[PATCH v9 1/7] arm64/acpi: Add acpi_get_cpu_uid() and switch arm_cspmu to use it

[Chengwen Feng <fengchengwen@xxxxxxxxxx>]

Add arch-specific acpi_get_cpu_uid() for arm64, and update dependent
code:
- Declare acpi_get_cpu_uid() in arch/arm64/include/asm/acpi.h
- Implement acpi_get_cpu_uid() with input parameter validation
- Replace get_acpi_id_for_cpu() with acpi_get_cpu_uid() in
  drivers/perf/arm_cspmu/arm_cspmu.c
- Reimplement get_cpu_for_acpi_id() based on acpi_get_cpu_uid() (to
  align with new interface) and move its implementation next to
  acpi_get_cpu_uid()

This is the first step towards unifying ACPI CPU UID retrieval interface
across architectures, while adding input validation for robustness.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Chengwen Feng <fengchengwen@xxxxxxxxxx>
Reviewed-by: Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>
---
 arch/arm64/include/asm/acpi.h      | 14 ++------------
 arch/arm64/kernel/acpi.c           | 30 ++++++++++++++++++++++++++++++
 drivers/perf/arm_cspmu/arm_cspmu.c |  6 ++++--
 3 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index c07a58b96329..2219a3301e72 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -118,18 +118,8 @@ static inline u32 get_acpi_id_for_cpu(unsigned int cpu)
 {
        return  acpi_cpu_get_madt_gicc(cpu)->uid;
 }
-
-static inline int get_cpu_for_acpi_id(u32 uid)
-{
-       int cpu;
-
-       for (cpu = 0; cpu < nr_cpu_ids; cpu++)
-               if (acpi_cpu_get_madt_gicc(cpu) &&
-                   uid == get_acpi_id_for_cpu(cpu))
-                       return cpu;
-
-       return -EINVAL;
-}
+int acpi_get_cpu_uid(unsigned int cpu, u32 *uid);
+int get_cpu_for_acpi_id(u32 uid);
 
 static inline void arch_fix_phys_package_id(int num, u32 slot) { }
 void __init acpi_init_cpus(void);
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index af90128cfed5..24b9d934be54 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -458,3 +458,33 @@ int acpi_unmap_cpu(int cpu)
 }
 EXPORT_SYMBOL(acpi_unmap_cpu);
 #endif /* CONFIG_ACPI_HOTPLUG_CPU */
+
+int acpi_get_cpu_uid(unsigned int cpu, u32 *uid)
+{
+       struct acpi_madt_generic_interrupt *gicc;
+
+       if (cpu >= nr_cpu_ids)
+               return -EINVAL;
+
+       gicc = acpi_cpu_get_madt_gicc(cpu);
+       if (!gicc)
+               return -ENODEV;
+
+       *uid = gicc->uid;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(acpi_get_cpu_uid);
+
+int get_cpu_for_acpi_id(u32 uid)
+{
+       u32 cpu_uid;
+       int ret;
+
+       for (int cpu = 0; cpu < nr_cpu_ids; cpu++) {
+               ret = acpi_get_cpu_uid(cpu, &cpu_uid);
+               if (ret == 0 && uid == cpu_uid)
+                       return cpu;
+       }
+
+       return -EINVAL;
+}
diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c 
b/drivers/perf/arm_cspmu/arm_cspmu.c
index 34430b68f602..ed72c3d1f796 100644
--- a/drivers/perf/arm_cspmu/arm_cspmu.c
+++ b/drivers/perf/arm_cspmu/arm_cspmu.c
@@ -1107,15 +1107,17 @@ static int arm_cspmu_acpi_get_cpus(struct arm_cspmu 
*cspmu)
 {
        struct acpi_apmt_node *apmt_node;
        int affinity_flag;
+       u32 cpu_uid;
        int cpu;
+       int ret;
 
        apmt_node = arm_cspmu_apmt_node(cspmu->dev);
        affinity_flag = apmt_node->flags & ACPI_APMT_FLAGS_AFFINITY;
 
        if (affinity_flag == ACPI_APMT_FLAGS_AFFINITY_PROC) {
                for_each_possible_cpu(cpu) {
-                       if (apmt_node->proc_affinity ==
-                           get_acpi_id_for_cpu(cpu)) {
+                       ret = acpi_get_cpu_uid(cpu, &cpu_uid);
+                       if (ret == 0 && apmt_node->proc_affinity == cpu_uid) {
                                cpumask_set_cpu(cpu, &cspmu->associated_cpus);
                                break;
                        }
-- 
2.17.1