/* GNU/Linux/Nios II specific low level interface, for the remote server for GDB. Copyright (C) 2008-2023 Free Software Foundation, Inc. Contributed by Mentor Graphics, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "server.h" #include "linux-low.h" #include "elf/common.h" #include "nat/gdb_ptrace.h" #include <endian.h> #include "gdb_proc_service.h" #include <asm/ptrace.h> #ifndef PTRACE_GET_THREAD_AREA #define PTRACE_GET_THREAD_AREA 25 #endif /* Linux target op definitions for the NIOS II architecture. */ class nios2_target : public linux_process_target { public: const regs_info *get_regs_info () override; const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override; protected: void low_arch_setup () override; bool low_cannot_fetch_register (int regno) override; bool low_cannot_store_register (int regno) override; bool low_supports_breakpoints () override; CORE_ADDR low_get_pc (regcache *regcache) override; void low_set_pc (regcache *regcache, CORE_ADDR newpc) override; bool low_breakpoint_at (CORE_ADDR pc) override; }; /* The singleton target ops object. */ static nios2_target the_nios2_target; bool nios2_target::low_supports_breakpoints () { return true; } CORE_ADDR nios2_target::low_get_pc (regcache *regcache) { return linux_get_pc_32bit (regcache); } void nios2_target::low_set_pc (regcache *regcache, CORE_ADDR pc) { linux_set_pc_32bit (regcache, pc); } /* The following definition must agree with the number of registers defined in "struct user_regs" in GLIBC (sysdeps/unix/sysv/linux/nios2/sys/user.h), and also with NIOS2_NUM_REGS in GDB proper. */ #define nios2_num_regs 49 /* Defined in auto-generated file nios2-linux.c. */ void init_registers_nios2_linux (void); extern const struct target_desc *tdesc_nios2_linux; /* This union is used to convert between int and byte buffer representations of register contents. */ union nios2_register { unsigned char buf[4]; int reg32; }; /* Return the ptrace ``address'' of register REGNO. */ static int nios2_regmap[] = { -1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 0 }; /* Implement the low_arch_setup linux target ops method. */ void nios2_target::low_arch_setup () { current_process ()->tdesc = tdesc_nios2_linux; } /* Implement the low_cannot_fetch_register linux target ops method. */ bool nios2_target::low_cannot_fetch_register (int regno) { return (nios2_regmap[regno] == -1); } /* Implement the low_cannot_store_register linux target ops method. */ bool nios2_target::low_cannot_store_register (int regno) { return (nios2_regmap[regno] == -1); } /* Breakpoint support. Also see comments on nios2_breakpoint_from_pc in nios2-tdep.c. */ #if defined(__nios2_arch__) && __nios2_arch__ == 2 #define NIOS2_BREAKPOINT 0xb7fd0020 #define CDX_BREAKPOINT 0xd7c9 #else #define NIOS2_BREAKPOINT 0x003b6ffa #endif /* We only register the 4-byte breakpoint, even on R2 targets which also support 2-byte breakpoints. Since there is no supports_z_point_type function provided, gdbserver never inserts software breakpoints itself and instead relies on GDB to insert the breakpoint of the correct length via a memory write. */ static const unsigned int nios2_breakpoint = NIOS2_BREAKPOINT; #define nios2_breakpoint_len 4 /* Implementation of target ops method "sw_breakpoint_from_kind". */ const gdb_byte * nios2_target::sw_breakpoint_from_kind (int kind, int *size) { *size = nios2_breakpoint_len; return (const gdb_byte *) &nios2_breakpoint; } /* Implement the low_breakpoint_at linux target ops method. */ bool nios2_target::low_breakpoint_at (CORE_ADDR where) { unsigned int insn; /* For R2, first check for the 2-byte CDX trap.n breakpoint encoding. */ #if defined(__nios2_arch__) && __nios2_arch__ == 2 read_memory (where, (unsigned char *) &insn, 2); if (insn == CDX_BREAKPOINT) return true; #endif read_memory (where, (unsigned char *) &insn, 4); if (insn == nios2_breakpoint) return true; return false; } /* Fetch the thread-local storage pointer for libthread_db. */ ps_err_e ps_get_thread_area (struct ps_prochandle *ph, lwpid_t lwpid, int idx, void **base) { if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0) return PS_ERR; /* IDX is the bias from the thread pointer to the beginning of the thread descriptor. It has to be subtracted due to implementation quirks in libthread_db. */ *base = (void *) ((char *) *base - idx); return PS_OK; } /* Helper functions to collect/supply a single register REGNO. */ static void nios2_collect_register (struct regcache *regcache, int regno, union nios2_register *reg) { union nios2_register tmp_reg; collect_register (regcache, regno, &tmp_reg.reg32); reg->reg32 = tmp_reg.reg32; } static void nios2_supply_register (struct regcache *regcache, int regno, const union nios2_register *reg) { supply_register (regcache, regno, reg->buf); } /* We have only a single register set on Nios II. */ static void nios2_fill_gregset (struct regcache *regcache, void *buf) { union nios2_register *regset = (union nios2_register *) buf; int i; for (i = 1; i < nios2_num_regs; i++) nios2_collect_register (regcache, i, regset + i); } static void nios2_store_gregset (struct regcache *regcache, const void *buf) { const union nios2_register *regset = (union nios2_register *) buf; int i; for (i = 0; i < nios2_num_regs; i++) nios2_supply_register (regcache, i, regset + i); } static struct regset_info nios2_regsets[] = { { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS, nios2_num_regs * 4, GENERAL_REGS, nios2_fill_gregset, nios2_store_gregset }, NULL_REGSET }; static struct regsets_info nios2_regsets_info = { nios2_regsets, /* regsets */ 0, /* num_regsets */ NULL, /* disabled_regsets */ }; static struct usrregs_info nios2_usrregs_info = { nios2_num_regs, nios2_regmap, }; static struct regs_info myregs_info = { NULL, /* regset_bitmap */ &nios2_usrregs_info, &nios2_regsets_info }; const regs_info * nios2_target::get_regs_info () { return &myregs_info; } /* The linux target ops object. */ linux_process_target *the_linux_target = &the_nios2_target; void initialize_low_arch (void) { init_registers_nios2_linux (); initialize_regsets_info (&nios2_regsets_info); }