linux-stable/arch/x86/crypto/crc32c-intel_glue.c
Uros Bizjak 3a95887e27 crypto: x86/crc32c-intel - Use CRC32 mnemonic
Current minimum required version of binutils is 2.23,
which supports CRC32 instruction mnemonic.

Replace the byte-wise specification of CRC32 with this proper mnemonic.
The compiler is now able to pass memory operand to the instruction,
so there is no need for a temporary register anymore.

Some examples of the improvement:

 12a:	48 8b 08             	mov    (%rax),%rcx
 12d:	f2 48 0f 38 f1 f1    	crc32q %rcx,%rsi
 133:	48 83 c0 08          	add    $0x8,%rax
 137:	48 39 d0             	cmp    %rdx,%rax
 13a:	75 ee                	jne    12a <crc32c_intel_update+0x1a>

to:

 125:	f2 48 0f 38 f1 06    	crc32q (%rsi),%rax
 12b:	48 83 c6 08          	add    $0x8,%rsi
 12f:	48 39 d6             	cmp    %rdx,%rsi
 132:	75 f1                	jne    125 <crc32c_intel_update+0x15>

and:

 146:	0f b6 08             	movzbl (%rax),%ecx
 149:	f2 0f 38 f0 f1       	crc32b %cl,%esi
 14e:	48 83 c0 01          	add    $0x1,%rax
 152:	48 39 d0             	cmp    %rdx,%rax
 155:	75 ef                	jne    146 <crc32c_intel_update+0x36>

to:

 13b:	f2 0f 38 f0 02       	crc32b (%rdx),%eax
 140:	48 83 c2 01          	add    $0x1,%rdx
 144:	48 39 ca             	cmp    %rcx,%rdx
 147:	75 f2                	jne    13b <crc32c_intel_update+0x2b>

As the compiler has some more freedom w.r.t. register allocation,
there is also a couple of reg-reg moves removed.

There are no hidden states for CRC32 insn, so there is no need to mark
assembly as volatile.

v2: Introduce CRC32_INST define.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: "David S. Miller" <davem@davemloft.net>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-08-21 14:45:28 +10:00

250 lines
6.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Using hardware provided CRC32 instruction to accelerate the CRC32 disposal.
* CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE)
* CRC32 is a new instruction in Intel SSE4.2, the reference can be found at:
* http://www.intel.com/products/processor/manuals/
* Intel(R) 64 and IA-32 Architectures Software Developer's Manual
* Volume 2A: Instruction Set Reference, A-M
*
* Copyright (C) 2008 Intel Corporation
* Authors: Austin Zhang <austin_zhang@linux.intel.com>
* Kent Liu <kent.liu@intel.com>
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/simd.h>
#include <asm/cpufeatures.h>
#include <asm/cpu_device_id.h>
#include <asm/simd.h>
#define CHKSUM_BLOCK_SIZE 1
#define CHKSUM_DIGEST_SIZE 4
#define SCALE_F sizeof(unsigned long)
#ifdef CONFIG_X86_64
#define CRC32_INST "crc32q %1, %q0"
#else
#define CRC32_INST "crc32l %1, %0"
#endif
#ifdef CONFIG_X86_64
/*
* use carryless multiply version of crc32c when buffer
* size is >= 512 to account
* for fpu state save/restore overhead.
*/
#define CRC32C_PCL_BREAKEVEN 512
asmlinkage unsigned int crc_pcl(const u8 *buffer, int len,
unsigned int crc_init);
#endif /* CONFIG_X86_64 */
static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length)
{
while (length--) {
asm("crc32b %1, %0"
: "+r" (crc) : "rm" (*data));
data++;
}
return crc;
}
static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len)
{
unsigned int iquotient = len / SCALE_F;
unsigned int iremainder = len % SCALE_F;
unsigned long *ptmp = (unsigned long *)p;
while (iquotient--) {
asm(CRC32_INST
: "+r" (crc) : "rm" (*ptmp));
ptmp++;
}
if (iremainder)
crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
iremainder);
return crc;
}
/*
* Setting the seed allows arbitrary accumulators and flexible XOR policy
* If your algorithm starts with ~0, then XOR with ~0 before you set
* the seed.
*/
static int crc32c_intel_setkey(struct crypto_shash *hash, const u8 *key,
unsigned int keylen)
{
u32 *mctx = crypto_shash_ctx(hash);
if (keylen != sizeof(u32))
return -EINVAL;
*mctx = le32_to_cpup((__le32 *)key);
return 0;
}
static int crc32c_intel_init(struct shash_desc *desc)
{
u32 *mctx = crypto_shash_ctx(desc->tfm);
u32 *crcp = shash_desc_ctx(desc);
*crcp = *mctx;
return 0;
}
static int crc32c_intel_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
u32 *crcp = shash_desc_ctx(desc);
*crcp = crc32c_intel_le_hw(*crcp, data, len);
return 0;
}
static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
u8 *out)
{
*(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
return 0;
}
static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out);
}
static int crc32c_intel_final(struct shash_desc *desc, u8 *out)
{
u32 *crcp = shash_desc_ctx(desc);
*(__le32 *)out = ~cpu_to_le32p(crcp);
return 0;
}
static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
out);
}
static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
{
u32 *key = crypto_tfm_ctx(tfm);
*key = ~0;
return 0;
}
#ifdef CONFIG_X86_64
static int crc32c_pcl_intel_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
u32 *crcp = shash_desc_ctx(desc);
/*
* use faster PCL version if datasize is large enough to
* overcome kernel fpu state save/restore overhead
*/
if (len >= CRC32C_PCL_BREAKEVEN && crypto_simd_usable()) {
kernel_fpu_begin();
*crcp = crc_pcl(data, len, *crcp);
kernel_fpu_end();
} else
*crcp = crc32c_intel_le_hw(*crcp, data, len);
return 0;
}
static int __crc32c_pcl_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
u8 *out)
{
if (len >= CRC32C_PCL_BREAKEVEN && crypto_simd_usable()) {
kernel_fpu_begin();
*(__le32 *)out = ~cpu_to_le32(crc_pcl(data, len, *crcp));
kernel_fpu_end();
} else
*(__le32 *)out =
~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
return 0;
}
static int crc32c_pcl_intel_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return __crc32c_pcl_intel_finup(shash_desc_ctx(desc), data, len, out);
}
static int crc32c_pcl_intel_digest(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return __crc32c_pcl_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
out);
}
#endif /* CONFIG_X86_64 */
static struct shash_alg alg = {
.setkey = crc32c_intel_setkey,
.init = crc32c_intel_init,
.update = crc32c_intel_update,
.final = crc32c_intel_final,
.finup = crc32c_intel_finup,
.digest = crc32c_intel_digest,
.descsize = sizeof(u32),
.digestsize = CHKSUM_DIGEST_SIZE,
.base = {
.cra_name = "crc32c",
.cra_driver_name = "crc32c-intel",
.cra_priority = 200,
.cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
.cra_blocksize = CHKSUM_BLOCK_SIZE,
.cra_ctxsize = sizeof(u32),
.cra_module = THIS_MODULE,
.cra_init = crc32c_intel_cra_init,
}
};
static const struct x86_cpu_id crc32c_cpu_id[] = {
X86_MATCH_FEATURE(X86_FEATURE_XMM4_2, NULL),
{}
};
MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id);
static int __init crc32c_intel_mod_init(void)
{
if (!x86_match_cpu(crc32c_cpu_id))
return -ENODEV;
#ifdef CONFIG_X86_64
if (boot_cpu_has(X86_FEATURE_PCLMULQDQ)) {
alg.update = crc32c_pcl_intel_update;
alg.finup = crc32c_pcl_intel_finup;
alg.digest = crc32c_pcl_intel_digest;
}
#endif
return crypto_register_shash(&alg);
}
static void __exit crc32c_intel_mod_fini(void)
{
crypto_unregister_shash(&alg);
}
module_init(crc32c_intel_mod_init);
module_exit(crc32c_intel_mod_fini);
MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>");
MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CRYPTO("crc32c");
MODULE_ALIAS_CRYPTO("crc32c-intel");