The PAS image initialization path always retains the metadata buffer when a valid qcom_scm_pas_context is provided, even if the caller does not require it. This implicit behavior leads to unclear buffer ownership and forces new users of qcom_mdt_pas_load() to manually release metadata, which is error‑ prone and incorrect.
Add a keep_mdt_buf flag to struct qcom_scm_pas_context to make metadata retention explicit. Metadata buffers are now freed by default and are only preserved when this flag is set. qcom_q6v5_pas enables this during probe for contexts that require retained metadata for subsequent PAS operations, while existing callers continue to work unchanged. Signed-off-by: Mukesh Ojha <[email protected]> --- drivers/firmware/qcom/qcom_scm.c | 18 +++++++++++++++--- drivers/remoteproc/qcom_q6v5_pas.c | 3 +++ include/linux/firmware/qcom/qcom_pas.h | 1 + 3 files changed, 19 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c index 16ae42e6c434..54ffec97cc26 100644 --- a/drivers/firmware/qcom/qcom_scm.c +++ b/drivers/firmware/qcom/qcom_scm.c @@ -625,7 +625,7 @@ static int qcom_scm_pas_prep_and_init_image(struct device *dev, mdata_phys = qcom_tzmem_to_phys(mdata_buf); ret = __qcom_scm_pas_init_image(dev, ctx->pas_id, mdata_phys, &res); - if (ret < 0) + if (ret < 0 || !ctx->keep_mdt_buf) qcom_tzmem_free(mdata_buf); else ctx->ptr = mdata_buf; @@ -664,9 +664,21 @@ static int qcom_scm_pas_init_image(struct device *dev, u32 pas_id, memcpy(mdata_buf, metadata, size); ret = __qcom_scm_pas_init_image(dev, pas_id, mdata_phys, &res); - if (ret < 0 || !ctx) { + + /* + * Some clients still pass the PAS context as NULL. Until all clients + * switch to qcom_mdt_pas_load() and provide a valid PAS context, check + * for NULL before dereferencing it. + * + * When a valid context is provided, keep_mdt_buf controls whether the + * metadata buffer is retained after PAS_INIT. PAS remoteproc subsystems + * set this flag so metadata persists until auth_and_reset() completes, + * as TrustZone keeps the buffers locked until then. Other callers leave + * it unset and metadata is freed immediately after the PAS_INIT call. + */ + if (ret < 0 || !ctx || !ctx->keep_mdt_buf) { dma_free_coherent(dev, size, mdata_buf, mdata_phys); - } else if (ctx) { + } else { ctx->ptr = mdata_buf; ctx->phys = mdata_phys; ctx->size = size; diff --git a/drivers/remoteproc/qcom_q6v5_pas.c b/drivers/remoteproc/qcom_q6v5_pas.c index 0391e30f42ba..38e6f6019825 100644 --- a/drivers/remoteproc/qcom_q6v5_pas.c +++ b/drivers/remoteproc/qcom_q6v5_pas.c @@ -722,6 +722,7 @@ static int qcom_pas_alloc_memory_region(struct qcom_pas *pas) if (IS_ERR(pas->pas_ctx)) return PTR_ERR(pas->pas_ctx); + pas->pas_ctx->keep_mdt_buf = true; if (!pas->dtb_pas_id) return 0; @@ -740,6 +741,8 @@ static int qcom_pas_alloc_memory_region(struct qcom_pas *pas) if (IS_ERR(pas->dtb_pas_ctx)) return PTR_ERR(pas->dtb_pas_ctx); + pas->dtb_pas_ctx->keep_mdt_buf = true; + return 0; } diff --git a/include/linux/firmware/qcom/qcom_pas.h b/include/linux/firmware/qcom/qcom_pas.h index fb2ec3be6a16..1d132e89536e 100644 --- a/include/linux/firmware/qcom/qcom_pas.h +++ b/include/linux/firmware/qcom/qcom_pas.h @@ -22,6 +22,7 @@ struct qcom_pas_context { dma_addr_t phys; ssize_t size; bool use_tzmem; + bool keep_mdt_buf; }; static inline void __iomem *qcom_pas_ctx_map(struct qcom_pas_context *ctx) -- 2.53.0
