/* GNU/Linux/Nios II specific low level interface, for the remote server for GDB. Copyright (C) 2008-2016 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 . */ #include "server.h" #include "linux-low.h" #include "elf/common.h" #include "nat/gdb_ptrace.h" #include #include "gdb_proc_service.h" #include #ifndef PTRACE_GET_THREAD_AREA #define PTRACE_GET_THREAD_AREA 25 #endif /* 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 arch_setup linux_target_ops method. */ static void nios2_arch_setup (void) { current_process ()->tdesc = tdesc_nios2_linux; } /* Implement the cannot_fetch_register linux_target_ops method. */ static int nios2_cannot_fetch_register (int regno) { if (nios2_regmap[regno] == -1) return 1; return 0; } /* Implement the cannot_store_register linux_target_ops method. */ static int nios2_cannot_store_register (int regno) { if (nios2_regmap[regno] == -1) return 1; return 0; } /* Implement the get_pc linux_target_ops method. */ static CORE_ADDR nios2_get_pc (struct regcache *regcache) { union nios2_register pc; collect_register_by_name (regcache, "pc", pc.buf); return pc.reg32; } /* Implement the set_pc linux_target_ops method. */ static void nios2_set_pc (struct regcache *regcache, CORE_ADDR pc) { union nios2_register newpc; newpc.reg32 = pc; supply_register_by_name (regcache, "pc", newpc.buf); } /* 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 linux_target_ops method "sw_breakpoint_from_kind". */ static const gdb_byte * nios2_sw_breakpoint_from_kind (int kind, int *size) { *size = nios2_breakpoint_len; return (const gdb_byte *) &nios2_breakpoint; } /* Implement the breakpoint_at linux_target_ops method. */ static int nios2_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 (*the_target->read_memory) (where, (unsigned char *) &insn, 2); if (insn == CDX_BREAKPOINT) return 1; #endif (*the_target->read_memory) (where, (unsigned char *) &insn, 4); if (insn == nios2_breakpoint) return 1; return 0; } /* Fetch the thread-local storage pointer for libthread_db. */ ps_err_e ps_get_thread_area (const 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 = 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 = 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 regs_info = { NULL, /* regset_bitmap */ &nios2_usrregs_info, &nios2_regsets_info }; static const struct regs_info * nios2_regs_info (void) { return ®s_info; } struct linux_target_ops the_low_target = { nios2_arch_setup, nios2_regs_info, nios2_cannot_fetch_register, nios2_cannot_store_register, NULL, nios2_get_pc, nios2_set_pc, NULL, /* breakpoint_kind_from_pc */ nios2_sw_breakpoint_from_kind, NULL, /* get_next_pcs */ 0, nios2_breakpoint_at, }; void initialize_low_arch (void) { init_registers_nios2_linux (); initialize_regsets_info (&nios2_regsets_info); }