From fdc915f7f71939ad5a3dda3389b8d2d7a7c5ee66 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Tue, 3 Jan 2017 09:07:32 -0800 Subject: tpm: expose spaces via a device link /dev/tpmrm Currently the tpm spaces are not exposed to userspace. Make this exposure via a separate device, which can now be opened multiple times because each read/write transaction goes separately via the space. Concurrency is protected by the chip->tpm_mutex for each read/write transaction separately. The TPM is cleared of all transient objects by the time the mutex is dropped, so there should be no interference between the kernel and userspace. Signed-off-by: James Bottomley Tested-by: Jarkko Sakkinen Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm-interface.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'drivers/char/tpm/tpm-interface.c') diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index d09cf26365c3..16abbf9cb53a 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -1262,9 +1262,17 @@ static int __init tpm_init(void) return PTR_ERR(tpm_class); } - rc = alloc_chrdev_region(&tpm_devt, 0, TPM_NUM_DEVICES, "tpm"); + tpmrm_class = class_create(THIS_MODULE, "tpmrm"); + if (IS_ERR(tpmrm_class)) { + pr_err("couldn't create tpmrm class\n"); + class_destroy(tpm_class); + return PTR_ERR(tpmrm_class); + } + + rc = alloc_chrdev_region(&tpm_devt, 0, 2*TPM_NUM_DEVICES, "tpm"); if (rc < 0) { pr_err("tpm: failed to allocate char dev region\n"); + class_destroy(tpmrm_class); class_destroy(tpm_class); return rc; } @@ -1276,7 +1284,8 @@ static void __exit tpm_exit(void) { idr_destroy(&dev_nums_idr); class_destroy(tpm_class); - unregister_chrdev_region(tpm_devt, TPM_NUM_DEVICES); + class_destroy(tpmrm_class); + unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES); } subsys_initcall(tpm_init); -- cgit v1.2.3