[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>

3 files changed, 72 insertions, 51 deletions

diff --git a/arch/ia64/kernel/cpufreq/Makefile b/arch/ia64/kernel/cpufreq/Makefile
index f748d34c02f0..642648361ed3 100644
--- a/arch/ia64/kernel/cpufreq/Makefile
+++ b/arch/ia64/kernel/cpufreq/Makefile
@@ -1 +1,6 @@
 obj-$(CONFIG_IA64_ACPI_CPUFREQ)         += acpi-cpufreq.o
+
+ifneq ($(CONFIG_ACPI_PROCESSOR),)
+obj-y                           += acpi-processor.o
+endif
+
diff --git a/arch/ia64/kernel/cpufreq/acpi-cpufreq.c b/arch/ia64/kernel/cpufreq/acpi-cpufreq.c
index da4d5cf80a48..5a1bf815282d 100644
--- a/arch/ia64/kernel/cpufreq/acpi-cpufreq.c
+++ b/arch/ia64/kernel/cpufreq/acpi-cpufreq.c
@@ -269,48 +269,6 @@ acpi_cpufreq_verify (
 }
 
 
-/*
- * processor_init_pdc - let BIOS know about the SMP capabilities
- * of this driver
- * @perf: processor-specific acpi_io_data struct
- * @cpu: CPU being initialized
- *
- * To avoid issues with legacy OSes, some BIOSes require to be informed of
- * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC
- * accordingly. Actual call to _PDC is done in driver/acpi/processor.c
- */
-static void
-processor_init_pdc (
-                struct acpi_processor_performance *perf,
-                unsigned int cpu,
-                struct acpi_object_list *obj_list
-                )
-{
-        union acpi_object *obj;
-        u32 *buf;
-
-        dprintk("processor_init_pdc\n");
-
-        perf->pdc = NULL;
-        /* Initialize pdc. It will be used later. */
-        if (!obj_list)
-                return;
-
-        if (!(obj_list->count && obj_list->pointer))
-                return;
-
-        obj = obj_list->pointer;
-        if ((obj->buffer.length == 12) && obj->buffer.pointer) {
-                buf = (u32 *)obj->buffer.pointer;
-                buf[0] = ACPI_PDC_REVISION_ID;
-                buf[1] = 1;
-                buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;
-                perf->pdc = obj_list;
-        }
-        return;
-}
-
-
 static int
 acpi_cpufreq_cpu_init (
         struct cpufreq_policy   *policy)
@@ -320,14 +278,7 @@ acpi_cpufreq_cpu_init (
         struct cpufreq_acpi_io  *data;
         unsigned int            result = 0;
 
-        union acpi_object               arg0 = {ACPI_TYPE_BUFFER};
-        u32                             arg0_buf[3];
-        struct acpi_object_list         arg_list = {1, &arg0};
-
         dprintk("acpi_cpufreq_cpu_init\n");
-        /* setup arg_list for _PDC settings */
-        arg0.buffer.length = 12;
-        arg0.buffer.pointer = (u8 *) arg0_buf;
 
         data = kmalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
         if (!data)
@@ -337,9 +288,7 @@ acpi_cpufreq_cpu_init (
 
         acpi_io_data[cpu] = data;
 
-        processor_init_pdc(&data->acpi_data, cpu, &arg_list);
         result = acpi_processor_register_performance(&data->acpi_data, cpu);
-        data->acpi_data.pdc = NULL;
 
         if (result)
                 goto err_free;
diff --git a/arch/ia64/kernel/cpufreq/acpi-processor.c b/arch/ia64/kernel/cpufreq/acpi-processor.c
new file mode 100644
index 000000000000..e683630c8ce2
--- /dev/null
+++ b/arch/ia64/kernel/cpufreq/acpi-processor.c
@@ -0,0 +1,67 @@
+/*
+ * arch/ia64/kernel/cpufreq/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 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)
+{
+        pr->pdc = NULL;
+        init_intel_pdc(pr);
+        return;
+}
+
+EXPORT_SYMBOL(arch_acpi_processor_init_pdc);