ACPI, APEI, Add APEI bit support in generic _OSC call

In APEI firmware first mode, hardware error is reported by hardware to
firmware firstly, then firmware reports the error to Linux in a GHES
error record via POLL/SCI/IRQ/NMI etc.

This may result in some issues if OS has no full APEI support.  So
some firmware implementation will work in a back-compatible mode by
default.  Where firmware will only notify OS in old-fashion, without
GHES record.  For example, for a fatal hardware error, only NMI is
signaled, no GHES record.

To gain full APEI power on these machines, APEI bit in generic _OSC
call can be specified to tell firmware that Linux has full APEI
support.  This patch adds the APEI bit support in generic _OSC call.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/bus.c

@@ -39,6 +39,7 @@
 #include <linux/pci.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
+#include <acpi/apei.h>
 #include <linux/dmi.h>
 #include <linux/suspend.h>
 
@@ -519,6 +520,7 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context)
 }
 EXPORT_SYMBOL(acpi_run_osc);
 
+bool osc_sb_apei_support_acked;
 static u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
 static void acpi_bus_osc_support(void)
 {
@@ -541,11 +543,21 @@ static void acpi_bus_osc_support(void)
 #if defined(CONFIG_ACPI_PROCESSOR) || defined(CONFIG_ACPI_PROCESSOR_MODULE)
 	capbuf[OSC_SUPPORT_TYPE] |= OSC_SB_PPC_OST_SUPPORT;
 #endif
+
+#ifdef CONFIG_ACPI_APEI_GHES
+	if (!ghes_disable)
+		capbuf[OSC_SUPPORT_TYPE] |= OSC_SB_APEI_SUPPORT;
+#endif
 	if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)))
 		return;
-	if (ACPI_SUCCESS(acpi_run_osc(handle, &context)))
+	if (ACPI_SUCCESS(acpi_run_osc(handle, &context))) {
+		u32 *capbuf_ret = context.ret.pointer;
+		if (context.ret.length > OSC_SUPPORT_TYPE)
+			osc_sb_apei_support_acked =
+				capbuf_ret[OSC_SUPPORT_TYPE] & OSC_SB_APEI_SUPPORT;
 		kfree(context.ret.pointer);
-	/* do we need to check the returned cap? Sounds no */
+	}
+	/* do we need to check other returned cap? Sounds no */
 }
 
 /* --------------------------------------------------------------------------

include/linux/acpi.h

@@ -280,6 +280,8 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context);
 #define OSC_SB_CPUHP_OST_SUPPORT	8
 #define OSC_SB_APEI_SUPPORT		16
 
+extern bool osc_sb_apei_support_acked;
+
 /* PCI defined _OSC bits */
 /* _OSC DW1 Definition (OS Support Fields) */
 #define OSC_EXT_PCI_CONFIG_SUPPORT		1