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From: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
To: linux-pm@vger.kernel.org, loongarch@lists.linux.dev,
	linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev,
	x86@kernel.org, acpica-devel@lists.linuxfoundation.org,
	linux-csky@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org
Cc: Salil Mehta <salil.mehta@huawei.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	jianyong.wu@arm.com, justin.he@arm.com,
	James Morse <james.morse@arm.com>,
	Jonathan Cameron <Jonathan.Cameron@Huawei.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>
Subject: [PATCH RFC v4 07/15] ACPI: Check _STA present bit before making CPUs not present
Date: Wed, 31 Jan 2024 16:50:12 +0000	[thread overview]
Message-ID: <E1rVDmu-0027Ys-An@rmk-PC.armlinux.org.uk> (raw)
In-Reply-To: <Zbp5xzmFhKDAgHws@shell.armlinux.org.uk>

From: James Morse <james.morse@arm.com>

When called acpi_processor_post_eject() unconditionally make a CPU
not-present and unregisters it.

To add support for AML events where the CPU has become disabled, but
remains present, the _STA method should be checked before calling
acpi_processor_remove().

Rename acpi_processor_post_eject() acpi_processor_remove_possible(), and
check the _STA before calling.

Adding the function prototype for arch_unregister_cpu() allows the
preprocessor guards to be removed.

After this change CPUs will remain registered and visible to
user-space as offline if buggy firmware triggers an eject-request,
but doesn't clear the corresponding _STA bits after _EJ0 has been
called.

Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: Jianyong Wu <jianyong.wu@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v3:
 * Move IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU) into separate patch.
---
 drivers/acpi/acpi_processor.c | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 5351095b6968..77d47e6c2474 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -458,16 +458,13 @@ static int acpi_processor_add(struct acpi_device *device,
 }
 
 /* Removal */
-static void acpi_processor_post_eject(struct acpi_device *device)
+static void acpi_processor_make_not_present(struct acpi_device *device)
 {
 	struct acpi_processor *pr;
 
 	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_CPU))
 		return;
 
-	if (!device || !acpi_driver_data(device))
-		return;
-
 	pr = acpi_driver_data(device);
 	if (pr->id >= nr_cpu_ids)
 		goto out;
@@ -504,6 +501,29 @@ static void acpi_processor_post_eject(struct acpi_device *device)
 	kfree(pr);
 }
 
+static void acpi_processor_post_eject(struct acpi_device *device)
+{
+	struct acpi_processor *pr;
+	unsigned long long sta;
+	acpi_status status;
+
+	if (!device)
+		return;
+
+	pr = acpi_driver_data(device);
+	if (!pr || pr->id >= nr_cpu_ids || invalid_phys_cpuid(pr->phys_id))
+		return;
+
+	status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
+	if (ACPI_FAILURE(status))
+		return;
+
+	if (cpu_present(pr->id) && !(sta & ACPI_STA_DEVICE_PRESENT)) {
+		acpi_processor_make_not_present(device);
+		return;
+	}
+}
+
 #ifdef CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC
 bool __init processor_physically_present(acpi_handle handle)
 {
-- 
2.30.2


  parent reply	other threads:[~2024-01-31 16:50 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-31 16:48 [RFC PATCH v4 00/15] ACPI/arm64: add support for virtual cpu hotplug Russell King (Oracle)
2024-01-31 16:49 ` [PATCH RFC v4 01/15] ACPI: Only enumerate enabled (or functional) processor devices Russell King
2024-01-31 17:25   ` Miguel Luis
2024-02-15 20:10   ` Rafael J. Wysocki
2024-02-19  9:45     ` Jonathan Cameron
2024-02-20 11:30     ` Russell King (Oracle)
2024-02-21 13:01   ` Rafael J. Wysocki
2024-01-31 16:49 ` [PATCH RFC v4 02/15] ACPI: processor: Register all CPUs from acpi_processor_get_info() Russell King
2024-02-15 19:22   ` Rafael J. Wysocki
2024-02-20 11:27     ` Russell King (Oracle)
2024-02-20 15:13       ` Russell King (Oracle)
2024-02-20 16:24         ` Jonathan Cameron
2024-02-20 19:59           ` Rafael J. Wysocki
2024-02-21 12:04             ` Rafael J. Wysocki
2024-02-20 20:59     ` Thomas Gleixner
2024-03-22 18:53     ` Jonathan Cameron
2024-04-10 12:43       ` Jonathan Cameron
2024-04-10 13:28         ` Rafael J. Wysocki
2024-04-10 13:50           ` Jonathan Cameron
2024-04-10 14:19             ` Rafael J. Wysocki
2024-04-10 15:58               ` Jonathan Cameron
2024-04-10 18:56             ` Russell King (Oracle)
2024-04-10 19:08               ` Rafael J. Wysocki
2024-04-10 21:07                 ` Jonathan Cameron
2024-01-31 16:49 ` [PATCH RFC v4 03/15] ACPI: Move acpi_bus_trim_one() before acpi_scan_hot_remove() Russell King
2024-01-31 16:49 ` [PATCH RFC v4 04/15] ACPI: Rename acpi_processor_hotadd_init and remove pre-processor guards Russell King
2024-01-31 16:50 ` [PATCH RFC v4 05/15] ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug Russell King
2024-01-31 16:50 ` [PATCH RFC v4 06/15] ACPI: convert acpi_processor_post_eject() to use IS_ENABLED() Russell King (Oracle)
2024-01-31 16:50 ` Russell King [this message]
2024-01-31 16:50 ` [PATCH RFC v4 08/15] ACPI: Warn when the present bit changes but the feature is not enabled Russell King
2024-01-31 16:50 ` [PATCH RFC v4 09/15] arm64: acpi: Move get_cpu_for_acpi_id() to a header Russell King
2024-01-31 16:50 ` [PATCH RFC v4 10/15] irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc() Russell King
2024-02-02 16:44   ` Jonathan Cameron
2024-01-31 16:50 ` [PATCH RFC v4 11/15] irqchip/gic-v3: Add support for ACPI's disabled but 'online capable' CPUs Russell King
2024-02-02 16:47   ` Jonathan Cameron
2024-01-31 16:50 ` [PATCH RFC v4 12/15] arm64: psci: Ignore DENIED CPUs Russell King
2024-04-11 11:35   ` Jonathan Cameron
2024-04-11 13:25     ` Jonathan Cameron
2024-01-31 16:50 ` [PATCH RFC v4 13/15] ACPI: add support to (un)register CPUs based on the _STA enabled bit Russell King
2024-01-31 16:50 ` [PATCH RFC v4 14/15] arm64: document virtual CPU hotplug's expectations Russell King
2024-02-02 17:04   ` Jonathan Cameron
2024-01-31 16:50 ` [PATCH RFC v4 15/15] cpumask: Add enabled cpumask for present CPUs that can be brought online Russell King

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