linux-kernel - [PATCH] ACPI: print error message and bail out early if failed to parse APIC ID for CPU

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Date:	Thu,  9 Jan 2014 16:15:19 +0800
From:	Jiang Liu <jiang.liu@...ux.intel.com>
To:	"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
	Len Brown <lenb@...nel.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Jiang Liu <jiang.liu@...ux.intel.com>, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] ACPI: print error message and bail out early if failed to parse APIC ID for CPU

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 <jiang.liu@...ux.intel.com>
---
 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:
-- 
1.7.10.4

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