2009-09-15 05:42:45

by [email protected]

[permalink] [raw]
Subject: [PATCH -v3] crypto: Add PCLMULQDQ accelerated GHASH implementation

Hi, Herbert,

The dependency to irq_fpu_usable has been merged by linus' tree.

Best Regards,
Huang Ying
-------------------------------------------------------------------------->
PCLMULQDQ is used to accelerate the most time-consuming part of GHASH,
carry-less multiplication. More information about PCLMULQDQ can be
found at:

http://software.intel.com/en-us/articles/carry-less-multiplication-and-its-usage-for-computing-the-gcm-mode/

Because PCLMULQDQ changes XMM state, its usage must be enclosed with
kernel_fpu_begin/end, which can be used only in process context, the
acceleration is implemented as crypto_ahash. That is, request in soft
IRQ context will be defered to the cryptd kernel thread.

v3:
- Revise GHASH implementation, performance increase about 2x.

Signed-off-by: Huang Ying <[email protected]>
---
arch/x86/crypto/Makefile | 3
arch/x86/crypto/ghash-clmulni-intel_asm.S | 157 +++++++++++++
arch/x86/crypto/ghash-clmulni-intel_glue.c | 331 +++++++++++++++++++++++++++++
arch/x86/include/asm/cpufeature.h | 1
crypto/Kconfig | 8
crypto/cryptd.c | 7
include/crypto/cryptd.h | 1
7 files changed, 508 insertions(+)
create mode 100644 arch/x86/crypto/ghash-clmulni-intel_asm.S
create mode 100644 arch/x86/crypto/ghash-clmulni-intel_glue.c

--- a/arch/x86/crypto/Makefile
+++ b/arch/x86/crypto/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_CRYPTO_AES_X86_64) += aes-x
obj-$(CONFIG_CRYPTO_TWOFISH_X86_64) += twofish-x86_64.o
obj-$(CONFIG_CRYPTO_SALSA20_X86_64) += salsa20-x86_64.o
obj-$(CONFIG_CRYPTO_AES_NI_INTEL) += aesni-intel.o
+obj-$(CONFIG_CRYPTO_GHASH_CLMUL_NI_INTEL) += ghash-clmulni-intel.o

obj-$(CONFIG_CRYPTO_CRC32C_INTEL) += crc32c-intel.o

@@ -24,3 +25,5 @@ twofish-x86_64-y := twofish-x86_64-asm_6
salsa20-x86_64-y := salsa20-x86_64-asm_64.o salsa20_glue.o

aesni-intel-y := aesni-intel_asm.o aesni-intel_glue.o
+
+ghash-clmulni-intel-y := ghash-clmulni-intel_asm.o ghash-clmulni-intel_glue.o
--- /dev/null
+++ b/arch/x86/crypto/ghash-clmulni-intel_asm.S
@@ -0,0 +1,157 @@
+/*
+ * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
+ * instructions. This file contains accelerated part of ghash
+ * implementation. More information about PCLMULQDQ can be found at:
+ *
+ * http://software.intel.com/en-us/articles/carry-less-multiplication-and-its-usage-for-computing-the-gcm-mode/
+ *
+ * Copyright (c) 2009 Intel Corp.
+ * Author: Huang Ying <[email protected]>
+ * Vinodh Gopal
+ * Erdinc Ozturk
+ * Deniz Karakoyunlu
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+
+.align 16
+.Lbswap_mask:
+ .octa 0x000102030405060708090a0b0c0d0e0f
+.Lpoly:
+ .octa 0xc2000000000000000000000000000001
+.Ltwo_one:
+ .octa 0x00000001000000000000000000000001
+
+#define DATA %xmm0
+#define SHASH %xmm1
+#define T1 %xmm2
+#define T2 %xmm3
+#define T3 %xmm4
+#define BSWAP %xmm5
+#define IN1 %xmm6
+
+.text
+
+/*
+ * __clmul_gf128mul_ble: internal ABI
+ * input:
+ * DATA: operand1
+ * SHASH: operand2, hash_key << 1 mod poly
+ * output:
+ * DATA: operand1 * operand2 mod poly
+ * changed:
+ * T1
+ * T2
+ * T3
+ */
+__clmul_gf128mul_ble:
+ movaps DATA, T1
+ pshufd $0b01001110, DATA, T2
+ pshufd $0b01001110, SHASH, T3
+ pxor DATA, T2
+ pxor SHASH, T3
+
+ # pclmulqdq $0x00, SHASH, DATA # DATA = a0 * b0
+ .byte 0x66, 0x0f, 0x3a, 0x44, 0xc1, 0x00
+ # pclmulqdq $0x11, SHASH, T1 # T1 = a1 * b1
+ .byte 0x66, 0x0f, 0x3a, 0x44, 0xd1, 0x11
+ # pclmulqdq $0x00, T3, T2 # T2 = (a1 + a0) * (b1 + b0)
+ .byte 0x66, 0x0f, 0x3a, 0x44, 0xdc, 0x00
+ pxor DATA, T2
+ pxor T1, T2 # T2 = a0 * b1 + a1 * b0
+
+ movaps T2, T3
+ pslldq $8, T3
+ psrldq $8, T2
+ pxor T3, DATA
+ pxor T2, T1 # <T1:DATA> is result of
+ # carry-less multiplication
+
+ # first phase of the reduction
+ movaps DATA, T3
+ psllq $1, T3
+ pxor DATA, T3
+ psllq $5, T3
+ pxor DATA, T3
+ psllq $57, T3
+ movaps T3, T2
+ pslldq $8, T2
+ psrldq $8, T3
+ pxor T2, DATA
+ pxor T3, T1
+
+ # second phase of the reduction
+ movaps DATA, T2
+ psrlq $5, T2
+ pxor DATA, T2
+ psrlq $1, T2
+ pxor DATA, T2
+ psrlq $1, T2
+ pxor T2, T1
+ pxor T1, DATA
+ ret
+
+/* void clmul_ghash_mul(char *dst, const be128 *shash) */
+ENTRY(clmul_ghash_mul)
+ movups (%rdi), DATA
+ movups (%rsi), SHASH
+ movaps .Lbswap_mask, BSWAP
+ pshufb BSWAP, DATA
+ call __clmul_gf128mul_ble
+ pshufb BSWAP, DATA
+ movups DATA, (%rdi)
+ ret
+
+/*
+ * void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
+ * const be128 *shash);
+ */
+ENTRY(clmul_ghash_update)
+ cmp $16, %rdx
+ jb .Lupdate_just_ret # check length
+ movaps .Lbswap_mask, BSWAP
+ movups (%rdi), DATA
+ movups (%rcx), SHASH
+ pshufb BSWAP, DATA
+.align 4
+.Lupdate_loop:
+ movups (%rsi), IN1
+ pshufb BSWAP, IN1
+ pxor IN1, DATA
+ call __clmul_gf128mul_ble
+ sub $16, %rdx
+ add $16, %rsi
+ cmp $16, %rdx
+ jge .Lupdate_loop
+ pshufb BSWAP, DATA
+ movups DATA, (%rdi)
+.Lupdate_just_ret:
+ ret
+
+/*
+ * void clmul_ghash_setkey(be128 *shash, const u8 *key);
+ *
+ * Calculate hash_key << 1 mod poly
+ */
+ENTRY(clmul_ghash_setkey)
+ movaps .Lbswap_mask, BSWAP
+ movups (%rsi), %xmm0
+ pshufb BSWAP, %xmm0
+ movaps %xmm0, %xmm1
+ psllq $1, %xmm0
+ psrlq $63, %xmm1
+ movaps %xmm1, %xmm2
+ pslldq $8, %xmm1
+ psrldq $8, %xmm2
+ por %xmm1, %xmm0
+ # reduction
+ pshufd $0b00100100, %xmm2, %xmm1
+ pcmpeqd .Ltwo_one, %xmm1
+ pand .Lpoly, %xmm1
+ pxor %xmm1, %xmm0
+ movups %xmm0, (%rdi)
+ ret
--- /dev/null
+++ b/arch/x86/crypto/ghash-clmulni-intel_glue.c
@@ -0,0 +1,331 @@
+/*
+ * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
+ * instructions. This file contains glue code.
+ *
+ * Copyright (c) 2009 Intel Corp.
+ * Author: Huang Ying <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/crypto.h>
+#include <crypto/algapi.h>
+#include <crypto/cryptd.h>
+#include <crypto/gf128mul.h>
+#include <crypto/internal/hash.h>
+#include <asm/i387.h>
+
+#define GHASH_BLOCK_SIZE 16
+#define GHASH_DIGEST_SIZE 16
+
+void clmul_ghash_mul(char *dst, const be128 *shash);
+
+void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
+ const be128 *shash);
+
+void clmul_ghash_setkey(be128 *shash, const u8 *key);
+
+struct ghash_async_ctx
+{
+ struct cryptd_ahash *cryptd_tfm;
+};
+
+struct ghash_ctx {
+ be128 shash;
+};
+
+struct ghash_desc_ctx {
+ u8 buffer[GHASH_BLOCK_SIZE];
+ u32 bytes;
+};
+
+static int ghash_init(struct shash_desc *desc)
+{
+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+
+ memset(dctx, 0, sizeof(*dctx));
+
+ return 0;
+}
+
+static int ghash_setkey(struct crypto_shash *tfm,
+ const u8 *key, unsigned int keylen)
+{
+ struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
+
+ if (keylen != GHASH_BLOCK_SIZE) {
+ crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+ return -EINVAL;
+ }
+
+ clmul_ghash_setkey(&ctx->shash, key);
+
+ return 0;
+}
+
+static int ghash_update(struct shash_desc *desc,
+ const u8 *src, unsigned int srclen)
+{
+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+ struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
+ u8 *dst = dctx->buffer;
+
+ kernel_fpu_begin();
+ if (dctx->bytes) {
+ int n = min(srclen, dctx->bytes);
+ u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
+
+ dctx->bytes -= n;
+ srclen -= n;
+
+ while (n--)
+ *pos++ ^= *src++;
+
+ if (!dctx->bytes)
+ clmul_ghash_mul(dst, &ctx->shash);
+ }
+
+ clmul_ghash_update(dst, src, srclen, &ctx->shash);
+ kernel_fpu_end();
+
+ if (srclen & 0xf) {
+ src += srclen - (srclen & 0xf);
+ srclen &= 0xf;
+ dctx->bytes = GHASH_BLOCK_SIZE - srclen;
+ while (srclen--)
+ *dst++ ^= *src++;
+ }
+
+ return 0;
+}
+
+static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
+{
+ u8 *dst = dctx->buffer;
+
+ if (dctx->bytes) {
+ u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
+
+ while (dctx->bytes--)
+ *tmp++ ^= 0;
+
+ kernel_fpu_begin();
+ clmul_ghash_mul(dst, &ctx->shash);
+ kernel_fpu_end();
+ }
+
+ dctx->bytes = 0;
+}
+
+static int ghash_final(struct shash_desc *desc, u8 *dst)
+{
+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+ struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
+ u8 *buf = dctx->buffer;
+
+ ghash_flush(ctx, dctx);
+ memcpy(dst, buf, GHASH_BLOCK_SIZE);
+
+ return 0;
+}
+
+static struct shash_alg ghash_alg = {
+ .digestsize = GHASH_DIGEST_SIZE,
+ .init = ghash_init,
+ .update = ghash_update,
+ .final = ghash_final,
+ .setkey = ghash_setkey,
+ .descsize = sizeof(struct ghash_desc_ctx),
+ .base = {
+ .cra_name = "__ghash",
+ .cra_driver_name = "__ghash-pclmulqdqni",
+ .cra_priority = 0,
+ .cra_flags = CRYPTO_ALG_TYPE_SHASH,
+ .cra_blocksize = GHASH_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct ghash_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(ghash_alg.base.cra_list),
+ },
+};
+
+static int ghash_async_init(struct ahash_request *req)
+{
+ struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+ struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
+ struct ahash_request *cryptd_req = ahash_request_ctx(req);
+ struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
+
+ if (irq_fpu_usable()) {
+ memcpy(cryptd_req, req, sizeof(*req));
+ ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
+ return crypto_ahash_init(cryptd_req);
+ } else {
+ struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
+ struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
+
+ desc->tfm = child;
+ desc->flags = req->base.flags;
+ return crypto_shash_init(desc);
+ }
+}
+
+static int ghash_async_update(struct ahash_request *req)
+{
+ struct ahash_request *cryptd_req = ahash_request_ctx(req);
+
+ if (irq_fpu_usable()) {
+ struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+ struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
+ struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
+
+ memcpy(cryptd_req, req, sizeof(*req));
+ ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
+ return crypto_ahash_update(cryptd_req);
+ } else {
+ struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
+ return shash_ahash_update(req, desc);
+ }
+}
+
+static int ghash_async_final(struct ahash_request *req)
+{
+ struct ahash_request *cryptd_req = ahash_request_ctx(req);
+
+ if (irq_fpu_usable()) {
+ struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+ struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
+ struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
+
+ memcpy(cryptd_req, req, sizeof(*req));
+ ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
+ return crypto_ahash_final(cryptd_req);
+ } else {
+ struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
+ return crypto_shash_final(desc, req->result);
+ }
+}
+
+static int ghash_async_digest(struct ahash_request *req)
+{
+ struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+ struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
+ struct ahash_request *cryptd_req = ahash_request_ctx(req);
+ struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
+
+ if (irq_fpu_usable()) {
+ memcpy(cryptd_req, req, sizeof(*req));
+ ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
+ return crypto_ahash_digest(cryptd_req);
+ } else {
+ struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
+ struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
+
+ desc->tfm = child;
+ desc->flags = req->base.flags;
+ return shash_ahash_digest(req, desc);
+ }
+}
+
+static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
+ unsigned int keylen)
+{
+ struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
+ struct crypto_ahash *child = &ctx->cryptd_tfm->base;
+ int err;
+
+ crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+ crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
+ & CRYPTO_TFM_REQ_MASK);
+ err = crypto_ahash_setkey(child, key, keylen);
+ crypto_ahash_set_flags(tfm, crypto_ahash_get_flags(child)
+ & CRYPTO_TFM_RES_MASK);
+
+ return 0;
+}
+
+static int ghash_async_init_tfm(struct crypto_tfm *tfm)
+{
+ struct cryptd_ahash *cryptd_tfm;
+ struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ cryptd_tfm = cryptd_alloc_ahash("__ghash-pclmulqdqni", 0, 0);
+ if (IS_ERR(cryptd_tfm))
+ return PTR_ERR(cryptd_tfm);
+ ctx->cryptd_tfm = cryptd_tfm;
+ crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
+ sizeof(struct ahash_request) +
+ crypto_ahash_reqsize(&cryptd_tfm->base));
+
+ return 0;
+}
+
+static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
+{
+ struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ cryptd_free_ahash(ctx->cryptd_tfm);
+}
+
+static struct ahash_alg ghash_async_alg = {
+ .init = ghash_async_init,
+ .update = ghash_async_update,
+ .final = ghash_async_final,
+ .setkey = ghash_async_setkey,
+ .digest = ghash_async_digest,
+ .halg = {
+ .digestsize = GHASH_DIGEST_SIZE,
+ .base = {
+ .cra_name = "ghash",
+ .cra_driver_name = "ghash-clmulni",
+ .cra_priority = 400,
+ .cra_flags = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC,
+ .cra_blocksize = GHASH_BLOCK_SIZE,
+ .cra_type = &crypto_ahash_type,
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(ghash_async_alg.halg.base.cra_list),
+ .cra_init = ghash_async_init_tfm,
+ .cra_exit = ghash_async_exit_tfm,
+ },
+ },
+};
+
+static int __init ghash_pclmulqdqni_mod_init(void)
+{
+ int err;
+
+ if (!cpu_has_pclmulqdq) {
+ printk(KERN_INFO "Intel PCLMULQDQ-NI instructions are not"
+ " detected.\n");
+ return -ENODEV;
+ }
+
+ if ((err = crypto_register_shash(&ghash_alg)))
+ goto err_out;
+ if ((err = crypto_register_ahash(&ghash_async_alg)))
+ goto err_shash;
+
+ return 0;
+
+err_shash:
+ crypto_unregister_shash(&ghash_alg);
+err_out:
+ return err;
+}
+
+static void __exit ghash_pclmulqdqni_mod_exit(void)
+{
+ crypto_unregister_ahash(&ghash_async_alg);
+ crypto_unregister_shash(&ghash_alg);
+}
+
+module_init(ghash_pclmulqdqni_mod_init);
+module_exit(ghash_pclmulqdqni_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("GHASH Message Digest Algorithm, acclerated by PCLMULQDQ-NI");
+MODULE_ALIAS("ghash");
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -247,6 +247,7 @@ extern const char * const x86_power_flag
#define cpu_has_x2apic boot_cpu_has(X86_FEATURE_X2APIC)
#define cpu_has_xsave boot_cpu_has(X86_FEATURE_XSAVE)
#define cpu_has_hypervisor boot_cpu_has(X86_FEATURE_HYPERVISOR)
+#define cpu_has_pclmulqdq boot_cpu_has(X86_FEATURE_PCLMULQDQ)

#if defined(CONFIG_X86_INVLPG) || defined(CONFIG_X86_64)
# define cpu_has_invlpg 1
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -440,6 +440,14 @@ config CRYPTO_WP512
See also:
<http://planeta.terra.com.br/informatica/paulobarreto/WhirlpoolPage.html>

+config CRYPTO_GHASH_CLMUL_NI_INTEL
+ tristate "GHASH digest algorithm (CLMUL-NI accelerated)"
+ select CRYPTO_SHASH
+ select CRYPTO_CRYPTD
+ help
+ GHASH is message digest algorithm for GCM (Galois/Counter Mode).
+ The implementation is accelerated by CLMUL-NI of Intel.
+
comment "Ciphers"

config CRYPTO_AES
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -711,6 +711,13 @@ struct crypto_shash *cryptd_ahash_child(
}
EXPORT_SYMBOL_GPL(cryptd_ahash_child);

+struct shash_desc *cryptd_shash_desc(struct ahash_request *req)
+{
+ struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
+ return &rctx->desc;
+}
+EXPORT_SYMBOL_GPL(cryptd_shash_desc);
+
void cryptd_free_ahash(struct cryptd_ahash *tfm)
{
crypto_free_ahash(&tfm->base);
--- a/include/crypto/cryptd.h
+++ b/include/crypto/cryptd.h
@@ -39,6 +39,7 @@ static inline struct cryptd_ahash *__cry
struct cryptd_ahash *cryptd_alloc_ahash(const char *alg_name,
u32 type, u32 mask);
struct crypto_shash *cryptd_ahash_child(struct cryptd_ahash *tfm);
+struct shash_desc *cryptd_shash_desc(struct ahash_request *req);
void cryptd_free_ahash(struct cryptd_ahash *tfm);

#endif




2009-09-15 14:41:18

by Daniel Walker

[permalink] [raw]
Subject: Re: [PATCH -v3] crypto: Add PCLMULQDQ accelerated GHASH implementation

On Tue, 2009-09-15 at 13:42 +0800, Huang Ying wrote:
> Hi, Herbert,
>
> The dependency to irq_fpu_usable has been merged by linus' tree.
>
> Best Regards,
> Huang Ying
> -------------------------------------------------------------------------->
> PCLMULQDQ is used to accelerate the most time-consuming part of GHASH,
> carry-less multiplication. More information about PCLMULQDQ can be
> found at:
>
> http://software.intel.com/en-us/articles/carry-less-multiplication-and-its-usage-for-computing-the-gcm-mode/
>
> Because PCLMULQDQ changes XMM state, its usage must be enclosed with
> kernel_fpu_begin/end, which can be used only in process context, the
> acceleration is implemented as crypto_ahash. That is, request in soft
> IRQ context will be defered to the cryptd kernel thread.
>
> v3:
> - Revise GHASH implementation, performance increase about 2x.


You have three style issues in this patch, for instance you shouldn't
set values inside if() statements .. If you run checkpatch on this it
will tell you all the style problems. Could you run this through
checkpatch and fix any errors it's find ?

Daniel


2009-09-16 01:20:30

by [email protected]

[permalink] [raw]
Subject: Re: [PATCH -v3] crypto: Add PCLMULQDQ accelerated GHASH implementation

On Tue, 2009-09-15 at 22:42 +0800, Daniel Walker wrote:
> On Tue, 2009-09-15 at 13:42 +0800, Huang Ying wrote:
> > Hi, Herbert,
> >
> > The dependency to irq_fpu_usable has been merged by linus' tree.
> >
> > Best Regards,
> > Huang Ying
> > -------------------------------------------------------------------------->
> > PCLMULQDQ is used to accelerate the most time-consuming part of GHASH,
> > carry-less multiplication. More information about PCLMULQDQ can be
> > found at:
> >
> > http://software.intel.com/en-us/articles/carry-less-multiplication-and-its-usage-for-computing-the-gcm-mode/
> >
> > Because PCLMULQDQ changes XMM state, its usage must be enclosed with
> > kernel_fpu_begin/end, which can be used only in process context, the
> > acceleration is implemented as crypto_ahash. That is, request in soft
> > IRQ context will be defered to the cryptd kernel thread.
> >
> > v3:
> > - Revise GHASH implementation, performance increase about 2x.
>
>
> You have three style issues in this patch, for instance you shouldn't
> set values inside if() statements .. If you run checkpatch on this it
> will tell you all the style problems. Could you run this through
> checkpatch and fix any errors it's find ?

Thanks, I will fix them.

Best Regards,
Huang Ying