[PATCH v6 04/16] ACPI: processor: Move checks and availability of acpi_processor earlier

Jonathan Cameron
2024-04-17T13:21:15Z

Make the per_cpu(processors, cpu) entries available earlier so that
they are available in arch_register_cpu() as ARM64 will need access
to the acpi_handle to distinguish between acpi_processor_add()
and earlier registration attempts (which will fail as _STA cannot
be checked).

Reorder the remove flow to clear this per_cpu() after
arch_unregister_cpu() has completed, allowing it to be used in
there as well.

Note that on x86 for the CPU hotplug case, the pr->id prior to
acpi_map_cpu() may be invalid. Thus the per_cpu() structures
must be initialized after that call or after checking the ID
is valid (not hotplug path).

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
v6: As per discussion in v5 thread, don't use the cpu->dev and
make this data available earlier by moving the assignment checks
int acpi_processor_get_info().
---
drivers/acpi/acpi_processor.c | 79 +++++++++++++++++++++--------------
1 file changed, 47 insertions(+), 32 deletions(-)

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index ba0a6f0ac841..2c164451ab53 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -184,7 +184,35 @@ static void __init acpi_pcc_cpufreq_init(void) {}

/* Initialization */
#ifdef CONFIG_ACPI_HOTPLUG_CPU
-static int acpi_processor_hotadd_init(struct acpi_processor *pr)
+static DEFINE_PER_CPU(void *, processor_device_array);
+
+static void acpi_processor_set_per_cpu(struct acpi_processor *pr,
+ struct acpi_device *device)
+{
+ BUG_ON(pr->id >= nr_cpu_ids);
+ /*
+ * Buggy BIOS check.
+ * ACPI id of processors can be reported wrongly by the BIOS.
+ * Don't trust it blindly
+ */
+ if (per_cpu(processor_device_array, pr->id) != NULL &&
+ per_cpu(processor_device_array, pr->id) != device) {
+ dev_warn(&device->dev,
+ "BIOS reported wrong ACPI id %d for the processor\n",
+ pr->id);
+ /* Give up, but do not abort the namespace scan. */
+ return;
+ }
+ /*
+ * processor_device_array is not cleared on errors to allow buggy BIOS
+ * checks.
+ */
+ per_cpu(processor_device_array, pr->id) = device;
+ per_cpu(processors, pr->id) = pr;
+}
+
+static int acpi_processor_hotadd_init(struct acpi_processor *pr,
+ struct acpi_device *device)
{
int ret;

@@ -198,6 +226,8 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr)
if (ret)
goto out;

+ acpi_processor_set_per_cpu(pr, device);
+
ret = arch_register_cpu(pr->id);
if (ret) {
acpi_unmap_cpu(pr->id);
@@ -217,7 +247,8 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr)
return ret;
}
#else
-static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
+static inline int acpi_processor_hotadd_init(struct acpi_processor *pr,
+ struct acpi_device *device)
{
return -ENODEV;
}
@@ -232,6 +263,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
acpi_status status = AE_OK;
static int cpu0_initialized;
unsigned long long value;
+ int ret;

acpi_processor_errata();

@@ -316,10 +348,12 @@ static int acpi_processor_get_info(struct acpi_device *device)
* because cpuid <-> apicid mapping is persistent now.
*/
if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {
- int ret = acpi_processor_hotadd_init(pr);
+ ret = acpi_processor_hotadd_init(pr, device);

if (ret)
- return ret;
+ goto err;
+ } else {
+ acpi_processor_set_per_cpu(pr, device);
}

/*
@@ -357,6 +391,10 @@ static int acpi_processor_get_info(struct acpi_device *device)
arch_fix_phys_package_id(pr->id, value);

return 0;
+
+err:
+ per_cpu(processors, pr->id) = NULL;
+ return ret;
}

/*
@@ -365,8 +403,6 @@ static int acpi_processor_get_info(struct acpi_device *device)
* (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
* Such things have to be put in and set up by the processor driver's .probe().
*/
-static DEFINE_PER_CPU(void *, processor_device_array);
-
static int acpi_processor_add(struct acpi_device *device,
const struct acpi_device_id *id)
{
@@ -395,28 +431,6 @@ static int acpi_processor_add(struct acpi_device *device,
if (result) /* Processor is not physically present or unavailable */
return 0;

- BUG_ON(pr->id >= nr_cpu_ids);
-
- /*
- * Buggy BIOS check.
- * ACPI id of processors can be reported wrongly by the BIOS.
- * Don't trust it blindly
- */
- if (per_cpu(processor_device_array, pr->id) != NULL &&
- per_cpu(processor_device_array, pr->id) != device) {
- dev_warn(&device->dev,
- "BIOS reported wrong ACPI id %d for the processor\n",
- pr->id);
- /* Give up, but do not abort the namespace scan. */
- goto err;
- }
- /*
- * processor_device_array is not cleared on errors to allow buggy BIOS
- * checks.
- */
- per_cpu(processor_device_array, pr->id) = device;
- per_cpu(processors, pr->id) = pr;
-
dev = get_cpu_device(pr->id);
if (!dev) {
result = -ENODEV;
@@ -469,15 +483,16 @@ static void acpi_processor_remove(struct acpi_device *device)
device_release_driver(pr->dev);
acpi_unbind_one(pr->dev);

- /* Clean up. */
- per_cpu(processor_device_array, pr->id) = NULL;
- per_cpu(processors, pr->id) = NULL;
-
cpu_maps_update_begin();
cpus_write_lock();

/* Remove the CPU. */
arch_unregister_cpu(pr->id);
+
+ /* Clean up. */
+ per_cpu(processor_device_array, pr->id) = NULL;
+ per_cpu(processors, pr->id) = NULL;
+
acpi_unmap_cpu(pr->id);

cpus_write_unlock();
--
2.39.2