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fc92099902
To pick up the changes in this cset:1e7933a575("uapi: Revert "bitops: avoid integer overflow in GENMASK(_ULL)"")5b572e8a9f("bits: introduce fixed-type BIT_U*()")19408200c0("bits: introduce fixed-type GENMASK_U*()")31299a5e02("bits: add comments and newlines to #if, #else and #endif directives") This addresses these perf build warnings: Warning: Kernel ABI header differences: diff -u tools/include/linux/bits.h include/linux/bits.h Please see tools/include/uapi/README for further details. Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Cc: I Hsin Cheng <richard120310@gmail.com> Cc: Yury Norov <yury.norov@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Ian Rogers <irogers@google.com> Cc: James Clark <james.clark@linaro.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Lucas De Marchi <lucas.demarchi@intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Yury Norov <yury.norov@gmail.com> Link: https://lore.kernel.org/r/aEr0ZJ60EbshEy6p@x1 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
107 lines
3.3 KiB
C
107 lines
3.3 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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#define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
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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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/*
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* Missing asm support
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*
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* GENMASK_U*() and BIT_U*() depend on BITS_PER_TYPE() which relies on sizeof(),
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* something not available in asm. Nevertheless, fixed width integers is a C
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* concept. Assembly code can rely on the long and long long versions instead.
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*/
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#include <linux/build_bug.h>
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#include <linux/compiler.h>
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#include <linux/overflow.h>
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#define GENMASK_INPUT_CHECK(h, l) BUILD_BUG_ON_ZERO(const_true((l) > (h)))
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/*
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* Generate a mask for the specified type @t. Additional checks are made to
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* guarantee the value returned fits in that type, relying on
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* -Wshift-count-overflow compiler check to detect incompatible arguments.
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* For example, all these create build errors or warnings:
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*
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* - GENMASK(15, 20): wrong argument order
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* - GENMASK(72, 15): doesn't fit unsigned long
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* - GENMASK_U32(33, 15): doesn't fit in a u32
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*/
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#define GENMASK_TYPE(t, h, l) \
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((t)(GENMASK_INPUT_CHECK(h, l) + \
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(type_max(t) << (l) & \
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type_max(t) >> (BITS_PER_TYPE(t) - 1 - (h)))))
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#define GENMASK_U8(h, l) GENMASK_TYPE(u8, h, l)
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#define GENMASK_U16(h, l) GENMASK_TYPE(u16, h, l)
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#define GENMASK_U32(h, l) GENMASK_TYPE(u32, h, l)
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#define GENMASK_U64(h, l) GENMASK_TYPE(u64, h, l)
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/*
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* Fixed-type variants of BIT(), with additional checks like GENMASK_TYPE(). The
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* following examples generate compiler warnings due to -Wshift-count-overflow:
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*
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* - BIT_U8(8)
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* - BIT_U32(-1)
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* - BIT_U32(40)
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*/
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#define BIT_INPUT_CHECK(type, nr) \
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BUILD_BUG_ON_ZERO(const_true((nr) >= BITS_PER_TYPE(type)))
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#define BIT_TYPE(type, nr) ((type)(BIT_INPUT_CHECK(type, nr) + BIT_ULL(nr)))
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#define BIT_U8(nr) BIT_TYPE(u8, nr)
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#define BIT_U16(nr) BIT_TYPE(u16, nr)
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#define BIT_U32(nr) BIT_TYPE(u32, nr)
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#define BIT_U64(nr) BIT_TYPE(u64, nr)
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#else /* defined(__ASSEMBLY__) */
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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 /* !defined(__ASSEMBLY__) */
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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 __int128' 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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