[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>

2 files changed, 77 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/acpi/Makefile b/arch/x86_64/kernel/acpi/Makefile
index 7da9ace890bd..4fe97071f297 100644
--- a/arch/x86_64/kernel/acpi/Makefile
+++ b/arch/x86_64/kernel/acpi/Makefile
@@ -1,3 +1,8 @@
 obj-y                   := boot.o
 boot-y                  := ../../../i386/kernel/acpi/boot.o
 obj-$(CONFIG_ACPI_SLEEP)        += sleep.o wakeup.o
+
+ifneq ($(CONFIG_ACPI_PROCESSOR),)
+obj-y                   += processor.o
+endif
+
diff --git a/arch/x86_64/kernel/acpi/processor.c b/arch/x86_64/kernel/acpi/processor.c
new file mode 100644
index 000000000000..3bdc2baa5bb1
--- /dev/null
+++ b/arch/x86_64/kernel/acpi/processor.c
@@ -0,0 +1,72 @@
+/*
+ * arch/x86_64/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_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 && cpu_has(c, X86_FEATURE_EST))
+                init_intel_pdc(pr, c);
+
+        return;
+}
+
+EXPORT_SYMBOL(arch_acpi_processor_init_pdc);