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>

1 files changed, 136 insertions, 66 deletions

diff --git a/drivers/crypto/nx/nx-aes-gcm.c b/drivers/crypto/nx/nx-aes-gcm.c
index c2d6f76e3677..9e89bdf34487 100644
--- 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 */