linux-kernel - [PATCH 05/12] ACPI: processor: add internal processor_physically

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Date:	Mon, 25 Jan 2010 14:41:03 -0700
From:	Alex Chiang <achiang@...com>
To:	lenb@...nel.org
Cc:	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 05/12] ACPI: processor: add internal
	processor_physically_present()

Detect if a processor is physically present before evaluating _PDC.

We want this because some BIOS will provide a _PDC even for processors
that are not present. These bogus _PDC methods then attempt to load
non-existent tables, which causes problems.

Avoid those bogus landmines.

Signed-off-by: Alex Chiang <achiang@...com>
---

 drivers/acpi/processor_core.c |   42 +++++++++++++++++++++++++++++++++++++++++
 1 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index ca12d70..e8b1246 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -194,6 +194,45 @@ int acpi_get_cpuid(acpi_handle handle, int type, u32 acpi_id)
 EXPORT_SYMBOL_GPL(acpi_get_cpuid);
 #endif
 
+static bool processor_physically_present(acpi_handle handle)
+{
+	int cpuid, type;
+	u32 acpi_id;
+	acpi_status status;
+	acpi_object_type acpi_type;
+	unsigned long long tmp;
+	union acpi_object object = { 0 };
+	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
+
+	status = acpi_get_type(handle, &acpi_type);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	switch (acpi_type) {
+	case ACPI_TYPE_PROCESSOR:
+		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
+		if (ACPI_FAILURE(status))
+			return false;
+		acpi_id = object.processor.proc_id;
+		break;
+	case ACPI_TYPE_DEVICE:
+		status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
+		if (ACPI_FAILURE(status))
+			return false;
+		acpi_id = tmp;
+		break;
+	default:
+		return false;
+	}
+
+	type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
+	cpuid = acpi_get_cpuid(handle, type, acpi_id);
+
+	if (cpuid == -1)
+		return false;
+
+	return true;
+}
 
 static void acpi_set_pdc_bits(u32 *buf)
 {
@@ -335,6 +374,9 @@ static struct dmi_system_id __cpuinitdata early_pdc_optin_table[] = {
 static acpi_status
 early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
 {
+	if (processor_physically_present(handle) == false)
+		return AE_OK;
+
 	acpi_processor_set_pdc(handle);
 	return AE_OK;
 }

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