320 lines
9.6 KiB
C
320 lines
9.6 KiB
C
/* Native-dependent code for GNU/Linux ARC.
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Copyright 2020-2022 Free Software Foundation, 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 "defs.h"
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#include "frame.h"
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#include "inferior.h"
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#include "gdbcore.h"
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#include "regcache.h"
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#include "gdbsupport/gdb_assert.h"
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#include "target.h"
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#include "linux-nat.h"
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#include "nat/gdb_ptrace.h"
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#include <stdint.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <signal.h>
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#include <sys/user.h>
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#include <sys/ioctl.h>
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#include "gdbsupport/gdb_wait.h"
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#include <fcntl.h>
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#include <sys/procfs.h>
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#include <linux/elf.h>
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#include "gregset.h"
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#include "arc-tdep.h"
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#include "arc-linux-tdep.h"
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#include "arch/arc.h"
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/* Defines ps_err_e, struct ps_prochandle. */
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#include "gdb_proc_service.h"
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/* Print an "arc-linux-nat" debug statement. */
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#define arc_linux_nat_debug_printf(fmt, ...) \
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debug_prefixed_printf_cond (arc_debug, "arc-linux-nat", fmt, ##__VA_ARGS__)
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/* Linux starting with 4.12 supports NT_ARC_V2 note type, which adds R30,
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R58 and R59 registers, which are specific to ARC HS and aren't
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available in ARC 700. */
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#if defined (NT_ARC_V2) && defined (__ARCHS__)
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#define ARC_HAS_V2_REGSET
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#endif
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class arc_linux_nat_target final : public linux_nat_target
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{
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public:
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/* Add ARC register access methods. */
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void fetch_registers (struct regcache *, int) override;
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void store_registers (struct regcache *, int) override;
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const struct target_desc *read_description () override;
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/* Handle threads */
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void low_prepare_to_resume (struct lwp_info *lp) override;
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};
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static arc_linux_nat_target the_arc_linux_nat_target;
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/* Read general registers from target process/thread (via ptrace)
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into REGCACHE. */
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static void
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fetch_gregs (struct regcache *regcache, int regnum)
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{
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const int tid = get_ptrace_pid (regcache->ptid ());
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struct iovec iov;
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gdb_gregset_t regs;
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iov.iov_base = ®s;
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iov.iov_len = sizeof (gdb_gregset_t);
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if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0)
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perror_with_name (_("Couldn't get general registers"));
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else
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arc_linux_supply_gregset (NULL, regcache, regnum, ®s, 0);
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}
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#ifdef ARC_HAS_V2_REGSET
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/* Read ARC v2 registers from target process/thread (via ptrace)
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into REGCACHE. */
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static void
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fetch_v2_regs (struct regcache *regcache, int regnum)
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{
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const int tid = get_ptrace_pid (regcache->ptid ());
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struct iovec iov;
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bfd_byte v2_buffer[ARC_LINUX_SIZEOF_V2_REGSET];
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iov.iov_base = &v2_buffer;
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iov.iov_len = ARC_LINUX_SIZEOF_V2_REGSET;
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if (ptrace (PTRACE_GETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0)
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perror_with_name (_("Couldn't get ARC HS registers"));
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else
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arc_linux_supply_v2_regset (NULL, regcache, regnum, v2_buffer, 0);
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}
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#endif
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/* Store general registers from REGCACHE into the target process/thread. */
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static void
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store_gregs (const struct regcache *regcache, int regnum)
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{
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const int tid = get_ptrace_pid (regcache->ptid ());
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struct iovec iov;
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gdb_gregset_t regs;
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iov.iov_base = ®s;
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iov.iov_len = sizeof (gdb_gregset_t);
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if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0)
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perror_with_name (_("Couldn't get general registers"));
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else
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{
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arc_linux_collect_gregset (NULL, regcache, regnum, regs, 0);
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if (ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0)
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perror_with_name (_("Couldn't write general registers"));
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}
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}
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#ifdef ARC_HAS_V2_REGSET
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/* Store ARC v2 registers from REGCACHE into the target process/thread. */
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static void
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store_v2_regs (const struct regcache *regcache, int regnum)
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{
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const int tid = get_ptrace_pid (regcache->ptid ());
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struct iovec iov;
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bfd_byte v2_buffer[ARC_LINUX_SIZEOF_V2_REGSET];
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iov.iov_base = &v2_buffer;
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iov.iov_len = ARC_LINUX_SIZEOF_V2_REGSET;
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if (ptrace (PTRACE_GETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0)
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perror_with_name (_("Couldn't get ARC HS registers"));
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else
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{
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arc_linux_collect_v2_regset (NULL, regcache, regnum, v2_buffer, 0);
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if (ptrace (PTRACE_SETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0)
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perror_with_name (_("Couldn't write ARC HS registers"));
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}
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}
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#endif
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/* Target operation: Read REGNUM register (all registers if REGNUM == -1)
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from target process into REGCACHE. */
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void
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arc_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
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{
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if (regnum == -1 || regnum <= ARC_LAST_REGNUM)
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fetch_gregs (regcache, regnum);
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#ifdef ARC_HAS_V2_REGSET
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if (regnum == -1
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|| regnum == ARC_R30_REGNUM
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|| regnum == ARC_R58_REGNUM
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|| regnum == ARC_R59_REGNUM)
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fetch_v2_regs (regcache, regnum);
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#endif
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}
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/* Target operation: Store REGNUM register (all registers if REGNUM == -1)
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to the target process from REGCACHE. */
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void
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arc_linux_nat_target::store_registers (struct regcache *regcache, int regnum)
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{
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if (regnum == -1 || regnum <= ARC_LAST_REGNUM)
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store_gregs (regcache, regnum);
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#ifdef ARC_HAS_V2_REGSET
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if (regnum == -1
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|| regnum == ARC_R30_REGNUM
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|| regnum == ARC_R58_REGNUM
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|| regnum == ARC_R59_REGNUM)
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store_v2_regs (regcache, regnum);
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#endif
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}
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/* Copy general purpose register(s) from REGCACHE into regset GREGS.
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This function is exported to proc-service.c */
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void
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fill_gregset (const struct regcache *regcache,
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gdb_gregset_t *gregs, int regnum)
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{
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arc_linux_collect_gregset (NULL, regcache, regnum, gregs, 0);
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}
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/* Copy all the general purpose registers from regset GREGS into REGCACHE.
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This function is exported to proc-service.c. */
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void
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supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregs)
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{
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arc_linux_supply_gregset (NULL, regcache, -1, gregs, 0);
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}
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/* ARC doesn't have separate FP registers. This function is exported
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to proc-service.c. */
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void
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fill_fpregset (const struct regcache *regcache,
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gdb_fpregset_t *fpregsetp, int regnum)
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{
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arc_linux_nat_debug_printf ("called");
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}
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/* ARC doesn't have separate FP registers. This function is exported
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to proc-service.c. */
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void
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supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp)
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{
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arc_linux_nat_debug_printf ("called");
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}
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/* Implement the "read_description" method of linux_nat_target. */
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const struct target_desc *
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arc_linux_nat_target::read_description ()
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{
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/* This is a native target, hence description is hardcoded. */
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#ifdef __ARCHS__
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arc_arch_features features (4, ARC_ISA_ARCV2);
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#else
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arc_arch_features features (4, ARC_ISA_ARCV1);
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#endif
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return arc_lookup_target_description (features);
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}
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/* As described in arc_linux_collect_gregset(), we need to write resume-PC
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to ERET. However by default GDB for native targets doesn't write
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registers if they haven't been changed. This is a callback called by
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generic GDB, and in this callback we have to rewrite PC value so it
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would force rewrite of register on target. It seems that the only
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other arch that utilizes this hook is x86/x86-64 for HW breakpoint
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support. But then, AFAIK no other arch has this stop_pc/eret
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complexity.
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No better way was found, other than this fake write of register value,
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to force GDB into writing register to target. Is there any? */
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void
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arc_linux_nat_target::low_prepare_to_resume (struct lwp_info *lwp)
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{
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/* When new processes and threads are created we do not have the address
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space for them and calling get_thread_regcache will cause an internal
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error in GDB. It looks like that checking for last_resume_kind is the
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sensible way to determine processes for which we cannot get regcache.
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Ultimately, a better way would be removing the need for
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low_prepare_to_resume in the first place. */
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if (lwp->last_resume_kind == resume_stop)
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return;
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struct regcache *regcache = get_thread_regcache (this, lwp->ptid);
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struct gdbarch *gdbarch = regcache->arch ();
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/* Read current PC value, then write it back. It is required to call
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invalidate(), otherwise GDB will note that new value is equal to old
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value and will skip write. */
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ULONGEST new_pc;
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regcache_cooked_read_unsigned (regcache, gdbarch_pc_regnum (gdbarch),
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&new_pc);
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regcache->invalidate (gdbarch_pc_regnum (gdbarch));
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regcache_cooked_write_unsigned (regcache, gdbarch_pc_regnum (gdbarch),
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new_pc);
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}
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/* Fetch the thread-local storage pointer for libthread_db. Note that
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this function is not called from GDB, but is called from libthread_db.
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This is required to debug multithreaded applications with NPTL. */
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ps_err_e
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ps_get_thread_area (struct ps_prochandle *ph, lwpid_t lwpid, int idx,
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void **base)
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{
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arc_linux_nat_debug_printf ("called");
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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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/* Suppress warning from -Wmissing-prototypes. */
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void _initialize_arc_linux_nat ();
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void
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_initialize_arc_linux_nat ()
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{
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/* Register the target. */
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linux_target = &the_arc_linux_nat_target;
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add_inf_child_target (&the_arc_linux_nat_target);
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}
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