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

This patch updates the NX driver to perform several hyper calls when necessary
so that the length limits of scatter/gather lists are respected.

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

1 files changed, 66 insertions, 47 deletions

diff --git a/drivers/crypto/nx/nx-aes-xcbc.c b/drivers/crypto/nx/nx-aes-xcbc.c
index 658da0fd3e1f..1a5d9e372b4e 100644
--- a/drivers/crypto/nx/nx-aes-xcbc.c
+++ b/drivers/crypto/nx/nx-aes-xcbc.c
@@ -88,78 +88,97 @@ static int nx_xcbc_update(struct shash_desc *desc,
         struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&desc->tfm->base);
         struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
         struct nx_sg *in_sg;
-        u32 to_process, leftover;
+        u32 to_process, leftover, total;
+        u32 max_sg_len;
         unsigned long irq_flags;
         int rc = 0;
 
         spin_lock_irqsave(&nx_ctx->lock, irq_flags);
 
-        if (NX_CPB_FDM(csbcpb) & NX_FDM_CONTINUATION) {
-                /* we've hit the nx chip previously and we're updating again,
-                 * so copy over the partial digest */
-                memcpy(csbcpb->cpb.aes_xcbc.cv,
-                       csbcpb->cpb.aes_xcbc.out_cv_mac, AES_BLOCK_SIZE);
-        }
+
+        total = sctx->count + len;
 
         /* 2 cases for total data len:
          *  1: <= AES_BLOCK_SIZE: copy into state, return 0
          *  2: > AES_BLOCK_SIZE: process X blocks, copy in leftover
          */
-        if (len + sctx->count <= AES_BLOCK_SIZE) {
+        if (total <= AES_BLOCK_SIZE) {
                 memcpy(sctx->buffer + sctx->count, data, len);
                 sctx->count += len;
                 goto out;
         }
 
-        /* to_process: the AES_BLOCK_SIZE data chunk to process in this
-         * update */
-        to_process = (sctx->count + len) & ~(AES_BLOCK_SIZE - 1);
-        leftover = (sctx->count + len) & (AES_BLOCK_SIZE - 1);
-
-        /* the hardware will not accept a 0 byte operation for this algorithm
-         * and the operation MUST be finalized to be correct. So if we happen
-         * to get an update that falls on a block sized boundary, we must
-         * save off the last block to finalize with later. */
-        if (!leftover) {
-                to_process -= AES_BLOCK_SIZE;
-                leftover = AES_BLOCK_SIZE;
-        }
-
-        if (sctx->count) {
-                in_sg = nx_build_sg_list(nx_ctx->in_sg, sctx->buffer,
-                                         sctx->count, nx_ctx->ap->sglen);
-                in_sg = nx_build_sg_list(in_sg, (u8 *)data,
-                                         to_process - sctx->count,
-                                         nx_ctx->ap->sglen);
+        in_sg = nx_ctx->in_sg;
+        max_sg_len = min_t(u32, nx_driver.of.max_sg_len/sizeof(struct nx_sg),
+                                nx_ctx->ap->sglen);
+
+        do {
+
+                /* to_process: the AES_BLOCK_SIZE data chunk to process in this
+                 * update */
+                to_process = min_t(u64, total, nx_ctx->ap->databytelen);
+                to_process = min_t(u64, to_process,
+                                        NX_PAGE_SIZE * (max_sg_len - 1));
+                to_process = to_process & ~(AES_BLOCK_SIZE - 1);
+                leftover = total - to_process;
+
+                /* the hardware will not accept a 0 byte operation for this
+                 * algorithm and the operation MUST be finalized to be correct.
+                 * So if we happen to get an update that falls on a block sized
+                 * boundary, we must save off the last block to finalize with
+                 * later. */
+                if (!leftover) {
+                        to_process -= AES_BLOCK_SIZE;
+                        leftover = AES_BLOCK_SIZE;
+                }
+
+                if (sctx->count) {
+                        in_sg = nx_build_sg_list(nx_ctx->in_sg,
+                                                (u8 *) sctx->buffer,
+                                                sctx->count,
+                                                max_sg_len);
+                }
+                in_sg = nx_build_sg_list(in_sg,
+                                        (u8 *) data,
+                                        to_process - sctx->count,
+                                        max_sg_len);
                 nx_ctx->op.inlen = (nx_ctx->in_sg - in_sg) *
                                         sizeof(struct nx_sg);
-        } else {
-                in_sg = nx_build_sg_list(nx_ctx->in_sg, (u8 *)data, to_process,
-                                         nx_ctx->ap->sglen);
-                nx_ctx->op.inlen = (nx_ctx->in_sg - in_sg) *
-                                        sizeof(struct nx_sg);
-        }
 
-        NX_CPB_FDM(csbcpb) |= NX_FDM_INTERMEDIATE;
+                /* we've hit the nx chip previously and we're updating again,
+                 * so copy over the partial digest */
+                if (NX_CPB_FDM(csbcpb) & NX_FDM_CONTINUATION) {
+                        memcpy(csbcpb->cpb.aes_xcbc.cv,
+                                csbcpb->cpb.aes_xcbc.out_cv_mac,
+                                AES_BLOCK_SIZE);
+                }
+
+                NX_CPB_FDM(csbcpb) |= NX_FDM_INTERMEDIATE;
+                if (!nx_ctx->op.inlen || !nx_ctx->op.outlen) {
+                        rc = -EINVAL;
+                        goto out;
+                }
+
+                rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
+                           desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP);
+                if (rc)
+                        goto out;
 
-        if (!nx_ctx->op.inlen || !nx_ctx->op.outlen) {
-                rc = -EINVAL;
-                goto out;
-        }
+                atomic_inc(&(nx_ctx->stats->aes_ops));
 
-        rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
-                           desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP);
-        if (rc)
-                goto out;
+                /* everything after the first update is continuation */
+                NX_CPB_FDM(csbcpb) |= NX_FDM_CONTINUATION;
 
-        atomic_inc(&(nx_ctx->stats->aes_ops));
+                total -= to_process;
+                data += to_process - sctx->count;
+                sctx->count = 0;
+                in_sg = nx_ctx->in_sg;
+        } while (leftover > AES_BLOCK_SIZE);
 
         /* copy the leftover back into the state struct */
-        memcpy(sctx->buffer, data + len - leftover, leftover);
+        memcpy(sctx->buffer, data, leftover);
         sctx->count = leftover;
 
-        /* everything after the first update is continuation */
-        NX_CPB_FDM(csbcpb) |= NX_FDM_CONTINUATION;
 out:
         spin_unlock_irqrestore(&nx_ctx->lock, irq_flags);
         return rc;