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