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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2014-03-04 01:10:04 (GMT)
committerChanho Park <chanho61.park@samsung.com>2014-04-16 12:36:50 (GMT)
commit3dbfd560ca99705148d257935c9f7eae3d0dbfc8 (patch)
tree5c6d602527054787c5adcb5ea63c1b8885761fff
parente16554bcd4a29ed78a0f4b1207344bd36f2c3850 (diff)
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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>
-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 8761193..f542be0 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -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
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
new file mode 100644
index 0000000..cd4ac05
--- /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