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- /* GNU/Linux/RISC-V specific low level interface, for the remote server
- for GDB.
- Copyright (C) 2020-2022 Free Software Foundation, 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 "tdesc.h"
- #include "elf/common.h"
- #include "nat/riscv-linux-tdesc.h"
- #include "opcode/riscv.h"
- /* Work around glibc header breakage causing ELF_NFPREG not to be usable. */
- #ifndef NFPREG
- # define NFPREG 33
- #endif
- /* Linux target op definitions for the RISC-V architecture. */
- class riscv_target : public linux_process_target
- {
- public:
- const regs_info *get_regs_info () override;
- int breakpoint_kind_from_pc (CORE_ADDR *pcptr) 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_fetch_register (regcache *regcache, 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 riscv_target the_riscv_target;
- bool
- riscv_target::low_cannot_fetch_register (int regno)
- {
- gdb_assert_not_reached ("linux target op low_cannot_fetch_register "
- "is not implemented by the target");
- }
- bool
- riscv_target::low_cannot_store_register (int regno)
- {
- gdb_assert_not_reached ("linux target op low_cannot_store_register "
- "is not implemented by the target");
- }
- /* Implementation of linux target ops method "low_arch_setup". */
- void
- riscv_target::low_arch_setup ()
- {
- static const char *expedite_regs[] = { "sp", "pc", NULL };
- const riscv_gdbarch_features features
- = riscv_linux_read_features (lwpid_of (current_thread));
- target_desc_up tdesc = riscv_create_target_description (features);
- if (!tdesc->expedite_regs)
- init_target_desc (tdesc.get (), expedite_regs);
- current_process ()->tdesc = tdesc.release ();
- }
- /* Collect GPRs from REGCACHE into BUF. */
- static void
- riscv_fill_gregset (struct regcache *regcache, void *buf)
- {
- const struct target_desc *tdesc = regcache->tdesc;
- elf_gregset_t *regset = (elf_gregset_t *) buf;
- int regno = find_regno (tdesc, "zero");
- int i;
- collect_register_by_name (regcache, "pc", *regset);
- for (i = 1; i < ARRAY_SIZE (*regset); i++)
- collect_register (regcache, regno + i, *regset + i);
- }
- /* Supply GPRs from BUF into REGCACHE. */
- static void
- riscv_store_gregset (struct regcache *regcache, const void *buf)
- {
- const elf_gregset_t *regset = (const elf_gregset_t *) buf;
- const struct target_desc *tdesc = regcache->tdesc;
- int regno = find_regno (tdesc, "zero");
- int i;
- supply_register_by_name (regcache, "pc", *regset);
- supply_register_zeroed (regcache, regno);
- for (i = 1; i < ARRAY_SIZE (*regset); i++)
- supply_register (regcache, regno + i, *regset + i);
- }
- /* Collect FPRs from REGCACHE into BUF. */
- static void
- riscv_fill_fpregset (struct regcache *regcache, void *buf)
- {
- const struct target_desc *tdesc = regcache->tdesc;
- int regno = find_regno (tdesc, "ft0");
- int flen = register_size (regcache->tdesc, regno);
- gdb_byte *regbuf = (gdb_byte *) buf;
- int i;
- for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen)
- collect_register (regcache, regno + i, regbuf);
- collect_register_by_name (regcache, "fcsr", regbuf);
- }
- /* Supply FPRs from BUF into REGCACHE. */
- static void
- riscv_store_fpregset (struct regcache *regcache, const void *buf)
- {
- const struct target_desc *tdesc = regcache->tdesc;
- int regno = find_regno (tdesc, "ft0");
- int flen = register_size (regcache->tdesc, regno);
- const gdb_byte *regbuf = (const gdb_byte *) buf;
- int i;
- for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen)
- supply_register (regcache, regno + i, regbuf);
- supply_register_by_name (regcache, "fcsr", regbuf);
- }
- /* RISC-V/Linux regsets. FPRs are optional and come in different sizes,
- so define multiple regsets for them marking them all as OPTIONAL_REGS
- rather than FP_REGS, so that "regsets_fetch_inferior_registers" picks
- the right one according to size. */
- static struct regset_info riscv_regsets[] = {
- { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS,
- sizeof (elf_gregset_t), GENERAL_REGS,
- riscv_fill_gregset, riscv_store_gregset },
- { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET,
- sizeof (struct __riscv_mc_q_ext_state), OPTIONAL_REGS,
- riscv_fill_fpregset, riscv_store_fpregset },
- { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET,
- sizeof (struct __riscv_mc_d_ext_state), OPTIONAL_REGS,
- riscv_fill_fpregset, riscv_store_fpregset },
- { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET,
- sizeof (struct __riscv_mc_f_ext_state), OPTIONAL_REGS,
- riscv_fill_fpregset, riscv_store_fpregset },
- NULL_REGSET
- };
- /* RISC-V/Linux regset information. */
- static struct regsets_info riscv_regsets_info =
- {
- riscv_regsets, /* regsets */
- 0, /* num_regsets */
- NULL, /* disabled_regsets */
- };
- /* Definition of linux_target_ops data member "regs_info". */
- static struct regs_info riscv_regs =
- {
- NULL, /* regset_bitmap */
- NULL, /* usrregs */
- &riscv_regsets_info,
- };
- /* Implementation of linux target ops method "get_regs_info". */
- const regs_info *
- riscv_target::get_regs_info ()
- {
- return &riscv_regs;
- }
- /* Implementation of linux target ops method "low_fetch_register". */
- bool
- riscv_target::low_fetch_register (regcache *regcache, int regno)
- {
- const struct target_desc *tdesc = regcache->tdesc;
- if (regno != find_regno (tdesc, "zero"))
- return false;
- supply_register_zeroed (regcache, regno);
- return true;
- }
- bool
- riscv_target::low_supports_breakpoints ()
- {
- return true;
- }
- /* Implementation of linux target ops method "low_get_pc". */
- CORE_ADDR
- riscv_target::low_get_pc (regcache *regcache)
- {
- elf_gregset_t regset;
- if (sizeof (regset[0]) == 8)
- return linux_get_pc_64bit (regcache);
- else
- return linux_get_pc_32bit (regcache);
- }
- /* Implementation of linux target ops method "low_set_pc". */
- void
- riscv_target::low_set_pc (regcache *regcache, CORE_ADDR newpc)
- {
- elf_gregset_t regset;
- if (sizeof (regset[0]) == 8)
- linux_set_pc_64bit (regcache, newpc);
- else
- linux_set_pc_32bit (regcache, newpc);
- }
- /* Correct in either endianness. */
- static const uint16_t riscv_ibreakpoint[] = { 0x0073, 0x0010 };
- static const uint16_t riscv_cbreakpoint = 0x9002;
- /* Implementation of target ops method "breakpoint_kind_from_pc". */
- int
- riscv_target::breakpoint_kind_from_pc (CORE_ADDR *pcptr)
- {
- union
- {
- gdb_byte bytes[2];
- uint16_t insn;
- }
- buf;
- if (target_read_memory (*pcptr, buf.bytes, sizeof (buf.insn)) == 0
- && riscv_insn_length (buf.insn == sizeof (riscv_ibreakpoint)))
- return sizeof (riscv_ibreakpoint);
- else
- return sizeof (riscv_cbreakpoint);
- }
- /* Implementation of target ops method "sw_breakpoint_from_kind". */
- const gdb_byte *
- riscv_target::sw_breakpoint_from_kind (int kind, int *size)
- {
- *size = kind;
- switch (kind)
- {
- case sizeof (riscv_ibreakpoint):
- return (const gdb_byte *) &riscv_ibreakpoint;
- default:
- return (const gdb_byte *) &riscv_cbreakpoint;
- }
- }
- /* Implementation of linux target ops method "low_breakpoint_at". */
- bool
- riscv_target::low_breakpoint_at (CORE_ADDR pc)
- {
- union
- {
- gdb_byte bytes[2];
- uint16_t insn;
- }
- buf;
- if (target_read_memory (pc, buf.bytes, sizeof (buf.insn)) == 0
- && (buf.insn == riscv_cbreakpoint
- || (buf.insn == riscv_ibreakpoint[0]
- && target_read_memory (pc + sizeof (buf.insn), buf.bytes,
- sizeof (buf.insn)) == 0
- && buf.insn == riscv_ibreakpoint[1])))
- return true;
- else
- return false;
- }
- /* The linux target ops object. */
- linux_process_target *the_linux_target = &the_riscv_target;
- /* Initialize the RISC-V/Linux target. */
- void
- initialize_low_arch ()
- {
- initialize_regsets_info (&riscv_regsets_info);
- }
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