@@ -16,6 +16,7 @@ config ARM64
select DCACHE_WORD_ACCESS
select GENERIC_CLOCKEVENTS
select GENERIC_CLOCKEVENTS_BROADCAST if SMP
+ select GENERIC_CPU_AUTOPROBE
select GENERIC_IOMAP
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
new file mode 100644
@@ -0,0 +1,30 @@
+/*
+ * 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/elf.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 sizeof(elf_hwcap)
+#define cpu_feature(x) ((unsigned int)ilog2(HWCAP_ ## x))
+
+static inline bool cpu_have_feature(unsigned int num)
+{
+ return !!(elf_hwcap & (1 << num));
+}
+
+#endif
This enables support for the generic CPU feature modalias implementation that wires up optional CPU features to udev based module autoprobing. A file <asm/cpufeatures.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> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/cpufeature.h | 30 ++++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) create mode 100644 arch/arm64/include/asm/cpufeature.h