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 ACPI/PPTT and remove unused get_acpi_id_for_cpu()
7: Fix ARM64 platform CPU steer-tag retrieval failure

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 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

Changes in v7:
- Refine first commit which address Jonathan's reviews
- Fix x86 implement bug (not consider INVALID-ID) which address Peter's
  review
- Fix CI error of x86 implement by moving function to acpi/boot.c

Changes in v6:
- Rename existing get_acpi_id_for_cpu() to acpi_get_cpu_uid()
- Split x86's modify as one commit

Chengwen Feng (7):
  arm64/acpi: Add acpi_get_cpu_uid() and switch arm_cspmu to use it
  loongarch/acpi: Add acpi_get_cpu_uid() declaration and implementation
  riscv/acpi: Add acpi_get_cpu_uid() implementation and update users
  x86/acpi: Add acpi_get_cpu_uid() implementation and update Xen users
  ACPI: Centralize acpi_get_cpu_uid() declaration in
    include/linux/acpi.h
  ACPI: PPTT: Use acpi_get_cpu_uid() and remove get_acpi_id_for_cpu()
  PCI/TPH: Fix get cpu steer-tag fail on ARM64 platform

 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(-)

-- 
2.17.1

On Thu, 19 Mar 2026 14:57:28 +0800
Chengwen Feng <fengchengwen@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 ACPI/PPTT and remove unused get_acpi_id_for_cpu()
> 7: Fix ARM64 platform CPU steer-tag retrieval failure
> 
> 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.

Given the structure of the series has slowly evolved since I gave
tags, I took another look.  All looks good to me.
Nice work.

Jonathan