From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- Documentation/driver-api/tee.rst | 54 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 Documentation/driver-api/tee.rst (limited to 'Documentation/driver-api/tee.rst') diff --git a/Documentation/driver-api/tee.rst b/Documentation/driver-api/tee.rst new file mode 100644 index 000000000..4d58ac071 --- /dev/null +++ b/Documentation/driver-api/tee.rst @@ -0,0 +1,54 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============================================== +TEE (Trusted Execution Environment) driver API +=============================================== + +Kernel provides a TEE bus infrastructure where a Trusted Application is +represented as a device identified via Universally Unique Identifier (UUID) and +client drivers register a table of supported device UUIDs. + +TEE bus infrastructure registers following APIs: + +match(): + iterates over the client driver UUID table to find a corresponding + match for device UUID. If a match is found, then this particular device is + probed via corresponding probe API registered by the client driver. This + process happens whenever a device or a client driver is registered with TEE + bus. + +uevent(): + notifies user-space (udev) whenever a new device is registered on + TEE bus for auto-loading of modularized client drivers. + +TEE bus device enumeration is specific to underlying TEE implementation, so it +is left open for TEE drivers to provide corresponding implementation. + +Then TEE client driver can talk to a matched Trusted Application using APIs +listed in include/linux/tee_drv.h. + +TEE client driver example +------------------------- + +Suppose a TEE client driver needs to communicate with a Trusted Application +having UUID: ``ac6a4085-0e82-4c33-bf98-8eb8e118b6c2``, so driver registration +snippet would look like:: + + static const struct tee_client_device_id client_id_table[] = { + {UUID_INIT(0xac6a4085, 0x0e82, 0x4c33, + 0xbf, 0x98, 0x8e, 0xb8, 0xe1, 0x18, 0xb6, 0xc2)}, + {} + }; + + MODULE_DEVICE_TABLE(tee, client_id_table); + + static struct tee_client_driver client_driver = { + .probe = client_probe, + .remove = client_remove, + .id_table = client_id_table, + .driver = { + .name = DRIVER_NAME, + }, + }; + + module_tee_client_driver(client_driver); -- cgit v1.3.1