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Subject[PATCH 1/4] lib/crc32: make core crc32() routines weak so they can be overridden
Date
Allow architectures to drop in accelerated CRC32 routines by making
the crc32_le/__crc32c_le entry points weak, and exposing non-weak
aliases for them that may be used by the accelerated versions as
fallbacks in case the instructions they rely upon are not available.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
lib/crc32.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/lib/crc32.c b/lib/crc32.c
index a6c9afafc8c8..45b1d67a1767 100644
--- a/lib/crc32.c
+++ b/lib/crc32.c
@@ -183,21 +183,21 @@ static inline u32 __pure crc32_le_generic(u32 crc, unsigned char const *p,
}

#if CRC_LE_BITS == 1
-u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len)
+u32 __pure __weak crc32_le(u32 crc, unsigned char const *p, size_t len)
{
return crc32_le_generic(crc, p, len, NULL, CRC32_POLY_LE);
}
-u32 __pure __crc32c_le(u32 crc, unsigned char const *p, size_t len)
+u32 __pure __weak __crc32c_le(u32 crc, unsigned char const *p, size_t len)
{
return crc32_le_generic(crc, p, len, NULL, CRC32C_POLY_LE);
}
#else
-u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len)
+u32 __pure __weak crc32_le(u32 crc, unsigned char const *p, size_t len)
{
return crc32_le_generic(crc, p, len,
(const u32 (*)[256])crc32table_le, CRC32_POLY_LE);
}
-u32 __pure __crc32c_le(u32 crc, unsigned char const *p, size_t len)
+u32 __pure __weak __crc32c_le(u32 crc, unsigned char const *p, size_t len)
{
return crc32_le_generic(crc, p, len,
(const u32 (*)[256])crc32ctable_le, CRC32C_POLY_LE);
@@ -206,6 +206,9 @@ u32 __pure __crc32c_le(u32 crc, unsigned char const *p, size_t len)
EXPORT_SYMBOL(crc32_le);
EXPORT_SYMBOL(__crc32c_le);

+u32 crc32_le_base(u32, unsigned char const *, size_t) __alias(crc32_le);
+u32 __crc32c_le_base(u32, unsigned char const *, size_t) __alias(__crc32c_le);
+
/*
* This multiplies the polynomials x and y modulo the given modulus.
* This follows the "little-endian" CRC convention that the lsbit
--
2.18.0
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