From 8d8409f773af2cfd52e23e4b138a7d55a31182cd Mon Sep 17 00:00:00 2001 From: Chuck Ebbert Date: Thu, 18 Jun 2009 19:31:09 +0800 Subject: [PATCH] crypto: padlock-aes - work around Nano CPU errata in CBC mode Extend previous workarounds for the prefetch bug to cover CBC mode, clean up the code a bit. Signed-off-by: Chuck Ebbert Acked-by: Harald Welte Signed-off-by: Herbert Xu --- drivers/crypto/padlock-aes.c | 83 ++++++++++++++++++++++++++++-------- 1 file changed, 65 insertions(+), 18 deletions(-) diff --git a/drivers/crypto/padlock-aes.c b/drivers/crypto/padlock-aes.c index e1d8776c6972..a9952b1236b0 100644 --- a/drivers/crypto/padlock-aes.c +++ b/drivers/crypto/padlock-aes.c @@ -22,11 +22,16 @@ #include #include "padlock.h" -/* number of data blocks actually fetched for each xcrypt insn */ +/* + * 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; -static unsigned int cbc_fetch_blocks = 1; - +#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. */ @@ -180,7 +185,7 @@ static inline void padlock_store_cword(struct cword *cword) * should be used only inside the irq_ts_save/restore() context */ -static inline void padlock_xcrypt(const u8 *input, u8 *output, void *key, +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 */ @@ -188,32 +193,65 @@ static inline void padlock_xcrypt(const u8 *input, u8 *output, void *key, : "d"(control_word), "b"(key), "c"(count)); } -static void aes_crypt_copy(const u8 *in, u8 *out, u32 *key, +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 * 7 + PADLOCK_ALIGNMENT - 1]; + 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); - padlock_xcrypt(tmp, out, key, cword, count); + rep_xcrypt_ecb(tmp, out, key, cword, count); } -static inline void aes_crypt(const u8 *in, u8 *out, u32 *key, +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_SIZE) + ecb_fetch_bytes > PAGE_SIZE)) { - aes_crypt_copy(in, out, key, cword, count); + ecb_crypt_copy(in, out, key, cword, count); return; } - padlock_xcrypt(in, out, key, cword, count); + 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_SIZE) + 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, @@ -222,7 +260,7 @@ static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key, u32 initial = count & (ecb_fetch_blocks - 1); if (count < ecb_fetch_blocks) { - aes_crypt(input, output, key, control_word, count); + ecb_crypt(input, output, key, control_word, count); return; } @@ -239,10 +277,19 @@ static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key, static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key, u8 *iv, void *control_word, u32 count) { - /* rep xcryptcbc */ - asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" + u32 initial = count & (cbc_fetch_blocks - 1); + + if (count < cbc_fetch_blocks) + return cbc_crypt(input, output, key, iv, control_word, count); + + if (initial) + asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep xcryptcbc */ + : "+S" (input), "+D" (output), "+a" (iv) + : "d" (control_word), "b" (key), "c" (count)); + + asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep xcryptcbc */ : "+S" (input), "+D" (output), "+a" (iv) - : "d" (control_word), "b" (key), "c" (count)); + : "d" (control_word), "b" (key), "c" (count-initial)); return iv; } @@ -253,7 +300,7 @@ static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) padlock_reset_key(&ctx->cword.encrypt); ts_state = irq_ts_save(); - aes_crypt(in, out, ctx->E, &ctx->cword.encrypt, 1); + ecb_crypt(in, out, ctx->E, &ctx->cword.encrypt, 1); irq_ts_restore(ts_state); padlock_store_cword(&ctx->cword.encrypt); } @@ -265,7 +312,7 @@ static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) padlock_reset_key(&ctx->cword.encrypt); ts_state = irq_ts_save(); - aes_crypt(in, out, ctx->D, &ctx->cword.decrypt, 1); + ecb_crypt(in, out, ctx->D, &ctx->cword.decrypt, 1); irq_ts_restore(ts_state); padlock_store_cword(&ctx->cword.encrypt); } @@ -482,8 +529,8 @@ static int __init padlock_init(void) printk(KERN_NOTICE PFX "Using VIA PadLock ACE for AES algorithm.\n"); if (c->x86 == 6 && c->x86_model == 15 && c->x86_mask == 2) { - ecb_fetch_blocks = 8; - cbc_fetch_blocks = 4; /* NOTE: notused */ + 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"); }