cyprot: powerpc/aes - glue code

Integrate the assembler modules into the kernel crypto
framework. Take care to avoid long intervals of disabled
preemption.
Signed-off-by: Markus Stockhausen <stockhausen@collogia.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/powerpc/crypto/aes_spe_glue.c

+/*
+ * Glue code for AES implementation for SPE instructions (PPC)
+ *
+ * Based on generic implementation. The assembler module takes care
+ * about the SPE registers so it can run from interrupt context.
+ *
+ * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
+ *
+ * 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 <crypto/aes.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/crypto.h>
+#include <asm/byteorder.h>
+#include <asm/switch_to.h>
+#include <crypto/algapi.h>
+
+/*
+ * MAX_BYTES defines the number of bytes that are allowed to be processed
+ * between preempt_disable() and preempt_enable(). e500 cores can issue two
+ * instructions per clock cycle using one 32/64 bit unit (SU1) and one 32
+ * bit unit (SU2). One of these can be a memory access that is executed via
+ * a single load and store unit (LSU). XTS-AES-256 takes ~780 operations per
+ * 16 byte block block or 25 cycles per byte. Thus 768 bytes of input data
+ * will need an estimated maximum of 20,000 cycles. Headroom for cache misses
+ * included. Even with the low end model clocked at 667 MHz this equals to a
+ * critical time window of less than 30us. The value has been choosen to
+ * process a 512 byte disk block in one or a large 1400 bytes IPsec network
+ * packet in two runs.
+ *
+ */
+#define MAX_BYTES 768
+
+struct ppc_aes_ctx {
+	u32 key_enc[AES_MAX_KEYLENGTH_U32];
+	u32 key_dec[AES_MAX_KEYLENGTH_U32];
+	u32 rounds;
+};
+
+struct ppc_xts_ctx {
+	u32 key_enc[AES_MAX_KEYLENGTH_U32];
+	u32 key_dec[AES_MAX_KEYLENGTH_U32];
+	u32 key_twk[AES_MAX_KEYLENGTH_U32];
+	u32 rounds;
+};
+
+extern void ppc_encrypt_aes(u8 *out, const u8 *in, u32 *key_enc, u32 rounds);
+extern void ppc_decrypt_aes(u8 *out, const u8 *in, u32 *key_dec, u32 rounds);
+extern void ppc_encrypt_ecb(u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
+			    u32 bytes);
+extern void ppc_decrypt_ecb(u8 *out, const u8 *in, u32 *key_dec, u32 rounds,
+			    u32 bytes);
+extern void ppc_encrypt_cbc(u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
+			    u32 bytes, u8 *iv);
+extern void ppc_decrypt_cbc(u8 *out, const u8 *in, u32 *key_dec, u32 rounds,
+			    u32 bytes, u8 *iv);
+extern void ppc_crypt_ctr  (u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
+			    u32 bytes, u8 *iv);
+extern void ppc_encrypt_xts(u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
+			    u32 bytes, u8 *iv, u32 *key_twk);
+extern void ppc_decrypt_xts(u8 *out, const u8 *in, u32 *key_dec, u32 rounds,
+			    u32 bytes, u8 *iv, u32 *key_twk);
+
+extern void ppc_expand_key_128(u32 *key_enc, const u8 *key);
+extern void ppc_expand_key_192(u32 *key_enc, const u8 *key);
+extern void ppc_expand_key_256(u32 *key_enc, const u8 *key);
+
+extern void ppc_generate_decrypt_key(u32 *key_dec,u32 *key_enc,
+				     unsigned int key_len);
+
+static void spe_begin(void)
+{
+	/* disable preemption and save users SPE registers if required */
+	preempt_disable();
+	enable_kernel_spe();
+}
+
+static void spe_end(void)
+{
+	/* reenable preemption */
+	preempt_enable();
+}
+
+static int ppc_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
+		unsigned int key_len)
+{
+	struct ppc_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	if (key_len != AES_KEYSIZE_128 &&
+	    key_len != AES_KEYSIZE_192 &&
+	    key_len != AES_KEYSIZE_256) {
+		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+
+	switch (key_len) {
+	case AES_KEYSIZE_128:
+		ctx->rounds = 4;
+		ppc_expand_key_128(ctx->key_enc, in_key);
+		break;
+	case AES_KEYSIZE_192:
+		ctx->rounds = 5;
+		ppc_expand_key_192(ctx->key_enc, in_key);
+		break;
+	case AES_KEYSIZE_256:
+		ctx->rounds = 6;
+		ppc_expand_key_256(ctx->key_enc, in_key);
+		break;
+	}
+
+	ppc_generate_decrypt_key(ctx->key_dec, ctx->key_enc, key_len);
+
+	return 0;
+}
+
+static int ppc_xts_setkey(struct crypto_tfm *tfm, const u8 *in_key,
+		   unsigned int key_len)
+{
+	struct ppc_xts_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	key_len >>= 1;
+
+	if (key_len != AES_KEYSIZE_128 &&
+	    key_len != AES_KEYSIZE_192 &&
+	    key_len != AES_KEYSIZE_256) {
+		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+
+	switch (key_len) {
+	case AES_KEYSIZE_128:
+		ctx->rounds = 4;
+		ppc_expand_key_128(ctx->key_enc, in_key);
+		ppc_expand_key_128(ctx->key_twk, in_key + AES_KEYSIZE_128);
+		break;
+	case AES_KEYSIZE_192:
+		ctx->rounds = 5;
+		ppc_expand_key_192(ctx->key_enc, in_key);
+		ppc_expand_key_192(ctx->key_twk, in_key + AES_KEYSIZE_192);
+		break;
+	case AES_KEYSIZE_256:
+		ctx->rounds = 6;
+		ppc_expand_key_256(ctx->key_enc, in_key);
+		ppc_expand_key_256(ctx->key_twk, in_key + AES_KEYSIZE_256);
+		break;
+	}
+
+	ppc_generate_decrypt_key(ctx->key_dec, ctx->key_enc, key_len);
+
+	return 0;
+}
+
+static void ppc_aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	struct ppc_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	spe_begin();
+	ppc_encrypt_aes(out, in, ctx->key_enc, ctx->rounds);
+	spe_end();
+}
+
+static void ppc_aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	struct ppc_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	spe_begin();
+	ppc_decrypt_aes(out, in, ctx->key_dec, ctx->rounds);
+	spe_end();
+}
+
+static int ppc_ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+			   struct scatterlist *src, unsigned int nbytes)
+{
+	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	struct blkcipher_walk walk;
+	unsigned int ubytes;
+	int err;
+
+	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt(desc, &walk);
+
+	while ((nbytes = walk.nbytes)) {
+		ubytes = nbytes > MAX_BYTES ?
+			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
+		nbytes -= ubytes;
+
+		spe_begin();
+		ppc_encrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
+				ctx->key_enc, ctx->rounds, nbytes);
+		spe_end();
+
+		err = blkcipher_walk_done(desc, &walk, ubytes);
+	}
+
+	return err;
+}
+
+static int ppc_ecb_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+			   struct scatterlist *src, unsigned int nbytes)
+{
+	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	struct blkcipher_walk walk;
+	unsigned int ubytes;
+	int err;
+
+	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt(desc, &walk);
+
+	while ((nbytes = walk.nbytes)) {
+		ubytes = nbytes > MAX_BYTES ?
+			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
+		nbytes -= ubytes;
+
+		spe_begin();
+		ppc_decrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
+				ctx->key_dec, ctx->rounds, nbytes);
+		spe_end();
+
+		err = blkcipher_walk_done(desc, &walk, ubytes);
+	}
+
+	return err;
+}
+
+static int ppc_cbc_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+			   struct scatterlist *src, unsigned int nbytes)
+{
+	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	struct blkcipher_walk walk;
+	unsigned int ubytes;
+	int err;
+
+	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt(desc, &walk);
+
+	while ((nbytes = walk.nbytes)) {
+		ubytes = nbytes > MAX_BYTES ?
+			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
+		nbytes -= ubytes;
+
+		spe_begin();
+		ppc_encrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
+				ctx->key_enc, ctx->rounds, nbytes, walk.iv);
+		spe_end();
+
+		err = blkcipher_walk_done(desc, &walk, ubytes);
+	}
+
+	return err;
+}
+
+static int ppc_cbc_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+			   struct scatterlist *src, unsigned int nbytes)
+{
+	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	struct blkcipher_walk walk;
+	unsigned int ubytes;
+	int err;
+
+	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt(desc, &walk);
+
+	while ((nbytes = walk.nbytes)) {
+		ubytes = nbytes > MAX_BYTES ?
+			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
+		nbytes -= ubytes;
+
+		spe_begin();
+		ppc_decrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
+				ctx->key_dec, ctx->rounds, nbytes, walk.iv);
+		spe_end();
+
+		err = blkcipher_walk_done(desc, &walk, ubytes);
+	}
+
+	return err;
+}
+
+static int ppc_ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+			 struct scatterlist *src, unsigned int nbytes)
+{
+	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	struct blkcipher_walk walk;
+	unsigned int pbytes, ubytes;
+	int err;
+
+	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
+
+	while ((pbytes = walk.nbytes)) {
+		pbytes = pbytes > MAX_BYTES ? MAX_BYTES : pbytes;
+		pbytes = pbytes == nbytes ?
+			 nbytes : pbytes & ~(AES_BLOCK_SIZE - 1);
+		ubytes = walk.nbytes - pbytes;
+
+		spe_begin();
+		ppc_crypt_ctr(walk.dst.virt.addr, walk.src.virt.addr,
+			      ctx->key_enc, ctx->rounds, pbytes , walk.iv);
+		spe_end();
+
+		nbytes -= pbytes;
+		err = blkcipher_walk_done(desc, &walk, ubytes);
+	}
+
+	return err;
+}
+
+static int ppc_xts_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+			   struct scatterlist *src, unsigned int nbytes)
+{
+	struct ppc_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	struct blkcipher_walk walk;
+	unsigned int ubytes;
+	int err;
+	u32 *twk;
+
+	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt(desc, &walk);
+	twk = ctx->key_twk;
+
+	while ((nbytes = walk.nbytes)) {
+		ubytes = nbytes > MAX_BYTES ?
+			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
+		nbytes -= ubytes;
+
+		spe_begin();
+		ppc_encrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
+				ctx->key_enc, ctx->rounds, nbytes, walk.iv, twk);
+		spe_end();
+
+		twk = NULL;
+		err = blkcipher_walk_done(desc, &walk, ubytes);
+	}
+
+	return err;
+}
+
+static int ppc_xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+			   struct scatterlist *src, unsigned int nbytes)
+{
+	struct ppc_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	struct blkcipher_walk walk;
+	unsigned int ubytes;
+	int err;
+	u32 *twk;
+
+	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt(desc, &walk);
+	twk = ctx->key_twk;
+
+	while ((nbytes = walk.nbytes)) {
+		ubytes = nbytes > MAX_BYTES ?
+			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
+		nbytes -= ubytes;
+
+		spe_begin();
+		ppc_decrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
+				ctx->key_dec, ctx->rounds, nbytes, walk.iv, twk);
+		spe_end();
+
+		twk = NULL;
+		err = blkcipher_walk_done(desc, &walk, ubytes);
+	}
+
+	return err;
+}
+
+/*
+ * Algorithm definitions. Disabling alignment (cra_alignmask=0) was chosen
+ * because the e500 platform can handle unaligned reads/writes very efficently.
+ * This improves IPsec thoughput by another few percent. Additionally we assume
+ * that AES context is always aligned to at least 8 bytes because it is created
+ * with kmalloc() in the crypto infrastructure
+ *
+ */
+static struct crypto_alg aes_algs[] = { {
+	.cra_name		=	"aes",
+	.cra_driver_name	=	"aes-ppc-spe",
+	.cra_priority		=	300,
+	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize		=	AES_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct ppc_aes_ctx),
+	.cra_alignmask		=	0,
+	.cra_module		=	THIS_MODULE,
+	.cra_u			=	{
+		.cipher = {
+			.cia_min_keysize	=	AES_MIN_KEY_SIZE,
+			.cia_max_keysize	=	AES_MAX_KEY_SIZE,
+			.cia_setkey		=	ppc_aes_setkey,
+			.cia_encrypt		=	ppc_aes_encrypt,
+			.cia_decrypt		=	ppc_aes_decrypt
+		}
+	}
+}, {
+	.cra_name		=	"ecb(aes)",
+	.cra_driver_name	=	"ecb-ppc-spe",
+	.cra_priority		=	300,
+	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		=	AES_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct ppc_aes_ctx),
+	.cra_alignmask		=	0,
+	.cra_type		=	&crypto_blkcipher_type,
+	.cra_module		=	THIS_MODULE,
+	.cra_u = {
+		.blkcipher = {
+			.min_keysize		=	AES_MIN_KEY_SIZE,
+			.max_keysize		=	AES_MAX_KEY_SIZE,
+			.ivsize			=	AES_BLOCK_SIZE,
+			.setkey			=	ppc_aes_setkey,
+			.encrypt		=	ppc_ecb_encrypt,
+			.decrypt		=	ppc_ecb_decrypt,
+		}
+	}
+}, {
+	.cra_name		=	"cbc(aes)",
+	.cra_driver_name	=	"cbc-ppc-spe",
+	.cra_priority		=	300,
+	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		=	AES_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct ppc_aes_ctx),
+	.cra_alignmask		=	0,
+	.cra_type		=	&crypto_blkcipher_type,
+	.cra_module		=	THIS_MODULE,
+	.cra_u = {
+		.blkcipher = {
+			.min_keysize		=	AES_MIN_KEY_SIZE,
+			.max_keysize		=	AES_MAX_KEY_SIZE,
+			.ivsize			=	AES_BLOCK_SIZE,
+			.setkey			=	ppc_aes_setkey,
+			.encrypt		=	ppc_cbc_encrypt,
+			.decrypt		=	ppc_cbc_decrypt,
+		}
+	}
+}, {
+	.cra_name		=	"ctr(aes)",
+	.cra_driver_name	=	"ctr-ppc-spe",
+	.cra_priority		=	300,
+	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		=	1,
+	.cra_ctxsize		=	sizeof(struct ppc_aes_ctx),
+	.cra_alignmask		=	0,
+	.cra_type		=	&crypto_blkcipher_type,
+	.cra_module		=	THIS_MODULE,
+	.cra_u = {
+		.blkcipher = {
+			.min_keysize		=	AES_MIN_KEY_SIZE,
+			.max_keysize		=	AES_MAX_KEY_SIZE,
+			.ivsize			=	AES_BLOCK_SIZE,
+			.setkey			=	ppc_aes_setkey,
+			.encrypt		=	ppc_ctr_crypt,
+			.decrypt		=	ppc_ctr_crypt,
+		}
+	}
+}, {
+	.cra_name		=	"xts(aes)",
+	.cra_driver_name	=	"xts-ppc-spe",
+	.cra_priority		=	300,
+	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		=	AES_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct ppc_xts_ctx),
+	.cra_alignmask		=	0,
+	.cra_type		=	&crypto_blkcipher_type,
+	.cra_module		=	THIS_MODULE,
+	.cra_u = {
+		.blkcipher = {
+			.min_keysize		=	AES_MIN_KEY_SIZE * 2,
+			.max_keysize		=	AES_MAX_KEY_SIZE * 2,
+			.ivsize			=	AES_BLOCK_SIZE,
+			.setkey			=	ppc_xts_setkey,
+			.encrypt		=	ppc_xts_encrypt,
+			.decrypt		=	ppc_xts_decrypt,
+		}
+	}
+} };
+
+static int __init ppc_aes_mod_init(void)
+{
+	return crypto_register_algs(aes_algs, ARRAY_SIZE(aes_algs));
+}
+
+static void __exit ppc_aes_mod_fini(void)
+{
+	crypto_unregister_algs(aes_algs, ARRAY_SIZE(aes_algs));
+}
+
+module_init(ppc_aes_mod_init);
+module_exit(ppc_aes_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS, SPE optimized");
+
+MODULE_ALIAS_CRYPTO("aes");
+MODULE_ALIAS_CRYPTO("ecb(aes)");
+MODULE_ALIAS_CRYPTO("cbc(aes)");
+MODULE_ALIAS_CRYPTO("ctr(aes)");
+MODULE_ALIAS_CRYPTO("xts(aes)");
+MODULE_ALIAS_CRYPTO("aes-ppc-spe");