Re: [PATCH -next v7 0/7] arm64: entry: Convert to generic irq entry

[Jinjie Ruan <ruanjinjie@xxxxxxxxxx>]

On 2025/8/12 19:19, Mark Rutland wrote:
> Hi,
> 
> This is looking pretty good now, thanks for continuing to work on this!
> 
> I've left a couple of minor comments, and Ada has left a few more. If
> you're able to address those and respin atop v6.17-rc1, I think we can
> start figuring out how to queue this.

Sure，I will revise these review comments based on v6.17-rc1 and release
a new version after local testing.

> 
> Mark.
> 
> On Tue, Jul 29, 2025 at 09:54:49AM +0800, Jinjie Ruan wrote:
>> Currently, x86, Riscv, Loongarch use the generic entry. Also convert
>> arm64 to use the generic entry infrastructure from kernel/entry/*.
>> The generic entry makes maintainers' work easier and codes more elegant,
>> which will make PREEMPT_DYNAMIC and PREEMPT_LAZY use the generic entry
>> common code and remove a lot of duplicate code.
>>
>> Since commit a70e9f647f50 ("entry: Split generic entry into generic
>> exception and syscall entry") split the generic entry into generic irq
>> entry and generic syscall entry, it is time to convert arm64 to use
>> the generic irq entry. And ARM64 will be completely converted to generic
>> entry in the upcoming patch series.
>>
>> The main convert steps are as follows:
>> - Split generic entry into generic irq entry and generic syscall to
>>   make the single patch more concentrated in switching to one thing.
>> - Make arm64 easier to use irqentry_enter/exit().
>> - Make arm64 closer to the PREEMPT_DYNAMIC code of generic entry.
>> - Switch to generic irq entry.
>>
>> It was tested ok with following test cases on QEMU virt platform:
>>  - Perf tests.
>>  - Different `dynamic preempt` mode switch.
>>  - Pseudo NMI tests.
>>  - Stress-ng CPU stress test.
>>  - MTE test case in Documentation/arch/arm64/memory-tagging-extension.rst
>>    and all test cases in tools/testing/selftests/arm64/mte/*.
>>
>> The test QEMU configuration is as follows:
>>
>>      qemu-system-aarch64 \
>>              -M virt,gic-version=3,virtualization=on,mte=on \
>>              -cpu max,pauth-impdef=on \
>>              -kernel Image \
>>              -smp 8,sockets=1,cores=4,threads=2 \
>>              -m 512m \
>>              -nographic \
>>              -no-reboot \
>>              -device virtio-rng-pci \
>>              -append "root=/dev/vda rw console=ttyAMA0 kgdboc=ttyAMA0,115200 
>> \
>>                      earlycon preempt=voluntary irqchip.gicv3_pseudo_nmi=1" \
>>              -drive if=none,file=images/rootfs.ext4,format=raw,id=hd0 \
>>              -device virtio-blk-device,drive=hd0 \
>>
>> Changes in v7:
>> - Rebased on v6.16-rc7 and remove the merged first patch.
>> - Update the commit message.
>>
>> Changes in v6:
>> - Rebased on 6.14 rc2 next.
>> - Put the syscall bits aside and split it out.
>> - Have the split patch before the arm64 changes.
>> - Merge some tightly coupled patches.
>> - Adjust the order of some patches to make them more reasonable.
>> - Define regs_irqs_disabled() by inline function.
>> - Define interrupts_enabled() in terms of regs_irqs_disabled().
>> - Delete the fast_interrupts_enabled() macro.
>> - irqentry_state_t -> arm64_irqentry_state_t.
>> - Remove arch_exit_to_user_mode_prepare() and pull local_daif_mask() later
>>   in the arm64 exit sequence
>> - Update the commit message.
>>
>> 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 (7):
>>   arm64: ptrace: Replace interrupts_enabled() with regs_irqs_disabled()
>>   arm64: entry: Refactor the entry and exit for exceptions from EL1
>>   arm64: entry: Rework arm64_preempt_schedule_irq()
>>   arm64: entry: Use preempt_count() and need_resched() helper
>>   arm64: entry: Refactor preempt_schedule_irq() check code
>>   arm64: entry: Move arm64_preempt_schedule_irq() into
>>     __exit_to_kernel_mode()
>>   arm64: entry: Switch to generic IRQ entry
>>
>>  arch/arm64/Kconfig                    |   1 +
>>  arch/arm64/include/asm/daifflags.h    |   2 +-
>>  arch/arm64/include/asm/entry-common.h |  56 ++++
>>  arch/arm64/include/asm/preempt.h      |   2 -
>>  arch/arm64/include/asm/ptrace.h       |  13 +-
>>  arch/arm64/include/asm/xen/events.h   |   2 +-
>>  arch/arm64/kernel/acpi.c              |   2 +-
>>  arch/arm64/kernel/debug-monitors.c    |   2 +-
>>  arch/arm64/kernel/entry-common.c      | 411 +++++++++-----------------
>>  arch/arm64/kernel/sdei.c              |   2 +-
>>  arch/arm64/kernel/signal.c            |   3 +-
>>  kernel/entry/common.c                 |  16 +-
>>  12 files changed, 217 insertions(+), 295 deletions(-)
>>  create mode 100644 arch/arm64/include/asm/entry-common.h
>>
>> -- 
>> 2.34.1
>>
>