[PATCH v10 0/8] ACPI: Unify CPU UID interface and fix ARM64 TPH steer-tag issue

[Rafael J. Wysocki]

On Fri, Mar 20, 2026 at 4:17 AM Chengwen Feng <fengchengwen at huawei.com> wrote:
>
> This patchset unifies ACPI Processor UID retrieval across
> arm64/loongarch/riscv/x86 via acpi_get_cpu_uid() (with input validation)
> and fixes ARM64 CPU steer-tag retrieval failure in PCI/TPH:
>
> 1-4: Add acpi_get_cpu_uid() for arm64/loongarch/riscv/x86 (update
>      respective users)
> 5: Centralize acpi_get_cpu_uid() declaration in include/linux/acpi.h
> 6: Clean up perf/arm_cspmu
> 7: Clean up ACPI/PPTT and remove unused get_acpi_id_for_cpu()
> 8: Pass ACPI Processor UID to Cache Locality _DSM
>
> The interface refactor ensures consistent CPU UID retrieval across
> architectures (no functional changes for valid inputs) and provides the
> unified interface required for the ARM64 TPH fix.
>
> ---
> Changes in v10:
> - Refine commit header&log according to Punit's and Bjorn's review
> - Split perf/arm_cspmu as a separate commit which address Punit's
>   review
>
> Changes in v9:
> - Address Bjorn's review: split commits to each platform so that make
>   them easy to review
>
> Changes in v8:
> - Moving arm64's get_cpu_for_acpi_id() to kernel/acpi.c which address
>   Jeremy's review
>
> Chengwen Feng (8):
>   arm64: acpi: Add acpi_get_cpu_uid() for unified ACPI CPU UID retrieval
>   LoongArch: Add acpi_get_cpu_uid() for unified ACPI CPU UID retrieval
>   RISC-V: ACPI: Add acpi_get_cpu_uid() for unified ACPI CPU UID
>     retrieval
>   x86/acpi: Add acpi_get_cpu_uid() for unified ACPI CPU UID retrieval
>   ACPI: Centralize acpi_get_cpu_uid() declaration in
>     include/linux/acpi.h
>   perf: arm_cspmu: Switch to acpi_get_cpu_uid() from
>     get_acpi_id_for_cpu()
>   ACPI: PPTT: Use acpi_get_cpu_uid() and remove get_acpi_id_for_cpu()
>   PCI/TPH: Pass ACPI Processor UID to Cache Locality _DSM
>
>  Documentation/PCI/tph.rst          |  4 +--
>  arch/arm64/include/asm/acpi.h      | 17 +---------
>  arch/arm64/kernel/acpi.c           | 30 ++++++++++++++++++
>  arch/loongarch/include/asm/acpi.h  |  5 ---
>  arch/loongarch/kernel/acpi.c       |  9 ++++++
>  arch/riscv/include/asm/acpi.h      |  4 ---
>  arch/riscv/kernel/acpi.c           | 16 ++++++++++
>  arch/riscv/kernel/acpi_numa.c      |  9 ++++--
>  arch/x86/include/asm/cpu.h         |  1 -
>  arch/x86/include/asm/smp.h         |  1 -
>  arch/x86/kernel/acpi/boot.c        | 20 ++++++++++++
>  arch/x86/xen/enlighten_hvm.c       |  5 +--
>  drivers/acpi/pptt.c                | 50 ++++++++++++++++++++++--------
>  drivers/acpi/riscv/rhct.c          |  7 ++++-
>  drivers/pci/tph.c                  | 16 +++++++---
>  drivers/perf/arm_cspmu/arm_cspmu.c |  6 ++--
>  include/linux/acpi.h               | 11 +++++++
>  include/linux/pci-tph.h            |  4 +--
>  18 files changed, 158 insertions(+), 57 deletions(-)
>
> --

It doesn't look like anyone has a particular heartburn related to this
series, so I could apply it in principle, but I'd appreciate some ACKs
from arch maintainers.

Why don't you resend it with all of the tags collected so far (and
please add x86 at kernel.org to the CC list)?