[PATCH v6 0/3] Fix get cpu steer-tag fail on ARM64 platform

Chengwen Feng
2026-03-12T07:23:55Z

This patchset fixes the failure of CPU steer tag retrieval on ARM64
platforms. The series is structured as follows:

1. First commit: Mechanical rename of the ACPI Processor UID retrieval
interface (no functional changes) to align naming conventions across
architectures;
2. Second commit: Implement acpi_get_cpu_uid() for the x86 platform to
complete the unified ACPI Processor UID interface across all
ACPI-enabled architectures;
3. Third commit: Implement the core fix for the CPU steer tag retrieval
logic on ARM64 (the root cause of the retrieval failure).

The renaming and x86 implementation lay the groundwork for the unified
ACPI interface required by the ARM64 steer tag fix, ensuring consistent
CPU UID retrieval across architectures before addressing the functional
bug.

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

Changes in v5:
- Refine commit-log of commit 2/2
- Replace cpu_acpi_id() by acpi_get_cpu_acpi_id() on x86

Changes in v4:
- Split the rename into a separate commit.

Changes in v3:
- Rename existing get_acpi_id_for_cpu() to acpi_get_cpu_acpi_id() other
than add one new API.

Changes in v2:
- Add ECN _DSM reference doc name and its URL.
- Separate implement acpi_get_cpu_acpi_id() in each arch which supports
ACPI.
- Refine commit-log.

Chengwen Feng (2):
ACPI: Rename get_acpi_id_for_cpu() to acpi_get_cpu_acpi_id() on
non-x86
PCI/TPH: Fix get cpu steer-tag fail on ARM64 platform

Chengwen Feng (3):
ACPI: Rename get_acpi_id_for_cpu() to acpi_get_cpu_uid() on non-x86
x86: Implement acpi_get_cpu_uid()
PCI/TPH: Fix get cpu steer-tag fail on ARM64 platform

Documentation/PCI/tph.rst | 4 +--
arch/arm64/include/asm/acpi.h | 16 +---------
arch/arm64/kernel/acpi.c | 16 ++++++++++
arch/arm64/kernel/acpi_numa.c | 15 ++++++++++
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 | 8 +++--
arch/x86/include/asm/cpu.h | 1 -
arch/x86/include/asm/smp.h | 1 -
arch/x86/kernel/cpu/common.c | 15 ++++++++++
arch/x86/xen/enlighten_hvm.c | 5 ++--
drivers/acpi/pptt.c | 47 +++++++++++++++++++++---------
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 +--
19 files changed, 151 insertions(+), 55 deletions(-)

--
2.17.1