_frame nios2_r1_linux_rt_sigreturn_tramp_frame = 162{ 163 SIGTRAMP_FRAME, 164 4, 165 { 166 { MATCH_R1_MOVI | SET_IW_I_B (2) | SET_IW_I_IMM16 (139), ULONGEST_MAX }, 167 { MATCH_R1_TRAP | SET_IW_R_IMM5 (0), ULONGEST_MAX}, 168 { TRAMP_SENTINEL_INSN } 169 }, 170 nios2_linux_rt_sigreturn_init 171}; 172 173static struct tramp_frame nios2_r2_linux_rt_sigreturn_tramp_frame = 174{ 175 SIGTRAMP_FRAME, 176 4, 177 { 178 { MATCH_R2_MOVI | SET_IW_F2I16_B (2) | SET_IW_F2I16_IMM16 (139), ULONGEST_MAX }, 179 { MATCH_R2_TRAP | SET_IW_X2L5_IMM5 (0), ULONGEST_MAX}, 180 { TRAMP_SENTINEL_INSN } 181 }, 182 nios2_linux_rt_sigreturn_init 183}; 184 185/* When FRAME is at a syscall instruction, return the PC of the next 186 instruction to be executed. */ 187 188static CORE_ADDR 189nios2_linux_syscall_next_pc (struct frame_info *frame, 190 const struct nios2_opcode *op) 191{ 192 CORE_ADDR pc = get_frame_pc (frame); 193 ULONGEST syscall_nr = get_frame_register_unsigned (frame, NIOS2_R2_REGNUM); 194 195 /* If we are about to make a sigreturn syscall, use the unwinder to 196 decode the signal frame. */ 197 if (syscall_nr == 139 /* rt_sigreturn */) 198 return frame_unwind_caller_pc (frame); 199 200 return pc + op->size; 201} 202 203/* Hook function for gdbarch_register_osabi. */ 204 205static void 206nios2_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 207{ 208 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 209 210 linux_init_abi (info, gdbarch); 211 212 /* Shared library handling. */ 213 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); 214 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); 215 216 set_solib_svr4_fetch_link_map_offsets (gdbarch, 217 svr4_ilp32_fetch_link_map_offsets); 218 /* Enable TLS support. */ 219 set_gdbarch_fetch_tls_load_module_address (gdbarch, 220 svr4_fetch_objfile_link_map); 221 /* Core file support. */ 222 set_gdbarch_iterate_over_regset_sections 223 (gdbarch, nios2_iterate_over_regset_sections); 224 /* Linux signal frame unwinders. */ 225 if (gdbarch_bfd_arch_info (gdbarch)->mach == bfd_mach_nios2r2) 226 tramp_frame_prepend_unwinder (gdbarch, 227 &nios2_r2_linux_rt_sigreturn_tramp_frame); 228 else 229 tramp_frame_prepend_unwinder (gdbarch, 230 &nios2_r1_linux_rt_sigreturn_tramp_frame); 231 232 tdep->syscall_next_pc = nios2_linux_syscall_next_pc; 233 234 /* Index of target address word in glibc jmp_buf. */ 235 tdep->jb_pc = 10; 236} 237 238void 239_initialize_nios2_linux_tdep (void) 240{ 241 242 const struct bfd_arch_info *arch_info; 243 244 for (arch_info = bfd_lookup_arch (bfd_arch_nios2, 0); 245 arch_info != NULL; 246 arch_info = arch_info->next) 247 gdbarch_register_osabi (bfd_arch_nios2, arch_info->mach, 248 GDB_OSABI_LINUX, nios2_linux_init_abi); 249} 250