From: Allen Pais apais@linux.microsoft.com
Implement a .shutdown hook that will be called during a kexec operation so that the TEE shared memory, session, and context that were set up during .probe can be properly freed/closed.
Additionally, don't use dma-buf backed shared memory for the multi-page dynamic shm that's private to the driver. dma-buf backed shared memory cannot be reliably freed and unregistered during a kexec operation even when tee_shm_free() is called on the shm from a .shutdown hook. The problem occurs because dma_buf_put() calls fput() which then uses task_work_add(), with the TWA_RESUME parameter, to queue tee_shm_release() to be called before the current task returns to user mode. However, the current task never returns to user mode before the kexec completes so the memory is never freed nor unregistered.
Continue to register the multi-page dynamic shm with the TEE so that all 4K chunks can be used.
Fixes: 246880958ac9 ("firmware: broadcom: add OP-TEE based BNXT f/w manager") Signed-off-by: Allen Pais apais@linux.microsoft.com Co-developed-by: Tyler Hicks tyhicks@linux.microsoft.com Signed-off-by: Tyler Hicks tyhicks@linux.microsoft.com --- drivers/firmware/broadcom/tee_bnxt_fw.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/broadcom/tee_bnxt_fw.c b/drivers/firmware/broadcom/tee_bnxt_fw.c index ed10da5313e8..c496723e9e8d 100644 --- a/drivers/firmware/broadcom/tee_bnxt_fw.c +++ b/drivers/firmware/broadcom/tee_bnxt_fw.c @@ -213,7 +213,7 @@ static int tee_bnxt_fw_probe(struct device *dev) pvt_data.dev = dev;
fw_shm_pool = tee_shm_alloc(pvt_data.ctx, MAX_SHM_MEM_SZ, - TEE_SHM_MAPPED | TEE_SHM_DMA_BUF); + TEE_SHM_MAPPED | TEE_SHM_REGISTER); if (IS_ERR(fw_shm_pool)) { dev_err(pvt_data.dev, "tee_shm_alloc failed\n"); err = PTR_ERR(fw_shm_pool); @@ -242,6 +242,14 @@ static int tee_bnxt_fw_remove(struct device *dev) return 0; }
+static void tee_bnxt_fw_shutdown(struct device *dev) +{ + tee_shm_free(pvt_data.fw_shm_pool); + tee_client_close_session(pvt_data.ctx, pvt_data.session_id); + tee_client_close_context(pvt_data.ctx); + pvt_data.ctx = NULL; +} + static const struct tee_client_device_id tee_bnxt_fw_id_table[] = { {UUID_INIT(0x6272636D, 0x2019, 0x0716, 0x42, 0x43, 0x4D, 0x5F, 0x53, 0x43, 0x48, 0x49)}, @@ -257,6 +265,7 @@ static struct tee_client_driver tee_bnxt_fw_driver = { .bus = &tee_bus_type, .probe = tee_bnxt_fw_probe, .remove = tee_bnxt_fw_remove, + .shutdown = tee_bnxt_fw_shutdown, }, };