[PATCH v9 06/19] ACPI: processor: Move checks and availability of acpi_processor earlier

Jonathan Cameron
2024-04-30T14:27:42Z

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>

---
v9: Add back a blank line accidentally removed in code move.
Fix up error returns so that the new cleanup in processor_add()
is triggered on detection of the bios bug.
Combined with the previous 2 patches, should solve the leak
that Gavin identified.
---
drivers/acpi/acpi_processor.c | 80 +++++++++++++++++++++--------------
1 file changed, 49 insertions(+), 31 deletions(-)

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 16e36e55a560..4a79b42d649e 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -183,8 +183,38 @@ static void __init acpi_pcc_cpufreq_init(void) {}
#endif /* CONFIG_X86 */

/* Initialization */
+static DEFINE_PER_CPU(void *, processor_device_array);
+
+static bool 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);
+ return false;
+ }
+ /*
+ * 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;
+
+ return true;
+}
+
#ifdef CONFIG_ACPI_HOTPLUG_CPU
-static int acpi_processor_hotadd_init(struct acpi_processor *pr)
+static int acpi_processor_hotadd_init(struct acpi_processor *pr,
+ struct acpi_device *device)
{
int ret;

@@ -198,8 +228,16 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr)
if (ret)
goto out;

+ if (!acpi_processor_set_per_cpu(pr, device)) {
+ ret = -EINVAL;
+ acpi_unmap_cpu(pr->id);
+ goto out;
+ }
+
ret = arch_register_cpu(pr->id);
if (ret) {
+ /* Leave the processor device array in place to detect buggy bios */
+ per_cpu(processors, pr->id) = NULL;
acpi_unmap_cpu(pr->id);
goto out;
}
@@ -217,7 +255,8 @@ 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;
}
@@ -316,10 +355,13 @@ 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);
+ int ret = acpi_processor_hotadd_init(pr, device);

if (ret)
return ret;
+ } else {
+ if (!acpi_processor_set_per_cpu(pr, device))
+ return -EINVAL;
}

/*
@@ -365,8 +407,6 @@ 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 +435,6 @@ static int acpi_processor_add(struct acpi_device *device,
if (result) /* Processor is not physically present or unavailable */
goto err_clear_driver_data;

- 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_clear_driver_data;
- }
- /*
- * 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;
@@ -470,10 +488,6 @@ 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();

@@ -481,6 +495,10 @@ static void acpi_processor_remove(struct acpi_device *device)
arch_unregister_cpu(pr->id);
acpi_unmap_cpu(pr->id);

+ /* Clean up. */
+ per_cpu(processor_device_array, pr->id) = NULL;
+ per_cpu(processors, pr->id) = NULL;
+
cpus_write_unlock();
cpu_maps_update_done();

--
2.39.2