crypto: omap-sham - Map SG pages if they are HIGHMEM before accessing

HIGHMEM pages may not be mapped so we must kmap them before accessing.
This resolves a random OOPs error that was showing up during OpenSSL SHA tests.
Signed-off-by: Joel Fernandes <joelf@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/omap-sham.c

@@ -636,11 +636,17 @@ static size_t omap_sham_append_buffer(struct omap_sham_reqctx *ctx,
 static size_t omap_sham_append_sg(struct omap_sham_reqctx *ctx)
 {
 	size_t count;
+	const u8 *vaddr;
 
 	while (ctx->sg) {
+		vaddr = kmap_atomic(sg_page(ctx->sg));
+
 		count = omap_sham_append_buffer(ctx,
-				sg_virt(ctx->sg) + ctx->offset,
+				vaddr + ctx->offset,
 				ctx->sg->length - ctx->offset);
+
+		kunmap_atomic((void *)vaddr);
+
 		if (!count)
 			break;
 		ctx->offset += count;