blob: 4493b46222074650cdd6cad8148a9adf546c2e50 [file] [log] [blame]
/*
* Cryptographic API.
*
* Support for VIA PadLock hardware crypto engine.
*
* Copyright (c) 2004 Michal Ludvig <michal@logix.cz>
*
*/
#include <crypto/algapi.h>
#include <crypto/aes.h>
#include <crypto/padlock.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/percpu.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <asm/cpu_device_id.h>
#include <asm/byteorder.h>
#include <asm/processor.h>
#include <asm/fpu/api.h>
/*
* Number of data blocks actually fetched for each xcrypt insn.
* Processors with prefetch errata will fetch extra blocks.
*/
static unsigned int ecb_fetch_blocks = 2;
#define MAX_ECB_FETCH_BLOCKS (8)
#define ecb_fetch_bytes (ecb_fetch_blocks * AES_BLOCK_SIZE)
static unsigned int cbc_fetch_blocks = 1;
#define MAX_CBC_FETCH_BLOCKS (4)
#define cbc_fetch_bytes (cbc_fetch_blocks * AES_BLOCK_SIZE)
/* Control word. */
struct cword {
unsigned int __attribute__ ((__packed__))
rounds:4,
algo:3,
keygen:1,
interm:1,
encdec:1,
ksize:2;
} __attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
/* Whenever making any changes to the following
* structure *make sure* you keep E, d_data
* and cword aligned on 16 Bytes boundaries and
* the Hardware can access 16 * 16 bytes of E and d_data
* (only the first 15 * 16 bytes matter but the HW reads
* more).
*/
struct aes_ctx {
u32 E[AES_MAX_KEYLENGTH_U32]
__attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
u32 d_data[AES_MAX_KEYLENGTH_U32]
__attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
struct {
struct cword encrypt;
struct cword decrypt;
} cword;
u32 *D;
};
static DEFINE_PER_CPU(struct cword *, paes_last_cword);
/* Tells whether the ACE is capable to generate
the extended key for a given key_len. */
static inline int
aes_hw_extkey_available(uint8_t key_len)
{
/* TODO: We should check the actual CPU model/stepping
as it's possible that the capability will be
added in the next CPU revisions. */
if (key_len == 16)
return 1;
return 0;
}
static inline struct aes_ctx *aes_ctx_common(void *ctx)
{
unsigned long addr = (unsigned long)ctx;
unsigned long align = PADLOCK_ALIGNMENT;
if (align <= crypto_tfm_ctx_alignment())
align = 1;
return (struct aes_ctx *)ALIGN(addr, align);
}
static inline struct aes_ctx *aes_ctx(struct crypto_tfm *tfm)
{
return aes_ctx_common(crypto_tfm_ctx(tfm));
}
static inline struct aes_ctx *blk_aes_ctx(struct crypto_blkcipher *tfm)
{
return aes_ctx_common(crypto_blkcipher_ctx(tfm));
}
static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct aes_ctx *ctx = aes_ctx(tfm);
const __le32 *key = (const __le32 *)in_key;
u32 *flags = &tfm->crt_flags;
struct crypto_aes_ctx gen_aes;
int cpu;
if (key_len % 8) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
/*
* If the hardware is capable of generating the extended key
* itself we must supply the plain key for both encryption
* and decryption.
*/
ctx->D = ctx->E;
ctx->E[0] = le32_to_cpu(key[0]);
ctx->E[1] = le32_to_cpu(key[1]);
ctx->E[2] = le32_to_cpu(key[2]);
ctx->E[3] = le32_to_cpu(key[3]);
/* Prepare control words. */
memset(&ctx->cword, 0, sizeof(ctx->cword));
ctx->cword.decrypt.encdec = 1;
ctx->cword.encrypt.rounds = 10 + (key_len - 16) / 4;
ctx->cword.decrypt.rounds = ctx->cword.encrypt.rounds;
ctx->cword.encrypt.ksize = (key_len - 16) / 8;
ctx->cword.decrypt.ksize = ctx->cword.encrypt.ksize;
/* Don't generate extended keys if the hardware can do it. */
if (aes_hw_extkey_available(key_len))
goto ok;
ctx->D = ctx->d_data;
ctx->cword.encrypt.keygen = 1;
ctx->cword.decrypt.keygen = 1;
if (crypto_aes_expand_key(&gen_aes, in_key, key_len)) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
memcpy(ctx->E, gen_aes.key_enc, AES_MAX_KEYLENGTH);
memcpy(ctx->D, gen_aes.key_dec, AES_MAX_KEYLENGTH);
ok:
for_each_online_cpu(cpu)
if (&ctx->cword.encrypt == per_cpu(paes_last_cword, cpu) ||
&ctx->cword.decrypt == per_cpu(paes_last_cword, cpu))
per_cpu(paes_last_cword, cpu) = NULL;
return 0;
}
/* ====== Encryption/decryption routines ====== */
/* These are the real call to PadLock. */
static inline void padlock_reset_key(struct cword *cword)
{
int cpu = raw_smp_processor_id();
if (cword != per_cpu(paes_last_cword, cpu))
#ifndef CONFIG_X86_64
asm volatile ("pushfl; popfl");
#else
asm volatile ("pushfq; popfq");
#endif
}
static inline void padlock_store_cword(struct cword *cword)
{
per_cpu(paes_last_cword, raw_smp_processor_id()) = cword;
}
/*
* While the padlock instructions don't use FP/SSE registers, they
* generate a spurious DNA fault when cr0.ts is '1'. These instructions
* should be used only inside the irq_ts_save/restore() context
*/
static inline void rep_xcrypt_ecb(const u8 *input, u8 *output, void *key,
struct cword *control_word, int count)
{
asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */
: "+S"(input), "+D"(output)
: "d"(control_word), "b"(key), "c"(count));
}
static inline u8 *rep_xcrypt_cbc(const u8 *input, u8 *output, void *key,
u8 *iv, struct cword *control_word, int count)
{
asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep xcryptcbc */
: "+S" (input), "+D" (output), "+a" (iv)
: "d" (control_word), "b" (key), "c" (count));
return iv;
}
static void ecb_crypt_copy(const u8 *in, u8 *out, u32 *key,
struct cword *cword, int count)
{
/*
* Padlock prefetches extra data so we must provide mapped input buffers.
* Assume there are at least 16 bytes of stack already in use.
*/
u8 buf[AES_BLOCK_SIZE * (MAX_ECB_FETCH_BLOCKS - 1) + PADLOCK_ALIGNMENT - 1];
u8 *tmp = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
memcpy(tmp, in, count * AES_BLOCK_SIZE);
rep_xcrypt_ecb(tmp, out, key, cword, count);
}
static u8 *cbc_crypt_copy(const u8 *in, u8 *out, u32 *key,
u8 *iv, struct cword *cword, int count)
{
/*
* Padlock prefetches extra data so we must provide mapped input buffers.
* Assume there are at least 16 bytes of stack already in use.
*/
u8 buf[AES_BLOCK_SIZE * (MAX_CBC_FETCH_BLOCKS - 1) + PADLOCK_ALIGNMENT - 1];
u8 *tmp = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
memcpy(tmp, in, count * AES_BLOCK_SIZE);
return rep_xcrypt_cbc(tmp, out, key, iv, cword, count);
}
static inline void ecb_crypt(const u8 *in, u8 *out, u32 *key,
struct cword *cword, int count)
{
/* Padlock in ECB mode fetches at least ecb_fetch_bytes of data.
* We could avoid some copying here but it's probably not worth it.
*/
if (unlikely(((unsigned long)in & ~PAGE_MASK) + ecb_fetch_bytes > PAGE_SIZE)) {
ecb_crypt_copy(in, out, key, cword, count);
return;
}
rep_xcrypt_ecb(in, out, key, cword, count);
}
static inline u8 *cbc_crypt(const u8 *in, u8 *out, u32 *key,
u8 *iv, struct cword *cword, int count)
{
/* Padlock in CBC mode fetches at least cbc_fetch_bytes of data. */
if (unlikely(((unsigned long)in & ~PAGE_MASK) + cbc_fetch_bytes > PAGE_SIZE))
return cbc_crypt_copy(in, out, key, iv, cword, count);
return rep_xcrypt_cbc(in, out, key, iv, cword, count);
}
static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key,
void *control_word, u32 count)
{
u32 initial = count & (ecb_fetch_blocks - 1);
if (count < ecb_fetch_blocks) {
ecb_crypt(input, output, key, control_word, count);
return;
}
count -= initial;
if (initial)
asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */
: "+S"(input), "+D"(output)
: "d"(control_word), "b"(key), "c"(initial));
asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */
: "+S"(input), "+D"(output)
: "d"(control_word), "b"(key), "c"(count));
}
static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
u8 *iv, void *control_word, u32 count)
{
u32 initial = count & (cbc_fetch_blocks - 1);
if (count < cbc_fetch_blocks)
return cbc_crypt(input, output, key, iv, control_word, count);
count -= initial;
if (initial)
asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep xcryptcbc */
: "+S" (input), "+D" (output), "+a" (iv)
: "d" (control_word), "b" (key), "c" (initial));
asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep xcryptcbc */
: "+S" (input), "+D" (output), "+a" (iv)
: "d" (control_word), "b" (key), "c" (count));
return iv;
}
static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
struct aes_ctx *ctx = aes_ctx(tfm);
int ts_state;
padlock_reset_key(&ctx->cword.encrypt);
ts_state = irq_ts_save();
ecb_crypt(in, out, ctx->E, &ctx->cword.encrypt, 1);
irq_ts_restore(ts_state);
padlock_store_cword(&ctx->cword.encrypt);
}
static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
struct aes_ctx *ctx = aes_ctx(tfm);
int ts_state;
padlock_reset_key(&ctx->cword.encrypt);
ts_state = irq_ts_save();
ecb_crypt(in, out, ctx->D, &ctx->cword.decrypt, 1);
irq_ts_restore(ts_state);
padlock_store_cword(&ctx->cword.encrypt);
}
static struct crypto_alg aes_alg = {
.cra_name = "aes",
.cra_driver_name = "aes-padlock",
.cra_priority = PADLOCK_CRA_PRIORITY,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct aes_ctx),
.cra_alignmask = PADLOCK_ALIGNMENT - 1,
.cra_module = THIS_MODULE,
.cra_u = {
.cipher = {
.cia_min_keysize = AES_MIN_KEY_SIZE,
.cia_max_keysize = AES_MAX_KEY_SIZE,
.cia_setkey = aes_set_key,
.cia_encrypt = aes_encrypt,
.cia_decrypt = aes_decrypt,
}
}
};
static int ecb_aes_encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
struct blkcipher_walk walk;
int err;
int ts_state;
padlock_reset_key(&ctx->cword.encrypt);
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt(desc, &walk);
ts_state = irq_ts_save();
while ((nbytes = walk.nbytes)) {
padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr,
ctx->E, &ctx->cword.encrypt,
nbytes / AES_BLOCK_SIZE);
nbytes &= AES_BLOCK_SIZE - 1;
err = blkcipher_walk_done(desc, &walk, nbytes);
}
irq_ts_restore(ts_state);
padlock_store_cword(&ctx->cword.encrypt);
return err;
}
static int ecb_aes_decrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
struct blkcipher_walk walk;
int err;
int ts_state;
padlock_reset_key(&ctx->cword.decrypt);
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt(desc, &walk);
ts_state = irq_ts_save();
while ((nbytes = walk.nbytes)) {
padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr,
ctx->D, &ctx->cword.decrypt,
nbytes / AES_BLOCK_SIZE);
nbytes &= AES_BLOCK_SIZE - 1;
err = blkcipher_walk_done(desc, &walk, nbytes);
}
irq_ts_restore(ts_state);
padlock_store_cword(&ctx->cword.encrypt);
return err;
}
static struct crypto_alg ecb_aes_alg = {
.cra_name = "ecb(aes)",
.cra_driver_name = "ecb-aes-padlock",
.cra_priority = PADLOCK_COMPOSITE_PRIORITY,
.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct aes_ctx),
.cra_alignmask = PADLOCK_ALIGNMENT - 1,
.cra_type = &crypto_blkcipher_type,
.cra_module = THIS_MODULE,
.cra_u = {
.blkcipher = {
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.setkey = aes_set_key,
.encrypt = ecb_aes_encrypt,
.decrypt = ecb_aes_decrypt,
}
}
};
static int cbc_aes_encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
struct blkcipher_walk walk;
int err;
int ts_state;
padlock_reset_key(&ctx->cword.encrypt);
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt(desc, &walk);
ts_state = irq_ts_save();
while ((nbytes = walk.nbytes)) {
u8 *iv = padlock_xcrypt_cbc(walk.src.virt.addr,
walk.dst.virt.addr, ctx->E,
walk.iv, &ctx->cword.encrypt,
nbytes / AES_BLOCK_SIZE);
memcpy(walk.iv, iv, AES_BLOCK_SIZE);
nbytes &= AES_BLOCK_SIZE - 1;
err = blkcipher_walk_done(desc, &walk, nbytes);
}
irq_ts_restore(ts_state);
padlock_store_cword(&ctx->cword.decrypt);
return err;
}
static int cbc_aes_decrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
struct blkcipher_walk walk;
int err;
int ts_state;
padlock_reset_key(&ctx->cword.encrypt);
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt(desc, &walk);
ts_state = irq_ts_save();
while ((nbytes = walk.nbytes)) {
padlock_xcrypt_cbc(walk.src.virt.addr, walk.dst.virt.addr,
ctx->D, walk.iv, &ctx->cword.decrypt,
nbytes / AES_BLOCK_SIZE);
nbytes &= AES_BLOCK_SIZE - 1;
err = blkcipher_walk_done(desc, &walk, nbytes);
}
irq_ts_restore(ts_state);
padlock_store_cword(&ctx->cword.encrypt);
return err;
}
static struct crypto_alg cbc_aes_alg = {
.cra_name = "cbc(aes)",
.cra_driver_name = "cbc-aes-padlock",
.cra_priority = PADLOCK_COMPOSITE_PRIORITY,
.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct aes_ctx),
.cra_alignmask = PADLOCK_ALIGNMENT - 1,
.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 = aes_set_key,
.encrypt = cbc_aes_encrypt,
.decrypt = cbc_aes_decrypt,
}
}
};
static struct x86_cpu_id padlock_cpu_id[] = {
X86_FEATURE_MATCH(X86_FEATURE_XCRYPT),
{}
};
MODULE_DEVICE_TABLE(x86cpu, padlock_cpu_id);
static int __init padlock_init(void)
{
int ret;
struct cpuinfo_x86 *c = &cpu_data(0);
if (!x86_match_cpu(padlock_cpu_id))
return -ENODEV;
if (!boot_cpu_has(X86_FEATURE_XCRYPT_EN)) {
printk(KERN_NOTICE PFX "VIA PadLock detected, but not enabled. Hmm, strange...\n");
return -ENODEV;
}
if ((ret = crypto_register_alg(&aes_alg)))
goto aes_err;
if ((ret = crypto_register_alg(&ecb_aes_alg)))
goto ecb_aes_err;
if ((ret = crypto_register_alg(&cbc_aes_alg)))
goto cbc_aes_err;
printk(KERN_NOTICE PFX "Using VIA PadLock ACE for AES algorithm.\n");
if (c->x86 == 6 && c->x86_model == 15 && c->x86_stepping == 2) {
ecb_fetch_blocks = MAX_ECB_FETCH_BLOCKS;
cbc_fetch_blocks = MAX_CBC_FETCH_BLOCKS;
printk(KERN_NOTICE PFX "VIA Nano stepping 2 detected: enabling workaround.\n");
}
out:
return ret;
cbc_aes_err:
crypto_unregister_alg(&ecb_aes_alg);
ecb_aes_err:
crypto_unregister_alg(&aes_alg);
aes_err:
printk(KERN_ERR PFX "VIA PadLock AES initialization failed.\n");
goto out;
}
static void __exit padlock_fini(void)
{
crypto_unregister_alg(&cbc_aes_alg);
crypto_unregister_alg(&ecb_aes_alg);
crypto_unregister_alg(&aes_alg);
}
module_init(padlock_init);
module_exit(padlock_fini);
MODULE_DESCRIPTION("VIA PadLock AES algorithm support");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michal Ludvig");
MODULE_ALIAS_CRYPTO("aes");