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linux/bitops.h: GENMASK copy from linux

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GENMASK is used to create a contiguous bitmask([hi:lo]).

This patch is a copy from Linux, with below commit details
"bitops: Fix shift overflow in GENMASK macros"
(sha1: 00b4d9a14125f1e51874def2b9de6092e007412d)

Cc: Tom Rini <trini@konsulko.com>
Cc: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Jagan Teki <jteki@openedev.com>
This commit is contained in:
Jagan Teki 2015-10-21 16:46:51 +05:30 committed by Tom Rini
parent 673452876f
commit 89b5c81b75
2 changed files with 19 additions and 0 deletions
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8
include/asm-generic/bitsperlong.h Normal file
View file

@ -0,0 +1,8 @@
#ifndef __ASM_GENERIC_BITS_PER_LONG
#define __ASM_GENERIC_BITS_PER_LONG
#ifndef BITS_PER_LONG_LONG
#define BITS_PER_LONG_LONG 64
#endif
#endif /* __ASM_GENERIC_BITS_PER_LONG */

11
include/linux/bitops.h
View file

@ -7,6 +7,17 @@
#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
/*
* Create a contiguous bitmask starting at bit position @l and ending at
* position @h. For example
* GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
*/
#define GENMASK(h, l) \
(((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
#define GENMASK_ULL(h, l) \
(((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
/*
* ffs: find first bit set. This is defined the same way as
* the libc and compiler builtin ffs routines, therefore