crypto: talitos - fix hash on SEC1.

On SEC1, hash provides wrong result when performing hashing in several
steps with input data SG list has more than one element. This was
detected with CONFIG_CRYPTO_MANAGER_EXTRA_TESTS:

[ 44.185947] alg: hash: md5-talitos test failed (wrong result) on test vector 6, cfg="random: may_sleep use_finup src_divs=[<reimport>25.88%@+8063, <flush>24.19%@+9588, 28.63%@+16333, <reimport>4.60%@+6756, 16.70%@+16281] dst_divs=[71.61%@alignmask+16361, 14.36%@+7756, 14.3%@+"
[ 44.325122] alg: hash: sha1-talitos test failed (wrong result) on test vector 3, cfg="random: inplace use_final src_divs=[<flush,nosimd>16.56%@+16378, <reimport>52.0%@+16329, 21.42%@alignmask+16380, 10.2%@alignmask+16380] iv_offset=39"
[ 44.493500] alg: hash: sha224-talitos test failed (wrong result) on test vector 4, cfg="random: use_final nosimd src_divs=[<reimport>52.27%@+7401, <reimport>17.34%@+16285, <flush>17.71%@+26, 12.68%@+10644] iv_offset=43"
[ 44.673262] alg: hash: sha256-talitos test failed (wrong result) on test vector 4, cfg="random: may_sleep use_finup src_divs=[<reimport>60.6%@+12790, 17.86%@+1329, <reimport>12.64%@alignmask+16300, 8.29%@+15, 0.40%@+13506, <reimport>0.51%@+16322, <reimport>0.24%@+16339] dst_divs"

This is due to two issues:
- We have an overlap between the buffer used for copying the input
data (SEC1 doesn't do scatter/gather) and the chained descriptor.
- Data copy is wrong when the previous hash left less than one
blocksize of data to hash, implying a complement of the previous
block with a few bytes from the new request.

Fix it by:
- Moving the second descriptor after the buffer, as moving the buffer
after the descriptor would make it more complex for other cipher
operations (AEAD, ABLKCIPHER)
- Skip the bytes taken from the new request to complete the previous
one by moving the SG list forward.

Fixes: 37b5e8897eb5 ("crypto: talitos - chain in buffered data for ahash on SEC1")
Cc: [e-mail]
Signed-off-by: Christophe Leroy <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/talitos.c

···
 	return -EINPROGRESS;
 }
 
+static __be32 get_request_hdr(struct talitos_request *request, bool is_sec1)
+{
+	struct talitos_edesc *edesc;
+
+	if (!is_sec1)
+		return request->desc->hdr;
+
+	if (!request->desc->next_desc)
+		return request->desc->hdr1;
+
+	edesc = container_of(request->desc, struct talitos_edesc, desc);
+
+	return ((struct talitos_desc *)(edesc->buf + edesc->dma_len))->hdr1;
+}
+
 /*
  * process what was done, notify callback of error if not
  */
···
 
 		/* descriptors with their done bits set don't get the error */
 		rmb();
-		if (!is_sec1)
-			hdr = request->desc->hdr;
-		else if (request->desc->next_desc)
-			hdr = (request->desc + 1)->hdr1;
-		else
-			hdr = request->desc->hdr1;
+		hdr = get_request_hdr(request, is_sec1);
 
 		if ((hdr & DESC_HDR_DONE) == DESC_HDR_DONE)
 			status = 0;
···
 		}
 	}
 
-	if (priv->chan[ch].fifo[iter].desc->next_desc == cur_desc)
-		return (priv->chan[ch].fifo[iter].desc + 1)->hdr;
+	if (priv->chan[ch].fifo[iter].desc->next_desc == cur_desc) {
+		struct talitos_edesc *edesc;
+
+		edesc = container_of(priv->chan[ch].fifo[iter].desc,
+				     struct talitos_edesc, desc);
+		return ((struct talitos_desc *)
+			(edesc->buf + edesc->dma_len))->hdr;
+	}
 
 	return priv->chan[ch].fifo[iter].desc->hdr;
 }
···
 	edesc->dst_nents = dst_nents;
 	edesc->iv_dma = iv_dma;
 	edesc->dma_len = dma_len;
-	if (dma_len) {
-		void *addr = &edesc->link_tbl[0];
-
-		if (is_sec1 && !dst)
-			addr += sizeof(struct talitos_desc);
-		edesc->dma_link_tbl = dma_map_single(dev, addr,
+	if (dma_len)
+		edesc->dma_link_tbl = dma_map_single(dev, &edesc->link_tbl[0],
 						     edesc->dma_len,
 						     DMA_BIDIRECTIONAL);
-	}
+
 	return edesc;
 }
 
···
 	struct talitos_private *priv = dev_get_drvdata(dev);
 	bool is_sec1 = has_ftr_sec1(priv);
 	struct talitos_desc *desc = &edesc->desc;
-	struct talitos_desc *desc2 = desc + 1;
+	struct talitos_desc *desc2 = (struct talitos_desc *)
+				     (edesc->buf + edesc->dma_len);
 
 	unmap_single_talitos_ptr(dev, &edesc->desc.ptr[5], DMA_FROM_DEVICE);
 	if (desc->next_desc &&
 	    desc->ptr[5].ptr != desc2->ptr[5].ptr)
 		unmap_single_talitos_ptr(dev, &desc2->ptr[5], DMA_FROM_DEVICE);
 
-	talitos_sg_unmap(dev, edesc, req_ctx->psrc, NULL, 0, 0);
+	if (req_ctx->psrc)
+		talitos_sg_unmap(dev, edesc, req_ctx->psrc, NULL, 0, 0);
 
 	/* When using hashctx-in, must unmap it. */
 	if (from_talitos_ptr_len(&edesc->desc.ptr[1], is_sec1))
···
 
 static int common_nonsnoop_hash(struct talitos_edesc *edesc,
 				struct ahash_request *areq, unsigned int length,
-				unsigned int offset,
 				void (*callback) (struct device *dev,
 						  struct talitos_desc *desc,
 						  void *context, int error))
···
 
 	sg_count = edesc->src_nents ?: 1;
 	if (is_sec1 && sg_count > 1)
-		sg_pcopy_to_buffer(req_ctx->psrc, sg_count,
-				   edesc->buf + sizeof(struct talitos_desc),
-				   length, req_ctx->nbuf);
+		sg_copy_to_buffer(req_ctx->psrc, sg_count, edesc->buf, length);
 	else if (length)
 		sg_count = dma_map_sg(dev, req_ctx->psrc, sg_count,
 				      DMA_TO_DEVICE);
···
 				       DMA_TO_DEVICE);
 	} else {
 		sg_count = talitos_sg_map(dev, req_ctx->psrc, length, edesc,
-					  &desc->ptr[3], sg_count, offset, 0);
+					  &desc->ptr[3], sg_count, 0, 0);
 		if (sg_count > 1)
 			sync_needed = true;
 	}
···
 		talitos_handle_buggy_hash(ctx, edesc, &desc->ptr[3]);
 
 	if (is_sec1 && req_ctx->nbuf && length) {
-		struct talitos_desc *desc2 = desc + 1;
+		struct talitos_desc *desc2 = (struct talitos_desc *)
+					     (edesc->buf + edesc->dma_len);
 		dma_addr_t next_desc;
 
 		memset(desc2, 0, sizeof(*desc2));
···
 						      DMA_TO_DEVICE);
 		copy_talitos_ptr(&desc2->ptr[2], &desc->ptr[2], is_sec1);
 		sg_count = talitos_sg_map(dev, req_ctx->psrc, length, edesc,
-					  &desc2->ptr[3], sg_count, offset, 0);
+					  &desc2->ptr[3], sg_count, 0, 0);
 		if (sg_count > 1)
 			sync_needed = true;
 		copy_talitos_ptr(&desc2->ptr[5], &desc->ptr[5], is_sec1);
···
 	struct device *dev = ctx->dev;
 	struct talitos_private *priv = dev_get_drvdata(dev);
 	bool is_sec1 = has_ftr_sec1(priv);
-	int offset = 0;
 	u8 *ctx_buf = req_ctx->buf[req_ctx->buf_idx];
 
 	if (!req_ctx->last && (nbytes + req_ctx->nbuf <= blocksize)) {
···
 			sg_chain(req_ctx->bufsl, 2, areq->src);
 		req_ctx->psrc = req_ctx->bufsl;
 	} else if (is_sec1 && req_ctx->nbuf && req_ctx->nbuf < blocksize) {
+		int offset;
+
 		if (nbytes_to_hash > blocksize)
 			offset = blocksize - req_ctx->nbuf;
 		else
···
 		sg_copy_to_buffer(areq->src, nents,
 				  ctx_buf + req_ctx->nbuf, offset);
 		req_ctx->nbuf += offset;
-		req_ctx->psrc = areq->src;
+		req_ctx->psrc = scatterwalk_ffwd(req_ctx->bufsl, areq->src,
+						 offset);
 	} else
 		req_ctx->psrc = areq->src;
 
···
 	if (ctx->keylen && (req_ctx->first || req_ctx->last))
 		edesc->desc.hdr |= DESC_HDR_MODE0_MDEU_HMAC;
 
-	return common_nonsnoop_hash(edesc, areq, nbytes_to_hash, offset,
-				    ahash_done);
+	return common_nonsnoop_hash(edesc, areq, nbytes_to_hash, ahash_done);
 }
 
 static int ahash_update(struct ahash_request *areq)