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- /* GNU/Linux/Nios II specific low level interface, for the remote server for
- GDB.
- Copyright (C) 2008-2022 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);
- }
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