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    Subject[PATCH] lib/libcrc32c, revised 040427
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    On Fri, 23 Apr 2004, David S. Miller outgrape:
    > On Mon, 19 Apr 2004 16:37:01 -0500
    > Clay Haapala <chaapala@cisco.com> wrote:
    >
    >> +#if __GNUC__ >= 3 /* 2.x has "attribute", but only 3.0 has "pure
    >> +*/ #define attribute(x) __attribute__(x) #else #define
    >> +attribute(x) #endif
    >
    > I was about to apply your two patches, but then I noticed this
    > thing. WHatever you may need this for exists in linux/compiler.h
    > and if it doesn't you should add the necessary macro interfaces
    > there.
    >
    > Thanks.

    Attribute(pure) was used, so I changed the patch to use the define in
    compiler.h, as you suggest. I will also change crc32.c, and submit in
    a second patch. This is a patch against 2.6.5 sources. I did not
    change the crypto patch, as this construct was not used there.

    Thanks!
    --
    Clay Haapala (chaapala@cisco.com) Cisco Systems SRBU +1 763-398-1056
    6450 Wedgwood Rd, Suite 130 Maple Grove MN 55311 PGP: C89240AD
    "Oh, *that* Physics Prize. Well, I just substituted 'stupidity' for
    'dark matter' in the equations, and it all came together."

    diff -ruN linux-2.6.5.orig/lib/Kconfig linux-2.6.5/lib/Kconfig
    --- linux-2.6.5.orig/lib/Kconfig Sat Apr 3 21:37:23 2004
    +++ linux-2.6.5/lib/Kconfig Tue Apr 27 13:39:03 2004
    @@ -12,6 +12,15 @@
    kernel tree does. Such modules that use library CRC32 functions
    require M here.

    +config LIBCRC32C
    + tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
    + help
    + This option is provided for the case where no in-kernel-tree
    + modules require CRC32c functions, but a module built outside the
    + kernel tree does. Such modules that use library CRC32c functions
    + require M here. See Castagnoli93.
    + Module will be libcrc32c.
    +
    #
    # compression support is select'ed if needed
    #
    diff -ruN linux-2.6.5.orig/lib/Makefile linux-2.6.5/lib/Makefile
    --- linux-2.6.5.orig/lib/Makefile Sat Apr 3 21:36:16 2004
    +++ linux-2.6.5/lib/Makefile Tue Apr 27 13:39:03 2004
    @@ -19,6 +19,7 @@
    endif

    obj-$(CONFIG_CRC32) += crc32.o
    +obj-$(CONFIG_LIBCRC32C) += libcrc32c.o

    obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
    obj-$(CONFIG_ZLIB_DEFLATE) += zlib_deflate/
    diff -ruN linux-2.6.5.orig/lib/libcrc32c.c linux-2.6.5/lib/libcrc32c.c
    --- linux-2.6.5.orig/lib/libcrc32c.c Wed Dec 31 18:00:00 1969
    +++ linux-2.6.5/lib/libcrc32c.c Tue Apr 27 14:34:10 2004
    @@ -0,0 +1,199 @@
    +/*
    + * CRC32C
    + *@Article{castagnoli-crc,
    + * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
    + * title = {{Optimization of Cyclic Redundancy-Check Codes with 24
    + * and 32 Parity Bits}},
    + * journal = IEEE Transactions on Communication,
    + * year = {1993},
    + * volume = {41},
    + * number = {6},
    + * pages = {},
    + * month = {June},
    + *}
    + * Used by the iSCSI driver, possibly others, and derived from the
    + * the iscsi-crc.c module of the linux-iscsi driver at
    + * http://linux-iscsi.sourceforge.net.
    + *
    + * Following the example of lib/crc32, this function is intended to be
    + * flexible and useful for all users. Modules that currently have their
    + * own crc32c, but hopefully may be able to use this one are:
    + * net/sctp (please add all your doco to here if you change to
    + * use this one!)
    + * <endoflist>
    + *
    + * Copyright (c) 2004 Cisco Systems, Inc.
    + *
    + * This program is free software; you can redistribute it and/or modify it
    + * under the terms of the GNU General Public License as published by the Free
    + * Software Foundation; either version 2 of the License, or (at your option)
    + * any later version.
    + *
    + */
    +#include <linux/crc32c.h>
    +#include <linux/module.h>
    +#include <asm/byteorder.h>
    +
    +MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
    +MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
    +MODULE_LICENSE("GPL");
    +
    +#define CRC32C_POLY_BE 0x1EDC6F41
    +#define CRC32C_POLY_LE 0x82F63B78
    +
    +#ifndef CRC_LE_BITS
    +# define CRC_LE_BITS 8
    +#endif
    +
    +
    +/*
    + * Haven't generated a big-endian table yet, but the bit-wise version
    + * should at least work.
    + */
    +#if defined CRC_BE_BITS && CRC_BE_BITS != 1
    +#undef CRC_BE_BITS
    +#endif
    +#ifndef CRC_BE_BITS
    +# define CRC_BE_BITS 1
    +#endif
    +
    +EXPORT_SYMBOL(crc32c_le);
    +
    +#if CRC_LE_BITS == 1
    +/*
    + * Compute things bit-wise, as done in crc32.c. We could share the tight
    + * loop below with crc32 and vary the POLY if we don't find value in terms
    + * of space and maintainability in keeping the two modules separate.
    + */
    +u32 __attribute_pure__
    +crc32c_le(u32 crc, unsigned char const *p, size_t len)
    +{
    + int i;
    + while (len--) {
    + crc ^= *p++;
    + for (i = 0; i < 8; i++)
    + crc = (crc >> 1) ^ ((crc & 1) ? CRC32C_POLY_LE : 0);
    + }
    + return crc;
    +}
    +#else
    +
    +/*
    + * This is the CRC-32C table
    + * Generated with:
    + * width = 32 bits
    + * poly = 0x1EDC6F41
    + * reflect input bytes = true
    + * reflect output bytes = true
    + */
    +
    +static u32 crc32c_table[256] = {
    + 0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
    + 0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
    + 0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
    + 0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
    + 0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
    + 0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
    + 0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
    + 0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
    + 0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
    + 0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
    + 0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
    + 0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
    + 0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
    + 0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
    + 0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
    + 0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
    + 0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
    + 0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
    + 0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
    + 0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
    + 0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
    + 0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
    + 0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
    + 0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
    + 0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
    + 0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
    + 0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
    + 0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
    + 0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
    + 0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
    + 0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
    + 0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
    + 0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
    + 0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
    + 0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
    + 0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
    + 0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
    + 0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
    + 0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
    + 0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
    + 0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
    + 0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
    + 0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
    + 0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
    + 0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
    + 0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
    + 0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
    + 0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
    + 0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
    + 0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
    + 0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
    + 0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
    + 0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
    + 0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
    + 0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
    + 0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
    + 0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
    + 0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
    + 0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
    + 0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
    + 0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
    + 0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
    + 0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
    + 0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
    +};
    +
    +/*
    + * Steps through buffer one byte at at time, calculates reflected
    + * crc using table.
    + */
    +
    +u32 __attribute_pure__
    +crc32c_le(u32 seed, unsigned char const *data, size_t length)
    +{
    + u32 crc = __cpu_to_le32(seed);
    +
    + while (length--)
    + crc =
    + crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
    +
    + return __le32_to_cpu(crc);
    +}
    +
    +#endif /* CRC_LE_BITS == 8 */
    +
    +EXPORT_SYMBOL(crc32c_be);
    +
    +#if CRC_BE_BITS == 1
    +u32 __attribute_pure__
    +crc32c_be(u32 crc, unsigned char const *p, size_t len)
    +{
    + int i;
    + while (len--) {
    + crc ^= *p++ << 24;
    + for (i = 0; i < 8; i++)
    + crc =
    + (crc << 1) ^ ((crc & 0x80000000) ? CRC32C_POLY_BE :
    + 0);
    + }
    + return crc;
    +}
    +#endif
    +
    +/*
    + * Unit test
    + *
    + * A small unit test suite is implemented as part of the crypto suite.
    + * Select CRYPTO_CRC32C and use the tcrypt module to run the tests.
    + */
    diff -ruN linux-2.6.5.orig/include/linux/crc32c.h linux-2.6.5/include/linux/crc32c.h
    --- linux-2.6.5.orig/include/linux/crc32c.h Wed Dec 31 18:00:00 1969
    +++ linux-2.6.5/include/linux/crc32c.h Tue Apr 27 13:39:03 2004
    @@ -0,0 +1,11 @@
    +#ifndef _LINUX_CRC32C_H
    +#define _LINUX_CRC32C_H
    +
    +#include <linux/types.h>
    +
    +extern u32 crc32c_le(u32 crc, unsigned char const *address, size_t length);
    +extern u32 crc32c_be(u32 crc, unsigned char const *address, size_t length);
    +
    +#define crc32c(seed, data, length) crc32c_le(seed, (unsigned char const *)data, length)
    +
    +#endif /* _LINUX_CRC32C_H */
    -
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