From: Al Stone <ahs3@xxxxxxxxxx>
In order to deprecate the use of _OSI for arm64 or other new architectures,
we need to make the default handler something we can change for various
platforms. This patch moves the definition of acpi_osi_handler() -- the
function used by ACPICA as a callback for evaluating _OSI -- into arch-
dependent ACPI files. The declaration of acpi_os_handler() was moved in
a previous patch.
Previously, _OSI behaved on arm64 as it did on x86. This patch changes
_OSI so that on arm64 it will issue a warning if invoked, and tell the
firmware that no features have been implemented (i.e., it will always
return false).
In some distant future version of ACPI where _OSI has been completely
deprecated, this implementation and all other architecture implementations
should be removed.
Signed-off-by: Al Stone <al.stone@xxxxxxxxxx>
---
arch/arm64/kernel/acpi/Makefile | 2 +-
arch/arm64/kernel/acpi/osi.c | 26 ++++++++++++++++++++++++++
2 files changed, 27 insertions(+), 1 deletion(-)
create mode 100644 arch/arm64/kernel/acpi/osi.c
diff --git a/arch/arm64/kernel/acpi/Makefile b/arch/arm64/kernel/acpi/Makefile
index e049f94..15a6172 100644
--- a/arch/arm64/kernel/acpi/Makefile
+++ b/arch/arm64/kernel/acpi/Makefile
@@ -1 +1 @@
-obj-$(CONFIG_ACPI) += acpi.o
+obj-$(CONFIG_ACPI) += acpi.o osi.o
diff --git a/arch/arm64/kernel/acpi/osi.c b/arch/arm64/kernel/acpi/osi.c
new file mode 100644
index 0000000..fa711dc
--- /dev/null
+++ b/arch/arm64/kernel/acpi/osi.c
@@ -0,0 +1,26 @@
+/*
+ * ARM64 Specific ACPI _OSI Support
+ *
+ * Copyright (C) 2015, Linaro Ltd.
+ * Author: Al Stone <al.stone@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) "ACPI: " fmt
+
+#include <linux/acpi.h>
+
+/*
+ * Consensus is to deprecate _OSI for all new ACPI-supported architectures.
+ * So, for arm64, reduce _OSI to a warning message, and tell the firmware
+ * nothing of value.
+ */
+u32 acpi_osi_handler(acpi_string interface, u32 supported)
+{
+ pr_warn("_OSI was called, but is deprecated for this architecture.\n");
+ return false;
+}
+
--
2.1.0
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