| 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
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| 2 | /* |
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| 3 | * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org> |
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| 4 | */ |
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| 5 | |
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| 6 | #ifndef __LINUX_CPUFEATURE_H |
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| 7 | #define __LINUX_CPUFEATURE_H |
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| 8 | |
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| 9 | #ifdef CONFIG_GENERIC_CPU_AUTOPROBE |
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| 10 | |
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| 11 | #include <linux/init.h> |
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| 12 | #include <linux/mod_devicetable.h> |
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| 13 | #include <asm/cpufeature.h> |
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| 14 | |
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| 15 | /* |
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| 16 | * Macros imported from <asm/cpufeature.h>: |
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| 17 | * - cpu_feature(x) ordinal value of feature called 'x' |
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| 18 | * - cpu_have_feature(u32 n) whether feature #n is available |
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| 19 | * - MAX_CPU_FEATURES upper bound for feature ordinal values |
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| 20 | * Optional: |
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| 21 | * - CPU_FEATURE_TYPEFMT format string fragment for printing the cpu type |
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| 22 | * - CPU_FEATURE_TYPEVAL set of values matching the format string above |
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| 23 | */ |
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| 24 | |
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| 25 | #ifndef CPU_FEATURE_TYPEFMT |
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| 26 | #define CPU_FEATURE_TYPEFMT "%s" |
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| 27 | #endif |
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| 28 | |
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| 29 | #ifndef CPU_FEATURE_TYPEVAL |
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| 30 | #define CPU_FEATURE_TYPEVAL ELF_PLATFORM |
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| 31 | #endif |
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| 32 | |
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| 33 | /* |
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| 34 | * Use module_cpu_feature_match(feature, module_init_function) to |
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| 35 | * declare that |
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| 36 | * a) the module shall be probed upon discovery of CPU feature 'feature' |
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| 37 | * (typically at boot time using udev) |
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| 38 | * b) the module must not be loaded if CPU feature 'feature' is not present |
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| 39 | * (not even by manual insmod). |
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| 40 | * |
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| 41 | * For a list of legal values for 'feature', please consult the file |
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| 42 | * 'asm/cpufeature.h' of your favorite architecture. |
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| 43 | */ |
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| 44 | #define module_cpu_feature_match(x, __initfunc) \ |
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| 45 | static struct cpu_feature const __maybe_unused cpu_feature_match_ ## x[] = \ |
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| 46 | { { .feature = cpu_feature(x) }, { } }; \ |
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| 47 | MODULE_DEVICE_TABLE(cpu, cpu_feature_match_ ## x); \ |
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| 48 | \ |
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| 49 | static int __init cpu_feature_match_ ## x ## _init(void) \ |
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| 50 | { \ |
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| 51 | if (!cpu_have_feature(cpu_feature(x))) \ |
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| 52 | return -ENODEV; \ |
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| 53 | return __initfunc(); \ |
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| 54 | } \ |
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| 55 | module_init(cpu_feature_match_ ## x ## _init) |
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| 56 | |
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| 57 | #endif |
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| 58 | #endif |
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| 59 | |
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