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947697c6f0
This adds GENMASK_U128() and __GENMASK_U128() macros using __BITS_PER_U128 and __int128 data types. These macros will be used in providing support for generating 128 bit masks. The macros wouldn't work in all assembler flavors for reasons described in the comments on top of declarations. Enforce it for more by adding !__ASSEMBLY__ guard. Cc: Yury Norov <yury.norov@gmail.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Arnd Bergmann <arnd@arndb.de>> Cc: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Yury Norov <yury.norov@gmail.com>
55 lines
1.6 KiB
C
55 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_BITS_H
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#define __LINUX_BITS_H
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#include <linux/const.h>
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#include <vdso/bits.h>
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#include <uapi/linux/bits.h>
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#include <asm/bitsperlong.h>
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#define BIT_MASK(nr) (UL(1) << ((nr) % BITS_PER_LONG))
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#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
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#define BIT_ULL_MASK(nr) (ULL(1) << ((nr) % BITS_PER_LONG_LONG))
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#define BIT_ULL_WORD(nr) ((nr) / BITS_PER_LONG_LONG)
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#define BITS_PER_BYTE 8
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/*
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* Create a contiguous bitmask starting at bit position @l and ending at
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* position @h. For example
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* GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
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*/
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#if !defined(__ASSEMBLY__)
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#include <linux/build_bug.h>
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#define GENMASK_INPUT_CHECK(h, l) \
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(BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
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__is_constexpr((l) > (h)), (l) > (h), 0)))
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#else
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/*
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* BUILD_BUG_ON_ZERO is not available in h files included from asm files,
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* disable the input check if that is the case.
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*/
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#define GENMASK_INPUT_CHECK(h, l) 0
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#endif
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#define GENMASK(h, l) \
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(GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
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#define GENMASK_ULL(h, l) \
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(GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l))
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#if !defined(__ASSEMBLY__)
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/*
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* Missing asm support
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*
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* __GENMASK_U128() depends on _BIT128() which would not work
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* in the asm code, as it shifts an 'unsigned __init128' data
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* type instead of direct representation of 128 bit constants
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* such as long and unsigned long. The fundamental problem is
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* that a 128 bit constant will get silently truncated by the
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* gcc compiler.
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*/
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#define GENMASK_U128(h, l) \
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(GENMASK_INPUT_CHECK(h, l) + __GENMASK_U128(h, l))
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#endif
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#endif /* __LINUX_BITS_H */
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