Currently, x86, Riscv, Loongarch use the generic entry. Convert arm64
to use the generic entry infrastructure from kernel/entry/*. The generic
entry makes maintainers' work easier and codes more elegant, which aslo
removed a lot of duplicate code.

The main steps are as follows:
- Make arm64 easier to use irqentry_enter/exit().
- Make arm64 closer to the PREEMPT_DYNAMIC code of generic entry.
- Split generic entry into generic irq entry and generic syscall to
  make the single patch more concentrated in switching to one thing.
- Switch to generic irq entry.
- Make arm64 closer to the generic syscall code.
- Switch to generic entry completely.

Changes in v5:
- Not change arm32 and keep inerrupts_enabled() macro for gicv3 driver.
- Move irqentry_state definition into arch/arm64/kernel/entry-common.c.
- Avoid removing the __enter_from_*() and __exit_to_*() wrappers.
- Update "irqentry_state_t ret/irq_state" to "state"
  to keep it consistently.
- Use generic irq entry header for PREEMPT_DYNAMIC after split
  the generic entry.
- Also refactor the ARM64 syscall code.
- Introduce arch_ptrace_report_syscall_entry/exit(), instead of
  arch_pre/post_report_syscall_entry/exit() to simplify code.
- Make the syscall patches clear separation.
- Update the commit message.

Changes in v4:
- Rework/cleanup split into a few patches as Mark suggested.
- Replace interrupts_enabled() macro with regs_irqs_disabled(), instead
  of left it here.
- Remove rcu and lockdep state in pt_regs by using temporary
  irqentry_state_t as Mark suggested.
- Remove some unnecessary intermediate functions to make it clear.
- Rework preempt irq and PREEMPT_DYNAMIC code
  to make the switch more clear.
- arch_prepare_*_entry/exit() -> arch_pre_*_entry/exit().
- Expand the arch functions comment.
- Make arch functions closer to its caller.
- Declare saved_reg in for block.
- Remove arch_exit_to_kernel_mode_prepare(), arch_enter_from_kernel_mode().
- Adjust "Add few arch functions to use generic entry" patch to be
  the penultimate.
- Update the commit message.
- Add suggested-by.

Changes in v3:
- Test the MTE test cases.
- Handle forget_syscall() in arch_post_report_syscall_entry()
- Make the arch funcs not use __weak as Thomas suggested, so move
  the arch funcs to entry-common.h, and make arch_forget_syscall() folded
  in arch_post_report_syscall_entry() as suggested.
- Move report_single_step() to thread_info.h for arm64
- Change __always_inline() to inline, add inline for the other arch funcs.
- Remove unused signal.h for entry-common.h.
- Add Suggested-by.
- Update the commit message.

Changes in v2:
- Add tested-by.
- Fix a bug that not call arch_post_report_syscall_entry() in
  syscall_trace_enter() if ptrace_report_syscall_entry() return not zero.
- Refactor report_syscall().
- Add comment for arch_prepare_report_syscall_exit().
- Adjust entry-common.h header file inclusion to alphabetical order.
- Update the commit message.

Jinjie Ruan (22):
  arm64: ptrace: Replace interrupts_enabled() with regs_irqs_disabled()
  arm64: entry: Refactor the entry and exit for exceptions from EL1
  arm64: entry: Move arm64_preempt_schedule_irq() into
    __exit_to_kernel_mode()
  arm64: entry: Rework arm64_preempt_schedule_irq()
  arm64: entry: Use preempt_count() and need_resched() helper
  arm64: entry: Expand the need_irq_preemption() macro ahead
  arm64: entry: preempt_schedule_irq() only if PREEMPTION enabled
  arm64: entry: Use different helpers to check resched for
    PREEMPT_DYNAMIC
  entry: Split generic entry into irq and syscall
  entry: Add arch_irqentry_exit_need_resched() for arm64
  arm64: entry: Switch to generic IRQ entry
  arm64/ptrace: Split report_syscall() function
  arm64/ptrace: Refactor syscall_trace_enter()
  arm64/ptrace: Refactor syscall_trace_exit()
  arm64/ptrace: Refator el0_svc_common()
  entry: Make syscall_exit_to_user_mode_prepare() not static
  arm64/ptrace: Return early for ptrace_report_syscall_entry() error
  arm64/ptrace: Expand secure_computing() in place
  arm64/ptrace: Use syscall_get_arguments() heleper
  entry: Add arch_ptrace_report_syscall_entry/exit()
  entry: Add has_syscall_work() helepr
  arm64: entry: Convert to generic entry

 MAINTAINERS                           |   1 +
 arch/Kconfig                          |   8 +
 arch/arm64/Kconfig                    |   1 +
 arch/arm64/include/asm/daifflags.h    |   2 +-
 arch/arm64/include/asm/entry-common.h | 134 +++++++++
 arch/arm64/include/asm/preempt.h      |   2 -
 arch/arm64/include/asm/ptrace.h       |  11 +-
 arch/arm64/include/asm/syscall.h      |   6 +-
 arch/arm64/include/asm/thread_info.h  |  23 +-
 arch/arm64/include/asm/xen/events.h   |   2 +-
 arch/arm64/kernel/acpi.c              |   2 +-
 arch/arm64/kernel/debug-monitors.c    |   9 +-
 arch/arm64/kernel/entry-common.c      | 377 ++++++++-----------------
 arch/arm64/kernel/ptrace.c            |  90 ------
 arch/arm64/kernel/sdei.c              |   2 +-
 arch/arm64/kernel/signal.c            |   3 +-
 arch/arm64/kernel/syscall.c           |  31 +-
 include/linux/entry-common.h          | 384 +------------------------
 include/linux/irq-entry-common.h      | 389 ++++++++++++++++++++++++++
 kernel/entry/Makefile                 |   3 +-
 kernel/entry/common.c                 | 176 ++----------
 kernel/entry/syscall-common.c         | 198 +++++++++++++
 kernel/sched/core.c                   |   8 +-
 23 files changed, 909 insertions(+), 953 deletions(-)
 create mode 100644 arch/arm64/include/asm/entry-common.h
 create mode 100644 include/linux/irq-entry-common.h
 create mode 100644 kernel/entry/syscall-common.c

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2.34.1