[ACPI] Avoid BIOS inflicted crashes by evaluating _PDC only once

Linux invokes the AML _PDC method (Processor Driver Capabilities)
to tell the BIOS what features it can handle.  While the ACPI
spec says nothing about the OS invoking _PDC multiple times,
doing so with changing bits seems to hopelessly confuse the BIOS
on multiple platforms up to and including crashing the system.

Factor out the _PDC invocation so Linux invokes it only once.

http://bugzilla.kernel.org/show_bug.cgi?id=5483

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/arch/i386/kernel/acpi/processor.c b/arch/i386/kernel/acpi/processor.c
new file mode 100644
index 00000000000..9f4cc02717e
--- /dev/null
+++ b/arch/i386/kernel/acpi/processor.c
@@ -0,0 +1,75 @@
+/*
+ * arch/i386/kernel/acpi/processor.c
+ *
+ * Copyright (C) 2005 Intel Corporation
+ * 	Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ * 	- Added _PDC for platforms with Intel CPUs
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/acpi.h>
+
+#include <acpi/processor.h>
+#include <asm/acpi.h>
+
+static void init_intel_pdc(struct acpi_processor *pr, struct cpuinfo_x86 *c)
+{
+	struct acpi_object_list *obj_list;
+	union acpi_object *obj;
+	u32 *buf;
+
+	/* allocate and initialize pdc. It will be used later. */
+	obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
+	if (!obj_list) {
+		printk(KERN_ERR "Memory allocation error\n");
+		return;
+	}
+
+	obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
+	if (!obj) {
+		printk(KERN_ERR "Memory allocation error\n");
+		kfree(obj_list);
+		return;
+	}
+
+	buf = kmalloc(12, GFP_KERNEL);
+	if (!buf) {
+		printk(KERN_ERR "Memory allocation error\n");
+		kfree(obj);
+		kfree(obj_list);
+		return;
+	}
+
+	buf[0] = ACPI_PDC_REVISION_ID;
+	buf[1] = 1;
+	buf[2] = ACPI_PDC_C_CAPABILITY_SMP;
+
+	if (cpu_has(c, X86_FEATURE_EST))
+		buf[2] |= ACPI_PDC_EST_CAPABILITY_SMP;
+
+	obj->type = ACPI_TYPE_BUFFER;
+	obj->buffer.length = 12;
+	obj->buffer.pointer = (u8 *) buf;
+	obj_list->count = 1;
+	obj_list->pointer = obj;
+	pr->pdc = obj_list;
+
+	return;
+}
+
+/* Initialize _PDC data based on the CPU vendor */
+void arch_acpi_processor_init_pdc(struct acpi_processor *pr)
+{
+	unsigned int cpu = pr->id;
+	struct cpuinfo_x86 *c = cpu_data + cpu;
+
+	pr->pdc = NULL;
+	if (c->x86_vendor == X86_VENDOR_INTEL)
+		init_intel_pdc(pr, c);
+
+	return;
+}
+
+EXPORT_SYMBOL(arch_acpi_processor_init_pdc);