On 2014/1/9 20:12, Rafael J. Wysocki wrote:

On Thursday, January 09, 2014 04:15:19 PM Jiang Liu wrote:

quoted

Enhance ACPI CPU hotplug driver to print clear error message and
bail out early if BIOS returns wrong value in ACPI MADT table or
_MAT method. Otherwise it will add the CPU device even if failed
to get APIC ID and fails any operations against sysfs interface:
/sys/devices/system/cpu/cpux/online

Signed-off-by: Jiang Liu <redacted>

Do you have any pointers to bug reports regarding this etc.?  If so,
it would be good to add links to them to the commit log.

Hi Rafael,
	I have no bug id for this. It was found during verifying an
internal BIOS version, so no external bug id for it yet.
Cheers!
Gerry

Thanks!

quoted

---
 drivers/acpi/acpi_processor.c |   24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 3c1d6b0..6ce71b0 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c

@@ -212,7 +212,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
 	union acpi_object object = { 0 };
 	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
 	struct acpi_processor *pr = acpi_driver_data(device);
-	int cpu_index, device_declaration = 0;
+	int apic_id, cpu_index, device_declaration = 0;
 	acpi_status status = AE_OK;
 	static int cpu0_initialized;
 	unsigned long long value;

@@ -258,18 +258,21 @@ static int acpi_processor_get_info(struct acpi_device *device)
 		device_declaration = 1;
 		pr->acpi_id = value;
 	}
-	pr->apic_id = acpi_get_apicid(pr->handle, device_declaration,
-					pr->acpi_id);
-	cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id);
 
-	/* Handle UP system running SMP kernel, with no LAPIC in MADT */
-	if (!cpu0_initialized && (cpu_index == -1) &&
-	    (num_online_cpus() == 1)) {
-		cpu_index = 0;
+	apic_id = acpi_get_apicid(pr->handle, device_declaration, pr->acpi_id);
+	if (apic_id < 0) {
+		acpi_handle_err(pr->handle, "failed to get CPU APIC ID.\n");
+		return -ENODEV;
 	}
+	pr->apic_id = apic_id;
 
-	cpu0_initialized = 1;
-
+	cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id);
+	if (!cpu0_initialized) {
+		cpu0_initialized = 1;
+		/* Handle UP system running SMP kernel, with no LAPIC in MADT */
+		if ((cpu_index == -1) && (num_online_cpus() == 1))
+			cpu_index = 0;
+	}
 	pr->id = cpu_index;
 
 	/*

@@ -282,6 +285,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
 		if (ret)
 			return ret;
 	}
+
 	/*
 	 * On some boxes several processors use the same processor bus id.
 	 * But they are located in different scope. For example: