crypto: tegra - Fix CMAC intermediate result handling

JIRA: https://issues.redhat.com/browse/RHEL-89531
Upstream Status: linux.git

commit ce390d6
Author: Akhil R <akhilrajeev@nvidia.com>
Date:   Mon Feb 24 14:46:07 2025 +0530

    crypto: tegra - Fix CMAC intermediate result handling

    Saving and restoring of the intermediate results are needed if there is
    context switch caused by another ongoing request on the same engine.
    This is therefore not only to support import/export functionality.
    Hence, save and restore the intermediate result for every non-first task.

    Fixes: 0880bb3 ("crypto: tegra - Add Tegra Security Engine driver")
    Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: Herbert Xu <herbert.xu@redhat.com>

Author: Herbert Xu

drivers/crypto/tegra/tegra-se-aes.c

@@ -1547,23 +1547,16 @@ static int tegra_cmac_do_update(struct ahash_request *req)
 	rctx->residue.size = nresidue;
 
 	/*
-	 * If this is not the first 'update' call, paste the previous copied
+	 * If this is not the first task, paste the previous copied
 	 * intermediate results to the registers so that it gets picked up.
-	 * This is to support the import/export functionality.
 	 */
 	if (!(rctx->task & SHA_FIRST))
 		tegra_cmac_paste_result(ctx->se, rctx);
 
 	cmdlen = tegra_cmac_prep_cmd(ctx, rctx);
 	ret = tegra_se_host1x_submit(se, se->cmdbuf, cmdlen);
 
-	/*
-	 * If this is not the final update, copy the intermediate results
-	 * from the registers so that it can be used in the next 'update'
-	 * call. This is to support the import/export functionality.
-	 */
-	if (!(rctx->task & SHA_FINAL))
-		tegra_cmac_copy_result(ctx->se, rctx);
+	tegra_cmac_copy_result(ctx->se, rctx);
 
 	dma_free_coherent(ctx->se->dev, rctx->datbuf.size,
 			  rctx->datbuf.buf, rctx->datbuf.addr);
@@ -1600,6 +1593,13 @@ static int tegra_cmac_do_final(struct ahash_request *req)
 	rctx->total_len += rctx->residue.size;
 	rctx->config = tegra234_aes_cfg(SE_ALG_CMAC, 0);
 
+	/*
+	 * If this is not the first task, paste the previous copied
+	 * intermediate results to the registers so that it gets picked up.
+	 */
+	if (!(rctx->task & SHA_FIRST))
+		tegra_cmac_paste_result(ctx->se, rctx);
+
 	/* Prepare command and submit */
 	cmdlen = tegra_cmac_prep_cmd(ctx, rctx);
 	ret = tegra_se_host1x_submit(se, se->cmdbuf, cmdlen);