Herbert,
Currently the CRC-T10DIF checksum is computed using a generic table lookup
algorithm. By switching the checksum to PCLMULQDQ based computation,
we can speedup the computation by 8x for checksumming 512 bytes and
even more for larger buffer size. This will improve performance of SCSI
drivers turning on the CRC-T10IDF checksum. In our SSD based experiments,
we have seen in disk throughput by 3.5x with T10DIF.
This patchset provide the x86_64 routine using PCLMULQDQ instruction
and switch the crc_t10dif library function to use the faster PCLMULQDQ
based routine when available.
Will appreciate if you can consider merging this for the 3.10 kernel.
Tim
Tim Chen (4):
Wrap crc_t10dif function all to use crypto transform framework
Accelerated CRC T10 DIF computation with PCLMULQDQ instruction
Glue code to cast accelerated CRCT10DIF assembly as a crypto
transform
Simple correctness and speed test for CRCT10DIF hash
arch/x86/crypto/Makefile | 2 +
arch/x86/crypto/crct10dif-pcl-asm_64.S | 659 ++++++++++++++++++++++++++++++++
arch/x86/crypto/crct10dif-pclmul_glue.c | 153 ++++++++
crypto/Kconfig | 21 +
crypto/tcrypt.c | 8 +
crypto/testmgr.c | 10 +
crypto/testmgr.h | 24 ++
include/linux/crc-t10dif.h | 10 +
lib/crc-t10dif.c | 96 +++++
9 files changed, 983 insertions(+)
create mode 100644 arch/x86/crypto/crct10dif-pcl-asm_64.S
create mode 100644 arch/x86/crypto/crct10dif-pclmul_glue.c
--
1.7.11.7
These are simple tests to do sanity check of CRC T10 DIF hash. The
correctness of the transform can be checked with the command
modprobe tcrypt mode=47
The speed of the transform can be evaluated with the command
modprobe tcrypt mode=320
Set the cpu frequency to constant and turn turbo off when running the
speed test so the frequency governor will not tweak the frequency and
affects the measurements.
Signed-off-by: Tim Chen <[email protected]>
Tested-by: Keith Busch <[email protected]>
---
crypto/tcrypt.c | 8 ++++++++
crypto/testmgr.c | 10 ++++++++++
crypto/testmgr.h | 24 ++++++++++++++++++++++++
3 files changed, 42 insertions(+)
diff --git a/crypto/tcrypt.c b/crypto/tcrypt.c
index 24ea7df..5e95722 100644
--- a/crypto/tcrypt.c
+++ b/crypto/tcrypt.c
@@ -1174,6 +1174,10 @@ static int do_test(int m)
ret += tcrypt_test("ghash");
break;
+ case 47:
+ ret += tcrypt_test("crct10dif");
+ break;
+
case 100:
ret += tcrypt_test("hmac(md5)");
break;
@@ -1498,6 +1502,10 @@ static int do_test(int m)
test_hash_speed("crc32c", sec, generic_hash_speed_template);
if (mode > 300 && mode < 400) break;
+ case 320:
+ test_hash_speed("crct10dif", sec, generic_hash_speed_template);
+ if (mode > 300 && mode < 400) break;
+
case 399:
break;
diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 3807084..b165316 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -1944,6 +1944,16 @@ static const struct alg_test_desc alg_test_descs[] = {
}
}
}, {
+ .alg = "crct10dif",
+ .test = alg_test_hash,
+ .fips_allowed = 1,
+ .suite = {
+ .hash = {
+ .vecs = crct10dif_tv_template,
+ .count = CRCT10DIF_TEST_VECTORS
+ }
+ }
+ }, {
.alg = "cryptd(__driver-cbc-aes-aesni)",
.test = alg_test_null,
.fips_allowed = 1,
diff --git a/crypto/testmgr.h b/crypto/testmgr.h
index d503660..6262b74 100644
--- a/crypto/testmgr.h
+++ b/crypto/testmgr.h
@@ -450,6 +450,30 @@ static struct hash_testvec rmd320_tv_template[] = {
}
};
+#define CRCT10DIF_TEST_VECTORS 2
+static struct hash_testvec crct10dif_tv_template[] = {
+ {
+ .plaintext = "abc",
+ .psize = 3,
+#ifdef __LITTLE_ENDIAN
+ .digest = "\x3b\x44",
+#else
+ .digest = "\x44\x3b",
+#endif
+ }, {
+ .plaintext =
+ "abcddddddddddddddddddddddddddddddddddddddddddddddddddddd",
+ .psize = 56,
+#ifdef __LITTLE_ENDIAN
+ .digest = "\xe3\x9c",
+#else
+ .digest = "\x9c\xe3",
+#endif
+ .np = 2,
+ .tap = { 28, 28 }
+ }
+};
+
/*
* SHA1 test vectors from from FIPS PUB 180-1
* Long vector from CAVS 5.0
--
1.7.11.7
When CRC T10 DIF is calculated using the crypto transform framework, we
wrap the crc_t10dif function call to utilize it. This allows us to
take advantage of any accelerated CRC T10 DIF transform that is
plugged into the crypto framework.
Signed-off-by: Tim Chen <[email protected]>
Tested-by: Keith Busch <[email protected]>
---
include/linux/crc-t10dif.h | 10 +++++
lib/crc-t10dif.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 106 insertions(+)
diff --git a/include/linux/crc-t10dif.h b/include/linux/crc-t10dif.h
index a9c96d8..f0eb4d5 100644
--- a/include/linux/crc-t10dif.h
+++ b/include/linux/crc-t10dif.h
@@ -3,6 +3,16 @@
#include <linux/types.h>
+#ifdef CONFIG_CRYPTO_CRCT10DIF
+
+#define CRC_T10DIF_DIGEST_SIZE 2
+#define CRC_T10DIF_BLOCK_SIZE 1
+
+__u16 crc_t10dif_generic(__u16 crc, const unsigned char *buffer, size_t len);
+void crc_t10dif_update_lib(void);
+
+#endif /* CONFIG_CRYPTO_CRCT10DIF */
+
__u16 crc_t10dif(unsigned char const *, size_t);
#endif
diff --git a/lib/crc-t10dif.c b/lib/crc-t10dif.c
index fbbd66e..41f469a 100644
--- a/lib/crc-t10dif.c
+++ b/lib/crc-t10dif.c
@@ -11,6 +11,9 @@
#include <linux/types.h>
#include <linux/module.h>
#include <linux/crc-t10dif.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <crypto/hash.h>
/* Table generated using the following polynomium:
* x^16 + x^15 + x^11 + x^9 + x^8 + x^7 + x^5 + x^4 + x^2 + x + 1
@@ -51,6 +54,98 @@ static const __u16 t10_dif_crc_table[256] = {
0xF0D8, 0x7B6F, 0x6C01, 0xE7B6, 0x42DD, 0xC96A, 0xDE04, 0x55B3
};
+#ifdef CONFIG_CRYPTO_CRCT10DIF
+
+static struct crypto_shash *crct10dif_tfm;
+
+/* flag to indicate update to new algorithm in progress*/
+static bool crc_t10dif_newalg;
+
+__u16 crc_t10dif_generic(__u16 crc, const unsigned char *buffer, size_t len)
+{
+ unsigned int i;
+
+ for (i = 0 ; i < len ; i++)
+ crc = (crc << 8) ^ t10_dif_crc_table[((crc >> 8) ^ buffer[i]) & 0xff];
+
+ return crc;
+}
+EXPORT_SYMBOL(crc_t10dif_generic);
+
+/*
+ * If we have defined crypto transform for CRC-T10DIF, use that instead.
+ * This allows us to plug in fast version of CRC-T10DIF when available.
+ */
+
+void crc_t10dif_update_lib()
+{
+ struct crypto_shash *old_tfm, *new_tfm;
+
+ old_tfm = crct10dif_tfm;
+ crc_t10dif_newalg = true;
+ /* make sure new alg flag is turned on before starting to switch tfm */
+ mb();
+
+ new_tfm = crypto_alloc_shash("crct10dif", 0, 0);
+ if (IS_ERR(new_tfm))
+ goto done;
+
+ if (old_tfm)
+ if (crypto_tfm_alg_priority(&old_tfm->base) >=
+ crypto_tfm_alg_priority(&new_tfm->base)) {
+ crypto_free_shash(new_tfm);
+ goto done;
+ }
+ crct10dif_tfm = new_tfm;
+ /* make sure update to tfm pointer is completed */
+ mb();
+ crypto_free_shash(old_tfm);
+
+done:
+ crc_t10dif_newalg = false;
+}
+EXPORT_SYMBOL(crc_t10dif_update_lib);
+
+__u16 crc_t10dif(const unsigned char *buffer, size_t len)
+{
+ struct {
+ struct shash_desc shash;
+ char ctx[2];
+ } desc;
+ int err;
+
+ /* plugging in new alg or not using a tfm? */
+ if (unlikely(crc_t10dif_newalg) || (!crct10dif_tfm))
+ return crc_t10dif_generic(0, buffer, len);
+
+ desc.shash.tfm = crct10dif_tfm;
+ desc.shash.flags = 0;
+ *(__u16 *)desc.ctx = 0;
+
+ err = crypto_shash_update(&desc.shash, buffer, len);
+ BUG_ON(err);
+
+ return *(__u16 *)desc.ctx;
+}
+EXPORT_SYMBOL(crc_t10dif);
+
+static int __init crc_t10dif_mod_init(void)
+{
+ crct10dif_tfm = NULL;
+ crc_t10dif_newalg = false;
+ return 0;
+}
+
+static void __exit crc_t10dif_mod_fini(void)
+{
+ if (crct10dif_tfm)
+ crypto_free_shash(crct10dif_tfm);
+}
+
+module_init(crc_t10dif_mod_init);
+module_exit(crc_t10dif_mod_fini);
+
+#else
__u16 crc_t10dif(const unsigned char *buffer, size_t len)
{
__u16 crc = 0;
@@ -62,6 +157,7 @@ __u16 crc_t10dif(const unsigned char *buffer, size_t len)
return crc;
}
EXPORT_SYMBOL(crc_t10dif);
+#endif
MODULE_DESCRIPTION("T10 DIF CRC calculation");
MODULE_LICENSE("GPL");
--
1.7.11.7
Glue code that plugs the PCLMULQDQ accelerated CRC T10 DIF hash into the
crypto framework. The config CRYPTO_CRCT10DIF_PCLMUL should be turned
on to enable the feature. The crc_t10dif crypto library function will
use this faster algorithm when crct10dif_pclmul module is loaded.
Signed-off-by: Tim Chen <[email protected]>
Tested-by: Keith Busch <[email protected]>
---
arch/x86/crypto/Makefile | 2 +
arch/x86/crypto/crct10dif-pclmul_glue.c | 153 ++++++++++++++++++++++++++++++++
crypto/Kconfig | 21 +++++
3 files changed, 176 insertions(+)
create mode 100644 arch/x86/crypto/crct10dif-pclmul_glue.c
diff --git a/arch/x86/crypto/Makefile b/arch/x86/crypto/Makefile
index 03cd731..d544a66 100644
--- a/arch/x86/crypto/Makefile
+++ b/arch/x86/crypto/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_CRYPTO_SHA1_SSSE3) += sha1-ssse3.o
obj-$(CONFIG_CRYPTO_CRC32_PCLMUL) += crc32-pclmul.o
obj-$(CONFIG_CRYPTO_SHA256_SSSE3) += sha256-ssse3.o
obj-$(CONFIG_CRYPTO_SHA512_SSSE3) += sha512-ssse3.o
+obj-$(CONFIG_CRYPTO_CRCT10DIF_PCLMUL) += crct10dif-pclmul.o
# These modules require assembler to support AVX.
ifeq ($(avx_supported),yes)
@@ -70,3 +71,4 @@ crc32c-intel-$(CONFIG_64BIT) += crc32c-pcl-intel-asm_64.o
crc32-pclmul-y := crc32-pclmul_asm.o crc32-pclmul_glue.o
sha256-ssse3-y := sha256-ssse3-asm.o sha256-avx-asm.o sha256-avx2-asm.o sha256_ssse3_glue.o
sha512-ssse3-y := sha512-ssse3-asm.o sha512-avx-asm.o sha512-avx2-asm.o sha512_ssse3_glue.o
+crct10dif-pclmul-y := crct10dif-pcl-asm_64.o crct10dif-pclmul_glue.o
diff --git a/arch/x86/crypto/crct10dif-pclmul_glue.c b/arch/x86/crypto/crct10dif-pclmul_glue.c
new file mode 100644
index 0000000..e87f8d8
--- /dev/null
+++ b/arch/x86/crypto/crct10dif-pclmul_glue.c
@@ -0,0 +1,153 @@
+/*
+ * Cryptographic API.
+ *
+ * T10 Data Integrity Field CRC16 Crypto Xform using PCLMULQDQ Instructions
+ *
+ * Copyright (C) 2013 Intel Corporation
+ * Author: Tim Chen <[email protected]>
+ *
+ * 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.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/crc-t10dif.h>
+#include <crypto/internal/hash.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <asm/i387.h>
+#include <asm/cpufeature.h>
+
+asmlinkage __u16 crc_t10dif_pcl(__u16 crc, const unsigned char *buf,
+ size_t len);
+
+struct chksum_desc_ctx {
+ __u16 crc;
+};
+
+/*
+ * Steps through buffer one byte at at time, calculates reflected
+ * crc using table.
+ */
+
+static int chksum_init(struct shash_desc *desc)
+{
+ struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+ ctx->crc = 0;
+
+ return 0;
+}
+
+static int chksum_update(struct shash_desc *desc, const u8 *data,
+ unsigned int length)
+{
+ struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+ if (irq_fpu_usable()) {
+ kernel_fpu_begin();
+ ctx->crc = crc_t10dif_pcl(ctx->crc, data, length);
+ kernel_fpu_end();
+ } else
+ ctx->crc = crc_t10dif_generic(ctx->crc, data, length);
+ return 0;
+}
+
+static int chksum_final(struct shash_desc *desc, u8 *out)
+{
+ struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+ *(__u16 *)out = ctx->crc;
+ return 0;
+}
+
+static int __chksum_finup(__u16 *crcp, const u8 *data, unsigned int len,
+ u8 *out)
+{
+ if (irq_fpu_usable()) {
+ kernel_fpu_begin();
+ *(__u16 *)out = crc_t10dif_pcl(*crcp, data, len);
+ kernel_fpu_end();
+ } else
+ *(__u16 *)out = crc_t10dif_generic(*crcp, data, len);
+ return 0;
+}
+
+static int chksum_finup(struct shash_desc *desc, const u8 *data,
+ unsigned int len, u8 *out)
+{
+ struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+ return __chksum_finup(&ctx->crc, data, len, out);
+}
+
+static int chksum_digest(struct shash_desc *desc, const u8 *data,
+ unsigned int length, u8 *out)
+{
+ struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+ return __chksum_finup(&ctx->crc, data, length, out);
+}
+
+static struct shash_alg alg = {
+ .digestsize = CRC_T10DIF_DIGEST_SIZE,
+ .init = chksum_init,
+ .update = chksum_update,
+ .final = chksum_final,
+ .finup = chksum_finup,
+ .digest = chksum_digest,
+ .descsize = sizeof(struct chksum_desc_ctx),
+ .base = {
+ .cra_name = "crct10dif",
+ .cra_driver_name = "crct10dif-pclmul",
+ .cra_priority = 200,
+ .cra_blocksize = CRC_T10DIF_BLOCK_SIZE,
+ .cra_module = THIS_MODULE,
+ }
+};
+
+static int __init crct10dif_intel_mod_init(void)
+{
+ int ret;
+
+ ret = 0;
+ if (cpu_has_pclmulqdq) {
+ ret = crypto_register_shash(&alg);
+ if (!ret)
+ crc_t10dif_update_lib();
+ }
+ return ret;
+}
+
+static void __exit crct10dif_intel_mod_fini(void)
+{
+ /* switch crc_t10dif library back to generic algorithm */
+ if (cpu_has_pclmulqdq) {
+ crypto_unregister_shash(&alg);
+ crc_t10dif_update_lib();
+ }
+}
+
+module_init(crct10dif_intel_mod_init);
+module_exit(crct10dif_intel_mod_fini);
+
+MODULE_AUTHOR("Tim Chen <[email protected]>");
+MODULE_DESCRIPTION("T10 DIF CRC calculation accelerated with PCLMULQDQ.");
+MODULE_LICENSE("GPL");
+
+MODULE_ALIAS("crct10dif");
+MODULE_ALIAS("crct10dif-pclmul");
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 0e7a237..f69b045 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -376,6 +376,27 @@ config CRYPTO_CRC32_PCLMUL
which will enable any routine to use the CRC-32-IEEE 802.3 checksum
and gain better performance as compared with the table implementation.
+config CRYPTO_CRCT10DIF
+ bool "CRCT10DIF algorithm"
+ select CRYPTO_HASH
+ select CRC_T10DIF
+ help
+ CRC T10 Data Integrity Field computation is being cast as
+ a crypto transform. This allows for faster crc t10 diff
+ transforms to be used if they are available.
+
+config CRYPTO_CRCT10DIF_PCLMUL
+ tristate "CRCT10DIF PCLMULQDQ hardware acceleration"
+ depends on X86 && 64BIT
+ select CRYPTO_HASH
+ select CRYPTO_CRCT10DIF
+ help
+ For x86_64 processors with SSE4.2 and PCLMULQDQ supported,
+ CRC T10 DIF PCLMULQDQ computation can be hardware
+ accelerated PCLMULQDQ instruction. This option will create
+ 'crct10dif-plcmul' module, which is faster when computing the
+ crct10dif checksum compared to the generic table implementation.
+
config CRYPTO_GHASH
tristate "GHASH digest algorithm"
select CRYPTO_GF128MUL
--
1.7.11.7
This is the x86_64 CRC T10 DIF transform accelerated with the PCLMULQDQ
instructions. Details discussing the implementation can be found in the
paper:
"Fast CRC Computation for Generic Polynomials Using PCLMULQDQ Instruction"
URL: http://download.intel.com/design/intarch/papers/323102.pdf
Signed-off-by: Tim Chen <[email protected]>
Tested-by: Keith Busch <[email protected]>
---
arch/x86/crypto/crct10dif-pcl-asm_64.S | 659 +++++++++++++++++++++++++++++++++
1 file changed, 659 insertions(+)
create mode 100644 arch/x86/crypto/crct10dif-pcl-asm_64.S
diff --git a/arch/x86/crypto/crct10dif-pcl-asm_64.S b/arch/x86/crypto/crct10dif-pcl-asm_64.S
new file mode 100644
index 0000000..c497d0e
--- /dev/null
+++ b/arch/x86/crypto/crct10dif-pcl-asm_64.S
@@ -0,0 +1,659 @@
+########################################################################
+# Implement fast CRC-T10DIF computation with SSE and PCLMULQDQ instructions
+#
+# Copyright (c) 2013, Intel Corporation
+#
+# Authors:
+# Erdinc Ozturk <[email protected]>
+# Vinodh Gopal <[email protected]>
+# James Guilford <[email protected]>
+# Tim Chen <[email protected]>
+#
+# This software is available to you under a choice of one of two
+# licenses. You may choose to be licensed under the terms of the GNU
+# General Public License (GPL) Version 2, available from the file
+# COPYING in the main directory of this source tree, or the
+# OpenIB.org BSD license below:
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#
+# * Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the
+# distribution.
+#
+# * Neither the name of the Intel Corporation nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+#
+# THIS SOFTWARE IS PROVIDED BY INTEL CORPORATION ""AS IS"" AND ANY
+# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL CORPORATION OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES# LOSS OF USE, DATA, OR
+# PROFITS# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+########################################################################
+# Function API:
+# UINT16 crc_t10dif_pcl(
+# UINT16 init_crc, //initial CRC value, 16 bits
+# const unsigned char *buf, //buffer pointer to calculate CRC on
+# UINT64 len //buffer length in bytes (64-bit data)
+# )#
+#
+# Reference paper titled "Fast CRC Computation for Generic
+# Polynomials Using PCLMULQDQ Instruction"
+# URL: http://download.intel.com/design/intarch/papers/323102.pdf
+#
+#
+
+#include <linux/linkage.h>
+
+.text
+
+#define arg1 %rdi
+#define arg2 %rsi
+#define arg3 %rdx
+
+#define arg1_low32 %edi
+
+ENTRY(crc_t10dif_pcl)
+.align 16
+
+ # adjust the 16-bit initial_crc value, scale it to 32 bits
+ shl $16, arg1_low32
+
+ # Allocate Stack Space
+ mov %rsp, %rcx
+ sub $16*10, %rsp
+ and $~(0x20 - 1), %rsp
+
+ # push the xmm registers into the stack to maintain
+ movdqa %xmm10, 16*2(%rsp)
+ movdqa %xmm11, 16*3(%rsp)
+ movdqa %xmm8 , 16*4(%rsp)
+ movdqa %xmm12, 16*5(%rsp)
+ movdqa %xmm13, 16*6(%rsp)
+ movdqa %xmm6, 16*7(%rsp)
+ movdqa %xmm7, 16*8(%rsp)
+ movdqa %xmm9, 16*9(%rsp)
+
+
+ # check if smaller than 256
+ cmp $256, arg3
+
+ # for sizes less than 128, we can't fold 64B at a time...
+ jl _less_than_128
+
+
+ # load the initial crc value
+ movd arg1_low32, %xmm10 # initial crc
+
+ # crc value does not need to be byte-reflected, but it needs
+ # to be moved to the high part of the register.
+ # because data will be byte-reflected and will align with
+ # initial crc at correct place.
+ pslldq $12, %xmm10
+
+ movdqa SHUF_MASK(%rip), %xmm11
+ # receive the initial 64B data, xor the initial crc value
+ movdqu 16*0(arg2), %xmm0
+ movdqu 16*1(arg2), %xmm1
+ movdqu 16*2(arg2), %xmm2
+ movdqu 16*3(arg2), %xmm3
+ movdqu 16*4(arg2), %xmm4
+ movdqu 16*5(arg2), %xmm5
+ movdqu 16*6(arg2), %xmm6
+ movdqu 16*7(arg2), %xmm7
+
+ pshufb %xmm11, %xmm0
+ # XOR the initial_crc value
+ pxor %xmm10, %xmm0
+ pshufb %xmm11, %xmm1
+ pshufb %xmm11, %xmm2
+ pshufb %xmm11, %xmm3
+ pshufb %xmm11, %xmm4
+ pshufb %xmm11, %xmm5
+ pshufb %xmm11, %xmm6
+ pshufb %xmm11, %xmm7
+
+ movdqa rk3(%rip), %xmm10 #xmm10 has rk3 and rk4
+ #imm value of pclmulqdq instruction
+ #will determine which constant to use
+
+ #################################################################
+ # we subtract 256 instead of 128 to save one instruction from the loop
+ sub $256, arg3
+
+ # at this section of the code, there is 64*x+y (0<=y<64) bytes of
+ # buffer. The _fold_64_B_loop will fold 64B at a time
+ # until we have 64+y Bytes of buffer
+
+
+ # fold 64B at a time. This section of the code folds 4 xmm
+ # registers in parallel
+_fold_64_B_loop:
+
+ # update the buffer pointer
+ add $128, arg2 # buf += 64#
+
+ movdqu 16*0(arg2), %xmm9
+ movdqu 16*1(arg2), %xmm12
+ pshufb %xmm11, %xmm9
+ pshufb %xmm11, %xmm12
+ movdqa %xmm0, %xmm8
+ movdqa %xmm1, %xmm13
+ pclmulqdq $0x0 , %xmm10, %xmm0
+ pclmulqdq $0x11, %xmm10, %xmm8
+ pclmulqdq $0x0 , %xmm10, %xmm1
+ pclmulqdq $0x11, %xmm10, %xmm13
+ pxor %xmm9 , %xmm0
+ xorps %xmm8 , %xmm0
+ pxor %xmm12, %xmm1
+ xorps %xmm13, %xmm1
+
+ movdqu 16*2(arg2), %xmm9
+ movdqu 16*3(arg2), %xmm12
+ pshufb %xmm11, %xmm9
+ pshufb %xmm11, %xmm12
+ movdqa %xmm2, %xmm8
+ movdqa %xmm3, %xmm13
+ pclmulqdq $0x0, %xmm10, %xmm2
+ pclmulqdq $0x11, %xmm10, %xmm8
+ pclmulqdq $0x0, %xmm10, %xmm3
+ pclmulqdq $0x11, %xmm10, %xmm13
+ pxor %xmm9 , %xmm2
+ xorps %xmm8 , %xmm2
+ pxor %xmm12, %xmm3
+ xorps %xmm13, %xmm3
+
+ movdqu 16*4(arg2), %xmm9
+ movdqu 16*5(arg2), %xmm12
+ pshufb %xmm11, %xmm9
+ pshufb %xmm11, %xmm12
+ movdqa %xmm4, %xmm8
+ movdqa %xmm5, %xmm13
+ pclmulqdq $0x0, %xmm10, %xmm4
+ pclmulqdq $0x11, %xmm10, %xmm8
+ pclmulqdq $0x0, %xmm10, %xmm5
+ pclmulqdq $0x11, %xmm10, %xmm13
+ pxor %xmm9 , %xmm4
+ xorps %xmm8 , %xmm4
+ pxor %xmm12, %xmm5
+ xorps %xmm13, %xmm5
+
+ movdqu 16*6(arg2), %xmm9
+ movdqu 16*7(arg2), %xmm12
+ pshufb %xmm11, %xmm9
+ pshufb %xmm11, %xmm12
+ movdqa %xmm6 , %xmm8
+ movdqa %xmm7 , %xmm13
+ pclmulqdq $0x0 , %xmm10, %xmm6
+ pclmulqdq $0x11, %xmm10, %xmm8
+ pclmulqdq $0x0 , %xmm10, %xmm7
+ pclmulqdq $0x11, %xmm10, %xmm13
+ pxor %xmm9 , %xmm6
+ xorps %xmm8 , %xmm6
+ pxor %xmm12, %xmm7
+ xorps %xmm13, %xmm7
+
+ sub $128, arg3
+
+ # check if there is another 64B in the buffer to be able to fold
+ jge _fold_64_B_loop
+ ##################################################################
+
+
+ add $128, arg2
+ # at this point, the buffer pointer is pointing at the last y Bytes
+ # of the buffer the 64B of folded data is in 4 of the xmm
+ # registers: xmm0, xmm1, xmm2, xmm3
+
+
+ # fold the 8 xmm registers to 1 xmm register with different constants
+
+ movdqa rk9(%rip), %xmm10
+ movdqa %xmm0, %xmm8
+ pclmulqdq $0x11, %xmm10, %xmm0
+ pclmulqdq $0x0 , %xmm10, %xmm8
+ pxor %xmm8, %xmm7
+ xorps %xmm0, %xmm7
+
+ movdqa rk11(%rip), %xmm10
+ movdqa %xmm1, %xmm8
+ pclmulqdq $0x11, %xmm10, %xmm1
+ pclmulqdq $0x0 , %xmm10, %xmm8
+ pxor %xmm8, %xmm7
+ xorps %xmm1, %xmm7
+
+ movdqa rk13(%rip), %xmm10
+ movdqa %xmm2, %xmm8
+ pclmulqdq $0x11, %xmm10, %xmm2
+ pclmulqdq $0x0 , %xmm10, %xmm8
+ pxor %xmm8, %xmm7
+ pxor %xmm2, %xmm7
+
+ movdqa rk15(%rip), %xmm10
+ movdqa %xmm3, %xmm8
+ pclmulqdq $0x11, %xmm10, %xmm3
+ pclmulqdq $0x0 , %xmm10, %xmm8
+ pxor %xmm8, %xmm7
+ xorps %xmm3, %xmm7
+
+ movdqa rk17(%rip), %xmm10
+ movdqa %xmm4, %xmm8
+ pclmulqdq $0x11, %xmm10, %xmm4
+ pclmulqdq $0x0 , %xmm10, %xmm8
+ pxor %xmm8, %xmm7
+ pxor %xmm4, %xmm7
+
+ movdqa rk19(%rip), %xmm10
+ movdqa %xmm5, %xmm8
+ pclmulqdq $0x11, %xmm10, %xmm5
+ pclmulqdq $0x0 , %xmm10, %xmm8
+ pxor %xmm8, %xmm7
+ xorps %xmm5, %xmm7
+
+ movdqa rk1(%rip), %xmm10 #xmm10 has rk1 and rk2
+ #imm value of pclmulqdq instruction
+ #will determine which constant to use
+ movdqa %xmm6, %xmm8
+ pclmulqdq $0x11, %xmm10, %xmm6
+ pclmulqdq $0x0 , %xmm10, %xmm8
+ pxor %xmm8, %xmm7
+ pxor %xmm6, %xmm7
+
+
+ # instead of 64, we add 48 to the loop counter to save 1 instruction
+ # from the loop instead of a cmp instruction, we use the negative
+ # flag with the jl instruction
+ add $128-16, arg3
+ jl _final_reduction_for_128
+
+ # now we have 16+y bytes left to reduce. 16 Bytes is in register xmm7
+ # and the rest is in memory. We can fold 16 bytes at a time if y>=16
+ # continue folding 16B at a time
+
+_16B_reduction_loop:
+ movdqa %xmm7, %xmm8
+ pclmulqdq $0x11, %xmm10, %xmm7
+ pclmulqdq $0x0 , %xmm10, %xmm8
+ pxor %xmm8, %xmm7
+ movdqu (arg2), %xmm0
+ pshufb %xmm11, %xmm0
+ pxor %xmm0 , %xmm7
+ add $16, arg2
+ sub $16, arg3
+ # instead of a cmp instruction, we utilize the flags with the
+ # jge instruction equivalent of: cmp arg3, 16-16
+ # check if there is any more 16B in the buffer to be able to fold
+ jge _16B_reduction_loop
+
+ #now we have 16+z bytes left to reduce, where 0<= z < 16.
+ #first, we reduce the data in the xmm7 register
+
+
+_final_reduction_for_128:
+ # check if any more data to fold. If not, compute the CRC of
+ # the final 128 bits
+ add $16, arg3
+ je _128_done
+
+ # here we are getting data that is less than 16 bytes.
+ # since we know that there was data before the pointer, we can
+ # offset the input pointer before the actual point, to receive
+ # exactly 16 bytes. after that the registers need to be adjusted.
+_get_last_two_xmms:
+ movdqa %xmm7, %xmm2
+
+ movdqu -16(arg2, arg3), %xmm1
+ pshufb %xmm11, %xmm1
+
+ # get rid of the extra data that was loaded before
+ # load the shift constant
+ lea pshufb_shf_table+16(%rip), %rax
+ sub arg3, %rax
+ movdqu (%rax), %xmm0
+
+ # shift xmm2 to the left by arg3 bytes
+ pshufb %xmm0, %xmm2
+
+ # shift xmm7 to the right by 16-arg3 bytes
+ pxor mask1(%rip), %xmm0
+ pshufb %xmm0, %xmm7
+ pblendvb %xmm2, %xmm1 #xmm0 is implicit
+
+ # fold 16 Bytes
+ movdqa %xmm1, %xmm2
+ movdqa %xmm7, %xmm8
+ pclmulqdq $0x11, %xmm10, %xmm7
+ pclmulqdq $0x0 , %xmm10, %xmm8
+ pxor %xmm8, %xmm7
+ pxor %xmm2, %xmm7
+
+_128_done:
+ # compute crc of a 128-bit value
+ movdqa rk5(%rip), %xmm10 # rk5 and rk6 in xmm10
+ movdqa %xmm7, %xmm0
+
+ #64b fold
+ pclmulqdq $0x1, %xmm10, %xmm7
+ pslldq $8 , %xmm0
+ pxor %xmm0, %xmm7
+
+ #32b fold
+ movdqa %xmm7, %xmm0
+
+ pand mask2(%rip), %xmm0
+
+ psrldq $12, %xmm7
+ pclmulqdq $0x10, %xmm10, %xmm7
+ pxor %xmm0, %xmm7
+
+ #barrett reduction
+_barrett:
+ movdqa rk7(%rip), %xmm10 # rk7 and rk8 in xmm10
+ movdqa %xmm7, %xmm0
+ pclmulqdq $0x01, %xmm10, %xmm7
+ pslldq $4, %xmm7
+ pclmulqdq $0x11, %xmm10, %xmm7
+
+ pslldq $4, %xmm7
+ pxor %xmm0, %xmm7
+ pextrd $1, %xmm7, %eax
+
+_cleanup:
+ # scale the result back to 16 bits
+ shr $16, %eax
+ movdqa 16*2(%rsp), %xmm10
+ movdqa 16*3(%rsp), %xmm11
+ movdqa 16*4(%rsp), %xmm8
+ movdqa 16*5(%rsp), %xmm12
+ movdqa 16*6(%rsp), %xmm13
+ movdqa 16*7(%rsp), %xmm6
+ movdqa 16*8(%rsp), %xmm7
+ movdqa 16*9(%rsp), %xmm9
+ mov %rcx, %rsp
+ ret
+ENDPROC(crc_t10dif_pcl)
+
+########################################################################
+
+.align 16
+_less_than_128:
+
+ # check if there is enough buffer to be able to fold 16B at a time
+ cmp $32, arg3
+ jl _less_than_32
+ movdqa SHUF_MASK(%rip), %xmm11
+
+ # now if there is, load the constants
+ movdqa rk1(%rip), %xmm10 # rk1 and rk2 in xmm10
+
+ movd arg1_low32, %xmm0 # get the initial crc value
+ pslldq $12, %xmm0 # align it to its correct place
+ movdqu (arg2), %xmm7 # load the plaintext
+ pshufb %xmm11, %xmm7 # byte-reflect the plaintext
+ pxor %xmm0, %xmm7
+
+
+ # update the buffer pointer
+ add $16, arg2
+
+ # update the counter. subtract 32 instead of 16 to save one
+ # instruction from the loop
+ sub $32, arg3
+
+ jmp _16B_reduction_loop
+
+
+.align 16
+_less_than_32:
+ # mov initial crc to the return value. this is necessary for
+ # zero-length buffers.
+ mov arg1_low32, %eax
+ test arg3, arg3
+ je _cleanup
+
+ movdqa SHUF_MASK(%rip), %xmm11
+
+ movd arg1_low32, %xmm0 # get the initial crc value
+ pslldq $12, %xmm0 # align it to its correct place
+
+ cmp $16, arg3
+ je _exact_16_left
+ jl _less_than_16_left
+
+ movdqu (arg2), %xmm7 # load the plaintext
+ pshufb %xmm11, %xmm7 # byte-reflect the plaintext
+ pxor %xmm0 , %xmm7 # xor the initial crc value
+ add $16, arg2
+ sub $16, arg3
+ movdqa rk1(%rip), %xmm10 # rk1 and rk2 in xmm10
+ jmp _get_last_two_xmms
+
+
+.align 16
+_less_than_16_left:
+ # use stack space to load data less than 16 bytes, zero-out
+ # the 16B in memory first.
+
+ pxor %xmm1, %xmm1
+ mov %rsp, %r11
+ movdqa %xmm1, (%r11)
+
+ cmp $4, arg3
+ jl _only_less_than_4
+
+ # backup the counter value
+ mov arg3, %r9
+ cmp $8, arg3
+ jl _less_than_8_left
+
+ # load 8 Bytes
+ mov (arg2), %rax
+ mov %rax, (%r11)
+ add $8, %r11
+ sub $8, arg3
+ add $8, arg2
+_less_than_8_left:
+
+ cmp $4, arg3
+ jl _less_than_4_left
+
+ # load 4 Bytes
+ mov (arg2), %eax
+ mov %eax, (%r11)
+ add $4, %r11
+ sub $4, arg3
+ add $4, arg2
+_less_than_4_left:
+
+ cmp $2, arg3
+ jl _less_than_2_left
+
+ # load 2 Bytes
+ mov (arg2), %ax
+ mov %ax, (%r11)
+ add $2, %r11
+ sub $2, arg3
+ add $2, arg2
+_less_than_2_left:
+ cmp $1, arg3
+ jl _zero_left
+
+ # load 1 Byte
+ mov (arg2), %al
+ mov %al, (%r11)
+_zero_left:
+ movdqa (%rsp), %xmm7
+ pshufb %xmm11, %xmm7
+ pxor %xmm0 , %xmm7 # xor the initial crc value
+
+ # shl r9, 4
+ lea pshufb_shf_table+16(%rip), %rax
+ sub %r9, %rax
+ movdqu (%rax), %xmm0
+ pxor mask1(%rip), %xmm0
+
+ pshufb %xmm0, %xmm7
+ jmp _128_done
+
+.align 16
+_exact_16_left:
+ movdqu (arg2), %xmm7
+ pshufb %xmm11, %xmm7
+ pxor %xmm0 , %xmm7 # xor the initial crc value
+
+ jmp _128_done
+
+_only_less_than_4:
+ cmp $3, arg3
+ jl _only_less_than_3
+
+ # load 3 Bytes
+ mov (arg2), %al
+ mov %al, (%r11)
+
+ mov 1(arg2), %al
+ mov %al, 1(%r11)
+
+ mov 2(arg2), %al
+ mov %al, 2(%r11)
+
+ movdqa (%rsp), %xmm7
+ pshufb %xmm11, %xmm7
+ pxor %xmm0 , %xmm7 # xor the initial crc value
+
+ psrldq $5, %xmm7
+
+ jmp _barrett
+_only_less_than_3:
+ cmp $2, arg3
+ jl _only_less_than_2
+
+ # load 2 Bytes
+ mov (arg2), %al
+ mov %al, (%r11)
+
+ mov 1(arg2), %al
+ mov %al, 1(%r11)
+
+ movdqa (%rsp), %xmm7
+ pshufb %xmm11, %xmm7
+ pxor %xmm0 , %xmm7 # xor the initial crc value
+
+ psrldq $6, %xmm7
+
+ jmp _barrett
+_only_less_than_2:
+
+ # load 1 Byte
+ mov (arg2), %al
+ mov %al, (%r11)
+
+ movdqa (%rsp), %xmm7
+ pshufb %xmm11, %xmm7
+ pxor %xmm0 , %xmm7 # xor the initial crc value
+
+ psrldq $7, %xmm7
+
+ jmp _barrett
+
+.data
+
+# precomputed constants
+# these constants are precomputed from the poly:
+# 0x8bb70000 (0x8bb7 scaled to 32 bits)
+.align 16
+# Q = 0x18BB70000
+# rk1 = 2^(32*3) mod Q << 32
+# rk2 = 2^(32*5) mod Q << 32
+# rk3 = 2^(32*15) mod Q << 32
+# rk4 = 2^(32*17) mod Q << 32
+# rk5 = 2^(32*3) mod Q << 32
+# rk6 = 2^(32*2) mod Q << 32
+# rk7 = floor(2^64/Q)
+# rk8 = Q
+rk1:
+.quad 0x2d56000000000000
+rk2:
+.quad 0x06df000000000000
+rk3:
+.quad 0x9d9d000000000000
+rk4:
+.quad 0x7cf5000000000000
+rk5:
+.quad 0x2d56000000000000
+rk6:
+.quad 0x1368000000000000
+rk7:
+.quad 0x00000001f65a57f8
+rk8:
+.quad 0x000000018bb70000
+
+rk9:
+.quad 0xceae000000000000
+rk10:
+.quad 0xbfd6000000000000
+rk11:
+.quad 0x1e16000000000000
+rk12:
+.quad 0x713c000000000000
+rk13:
+.quad 0xf7f9000000000000
+rk14:
+.quad 0x80a6000000000000
+rk15:
+.quad 0x044c000000000000
+rk16:
+.quad 0xe658000000000000
+rk17:
+.quad 0xad18000000000000
+rk18:
+.quad 0xa497000000000000
+rk19:
+.quad 0x6ee3000000000000
+rk20:
+.quad 0xe7b5000000000000
+
+
+
+mask1:
+.octa 0x80808080808080808080808080808080
+mask2:
+.octa 0x00000000FFFFFFFFFFFFFFFFFFFFFFFF
+
+SHUF_MASK:
+.octa 0x000102030405060708090A0B0C0D0E0F
+
+pshufb_shf_table:
+# use these values for shift constants for the pshufb instruction
+# different alignments result in values as shown:
+# DDQ 0x008f8e8d8c8b8a898887868584838281 # shl 15 (16-1) / shr1
+# DDQ 0x01008f8e8d8c8b8a8988878685848382 # shl 14 (16-3) / shr2
+# DDQ 0x0201008f8e8d8c8b8a89888786858483 # shl 13 (16-4) / shr3
+# DDQ 0x030201008f8e8d8c8b8a898887868584 # shl 12 (16-4) / shr4
+# DDQ 0x04030201008f8e8d8c8b8a8988878685 # shl 11 (16-5) / shr5
+# DDQ 0x0504030201008f8e8d8c8b8a89888786 # shl 10 (16-6) / shr6
+# DDQ 0x060504030201008f8e8d8c8b8a898887 # shl 9 (16-7) / shr7
+# DDQ 0x07060504030201008f8e8d8c8b8a8988 # shl 8 (16-8) / shr8
+# DDQ 0x0807060504030201008f8e8d8c8b8a89 # shl 7 (16-9) / shr9
+# DDQ 0x090807060504030201008f8e8d8c8b8a # shl 6 (16-10) / shr10
+# DDQ 0x0a090807060504030201008f8e8d8c8b # shl 5 (16-11) / shr11
+# DDQ 0x0b0a090807060504030201008f8e8d8c # shl 4 (16-12) / shr12
+# DDQ 0x0c0b0a090807060504030201008f8e8d # shl 3 (16-13) / shr13
+# DDQ 0x0d0c0b0a090807060504030201008f8e # shl 2 (16-14) / shr14
+# DDQ 0x0e0d0c0b0a090807060504030201008f # shl 1 (16-15) / shr15
+.octa 0x8f8e8d8c8b8a89888786858483828100
+.octa 0x000e0d0c0b0a09080706050403020100
--
1.7.11.7
On 16.04.2013 19:20, Tim Chen wrote:
> This is the x86_64 CRC T10 DIF transform accelerated with the PCLMULQDQ
> instructions. Details discussing the implementation can be found in the
> paper:
>
> "Fast CRC Computation for Generic Polynomials Using PCLMULQDQ Instruction"
> URL: http://download.intel.com/design/intarch/papers/323102.pdf
URL does not work.
>
> Signed-off-by: Tim Chen <[email protected]>
> Tested-by: Keith Busch <[email protected]>
> ---
> arch/x86/crypto/crct10dif-pcl-asm_64.S | 659 +++++++++++++++++++++++++++++++++
> 1 file changed, 659 insertions(+)
> create mode 100644 arch/x86/crypto/crct10dif-pcl-asm_64.S
<snip>
> +
> + # Allocate Stack Space
> + mov %rsp, %rcx
> + sub $16*10, %rsp
> + and $~(0x20 - 1), %rsp
> +
> + # push the xmm registers into the stack to maintain
> + movdqa %xmm10, 16*2(%rsp)
> + movdqa %xmm11, 16*3(%rsp)
> + movdqa %xmm8 , 16*4(%rsp)
> + movdqa %xmm12, 16*5(%rsp)
> + movdqa %xmm13, 16*6(%rsp)
> + movdqa %xmm6, 16*7(%rsp)
> + movdqa %xmm7, 16*8(%rsp)
> + movdqa %xmm9, 16*9(%rsp)
You don't need to store (and restore) these, as 'crc_t10dif_pcl' is called between kernel_fpu_begin/_end.
> +
> +
> + # check if smaller than 256
> + cmp $256, arg3
> +
<snip>
> +_cleanup:
> + # scale the result back to 16 bits
> + shr $16, %eax
> + movdqa 16*2(%rsp), %xmm10
> + movdqa 16*3(%rsp), %xmm11
> + movdqa 16*4(%rsp), %xmm8
> + movdqa 16*5(%rsp), %xmm12
> + movdqa 16*6(%rsp), %xmm13
> + movdqa 16*7(%rsp), %xmm6
> + movdqa 16*8(%rsp), %xmm7
> + movdqa 16*9(%rsp), %xmm9
Registers are overwritten by kernel_fpu_end.
> + mov %rcx, %rsp
> + ret
> +ENDPROC(crc_t10dif_pcl)
> +
You should move ENDPROC at end of the full function.
> +########################################################################
> +
> +.align 16
> +_less_than_128:
> +
> + # check if there is enough buffer to be able to fold 16B at a time
> + cmp $32, arg3
<snip>
> + movdqa (%rsp), %xmm7
> + pshufb %xmm11, %xmm7
> + pxor %xmm0 , %xmm7 # xor the initial crc value
> +
> + psrldq $7, %xmm7
> +
> + jmp _barrett
Move ENDPROC here.
-Jussi
On 16.04.2013 19:20, Tim Chen wrote:
> These are simple tests to do sanity check of CRC T10 DIF hash. The
> correctness of the transform can be checked with the command
> modprobe tcrypt mode=47
> The speed of the transform can be evaluated with the command
> modprobe tcrypt mode=320
>
> Set the cpu frequency to constant and turn turbo off when running the
> speed test so the frequency governor will not tweak the frequency and
> affects the measurements.
>
> Signed-off-by: Tim Chen <[email protected]>
> Tested-by: Keith Busch <[email protected]>
<snip>
>
> +#define CRCT10DIF_TEST_VECTORS 2
> +static struct hash_testvec crct10dif_tv_template[] = {
> + {
> + .plaintext = "abc",
> + .psize = 3,
> +#ifdef __LITTLE_ENDIAN
> + .digest = "\x3b\x44",
> +#else
> + .digest = "\x44\x3b",
> +#endif
> + }, {
> + .plaintext =
> + "abcddddddddddddddddddddddddddddddddddddddddddddddddddddd",
> + .psize = 56,
> +#ifdef __LITTLE_ENDIAN
> + .digest = "\xe3\x9c",
> +#else
> + .digest = "\x9c\xe3",
> +#endif
> + .np = 2,
> + .tap = { 28, 28 }
> + }
> +};
> +
Are these large enough to test all code paths in the PCLMULQDQ implementation?
-Jussi
On Wed, 2013-04-17 at 20:58 +0300, Jussi Kivilinna wrote:
> On 16.04.2013 19:20, Tim Chen wrote:
> > These are simple tests to do sanity check of CRC T10 DIF hash. The
> > correctness of the transform can be checked with the command
> > modprobe tcrypt mode=47
> > The speed of the transform can be evaluated with the command
> > modprobe tcrypt mode=320
> >
> > Set the cpu frequency to constant and turn turbo off when running the
> > speed test so the frequency governor will not tweak the frequency and
> > affects the measurements.
> >
> > Signed-off-by: Tim Chen <[email protected]>
> > Tested-by: Keith Busch <[email protected]>
> <snip>
> >
> > +#define CRCT10DIF_TEST_VECTORS 2
> > +static struct hash_testvec crct10dif_tv_template[] = {
> > + {
> > + .plaintext = "abc",
> > + .psize = 3,
> > +#ifdef __LITTLE_ENDIAN
> > + .digest = "\x3b\x44",
> > +#else
> > + .digest = "\x44\x3b",
> > +#endif
> > + }, {
> > + .plaintext =
> > + "abcddddddddddddddddddddddddddddddddddddddddddddddddddddd",
> > + .psize = 56,
> > +#ifdef __LITTLE_ENDIAN
> > + .digest = "\xe3\x9c",
> > +#else
> > + .digest = "\x9c\xe3",
> > +#endif
> > + .np = 2,
> > + .tap = { 28, 28 }
> > + }
> > +};
> > +
>
> Are these large enough to test all code paths in the PCLMULQDQ implementation?
We have tested the implementation exhaustively for large number of code paths.
The tcrypt tests here are only meant for sanity check, and not for
exhaustive tests.
Tim
On Wed, 2013-04-17 at 20:58 +0300, Jussi Kivilinna wrote:
> On 16.04.2013 19:20, Tim Chen wrote:
> > This is the x86_64 CRC T10 DIF transform accelerated with the PCLMULQDQ
> > instructions. Details discussing the implementation can be found in the
> > paper:
> >
> > "Fast CRC Computation for Generic Polynomials Using PCLMULQDQ Instruction"
> > URL: http://download.intel.com/design/intarch/papers/323102.pdf
>
> URL does not work.
Thanks for catching this. Will update.
>
> >
> > Signed-off-by: Tim Chen <[email protected]>
> > Tested-by: Keith Busch <[email protected]>
> > ---
> > arch/x86/crypto/crct10dif-pcl-asm_64.S | 659 +++++++++++++++++++++++++++++++++
> > 1 file changed, 659 insertions(+)
> > create mode 100644 arch/x86/crypto/crct10dif-pcl-asm_64.S
> <snip>
> > +
> > + # Allocate Stack Space
> > + mov %rsp, %rcx
> > + sub $16*10, %rsp
> > + and $~(0x20 - 1), %rsp
> > +
> > + # push the xmm registers into the stack to maintain
> > + movdqa %xmm10, 16*2(%rsp)
> > + movdqa %xmm11, 16*3(%rsp)
> > + movdqa %xmm8 , 16*4(%rsp)
> > + movdqa %xmm12, 16*5(%rsp)
> > + movdqa %xmm13, 16*6(%rsp)
> > + movdqa %xmm6, 16*7(%rsp)
> > + movdqa %xmm7, 16*8(%rsp)
> > + movdqa %xmm9, 16*9(%rsp)
>
> You don't need to store (and restore) these, as 'crc_t10dif_pcl' is called between kernel_fpu_begin/_end.
That's true. Will skip the xmm save/restore in update to the patch.
>
> > +
> > +
> > + # check if smaller than 256
> > + cmp $256, arg3
> > +
> <snip>
> > +_cleanup:
> > + # scale the result back to 16 bits
> > + shr $16, %eax
> > + movdqa 16*2(%rsp), %xmm10
> > + movdqa 16*3(%rsp), %xmm11
> > + movdqa 16*4(%rsp), %xmm8
> > + movdqa 16*5(%rsp), %xmm12
> > + movdqa 16*6(%rsp), %xmm13
> > + movdqa 16*7(%rsp), %xmm6
> > + movdqa 16*8(%rsp), %xmm7
> > + movdqa 16*9(%rsp), %xmm9
>
> Registers are overwritten by kernel_fpu_end.
>
> > + mov %rcx, %rsp
> > + ret
> > +ENDPROC(crc_t10dif_pcl)
> > +
>
> You should move ENDPROC at end of the full function.
>
> > +########################################################################
> > +
> > +.align 16
> > +_less_than_128:
> > +
> > + # check if there is enough buffer to be able to fold 16B at a time
> > + cmp $32, arg3
> <snip>
> > + movdqa (%rsp), %xmm7
> > + pshufb %xmm11, %xmm7
> > + pxor %xmm0 , %xmm7 # xor the initial crc value
> > +
> > + psrldq $7, %xmm7
> > +
> > + jmp _barrett
>
> Move ENDPROC here.
>
Will do.
Tim