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Message-Id: <20230203135043.409192-18-james.morse@arm.com>
Date: Fri, 3 Feb 2023 13:50:28 +0000
From: James Morse <james.morse@....com>
To: linux-pm@...r.kernel.org, loongarch@...ts.linux.dev,
kvmarm@...ts.linux.dev, kvm@...r.kernel.org,
linux-acpi@...r.kernel.org, linux-arch@...r.kernel.org,
linux-ia64@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, x86@...nel.org
Cc: Marc Zyngier <maz@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Sudeep Holla <sudeep.holla@....com>,
Borislav Petkov <bp@...en8.de>, H Peter Anvin <hpa@...or.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Huacai Chen <chenhuacai@...nel.org>,
James Morse <james.morse@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Oliver Upton <oliver.upton@...ux.dev>,
Len Brown <lenb@...nel.org>,
Rafael Wysocki <rafael@...nel.org>,
WANG Xuerui <kernel@...0n.name>,
Salil Mehta <salil.mehta@...wei.com>,
Russell King <linux@...linux.org.uk>,
Jean-Philippe Brucker <jean-philippe@...aro.org>
Subject: [RFC PATCH 17/32] ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug
struct acpi_scan_handler has a detach callback that is used to remove
a driver when a bus is changed. When interacting with an eject-request,
the detach callback is called before _EJ0.
This means the ACPI processor driver can't use _STA to determine if a
CPU has been made not-present, or some of the other _STA bits have been
changed. acpi_processor_remove() needs to know the value of _STA after
_EJ0 has been called.
Add a post_eject callback to struct acpi_scan_handler. This is called
after acpi_scan_hot_remove() has successfully called _EJ0. Because
acpi_bus_trim_one() also clears the handler pointer, it needs to be
told if the caller will go on to call acpi_bus_post_eject(), so
that acpi_device_clear_enumerated() and clearing the handler pointer
can be deferred. The existing not-used pointer is used for this.
Signed-off-by: James Morse <james.morse@....com>
---
drivers/acpi/acpi_processor.c | 4 +--
drivers/acpi/scan.c | 52 ++++++++++++++++++++++++++++++-----
include/acpi/acpi_bus.h | 1 +
3 files changed, 48 insertions(+), 9 deletions(-)
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 6ab55f109417..ab0f80b83773 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -411,7 +411,7 @@ static int acpi_processor_add(struct acpi_device *device,
#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU
/* Removal */
-static void acpi_processor_remove(struct acpi_device *device)
+static void acpi_processor_post_eject(struct acpi_device *device)
{
struct acpi_processor *pr;
@@ -523,7 +523,7 @@ static struct acpi_scan_handler processor_handler = {
.ids = processor_device_ids,
.attach = acpi_processor_add,
#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU
- .detach = acpi_processor_remove,
+ .post_eject = acpi_processor_post_eject,
#endif
.hotplug = {
.enabled = true,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index cecf94192771..cd9bedb54393 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -245,18 +245,28 @@ static int acpi_scan_try_to_offline(struct acpi_device *device)
return 0;
}
-static int acpi_bus_trim_one(struct acpi_device *adev, void *not_used)
+/**
+ * acpi_bus_trim_one() - Detach scan handlers and drivers from ACPI device
+ * objects.
+ * @adev: Root of the ACPI namespace scope to walk.
+ * @eject: Pointer to a bool that indicates if this was due to an
+ * eject-request.
+ *
+ * Must be called under acpi_scan_lock.
+ * If @eject points to true, clearing the device enumeration is deferred until
+ * acpi_bus_post_eject() is called.
+ */
+static int acpi_bus_trim_one(struct acpi_device *adev, void *eject)
{
struct acpi_scan_handler *handler = adev->handler;
+ bool is_eject = *(bool *)eject;
- acpi_dev_for_each_child_reverse(adev, acpi_bus_trim_one, NULL);
+ acpi_dev_for_each_child_reverse(adev, acpi_bus_trim_one, eject);
adev->flags.match_driver = false;
if (handler) {
if (handler->detach)
handler->detach(adev);
-
- adev->handler = NULL;
} else {
device_release_driver(&adev->dev);
}
@@ -266,7 +276,12 @@ static int acpi_bus_trim_one(struct acpi_device *adev, void *not_used)
*/
acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
adev->flags.initialized = false;
- acpi_device_clear_enumerated(adev);
+
+ /* For eject this is deferred to acpi_bus_post_eject() */
+ if (!is_eject) {
+ adev->handler = NULL;
+ acpi_device_clear_enumerated(adev);
+ }
return 0;
}
@@ -279,15 +294,36 @@ static int acpi_bus_trim_one(struct acpi_device *adev, void *not_used)
*/
void acpi_bus_trim(struct acpi_device *adev)
{
- acpi_bus_trim_one(adev, NULL);
+ bool eject = false;
+
+ acpi_bus_trim_one(adev, &eject);
}
EXPORT_SYMBOL_GPL(acpi_bus_trim);
+static int acpi_bus_post_eject(struct acpi_device *adev, void *not_used)
+{
+ struct acpi_scan_handler *handler = adev->handler;
+
+ acpi_dev_for_each_child_reverse(adev, acpi_bus_post_eject, NULL);
+
+ if (handler) {
+ if (handler->post_eject)
+ handler->post_eject(adev);
+
+ adev->handler = NULL;
+ }
+
+ acpi_device_clear_enumerated(adev);
+
+ return 0;
+}
+
static int acpi_scan_hot_remove(struct acpi_device *device)
{
acpi_handle handle = device->handle;
unsigned long long sta;
acpi_status status;
+ bool eject = true;
if (device->handler && device->handler->hotplug.demand_offline) {
if (!acpi_scan_is_offline(device, true))
@@ -300,7 +336,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
acpi_handle_debug(handle, "Ejecting\n");
- acpi_bus_trim(device);
+ acpi_bus_trim_one(device, &eject);
acpi_evaluate_lck(handle, 0);
/*
@@ -323,6 +359,8 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
} else if (sta & ACPI_STA_DEVICE_ENABLED) {
acpi_handle_warn(handle,
"Eject incomplete - status 0x%llx\n", sta);
+ } else {
+ acpi_bus_post_eject(device, NULL);
}
return 0;
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index cd3b75e08ec3..dc4028cafd33 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -126,6 +126,7 @@ struct acpi_scan_handler {
bool (*match)(const char *idstr, const struct acpi_device_id **matchid);
int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);
void (*detach)(struct acpi_device *dev);
+ void (*post_eject)(struct acpi_device *dev);
void (*bind)(struct device *phys_dev);
void (*unbind)(struct device *phys_dev);
struct acpi_hotplug_profile hotplug;
--
2.30.2
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