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[PATCH v5 1/2] ACPI: Rename get_acpi_id_for_cpu() to acpi_get_cpu_acpi_id() on non-x86

Chengwen Feng posted 2 patches 1 month ago
There is a newer version of this series
[PATCH v5 1/2] ACPI: Rename get_acpi_id_for_cpu() to acpi_get_cpu_acpi_id() on non-x86
Posted by Chengwen Feng 1 month ago 
To unify the CPU ACPI ID retrieval interface across architectures,
rename the existing get_acpi_id_for_cpu() function to
acpi_get_cpu_acpi_id() on arm64/riscv/loongarch platforms.

This is a pure rename with no functional change, preparing for a
consistent ACPI Processor UID retrieval interface across all ACPI-enabled
platforms.

Cc: stable@vger.kernel.org
Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
---
 arch/arm64/include/asm/acpi.h      |  4 ++--
 arch/loongarch/include/asm/acpi.h  |  2 +-
 arch/riscv/include/asm/acpi.h      |  2 +-
 arch/riscv/kernel/acpi_numa.c      |  2 +-
 drivers/acpi/pptt.c                | 16 ++++++++--------
 drivers/acpi/riscv/rhct.c          |  2 +-
 drivers/perf/arm_cspmu/arm_cspmu.c |  2 +-
 7 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index c07a58b96329..202107aeb05b 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -114,7 +114,7 @@ static inline bool acpi_has_cpu_in_madt(void)
 }
 
 struct acpi_madt_generic_interrupt *acpi_cpu_get_madt_gicc(int cpu);
-static inline u32 get_acpi_id_for_cpu(unsigned int cpu)
+static inline u32 acpi_get_cpu_acpi_id(unsigned int cpu)
 {
 	return	acpi_cpu_get_madt_gicc(cpu)->uid;
 }
@@ -125,7 +125,7 @@ static inline int get_cpu_for_acpi_id(u32 uid)
 
 	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
 		if (acpi_cpu_get_madt_gicc(cpu) &&
-		    uid == get_acpi_id_for_cpu(cpu))
+		    uid == acpi_get_cpu_acpi_id(cpu))
 			return cpu;
 
 	return -EINVAL;
diff --git a/arch/loongarch/include/asm/acpi.h b/arch/loongarch/include/asm/acpi.h
index 7376840fa9f7..89c6c8f52cc3 100644
--- a/arch/loongarch/include/asm/acpi.h
+++ b/arch/loongarch/include/asm/acpi.h
@@ -40,7 +40,7 @@ extern struct acpi_madt_core_pic acpi_core_pic[MAX_CORE_PIC];
 
 extern int __init parse_acpi_topology(void);
 
-static inline u32 get_acpi_id_for_cpu(unsigned int cpu)
+static inline u32 acpi_get_cpu_acpi_id(unsigned int cpu)
 {
 	return acpi_core_pic[cpu_logical_map(cpu)].processor_id;
 }
diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
index 6e13695120bc..1d23681b61b5 100644
--- a/arch/riscv/include/asm/acpi.h
+++ b/arch/riscv/include/asm/acpi.h
@@ -61,7 +61,7 @@ static inline void arch_fix_phys_package_id(int num, u32 slot) { }
 
 void acpi_init_rintc_map(void);
 struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu);
-static inline u32 get_acpi_id_for_cpu(int cpu)
+static inline u32 acpi_get_cpu_acpi_id(int cpu)
 {
 	return acpi_cpu_get_madt_rintc(cpu)->uid;
 }
diff --git a/arch/riscv/kernel/acpi_numa.c b/arch/riscv/kernel/acpi_numa.c
index 130769e3a99c..c2eb4824d0f7 100644
--- a/arch/riscv/kernel/acpi_numa.c
+++ b/arch/riscv/kernel/acpi_numa.c
@@ -40,7 +40,7 @@ static inline int get_cpu_for_acpi_id(u32 uid)
 	int cpu;
 
 	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
-		if (uid == get_acpi_id_for_cpu(cpu))
+		if (uid == acpi_get_cpu_acpi_id(cpu))
 			return cpu;
 
 	return -EINVAL;
diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
index de5f8c018333..c1a8fba4c2b2 100644
--- a/drivers/acpi/pptt.c
+++ b/drivers/acpi/pptt.c
@@ -459,7 +459,7 @@ static void cache_setup_acpi_cpu(struct acpi_table_header *table,
 {
 	struct acpi_pptt_cache *found_cache;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
-	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+	u32 acpi_cpu_id = acpi_get_cpu_acpi_id(cpu);
 	struct cacheinfo *this_leaf;
 	unsigned int index = 0;
 	struct acpi_pptt_processor *cpu_node = NULL;
@@ -546,7 +546,7 @@ static int topology_get_acpi_cpu_tag(struct acpi_table_header *table,
 				     unsigned int cpu, int level, int flag)
 {
 	struct acpi_pptt_processor *cpu_node;
-	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+	u32 acpi_cpu_id = acpi_get_cpu_acpi_id(cpu);
 
 	cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
 	if (cpu_node) {
@@ -622,7 +622,7 @@ static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag)
 static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag)
 {
 	struct acpi_table_header *table;
-	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+	u32 acpi_cpu_id = acpi_get_cpu_acpi_id(cpu);
 	struct acpi_pptt_processor *cpu_node = NULL;
 	int ret = -ENOENT;
 
@@ -671,7 +671,7 @@ int acpi_get_cache_info(unsigned int cpu, unsigned int *levels,
 
 	pr_debug("Cache Setup: find cache levels for CPU=%d\n", cpu);
 
-	acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+	acpi_cpu_id = acpi_get_cpu_acpi_id(cpu);
 	cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
 	if (!cpu_node)
 		return -ENOENT;
@@ -797,7 +797,7 @@ int find_acpi_cpu_topology_cluster(unsigned int cpu)
 	if (!table)
 		return -ENOENT;
 
-	acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+	acpi_cpu_id = acpi_get_cpu_acpi_id(cpu);
 	cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
 	if (!cpu_node || !cpu_node->parent)
 		return -ENOENT;
@@ -872,7 +872,7 @@ static void acpi_pptt_get_child_cpus(struct acpi_table_header *table_hdr,
 	cpumask_clear(cpus);
 
 	for_each_possible_cpu(cpu) {
-		acpi_id = get_acpi_id_for_cpu(cpu);
+		acpi_id = acpi_get_cpu_acpi_id(cpu);
 		cpu_node = acpi_find_processor_node(table_hdr, acpi_id);
 
 		while (cpu_node) {
@@ -966,7 +966,7 @@ int find_acpi_cache_level_from_id(u32 cache_id)
 	for_each_possible_cpu(cpu) {
 		bool empty;
 		int level = 1;
-		u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+		u32 acpi_cpu_id = acpi_get_cpu_acpi_id(cpu);
 		struct acpi_pptt_cache *cache;
 		struct acpi_pptt_processor *cpu_node;
 
@@ -1030,7 +1030,7 @@ int acpi_pptt_get_cpumask_from_cache_id(u32 cache_id, cpumask_t *cpus)
 	for_each_possible_cpu(cpu) {
 		bool empty;
 		int level = 1;
-		u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+		u32 acpi_cpu_id = acpi_get_cpu_acpi_id(cpu);
 		struct acpi_pptt_cache *cache;
 		struct acpi_pptt_processor *cpu_node;
 
diff --git a/drivers/acpi/riscv/rhct.c b/drivers/acpi/riscv/rhct.c
index caa2c16e1697..c15ce8c13136 100644
--- a/drivers/acpi/riscv/rhct.c
+++ b/drivers/acpi/riscv/rhct.c
@@ -44,7 +44,7 @@ int acpi_get_riscv_isa(struct acpi_table_header *table, unsigned int cpu, const
 	struct acpi_rhct_isa_string *isa_node;
 	struct acpi_table_rhct *rhct;
 	u32 *hart_info_node_offset;
-	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+	u32 acpi_cpu_id = acpi_get_cpu_acpi_id(cpu);
 
 	BUG_ON(acpi_disabled);
 
diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c b/drivers/perf/arm_cspmu/arm_cspmu.c
index 34430b68f602..506b661c60fd 100644
--- a/drivers/perf/arm_cspmu/arm_cspmu.c
+++ b/drivers/perf/arm_cspmu/arm_cspmu.c
@@ -1115,7 +1115,7 @@ static int arm_cspmu_acpi_get_cpus(struct arm_cspmu *cspmu)
 	if (affinity_flag == ACPI_APMT_FLAGS_AFFINITY_PROC) {
 		for_each_possible_cpu(cpu) {
 			if (apmt_node->proc_affinity ==
-			    get_acpi_id_for_cpu(cpu)) {
+			    acpi_get_cpu_acpi_id(cpu)) {
 				cpumask_set_cpu(cpu, &cspmu->associated_cpus);
 				break;
 			}
-- 
2.17.1
Re: [PATCH v5 1/2] ACPI: Rename get_acpi_id_for_cpu() to acpi_get_cpu_acpi_id() on non-x86
Posted by Bjorn Helgaas 4 weeks, 1 day ago 
On Tue, Mar 10, 2026 at 11:20:48AM +0800, Chengwen Feng wrote:
> To unify the CPU ACPI ID retrieval interface across architectures,
> rename the existing get_acpi_id_for_cpu() function to
> acpi_get_cpu_acpi_id() on arm64/riscv/loongarch platforms.
> 
> This is a pure rename with no functional change, preparing for a
> consistent ACPI Processor UID retrieval interface across all ACPI-enabled
> platforms.

Really a question for the ACPI folks, but my preferences would be:

  - Simpler name for the interface, e.g., "acpi_get_cpu_id()"

  - Single prototype in generic header, e.g., include/linux/acpi.h

  - Split the x86 part to a separate patch and maybe (a tangent, but
    looks dubious to me) figure out whether/why xen needs xen_vcpu_id
    to be ACPI CPU IDs

> Cc: stable@vger.kernel.org
> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> ---
>  arch/arm64/include/asm/acpi.h      |  4 ++--
>  arch/loongarch/include/asm/acpi.h  |  2 +-
>  arch/riscv/include/asm/acpi.h      |  2 +-
>  arch/riscv/kernel/acpi_numa.c      |  2 +-
>  drivers/acpi/pptt.c                | 16 ++++++++--------
>  drivers/acpi/riscv/rhct.c          |  2 +-
>  drivers/perf/arm_cspmu/arm_cspmu.c |  2 +-
>  7 files changed, 15 insertions(+), 15 deletions(-)
Re: [PATCH v5 1/2] ACPI: Rename get_acpi_id_for_cpu() to acpi_get_cpu_acpi_id() on non-x86
Posted by fengchengwen 4 weeks, 1 day ago 
On 3/11/2026 1:53 AM, Bjorn Helgaas wrote:
> On Tue, Mar 10, 2026 at 11:20:48AM +0800, Chengwen Feng wrote:
>> To unify the CPU ACPI ID retrieval interface across architectures,
>> rename the existing get_acpi_id_for_cpu() function to
>> acpi_get_cpu_acpi_id() on arm64/riscv/loongarch platforms.
>>
>> This is a pure rename with no functional change, preparing for a
>> consistent ACPI Processor UID retrieval interface across all ACPI-enabled
>> platforms.
> 
> Really a question for the ACPI folks, but my preferences would be:
> 
>   - Simpler name for the interface, e.g., "acpi_get_cpu_id()"

OK, and how about add u-, like: acpi_get_cpu_uid()

> 
>   - Single prototype in generic header, e.g., include/linux/acpi.h

OK

> 
>   - Split the x86 part to a separate patch and maybe (a tangent, but
>     looks dubious to me) figure out whether/why xen needs xen_vcpu_id
>     to be ACPI CPU IDs

OK for a separate patch for x86.

Btw: the x86 implementation in 2/2 commit may has problem, please see the reply in 2/2 for detail.

> 
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
>> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
>> ---
>>  arch/arm64/include/asm/acpi.h      |  4 ++--
>>  arch/loongarch/include/asm/acpi.h  |  2 +-
>>  arch/riscv/include/asm/acpi.h      |  2 +-
>>  arch/riscv/kernel/acpi_numa.c      |  2 +-
>>  drivers/acpi/pptt.c                | 16 ++++++++--------
>>  drivers/acpi/riscv/rhct.c          |  2 +-
>>  drivers/perf/arm_cspmu/arm_cspmu.c |  2 +-
>>  7 files changed, 15 insertions(+), 15 deletions(-)
>
Re: [PATCH v5 1/2] ACPI: Rename get_acpi_id_for_cpu() to acpi_get_cpu_acpi_id() on non-x86
Posted by Andrew Cooper 4 weeks, 1 day ago 
On 10/03/2026 5:53 pm, Bjorn Helgaas wrote:
>   - Split the x86 part to a separate patch and maybe (a tangent, but
>     looks dubious to me) figure out whether/why xen needs xen_vcpu_id
>     to be ACPI CPU IDs

This is an unfortunate mess made decades ago with no good solution. 
It's to do with how Xen and dom0 share responsibility for the system.

Xen PV dom0 (only, but still widely in use; ring-deprivileging and
predates hardware virt) is OSPM for the whole system, seeing the real
ACPI tables but with a number of vCPUs generally less than the whole system.

This causes Linux to have a split idea of what CPUs are, held together
by hope and duct tape.

Xen PVH dom0 (hardware virt) is OSPM, but has an MADT matching it's vCPU
layout.  It still sees the system DSDT/etc, so while this is better from
Linux's point of view, it's still not great.

Regular unprivileged VMs get a fully coherent set of CPUID + ACPI tables.

~Andrew

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