On 4/26/24 23:51, Jonathan Cameron wrote:
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@xxxxxxxxxx>
---
v8: On buggy bios detection when setting per_cpu structures
do not carry on.
Fix up the clearing of per cpu structures to remove unwanted
side effects and ensure an error code isn't use to reference them.
---
drivers/acpi/acpi_processor.c | 79 +++++++++++++++++++++--------------
1 file changed, 48 insertions(+), 31 deletions(-)
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index ba0a6f0ac841..3b180e21f325 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);
One blank line after BUG_ON() if we need to follow original implementation.
+ /*
+ * 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. */
It depends on how the return value is handled by the caller if the namespace
is continued to be scanned. The caller can be acpi_processor_hotadd_init()
and acpi_processor_get_info() after this patch is applied. So I think this
specific comment need to be moved to the caller.
Besides, it seems acpi_processor_set_per_cpu() isn't properly called and
memory leakage can happen. More details are given below.
+ 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 +228,15 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr)
if (ret)
goto out;
+ if (!acpi_processor_set_per_cpu(pr, device)) {
+ acpi_unmap_cpu(pr->id);
+ goto out;
+ }
+
With the 'goto out', zero is returned from acpi_processor_hotadd_init() to acpi_processor_get_info().
The zero return value is carried from acpi_map_cpu() in acpi_processor_hotadd_init(). If I'm correct,
we need return errno from acpi_processor_get_info() to acpi_processor_add() so that cleanup can be
done. For example, the cleanup corresponding to the 'err' tag can be done in acpi_processor_add().
Otherwise, we will have memory leakage.
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 +254,8 @@ 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 +354,13 @@ 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 0;
}
For non-hotplug case, we still need pass the error to acpi_processor_add() so that
cleanup corresponding 'err' tag can be done. Otherwise, we will have memory leakage.
/*
@@ -365,8 +406,6 @@ 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 +434,6 @@ 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;
@@ -469,10 +486,6 @@ 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();
@@ -480,6 +493,10 @@ 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();
Thanks,
Gavin
