gdbserver/linux-microblaze-low.cc

/* GNU/Linux/Microblaze specific low level interface, for the remote server for
   GDB.
   Copyright (C) 1995-2025 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 "elf/common.h"
#include "nat/gdb_ptrace.h"
#include <endian.h>

#include <asm/ptrace.h>
#include <sys/procfs.h>
#include <sys/ptrace.h>

#include "gdb_proc_service.h"


static int microblaze_regmap[] =
 {PT_GPR(0),     PT_GPR(1),     PT_GPR(2),     PT_GPR(3),
  PT_GPR(4),     PT_GPR(5),     PT_GPR(6),     PT_GPR(7),
  PT_GPR(8),     PT_GPR(9),     PT_GPR(10),    PT_GPR(11),
  PT_GPR(12),    PT_GPR(13),    PT_GPR(14),    PT_GPR(15),
  PT_GPR(16),    PT_GPR(17),    PT_GPR(18),    PT_GPR(19),
  PT_GPR(20),    PT_GPR(21),    PT_GPR(22),    PT_GPR(23),
  PT_GPR(24),    PT_GPR(25),    PT_GPR(26),    PT_GPR(27),
  PT_GPR(28),    PT_GPR(29),    PT_GPR(30),    PT_GPR(31),
  PT_PC,         PT_MSR,        PT_EAR,        PT_ESR,
  PT_FSR
  };



class microblaze_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 microblaze_target the_microblaze_target;

constexpr auto microblaze_num_regs
  = sizeof (microblaze_regmap) / sizeof (microblaze_regmap[0]);

/* Defined in auto-generated file microblaze-linux-generated.c.  */
void init_registers_microblaze_linux ();
extern const target_desc *tdesc_microblaze_linux;

bool
microblaze_target::low_supports_breakpoints ()
{
  return true;
}

bool
microblaze_target::low_cannot_store_register (int regno)
{
  if (microblaze_regmap[regno] == -1 || regno == 0)
    return 1;

  return 0;
}

bool
microblaze_target::low_cannot_fetch_register (int regno)
{
  return 0;
}

CORE_ADDR
microblaze_target::low_get_pc (regcache *regcache)
{
  unsigned long pc;

  collect_register_by_name (regcache, "rpc", &pc);
  return pc;
}

void
microblaze_target::low_set_pc (regcache *regcache, CORE_ADDR pc)
{
  unsigned long newpc = pc;

  supply_register_by_name (regcache, "rpc", &newpc);
}

/* dbtrap insn */
/* brki r16, 0x18; */
static const uint32_t microblaze_breakpoint = 0xba0c0018;
#define microblaze_breakpoint_len 4

const gdb_byte *
microblaze_target::sw_breakpoint_from_kind (int kind, int *size)
{
  *size = microblaze_breakpoint_len;
  return reinterpret_cast<const gdb_byte *> (&microblaze_breakpoint);
}

bool
microblaze_target::low_breakpoint_at (CORE_ADDR where)
{
  uint32_t insn;

  read_memory (where, (unsigned char *) &insn, 4);
  /* If necessary, recognize more trap instructions here.  GDB only uses the
     one.  */
  return insn == microblaze_breakpoint;
}

#ifdef HAVE_PTRACE_GETREGS

static void
microblaze_collect_ptrace_register (struct regcache *regcache, int regno,
				    char *buf)
{
  memset (buf, 0, sizeof (long));

  if (__BYTE_ORDER == __LITTLE_ENDIAN)
    {
      collect_register (regcache, regno, buf);
    }
  else if (__BYTE_ORDER == __BIG_ENDIAN)
    {
	int size = register_size (regcache->tdesc, regno);

	if (size < sizeof (long))
		collect_register (regcache, regno, buf + sizeof (long) - size);
	else
		collect_register (regcache, regno, buf);
    }
}

/* Collect GPRs from REGCACHE into BUF.  */

static void microblaze_fill_gregset (struct regcache *regcache, void *buf)
{
  int i;

  for (i = 0; i < microblaze_num_regs; i++)
    microblaze_collect_ptrace_register (regcache, i,
					(char *) buf + microblaze_regmap[i]);
}

/* Supply GPRs from BUF into REGCACHE.  */

static void
microblaze_store_gregset (struct regcache *regcache, const void *buf)
{
  int i;

  for (i = 0; i < microblaze_num_regs; i++)
    supply_register (regcache, i, (char *) buf + microblaze_regmap[i]);
}

static struct regset_info microblaze_regsets[] = {
  { PTRACE_GETREGS, PTRACE_SETREGS, NT_PRSTATUS,
    sizeof (elf_gregset_t), GENERAL_REGS,
    microblaze_fill_gregset, microblaze_store_gregset
  },
  NULL_REGSET
};
#endif /* HAVE_PTRACE_GETREGS */

static struct usrregs_info microblaze_usrregs_info =
  {
    microblaze_num_regs,
    microblaze_regmap,
  };

#ifdef HAVE_PTRACE_GETREGS
static struct regsets_info microblaze_regsets_info =
  {
    microblaze_regsets, /* regsets */
    0, /* num_regsets */
    nullptr /* disabled_regsets */
  };
#endif /* HAVE_PTRACE_GETREGS */

static struct regs_info microblaze_regs_info =
  {
    nullptr, /* regset_bitmap */
    &microblaze_usrregs_info,
#ifdef HAVE_PTRACE_GETREGS
    &microblaze_regsets_info
#endif /* HAVE_PTRACE_GETREGS */
  };

const regs_info *
microblaze_target::get_regs_info ()
{
  return &microblaze_regs_info;
}

void
microblaze_target::low_arch_setup ()
{
  current_process ()->tdesc = tdesc_microblaze_linux;
}

linux_process_target *the_linux_target = &the_microblaze_target;

void
initialize_low_arch ()
{
  init_registers_microblaze_linux ();
#ifdef HAVE_PTRACE_GETREGS
  initialize_regsets_info (&microblaze_regsets_info);
#endif /* HAVE_PTRACE_GETREGS */
}