diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-13 19:13:38 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-13 19:13:38 -0700 |
commit | 9b27efe08180444e66c0922f89f3f883f4f9e35e (patch) | |
tree | 287652f84a63079543e83e98fbcc0dab5db742c7 /arch/arm/include/asm/bitops.h | |
parent | 85a0b791bc17f7a49280b33e2905d109c062a47b (diff) | |
parent | c61b466d4f886613c7e71de8282701646a4d999d (diff) |
Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King:
- further Spectre variant 1 fixes for user accessors.
- kbuild cleanups (Masahiro Yamada)
- hook up sync core functionality (Will Deacon)
- nommu updates for hypervisor mode booting (Vladimir Murzin)
- use compiler built-ins for fls and ffs (Nicolas Pitre)
* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: spectre-v1: mitigate user accesses
ARM: spectre-v1: use get_user() for __get_user()
ARM: use __inttype() in get_user()
ARM: oabi-compat: copy semops using __copy_from_user()
ARM: vfp: use __copy_from_user() when restoring VFP state
ARM: 8785/1: use compiler built-ins for ffs and fls
ARM: 8784/1: NOMMU: Allow enter in Hyp mode
ARM: 8783/1: NOMMU: Extend check for VBAR support
ARM: 8782/1: vfp: clean up arch/arm/vfp/Makefile
ARM: signal: copy registers using __copy_from_user()
ARM: tcm: ensure inline stub functions are marked static
ARM: 8779/1: add endianness option to LDFLAGS instead of LD
ARM: 8777/1: Hook up SYNC_CORE functionality for sys_membarrier()
Diffstat (limited to 'arch/arm/include/asm/bitops.h')
-rw-r--r-- | arch/arm/include/asm/bitops.h | 92 |
1 files changed, 9 insertions, 83 deletions
diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h index 4cab9bb823fb..c92e42a5c8f7 100644 --- a/arch/arm/include/asm/bitops.h +++ b/arch/arm/include/asm/bitops.h @@ -215,7 +215,6 @@ extern int _find_next_bit_be(const unsigned long *p, int size, int offset); #if __LINUX_ARM_ARCH__ < 5 -#include <asm-generic/bitops/ffz.h> #include <asm-generic/bitops/__fls.h> #include <asm-generic/bitops/__ffs.h> #include <asm-generic/bitops/fls.h> @@ -223,93 +222,20 @@ extern int _find_next_bit_be(const unsigned long *p, int size, int offset); #else -static inline int constant_fls(int x) -{ - int r = 32; - - if (!x) - return 0; - if (!(x & 0xffff0000u)) { - x <<= 16; - r -= 16; - } - if (!(x & 0xff000000u)) { - x <<= 8; - r -= 8; - } - if (!(x & 0xf0000000u)) { - x <<= 4; - r -= 4; - } - if (!(x & 0xc0000000u)) { - x <<= 2; - r -= 2; - } - if (!(x & 0x80000000u)) { - x <<= 1; - r -= 1; - } - return r; -} - -/* - * On ARMv5 and above those functions can be implemented around the - * clz instruction for much better code efficiency. __clz returns - * the number of leading zeros, zero input will return 32, and - * 0x80000000 will return 0. - */ -static inline unsigned int __clz(unsigned int x) -{ - unsigned int ret; - - asm("clz\t%0, %1" : "=r" (ret) : "r" (x)); - - return ret; -} - -/* - * fls() returns zero if the input is zero, otherwise returns the bit - * position of the last set bit, where the LSB is 1 and MSB is 32. - */ -static inline int fls(int x) -{ - if (__builtin_constant_p(x)) - return constant_fls(x); - - return 32 - __clz(x); -} - -/* - * __fls() returns the bit position of the last bit set, where the - * LSB is 0 and MSB is 31. Zero input is undefined. - */ -static inline unsigned long __fls(unsigned long x) -{ - return fls(x) - 1; -} - -/* - * ffs() returns zero if the input was zero, otherwise returns the bit - * position of the first set bit, where the LSB is 1 and MSB is 32. - */ -static inline int ffs(int x) -{ - return fls(x & -x); -} - /* - * __ffs() returns the bit position of the first bit set, where the - * LSB is 0 and MSB is 31. Zero input is undefined. + * On ARMv5 and above, the gcc built-ins may rely on the clz instruction + * and produce optimal inlined code in all cases. On ARMv7 it is even + * better by also using the rbit instruction. */ -static inline unsigned long __ffs(unsigned long x) -{ - return ffs(x) - 1; -} - -#define ffz(x) __ffs( ~(x) ) +#include <asm-generic/bitops/builtin-__fls.h> +#include <asm-generic/bitops/builtin-__ffs.h> +#include <asm-generic/bitops/builtin-fls.h> +#include <asm-generic/bitops/builtin-ffs.h> #endif +#include <asm-generic/bitops/ffz.h> + #include <asm-generic/bitops/fls64.h> #include <asm-generic/bitops/sched.h> |