260 lines
6.4 KiB
C
260 lines
6.4 KiB
C
/* GNU/Linux/Nios II specific low level interface, for the remote server for
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GDB.
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Copyright (C) 2008-2018 Free Software Foundation, Inc.
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Contributed by Mentor Graphics, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "server.h"
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#include "linux-low.h"
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#include "elf/common.h"
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#include "nat/gdb_ptrace.h"
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#include <endian.h>
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#include "gdb_proc_service.h"
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#include <asm/ptrace.h>
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#ifndef PTRACE_GET_THREAD_AREA
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#define PTRACE_GET_THREAD_AREA 25
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#endif
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/* The following definition must agree with the number of registers
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defined in "struct user_regs" in GLIBC
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(sysdeps/unix/sysv/linux/nios2/sys/user.h), and also with
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NIOS2_NUM_REGS in GDB proper. */
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#define nios2_num_regs 49
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/* Defined in auto-generated file nios2-linux.c. */
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void init_registers_nios2_linux (void);
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extern const struct target_desc *tdesc_nios2_linux;
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/* This union is used to convert between int and byte buffer
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representations of register contents. */
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union nios2_register
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{
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unsigned char buf[4];
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int reg32;
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};
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/* Return the ptrace ``address'' of register REGNO. */
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static int nios2_regmap[] = {
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-1, 1, 2, 3, 4, 5, 6, 7,
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8, 9, 10, 11, 12, 13, 14, 15,
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16, 17, 18, 19, 20, 21, 22, 23,
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24, 25, 26, 27, 28, 29, 30, 31,
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32, 33, 34, 35, 36, 37, 38, 39,
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40, 41, 42, 43, 44, 45, 46, 47,
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48,
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0
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};
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/* Implement the arch_setup linux_target_ops method. */
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static void
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nios2_arch_setup (void)
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{
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current_process ()->tdesc = tdesc_nios2_linux;
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}
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/* Implement the cannot_fetch_register linux_target_ops method. */
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static int
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nios2_cannot_fetch_register (int regno)
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{
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if (nios2_regmap[regno] == -1)
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return 1;
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return 0;
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}
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/* Implement the cannot_store_register linux_target_ops method. */
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static int
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nios2_cannot_store_register (int regno)
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{
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if (nios2_regmap[regno] == -1)
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return 1;
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return 0;
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}
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/* Breakpoint support. Also see comments on nios2_breakpoint_from_pc
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in nios2-tdep.c. */
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#if defined(__nios2_arch__) && __nios2_arch__ == 2
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#define NIOS2_BREAKPOINT 0xb7fd0020
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#define CDX_BREAKPOINT 0xd7c9
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#else
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#define NIOS2_BREAKPOINT 0x003b6ffa
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#endif
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/* We only register the 4-byte breakpoint, even on R2 targets which also
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support 2-byte breakpoints. Since there is no supports_z_point_type
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function provided, gdbserver never inserts software breakpoints itself
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and instead relies on GDB to insert the breakpoint of the correct length
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via a memory write. */
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static const unsigned int nios2_breakpoint = NIOS2_BREAKPOINT;
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#define nios2_breakpoint_len 4
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/* Implementation of linux_target_ops method "sw_breakpoint_from_kind". */
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static const gdb_byte *
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nios2_sw_breakpoint_from_kind (int kind, int *size)
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{
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*size = nios2_breakpoint_len;
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return (const gdb_byte *) &nios2_breakpoint;
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}
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/* Implement the breakpoint_at linux_target_ops method. */
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static int
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nios2_breakpoint_at (CORE_ADDR where)
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{
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unsigned int insn;
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/* For R2, first check for the 2-byte CDX trap.n breakpoint encoding. */
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#if defined(__nios2_arch__) && __nios2_arch__ == 2
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(*the_target->read_memory) (where, (unsigned char *) &insn, 2);
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if (insn == CDX_BREAKPOINT)
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return 1;
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#endif
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(*the_target->read_memory) (where, (unsigned char *) &insn, 4);
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if (insn == nios2_breakpoint)
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return 1;
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return 0;
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}
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/* Fetch the thread-local storage pointer for libthread_db. */
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ps_err_e
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ps_get_thread_area (struct ps_prochandle *ph,
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lwpid_t lwpid, int idx, void **base)
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{
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if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
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return PS_ERR;
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/* IDX is the bias from the thread pointer to the beginning of the
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thread descriptor. It has to be subtracted due to implementation
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quirks in libthread_db. */
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*base = (void *) ((char *) *base - idx);
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return PS_OK;
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}
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/* Helper functions to collect/supply a single register REGNO. */
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static void
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nios2_collect_register (struct regcache *regcache, int regno,
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union nios2_register *reg)
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{
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union nios2_register tmp_reg;
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collect_register (regcache, regno, &tmp_reg.reg32);
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reg->reg32 = tmp_reg.reg32;
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}
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static void
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nios2_supply_register (struct regcache *regcache, int regno,
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const union nios2_register *reg)
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{
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supply_register (regcache, regno, reg->buf);
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}
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/* We have only a single register set on Nios II. */
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static void
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nios2_fill_gregset (struct regcache *regcache, void *buf)
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{
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union nios2_register *regset = (union nios2_register *) buf;
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int i;
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for (i = 1; i < nios2_num_regs; i++)
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nios2_collect_register (regcache, i, regset + i);
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}
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static void
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nios2_store_gregset (struct regcache *regcache, const void *buf)
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{
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const union nios2_register *regset = (union nios2_register *) buf;
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int i;
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for (i = 0; i < nios2_num_regs; i++)
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nios2_supply_register (regcache, i, regset + i);
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}
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static struct regset_info nios2_regsets[] =
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{
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{ PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS,
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nios2_num_regs * 4, GENERAL_REGS,
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nios2_fill_gregset, nios2_store_gregset },
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NULL_REGSET
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};
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static struct regsets_info nios2_regsets_info =
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{
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nios2_regsets, /* regsets */
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0, /* num_regsets */
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NULL, /* disabled_regsets */
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};
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static struct usrregs_info nios2_usrregs_info =
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{
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nios2_num_regs,
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nios2_regmap,
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};
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static struct regs_info regs_info =
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{
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NULL, /* regset_bitmap */
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&nios2_usrregs_info,
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&nios2_regsets_info
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};
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static const struct regs_info *
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nios2_regs_info (void)
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{
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return ®s_info;
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}
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struct linux_target_ops the_low_target =
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{
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nios2_arch_setup,
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nios2_regs_info,
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nios2_cannot_fetch_register,
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nios2_cannot_store_register,
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NULL,
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linux_get_pc_32bit,
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linux_set_pc_32bit,
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NULL, /* breakpoint_kind_from_pc */
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nios2_sw_breakpoint_from_kind,
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NULL, /* get_next_pcs */
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0,
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nios2_breakpoint_at,
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};
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void
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initialize_low_arch (void)
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{
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init_registers_nios2_linux ();
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initialize_regsets_info (&nios2_regsets_info);
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}
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