cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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crc7.c (2562B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *      crc7.c
      4 */
      5
      6#include <linux/types.h>
      7#include <linux/module.h>
      8#include <linux/crc7.h>
      9
     10
     11/*
     12 * Table for CRC-7 (polynomial x^7 + x^3 + 1).
     13 * This is a big-endian CRC (msbit is highest power of x),
     14 * aligned so the msbit of the byte is the x^6 coefficient
     15 * and the lsbit is not used.
     16 */
     17const u8 crc7_be_syndrome_table[256] = {
     18	0x00, 0x12, 0x24, 0x36, 0x48, 0x5a, 0x6c, 0x7e,
     19	0x90, 0x82, 0xb4, 0xa6, 0xd8, 0xca, 0xfc, 0xee,
     20	0x32, 0x20, 0x16, 0x04, 0x7a, 0x68, 0x5e, 0x4c,
     21	0xa2, 0xb0, 0x86, 0x94, 0xea, 0xf8, 0xce, 0xdc,
     22	0x64, 0x76, 0x40, 0x52, 0x2c, 0x3e, 0x08, 0x1a,
     23	0xf4, 0xe6, 0xd0, 0xc2, 0xbc, 0xae, 0x98, 0x8a,
     24	0x56, 0x44, 0x72, 0x60, 0x1e, 0x0c, 0x3a, 0x28,
     25	0xc6, 0xd4, 0xe2, 0xf0, 0x8e, 0x9c, 0xaa, 0xb8,
     26	0xc8, 0xda, 0xec, 0xfe, 0x80, 0x92, 0xa4, 0xb6,
     27	0x58, 0x4a, 0x7c, 0x6e, 0x10, 0x02, 0x34, 0x26,
     28	0xfa, 0xe8, 0xde, 0xcc, 0xb2, 0xa0, 0x96, 0x84,
     29	0x6a, 0x78, 0x4e, 0x5c, 0x22, 0x30, 0x06, 0x14,
     30	0xac, 0xbe, 0x88, 0x9a, 0xe4, 0xf6, 0xc0, 0xd2,
     31	0x3c, 0x2e, 0x18, 0x0a, 0x74, 0x66, 0x50, 0x42,
     32	0x9e, 0x8c, 0xba, 0xa8, 0xd6, 0xc4, 0xf2, 0xe0,
     33	0x0e, 0x1c, 0x2a, 0x38, 0x46, 0x54, 0x62, 0x70,
     34	0x82, 0x90, 0xa6, 0xb4, 0xca, 0xd8, 0xee, 0xfc,
     35	0x12, 0x00, 0x36, 0x24, 0x5a, 0x48, 0x7e, 0x6c,
     36	0xb0, 0xa2, 0x94, 0x86, 0xf8, 0xea, 0xdc, 0xce,
     37	0x20, 0x32, 0x04, 0x16, 0x68, 0x7a, 0x4c, 0x5e,
     38	0xe6, 0xf4, 0xc2, 0xd0, 0xae, 0xbc, 0x8a, 0x98,
     39	0x76, 0x64, 0x52, 0x40, 0x3e, 0x2c, 0x1a, 0x08,
     40	0xd4, 0xc6, 0xf0, 0xe2, 0x9c, 0x8e, 0xb8, 0xaa,
     41	0x44, 0x56, 0x60, 0x72, 0x0c, 0x1e, 0x28, 0x3a,
     42	0x4a, 0x58, 0x6e, 0x7c, 0x02, 0x10, 0x26, 0x34,
     43	0xda, 0xc8, 0xfe, 0xec, 0x92, 0x80, 0xb6, 0xa4,
     44	0x78, 0x6a, 0x5c, 0x4e, 0x30, 0x22, 0x14, 0x06,
     45	0xe8, 0xfa, 0xcc, 0xde, 0xa0, 0xb2, 0x84, 0x96,
     46	0x2e, 0x3c, 0x0a, 0x18, 0x66, 0x74, 0x42, 0x50,
     47	0xbe, 0xac, 0x9a, 0x88, 0xf6, 0xe4, 0xd2, 0xc0,
     48	0x1c, 0x0e, 0x38, 0x2a, 0x54, 0x46, 0x70, 0x62,
     49	0x8c, 0x9e, 0xa8, 0xba, 0xc4, 0xd6, 0xe0, 0xf2
     50};
     51EXPORT_SYMBOL(crc7_be_syndrome_table);
     52
     53/**
     54 * crc7_be - update the CRC7 for the data buffer
     55 * @crc:     previous CRC7 value
     56 * @buffer:  data pointer
     57 * @len:     number of bytes in the buffer
     58 * Context: any
     59 *
     60 * Returns the updated CRC7 value.
     61 * The CRC7 is left-aligned in the byte (the lsbit is always 0), as that
     62 * makes the computation easier, and all callers want it in that form.
     63 *
     64 */
     65u8 crc7_be(u8 crc, const u8 *buffer, size_t len)
     66{
     67	while (len--)
     68		crc = crc7_be_byte(crc, *buffer++);
     69	return crc;
     70}
     71EXPORT_SYMBOL(crc7_be);
     72
     73MODULE_DESCRIPTION("CRC7 calculations");
     74MODULE_LICENSE("GPL");