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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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0b5a58c078
There's no need for crc32() to be a macro. Make it an inline function instead. Also, remove the cast of the data pointer to 'unsigned char const *', which is no longer necessary now that the type used in the function prototype is 'const void *'. Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20250619183414.100082-3-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org>
111 lines
4.1 KiB
C
111 lines
4.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef _LINUX_CRC32_H
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#define _LINUX_CRC32_H
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#include <linux/types.h>
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#include <linux/bitrev.h>
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/**
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* crc32_le() - Compute least-significant-bit-first IEEE CRC-32
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* @crc: Initial CRC value. ~0 (recommended) or 0 for a new CRC computation, or
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* the previous CRC value if computing incrementally.
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* @p: Pointer to the data buffer
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* @len: Length of data in bytes
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*
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* This implements the CRC variant that is often known as the IEEE CRC-32, or
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* simply CRC-32, and is widely used in Ethernet and other applications:
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*
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* - Polynomial: x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^10 + x^8 +
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* x^7 + x^5 + x^4 + x^2 + x^1 + x^0
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* - Bit order: Least-significant-bit-first
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* - Polynomial in integer form: 0xedb88320
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*
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* This does *not* invert the CRC at the beginning or end. The caller is
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* expected to do that if it needs to. Inverting at both ends is recommended.
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*
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* For new applications, prefer to use CRC-32C instead. See crc32c().
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*
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* Context: Any context
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* Return: The new CRC value
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*/
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u32 crc32_le(u32 crc, const void *p, size_t len);
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/* This is just an alias for crc32_le(). */
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static inline u32 crc32(u32 crc, const void *p, size_t len)
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{
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return crc32_le(crc, p, len);
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}
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/**
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* crc32_be() - Compute most-significant-bit-first IEEE CRC-32
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* @crc: Initial CRC value. ~0 (recommended) or 0 for a new CRC computation, or
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* the previous CRC value if computing incrementally.
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* @p: Pointer to the data buffer
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* @len: Length of data in bytes
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*
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* crc32_be() is the same as crc32_le() except that crc32_be() computes the
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* *most-significant-bit-first* variant of the CRC. I.e., within each byte, the
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* most significant bit is processed first (treated as highest order polynomial
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* coefficient). The same bit order is also used for the CRC value itself:
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*
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* - Polynomial: x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^10 + x^8 +
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* x^7 + x^5 + x^4 + x^2 + x^1 + x^0
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* - Bit order: Most-significant-bit-first
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* - Polynomial in integer form: 0x04c11db7
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*
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* Context: Any context
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* Return: The new CRC value
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*/
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u32 crc32_be(u32 crc, const void *p, size_t len);
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/**
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* crc32c() - Compute CRC-32C
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* @crc: Initial CRC value. ~0 (recommended) or 0 for a new CRC computation, or
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* the previous CRC value if computing incrementally.
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* @p: Pointer to the data buffer
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* @len: Length of data in bytes
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*
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* This implements CRC-32C, i.e. the Castagnoli CRC. This is the recommended
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* CRC variant to use in new applications that want a 32-bit CRC.
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*
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* - Polynomial: x^32 + x^28 + x^27 + x^26 + x^25 + x^23 + x^22 + x^20 + x^19 +
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* x^18 + x^14 + x^13 + x^11 + x^10 + x^9 + x^8 + x^6 + x^0
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* - Bit order: Least-significant-bit-first
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* - Polynomial in integer form: 0x82f63b78
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*
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* This does *not* invert the CRC at the beginning or end. The caller is
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* expected to do that if it needs to. Inverting at both ends is recommended.
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*
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* Context: Any context
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* Return: The new CRC value
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*/
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u32 crc32c(u32 crc, const void *p, size_t len);
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/*
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* crc32_optimizations() returns flags that indicate which CRC32 library
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* functions are using architecture-specific optimizations. Unlike
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* IS_ENABLED(CONFIG_CRC32_ARCH) it takes into account the different CRC32
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* variants and also whether any needed CPU features are available at runtime.
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*/
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#define CRC32_LE_OPTIMIZATION BIT(0) /* crc32_le() is optimized */
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#define CRC32_BE_OPTIMIZATION BIT(1) /* crc32_be() is optimized */
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#define CRC32C_OPTIMIZATION BIT(2) /* crc32c() is optimized */
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#if IS_ENABLED(CONFIG_CRC32_ARCH)
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u32 crc32_optimizations(void);
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#else
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static inline u32 crc32_optimizations(void) { return 0; }
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#endif
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/*
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* Helpers for hash table generation of ethernet nics:
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*
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* Ethernet sends the least significant bit of a byte first, thus crc32_le
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* is used. The output of crc32_le is bit reversed [most significant bit
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* is in bit nr 0], thus it must be reversed before use. Except for
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* nics that bit swap the result internally...
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*/
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#define ether_crc(length, data) bitrev32(crc32_le(~0, data, length))
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#define ether_crc_le(length, data) crc32_le(~0, data, length)
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#endif /* _LINUX_CRC32_H */
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