crypto: nx - fix limits to sg lists for AES-GCM

This patch updates the nx-aes-gcm implementation to perform several
hyper calls if needed in order to always respect the length limits for
scatter/gather lists.

Two different limits are considered:

 - "ibm,max-sg-len": maximum number of bytes of each scatter/gather
   list.

 - "ibm,max-sync-cop":
    - The total number of bytes that a scatter/gather list can hold.
    - The maximum number of elements that a scatter/gather list can have.

Reviewed-by: Joy Latten <jmlatten@linux.vnet.ibm.com>
Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/nx/nx-aes-gcm.c b/drivers/crypto/nx/nx-aes-gcm.c
index c2d6f76e3677ef9277b1d4a1446d90bd2bc2dad3..9e89bdf344877b8b589d66e64e041bbb88f091bb 100644 (file)
--- a/drivers/crypto/nx/nx-aes-gcm.c
+++ b/drivers/crypto/nx/nx-aes-gcm.c
@@ -125,37 +125,101 @@ static int nx_gca(struct nx_crypto_ctx  *nx_ctx,
                  struct aead_request   *req,
                  u8                    *out)
 {
+       int rc;
        struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;
-       int rc = -EINVAL;
        struct scatter_walk walk;
        struct nx_sg *nx_sg = nx_ctx->in_sg;
+       unsigned int nbytes = req->assoclen;
+       unsigned int processed = 0, to_process;
+       u32 max_sg_len;
 
-       if (req->assoclen > nx_ctx->ap->databytelen)
-               goto out;
-
-       if (req->assoclen <= AES_BLOCK_SIZE) {
+       if (nbytes <= AES_BLOCK_SIZE) {
                scatterwalk_start(&walk, req->assoc);
-               scatterwalk_copychunks(out, &walk, req->assoclen,
-                                      SCATTERWALK_FROM_SG);
+               scatterwalk_copychunks(out, &walk, nbytes, SCATTERWALK_FROM_SG);
                scatterwalk_done(&walk, SCATTERWALK_FROM_SG, 0);
-
-               rc = 0;
-               goto out;
+               return 0;
        }
 
-       nx_sg = nx_walk_and_build(nx_sg, nx_ctx->ap->sglen, req->assoc, 0,
-                                 req->assoclen);
-       nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_sg) * sizeof(struct nx_sg);
+       NX_CPB_FDM(csbcpb_aead) &= ~NX_FDM_CONTINUATION;
 
-       rc = nx_hcall_sync(nx_ctx, &nx_ctx->op_aead,
-                          req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
-       if (rc)
-               goto out;
+       /* page_limit: number of sg entries that fit on one page */
+       max_sg_len = min_t(u32, nx_driver.of.max_sg_len/sizeof(struct nx_sg),
+                          nx_ctx->ap->sglen);
 
-       atomic_inc(&(nx_ctx->stats->aes_ops));
-       atomic64_add(req->assoclen, &(nx_ctx->stats->aes_bytes));
+       do {
+               /*
+                * to_process: the data chunk to process in this update.
+                * This value is bound by sg list limits.
+                */
+               to_process = min_t(u64, nbytes - processed,
+                                  nx_ctx->ap->databytelen);
+               to_process = min_t(u64, to_process,
+                                  NX_PAGE_SIZE * (max_sg_len - 1));
+
+               if ((to_process + processed) < nbytes)
+                       NX_CPB_FDM(csbcpb_aead) |= NX_FDM_INTERMEDIATE;
+               else
+                       NX_CPB_FDM(csbcpb_aead) &= ~NX_FDM_INTERMEDIATE;
+
+               nx_sg = nx_walk_and_build(nx_ctx->in_sg, nx_ctx->ap->sglen,
+                                         req->assoc, processed, to_process);
+               nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_sg)
+                                       * sizeof(struct nx_sg);
+
+               rc = nx_hcall_sync(nx_ctx, &nx_ctx->op_aead,
+                               req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
+               if (rc)
+                       return rc;
+
+               memcpy(csbcpb_aead->cpb.aes_gca.in_pat,
+                               csbcpb_aead->cpb.aes_gca.out_pat,
+                               AES_BLOCK_SIZE);
+               NX_CPB_FDM(csbcpb_aead) |= NX_FDM_CONTINUATION;
+
+               atomic_inc(&(nx_ctx->stats->aes_ops));
+               atomic64_add(req->assoclen, &(nx_ctx->stats->aes_bytes));
+
+               processed += to_process;
+       } while (processed < nbytes);
 
        memcpy(out, csbcpb_aead->cpb.aes_gca.out_pat, AES_BLOCK_SIZE);
+
+       return rc;
+}
+
+static int gcm_empty(struct aead_request *req, struct blkcipher_desc *desc,
+                    int enc)
+{
+       int rc;
+       struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+       struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
+
+       /* For scenarios where the input message is zero length, AES CTR mode
+        * may be used. Set the source data to be a single block (16B) of all
+        * zeros, and set the input IV value to be the same as the GMAC IV
+        * value. - nx_wb 4.8.1.3 */
+       char src[AES_BLOCK_SIZE] = {};
+       struct scatterlist sg;
+
+       desc->tfm = crypto_alloc_blkcipher("ctr(aes)", 0, 0);
+       if (IS_ERR(desc->tfm)) {
+               rc = -ENOMEM;
+               goto out;
+       }
+
+       crypto_blkcipher_setkey(desc->tfm, csbcpb->cpb.aes_gcm.key,
+               NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_128 ? 16 :
+               NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_192 ? 24 : 32);
+
+       sg_init_one(&sg, src, AES_BLOCK_SIZE);
+       if (enc)
+               rc = crypto_blkcipher_encrypt_iv(desc, req->dst, &sg,
+                                                AES_BLOCK_SIZE);
+       else
+               rc = crypto_blkcipher_decrypt_iv(desc, req->dst, &sg,
+                                                AES_BLOCK_SIZE);
+       crypto_free_blkcipher(desc->tfm);
+
 out:
        return rc;
 }
@@ -166,79 +230,85 @@ static int gcm_aes_nx_crypt(struct aead_request *req, int enc)
        struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
        struct blkcipher_desc desc;
        unsigned int nbytes = req->cryptlen;
+       unsigned int processed = 0, to_process;
        unsigned long irq_flags;
+       u32 max_sg_len;
        int rc = -EINVAL;
 
        spin_lock_irqsave(&nx_ctx->lock, irq_flags);
 
-       if (nbytes > nx_ctx->ap->databytelen)
-               goto out;
-
        desc.info = nx_ctx->priv.gcm.iv;
        /* initialize the counter */
        *(u32 *)(desc.info + NX_GCM_CTR_OFFSET) = 1;
 
-       /* For scenarios where the input message is zero length, AES CTR mode
-        * may be used. Set the source data to be a single block (16B) of all
-        * zeros, and set the input IV value to be the same as the GMAC IV
-        * value. - nx_wb 4.8.1.3 */
        if (nbytes == 0) {
-               char src[AES_BLOCK_SIZE] = {};
-               struct scatterlist sg;
-
-               desc.tfm = crypto_alloc_blkcipher("ctr(aes)", 0, 0);
-               if (IS_ERR(desc.tfm)) {
-                       rc = -ENOMEM;
-                       goto out;
-               }
-
-               crypto_blkcipher_setkey(desc.tfm, csbcpb->cpb.aes_gcm.key,
-                       NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_128 ? 16 :
-                       NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_192 ? 24 : 32);
-
-               sg_init_one(&sg, src, AES_BLOCK_SIZE);
-               if (enc)
-                       crypto_blkcipher_encrypt_iv(&desc, req->dst, &sg,
-                                                   AES_BLOCK_SIZE);
-               else
-                       crypto_blkcipher_decrypt_iv(&desc, req->dst, &sg,
-                                                   AES_BLOCK_SIZE);
-               crypto_free_blkcipher(desc.tfm);
-
-               rc = 0;
+               rc = gcm_empty(req, &desc, enc);
                goto out;
        }
 
-       desc.tfm = (struct crypto_blkcipher *)req->base.tfm;
-
+       /* Process associated data */
        csbcpb->cpb.aes_gcm.bit_length_aad = req->assoclen * 8;
-
        if (req->assoclen) {
                rc = nx_gca(nx_ctx, req, csbcpb->cpb.aes_gcm.in_pat_or_aad);
                if (rc)
                        goto out;
        }
 
-       if (enc)
+       /* Set flags for encryption */
+       NX_CPB_FDM(csbcpb) &= ~NX_FDM_CONTINUATION;
+       if (enc) {
                NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
-       else
+       } else {
+               NX_CPB_FDM(csbcpb) &= ~NX_FDM_ENDE_ENCRYPT;
                nbytes -= crypto_aead_authsize(crypto_aead_reqtfm(req));
+       }
 
-       csbcpb->cpb.aes_gcm.bit_length_data = nbytes * 8;
+       /* page_limit: number of sg entries that fit on one page */
+       max_sg_len = min_t(u32, nx_driver.of.max_sg_len/sizeof(struct nx_sg),
+                          nx_ctx->ap->sglen);
+
+       do {
+               /*
+                * to_process: the data chunk to process in this update.
+                * This value is bound by sg list limits.
+                */
+               to_process = min_t(u64, nbytes - processed,
+                                  nx_ctx->ap->databytelen);
+               to_process = min_t(u64, to_process,
+                                  NX_PAGE_SIZE * (max_sg_len - 1));
+
+               if ((to_process + processed) < nbytes)
+                       NX_CPB_FDM(csbcpb) |= NX_FDM_INTERMEDIATE;
+               else
+                       NX_CPB_FDM(csbcpb) &= ~NX_FDM_INTERMEDIATE;
 
-       rc = nx_build_sg_lists(nx_ctx, &desc, req->dst, req->src, nbytes, 0,
-                              csbcpb->cpb.aes_gcm.iv_or_cnt);
-       if (rc)
-               goto out;
+               csbcpb->cpb.aes_gcm.bit_length_data = nbytes * 8;
+               desc.tfm = (struct crypto_blkcipher *) req->base.tfm;
+               rc = nx_build_sg_lists(nx_ctx, &desc, req->dst,
+                                      req->src, to_process, processed,
+                                      csbcpb->cpb.aes_gcm.iv_or_cnt);
+               if (rc)
+                       goto out;
 
-       rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
-                          req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
-       if (rc)
-               goto out;
+               rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
+                                  req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
+               if (rc)
+                       goto out;
+
+               memcpy(desc.info, csbcpb->cpb.aes_gcm.out_cnt, AES_BLOCK_SIZE);
+               memcpy(csbcpb->cpb.aes_gcm.in_pat_or_aad,
+                       csbcpb->cpb.aes_gcm.out_pat_or_mac, AES_BLOCK_SIZE);
+               memcpy(csbcpb->cpb.aes_gcm.in_s0,
+                       csbcpb->cpb.aes_gcm.out_s0, AES_BLOCK_SIZE);
+
+               NX_CPB_FDM(csbcpb) |= NX_FDM_CONTINUATION;
+
+               atomic_inc(&(nx_ctx->stats->aes_ops));
+               atomic64_add(csbcpb->csb.processed_byte_count,
+                            &(nx_ctx->stats->aes_bytes));
 
-       atomic_inc(&(nx_ctx->stats->aes_ops));
-       atomic64_add(csbcpb->csb.processed_byte_count,
-                    &(nx_ctx->stats->aes_bytes));
+               processed += to_process;
+       } while (processed < nbytes);
 
        if (enc) {
                /* copy out the auth tag */