mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-19 18:53:52 +08:00
67bad2fdb7
This patch adds support for advertising optional CPU features over udev using the modalias, and for declaring compatibility with/dependency upon such a feature in a module. The mapping between feature numbers and actual features should be provided by the architecture in a file called <asm/cpufeature.h> which exports the following functions/macros: - cpu_feature(FEAT), a preprocessor macro that maps token FEAT to a numeric index; - bool cpu_have_feature(n), returning whether this CPU has support for feature #n; - MAX_CPU_FEATURES, an upper bound for 'n' in the previous function. The feature can then be enabled by setting CONFIG_GENERIC_CPU_AUTOPROBE for the architecture. For instance, a module that registers its module init function using module_cpu_feature_match(FEAT_X, module_init_function) will be probed automatically when the CPU's support for the 'FEAT_X' feature is advertised over udev, and will only allow the module to be loaded by hand if the 'FEAT_X' feature is supported. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/*
|
|
* 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 __LINUX_CPUFEATURE_H
|
|
#define __LINUX_CPUFEATURE_H
|
|
|
|
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
|
|
|
|
#include <linux/mod_devicetable.h>
|
|
#include <asm/cpufeature.h>
|
|
|
|
/*
|
|
* Macros imported from <asm/cpufeature.h>:
|
|
* - cpu_feature(x) ordinal value of feature called 'x'
|
|
* - cpu_have_feature(u32 n) whether feature #n is available
|
|
* - MAX_CPU_FEATURES upper bound for feature ordinal values
|
|
* Optional:
|
|
* - CPU_FEATURE_TYPEFMT format string fragment for printing the cpu type
|
|
* - CPU_FEATURE_TYPEVAL set of values matching the format string above
|
|
*/
|
|
|
|
#ifndef CPU_FEATURE_TYPEFMT
|
|
#define CPU_FEATURE_TYPEFMT "%s"
|
|
#endif
|
|
|
|
#ifndef CPU_FEATURE_TYPEVAL
|
|
#define CPU_FEATURE_TYPEVAL ELF_PLATFORM
|
|
#endif
|
|
|
|
/*
|
|
* Use module_cpu_feature_match(feature, module_init_function) to
|
|
* declare that
|
|
* a) the module shall be probed upon discovery of CPU feature 'feature'
|
|
* (typically at boot time using udev)
|
|
* b) the module must not be loaded if CPU feature 'feature' is not present
|
|
* (not even by manual insmod).
|
|
*
|
|
* For a list of legal values for 'feature', please consult the file
|
|
* 'asm/cpufeature.h' of your favorite architecture.
|
|
*/
|
|
#define module_cpu_feature_match(x, __init) \
|
|
static struct cpu_feature const cpu_feature_match_ ## x[] = \
|
|
{ { .feature = cpu_feature(x) }, { } }; \
|
|
MODULE_DEVICE_TABLE(cpu, cpu_feature_match_ ## x); \
|
|
\
|
|
static int cpu_feature_match_ ## x ## _init(void) \
|
|
{ \
|
|
if (!cpu_have_feature(cpu_feature(x))) \
|
|
return -ENODEV; \
|
|
return __init(); \
|
|
} \
|
|
module_init(cpu_feature_match_ ## x ## _init)
|
|
|
|
#endif
|
|
#endif
|