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Commit 930da09f authored by Andre Przywara's avatar Andre Przywara Committed by Will Deacon
Browse files

arm64: add cpu_capabilities bitmap 



For taking note if at least one CPU in the system needs a bug
workaround or would benefit from a code optimization, we create a new
bitmap to hold (artificial) feature bits.
Since elf_hwcap is part of the userland ABI, we keep it alone and
introduce a new data structure for that (along with some accessors).

Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 90963395

arch/arm64/include/asm/cpufeature.h

+20 −0
Original line number Diff line number Diff line
@@ -21,9 +21,29 @@ 
#define MAX_CPU_FEATURES	(8 * sizeof(elf_hwcap))

#define cpu_feature(x)		ilog2(HWCAP_ ## x)



#define NCAPS			0



extern DECLARE_BITMAP(cpu_hwcaps, NCAPS);



static inline bool cpu_have_feature(unsigned int num)

{

	return elf_hwcap & (1UL << num);

}



static inline bool cpus_have_cap(unsigned int num)

{

	if (num >= NCAPS)

		return false;

	return test_bit(num, cpu_hwcaps);

}



static inline void cpus_set_cap(unsigned int num)

{

	if (num >= NCAPS)

		pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",

			num, NCAPS);

	else

		__set_bit(num, cpu_hwcaps);

}



#endif

arch/arm64/kernel/setup.c

+3 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ 
#include <asm/cputype.h>

#include <asm/elf.h>

#include <asm/cputable.h>

#include <asm/cpufeature.h>

#include <asm/cpu_ops.h>

#include <asm/sections.h>

#include <asm/setup.h>
@@ -79,6 +80,8 @@ unsigned int compat_elf_hwcap __read_mostly = COMPAT_ELF_HWCAP_DEFAULT; 
unsigned int compat_elf_hwcap2 __read_mostly;

#endif



DECLARE_BITMAP(cpu_hwcaps, NCAPS);



static const char *cpu_name;

phys_addr_t __fdt_pointer __initdata;