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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2014-03-04 01:10:04 +0000
committerMark Brown <broonie@linaro.org>2014-06-16 18:11:35 +0100
commit581a6bd433c6ec65fdb5b4667258a8b275ae5c96 (patch)
tree0bde60a19ca6b764b87e8e3ef529da38c2b9f1fe
parent126ef42a10e491015dcb40477b042db50c3d2acf (diff)
downloadlinux-581a6bd433c6ec65fdb5b4667258a8b275ae5c96.tar.gz
arm64: enable generic CPU feature modalias matching for this architecture
This enables support for the generic CPU feature modalias implementation that wires up optional CPU features to udev based module autoprobing. A file <asm/cpufeature.h> is provided that maps CPU feature numbers to elf_hwcap bits, which is the standard way on arm64 to advertise optional CPU features both internally and to user space. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> [catalin.marinas@arm.com: removed unnecessary "!!"] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> (cherry picked from commit 3be1a5c4f75989cf457f13f38ff0913dff6d4996) Signed-off-by: Mark Brown <broonie@linaro.org> Conflicts: arch/arm64/Kconfig
-rw-r--r--arch/arm64/Kconfig1
-rw-r--r--arch/arm64/include/asm/cpufeature.h29
2 files changed, 30 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f7ef3f6ee97..df62331c3e4 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -10,6 +10,7 @@ config ARM64
select CLONE_BACKWARDS
select COMMON_CLK
select GENERIC_CLOCKEVENTS
+ select GENERIC_CPU_AUTOPROBE
select GENERIC_IOMAP
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
new file mode 100644
index 00000000000..cd4ac051648
--- /dev/null
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
+ *
+ * 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.
+ */
+
+#ifndef __ASM_CPUFEATURE_H
+#define __ASM_CPUFEATURE_H
+
+#include <asm/hwcap.h>
+
+/*
+ * In the arm64 world (as in the ARM world), elf_hwcap is used both internally
+ * in the kernel and for user space to keep track of which optional features
+ * are supported by the current system. So let's map feature 'x' to HWCAP_x.
+ * Note that HWCAP_x constants are bit fields so we need to take the log.
+ */
+
+#define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap))
+#define cpu_feature(x) ilog2(HWCAP_ ## x)
+
+static inline bool cpu_have_feature(unsigned int num)
+{
+ return elf_hwcap & (1UL << num);
+}
+
+#endif