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authorArnd Bergmann <arnd@arndb.de>2017-03-30 16:16:28 +0200
committerArnd Bergmann <arnd@arndb.de>2017-03-30 16:16:28 +0200
commit414d06ace9cca3725b6c2072e1951e1e03807f63 (patch)
tree31e3c2c3da9260d5541e3d8de7045aabcbf66033 /Documentation
parent97da3854c526d3a6ee05c849c96e48d21527606c (diff)
parent14e21cb8f811100a2104e952b8f5bc0326a5e213 (diff)
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Merge tag 'tee-drv-for-4.12' of git://git.linaro.org:/people/jens.wiklander/linux-tee into next/tee
Pull "generic TEE subsystem for v4.12" Introduce generic TEE subsystem: - the TEE subsystem itself - an OP-TEE driver using the subsystem - optee bindings - optee node for hi6220-hikey.dts * tag 'tee-drv-for-4.12' of git://git.linaro.org:/people/jens.wiklander/linux-tee: arm64: dt: hikey: Add optee node Documentation: tee subsystem and op-tee driver tee: add OP-TEE driver tee: generic TEE subsystem dt/bindings: add bindings for optee
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/00-INDEX2
-rw-r--r--Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.txt31
-rw-r--r--Documentation/devicetree/bindings/vendor-prefixes.txt1
-rw-r--r--Documentation/ioctl/ioctl-number.txt1
-rw-r--r--Documentation/tee.txt118
5 files changed, 153 insertions, 0 deletions
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX
index 793acf999e9e..ed3e5e949fce 100644
--- a/Documentation/00-INDEX
+++ b/Documentation/00-INDEX
@@ -412,6 +412,8 @@ sysctl/
- directory with info on the /proc/sys/* files.
target/
- directory with info on generating TCM v4 fabric .ko modules
+tee.txt
+ - info on the TEE subsystem and drivers
this_cpu_ops.txt
- List rationale behind and the way to use this_cpu operations.
thermal/
diff --git a/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.txt b/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.txt
new file mode 100644
index 000000000000..d38834c67dff
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.txt
@@ -0,0 +1,31 @@
+OP-TEE Device Tree Bindings
+
+OP-TEE is a piece of software using hardware features to provide a Trusted
+Execution Environment. The security can be provided with ARM TrustZone, but
+also by virtualization or a separate chip.
+
+We're using "linaro" as the first part of the compatible property for
+the reference implementation maintained by Linaro.
+
+* OP-TEE based on ARM TrustZone required properties:
+
+- compatible : should contain "linaro,optee-tz"
+
+- method : The method of calling the OP-TEE Trusted OS. Permitted
+ values are:
+
+ "smc" : SMC #0, with the register assignments specified
+ in drivers/tee/optee/optee_smc.h
+
+ "hvc" : HVC #0, with the register assignments specified
+ in drivers/tee/optee/optee_smc.h
+
+
+
+Example:
+ firmware {
+ optee {
+ compatible = "linaro,optee-tz";
+ method = "smc";
+ };
+ };
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index ec0bfb9bbebd..e18a96cf7c3a 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -168,6 +168,7 @@ lego LEGO Systems A/S
lenovo Lenovo Group Ltd.
lg LG Corporation
licheepi Lichee Pi
+linaro Linaro Limited
linux Linux-specific binding
lltc Linear Technology Corporation
lsi LSI Corp. (LSI Logic)
diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 08244bea5048..002331b0b48a 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -308,6 +308,7 @@ Code Seq#(hex) Include File Comments
0xA3 80-8F Port ACL in development:
<mailto:tlewis@mindspring.com>
0xA3 90-9F linux/dtlk.h
+0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
0xAA 00-3F linux/uapi/linux/userfaultfd.h
0xAB 00-1F linux/nbd.h
0xAC 00-1F linux/raw.h
diff --git a/Documentation/tee.txt b/Documentation/tee.txt
new file mode 100644
index 000000000000..718599357596
--- /dev/null
+++ b/Documentation/tee.txt
@@ -0,0 +1,118 @@
+TEE subsystem
+This document describes the TEE subsystem in Linux.
+
+A TEE (Trusted Execution Environment) is a trusted OS running in some
+secure environment, for example, TrustZone on ARM CPUs, or a separate
+secure co-processor etc. A TEE driver handles the details needed to
+communicate with the TEE.
+
+This subsystem deals with:
+
+- Registration of TEE drivers
+
+- Managing shared memory between Linux and the TEE
+
+- Providing a generic API to the TEE
+
+The TEE interface
+=================
+
+include/uapi/linux/tee.h defines the generic interface to a TEE.
+
+User space (the client) connects to the driver by opening /dev/tee[0-9]* or
+/dev/teepriv[0-9]*.
+
+- TEE_IOC_SHM_ALLOC allocates shared memory and returns a file descriptor
+ which user space can mmap. When user space doesn't need the file
+ descriptor any more, it should be closed. When shared memory isn't needed
+ any longer it should be unmapped with munmap() to allow the reuse of
+ memory.
+
+- TEE_IOC_VERSION lets user space know which TEE this driver handles and
+ the its capabilities.
+
+- TEE_IOC_OPEN_SESSION opens a new session to a Trusted Application.
+
+- TEE_IOC_INVOKE invokes a function in a Trusted Application.
+
+- TEE_IOC_CANCEL may cancel an ongoing TEE_IOC_OPEN_SESSION or TEE_IOC_INVOKE.
+
+- TEE_IOC_CLOSE_SESSION closes a session to a Trusted Application.
+
+There are two classes of clients, normal clients and supplicants. The latter is
+a helper process for the TEE to access resources in Linux, for example file
+system access. A normal client opens /dev/tee[0-9]* and a supplicant opens
+/dev/teepriv[0-9].
+
+Much of the communication between clients and the TEE is opaque to the
+driver. The main job for the driver is to receive requests from the
+clients, forward them to the TEE and send back the results. In the case of
+supplicants the communication goes in the other direction, the TEE sends
+requests to the supplicant which then sends back the result.
+
+OP-TEE driver
+=============
+
+The OP-TEE driver handles OP-TEE [1] based TEEs. Currently it is only the ARM
+TrustZone based OP-TEE solution that is supported.
+
+Lowest level of communication with OP-TEE builds on ARM SMC Calling
+Convention (SMCCC) [2], which is the foundation for OP-TEE's SMC interface
+[3] used internally by the driver. Stacked on top of that is OP-TEE Message
+Protocol [4].
+
+OP-TEE SMC interface provides the basic functions required by SMCCC and some
+additional functions specific for OP-TEE. The most interesting functions are:
+
+- OPTEE_SMC_FUNCID_CALLS_UID (part of SMCCC) returns the version information
+ which is then returned by TEE_IOC_VERSION
+
+- OPTEE_SMC_CALL_GET_OS_UUID returns the particular OP-TEE implementation, used
+ to tell, for instance, a TrustZone OP-TEE apart from an OP-TEE running on a
+ separate secure co-processor.
+
+- OPTEE_SMC_CALL_WITH_ARG drives the OP-TEE message protocol
+
+- OPTEE_SMC_GET_SHM_CONFIG lets the driver and OP-TEE agree on which memory
+ range to used for shared memory between Linux and OP-TEE.
+
+The GlobalPlatform TEE Client API [5] is implemented on top of the generic
+TEE API.
+
+Picture of the relationship between the different components in the
+OP-TEE architecture.
+
+ User space Kernel Secure world
+ ~~~~~~~~~~ ~~~~~~ ~~~~~~~~~~~~
+ +--------+ +-------------+
+ | Client | | Trusted |
+ +--------+ | Application |
+ /\ +-------------+
+ || +----------+ /\
+ || |tee- | ||
+ || |supplicant| \/
+ || +----------+ +-------------+
+ \/ /\ | TEE Internal|
+ +-------+ || | API |
+ + TEE | || +--------+--------+ +-------------+
+ | Client| || | TEE | OP-TEE | | OP-TEE |
+ | API | \/ | subsys | driver | | Trusted OS |
+ +-------+----------------+----+-------+----+-----------+-------------+
+ | Generic TEE API | | OP-TEE MSG |
+ | IOCTL (TEE_IOC_*) | | SMCCC (OPTEE_SMC_CALL_*) |
+ +-----------------------------+ +------------------------------+
+
+RPC (Remote Procedure Call) are requests from secure world to kernel driver
+or tee-supplicant. An RPC is identified by a special range of SMCCC return
+values from OPTEE_SMC_CALL_WITH_ARG. RPC messages which are intended for the
+kernel are handled by the kernel driver. Other RPC messages will be forwarded to
+tee-supplicant without further involvement of the driver, except switching
+shared memory buffer representation.
+
+References:
+[1] https://github.com/OP-TEE/optee_os
+[2] http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html
+[3] drivers/tee/optee/optee_smc.h
+[4] drivers/tee/optee/optee_msg.h
+[5] http://www.globalplatform.org/specificationsdevice.asp look for
+ "TEE Client API Specification v1.0" and click download.