On Fri, 23 Jan 2026 at 15:39, Mukesh Kumar Chaurasiya
<[email protected]> wrote:
>
> Adding support for the generic irq entry/exit handling for PowerPC. The
> goal is to bring PowerPC in line with other architectures that already
> use the common irq entry infrastructure, reducing duplicated code and
> making it easier to share future changes in entry/exit paths.
>
> This is slightly tested of ppc64le and ppc32.
>
> The performance benchmarks are below:
>
> perf bench syscall usec/op (-ve is improvement)
>
> | Syscall | Base        | test        | change % |
> | ------- | ----------- | ----------- | -------- |
> | basic   | 0.093543    | 0.093023    | -0.56    |
> | execve  | 446.557781  | 450.107172  | +0.79    |
> | fork    | 1142.204391 | 1156.377214 | +1.24    |
> | getpgid | 0.097666    | 0.092677    | -5.11    |
>
> perf bench syscall ops/sec (+ve is improvement)
>
> | Syscall | Base     | New      | change % |
> | ------- | -------- | -------- | -------- |
> | basic   | 10690548 | 10750140 | +0.56    |
> | execve  | 2239     | 2221     | -0.80    |
> | fork    | 875      | 864      | -1.26    |
> | getpgid | 10239026 | 10790324 | +5.38    |
>
>
> IPI latency benchmark (-ve is improvement)
>
> | Metric         | Base (ns)     | New (ns)      | % Change |
> | -------------- | ------------- | ------------- | -------- |
> | Dry run        | 583136.56     | 584136.35     | 0.17%    |
> | Self IPI       | 4167393.42    | 4149093.90    | -0.44%   |
> | Normal IPI     | 61769347.82   | 61753728.39   | -0.03%   |
> | Broadcast IPI  | 2235584825.02 | 2227521401.45 | -0.36%   |
> | Broadcast lock | 2164964433.31 | 2125658641.76 | -1.82%   |
>
>
> Thats very close to performance earlier with arch specific handling.
>
> Tests done:
>  - Build and boot on ppc64le pseries.
>  - Build and boot on ppc64le powernv8 powernv9 powernv10.
>  - Build and boot on ppc32.
>  - Performance benchmark done with perf syscall basic on pseries.
>

Passes the irq_test_cases KUnit suite on (qemu) powerpc(64),
powerpcle, and powerpc32 targets.

./tools/testing/kunit/kunit.py run --arch powerpc  irq_test_cases
./tools/testing/kunit/kunit.py run --arch powerpcle  irq_test_cases
./tools/testing/kunit/kunit.py run --arch powerpc32  irq_test_cases

Tested-by: David Gow <[email protected]>

Cheers,
-- David

> Changelog:
> V3 -> V4
>  - Fixed the issue in older gcc version where linker couldn't find
>    mem functions
>  - Merged IRQ enable and syscall enable into a single patch
>  - Cleanup for unused functions done in separate patch.
>  - Some other cosmetic changes
> V3: 
> https://lore.kernel.org/all/[email protected]/
>
> V2 -> V3
>  - #ifdef CONFIG_GENERIC_IRQ_ENTRY removed from unnecessary places
>  - Some functions made __always_inline
>  - pt_regs padding changed to match 16byte interrupt stack alignment
>  - And some cosmetic changes from reviews from earlier patch
> V2: 
> https://lore.kernel.org/all/[email protected]/
>
> V1 -> V2
>  - Fix an issue where context tracking was showing warnings for
>    incorrect context
> V1: 
> https://lore.kernel.org/all/[email protected]/
>
> RFC -> PATCH V1
>  - Fix for ppc32 spitting out kuap lock warnings.
>  - ppc64le powernv8 crash fix.
>  - Review comments incorporated from previous RFC.
> RFC 
> https://lore.kernel.org/all/[email protected]/
>
> Mukesh Kumar Chaurasiya (8):
>   powerpc: rename arch_irq_disabled_regs
>   powerpc: Prepare to build with generic entry/exit framework
>   powerpc: introduce arch_enter_from_user_mode
>   powerpc: Introduce syscall exit arch functions
>   powerpc: add exit_flags field in pt_regs
>   powerpc: Prepare for IRQ entry exit
>   powerpc: Enable GENERIC_ENTRY feature
>   powerpc: Remove unused functions
>
>  arch/powerpc/Kconfig                    |   1 +
>  arch/powerpc/include/asm/entry-common.h | 533 ++++++++++++++++++++++++
>  arch/powerpc/include/asm/hw_irq.h       |   4 +-
>  arch/powerpc/include/asm/interrupt.h    | 386 +++--------------
>  arch/powerpc/include/asm/kasan.h        |  15 +-
>  arch/powerpc/include/asm/ptrace.h       |   6 +-
>  arch/powerpc/include/asm/signal.h       |   1 -
>  arch/powerpc/include/asm/stacktrace.h   |   6 +
>  arch/powerpc/include/asm/syscall.h      |   5 +
>  arch/powerpc/include/asm/thread_info.h  |   1 +
>  arch/powerpc/include/uapi/asm/ptrace.h  |  14 +-
>  arch/powerpc/kernel/interrupt.c         | 254 ++---------
>  arch/powerpc/kernel/ptrace/ptrace.c     | 142 +------
>  arch/powerpc/kernel/signal.c            |  25 +-
>  arch/powerpc/kernel/syscall.c           | 119 +-----
>  arch/powerpc/kernel/traps.c             |   2 +-
>  arch/powerpc/kernel/watchdog.c          |   2 +-
>  arch/powerpc/perf/core-book3s.c         |   2 +-
>  18 files changed, 690 insertions(+), 828 deletions(-)
>  create mode 100644 arch/powerpc/include/asm/entry-common.h
>
> --
> 2.52.0
>
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