crypto: talitos - use dma_sync_single_for_cpu() before reading descriptor header

commit e17ff3d upstream.

In order to know if a descriptor has been processed by the device,
the driver polls the FIFO to see if DESC_HDR_DONE is set on a descriptor
header to confirm completion.
The current code does not make sure that the CPU gets up to date data
before reading the descriptor.

Fix this by calling dma_sync_single_for_cpu() before reading memory
written by the device.

Cc: stable@vger.kernel.org
Fixes: 58cdbc6 ("crypto: talitos - fix hash on SEC1.")
Signed-off-by: Paul Louvel <paul.louvel@bootlin.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: noctuelles

drivers/crypto/talitos.c

@@ -321,19 +321,31 @@ static int talitos_submit(struct device *dev, int ch, struct talitos_desc *desc,
 	return -EINPROGRESS;
 }
 
-static __be32 get_request_hdr(struct talitos_request *request, bool is_sec1)
+static __be32 get_request_hdr(struct device *dev,
+			      struct talitos_request *request, bool is_sec1)
 {
 	struct talitos_edesc *edesc;
 
-	if (!is_sec1)
+	if (!is_sec1) {
+		dma_sync_single_for_cpu(dev, request->dma_desc,
+					TALITOS_DESC_SIZE, DMA_BIDIRECTIONAL);
+
 		return request->desc->hdr;
+	}
 
-	if (!request->desc->next_desc)
+	if (!request->desc->next_desc) {
+		dma_sync_single_for_cpu(dev, request->dma_desc,
+					TALITOS_DESC_SIZE, DMA_BIDIRECTIONAL);
 		return request->desc->hdr1;
+	} else {
+		dma_sync_single_for_cpu(dev,
+					be32_to_cpu(request->desc->next_desc),
+					TALITOS_DESC_SIZE, DMA_BIDIRECTIONAL);
+		edesc = container_of(request->desc, struct talitos_edesc, desc);
 
-	edesc = container_of(request->desc, struct talitos_edesc, desc);
-
-	return ((struct talitos_desc *)(edesc->buf + edesc->dma_len))->hdr1;
+		return ((struct talitos_desc *)(edesc->buf + edesc->dma_len))
+			->hdr1;
+	}
 }
 
 /*
@@ -357,7 +369,7 @@ static void flush_channel(struct device *dev, int ch, int error, int reset_ch)
 
 		/* descriptors with their done bits set don't get the error */
 		rmb();
-		hdr = get_request_hdr(request, is_sec1);
+		hdr = get_request_hdr(dev, request, is_sec1);
 
 		if ((hdr & DESC_HDR_DONE) == DESC_HDR_DONE)
 			status = 0;