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author | Alistair Delva <adelva@google.com> | 2021-02-16 21:01:22 +0000 |
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committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | 2021-02-16 21:01:22 +0000 |
commit | efb2826bb8160e2d8e0fcec85133a7468484f9fd (patch) | |
tree | 37a21c69306801ee7cdda5167a30896c8740155b /docs/components/secure-partition-manager-design.rst | |
parent | b00a71fc312c9781fa6f404dccfb55b062b2ccac (diff) | |
parent | faa476c0caaa598afa5a6109d17102db5fe35ec6 (diff) | |
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Merge branch 'aosp/upstream-master' into HEAD am: faa476c0caHEADandroid-s-beta-5android-s-beta-4android-s-beta-3android-s-beta-2android-s-beta-1mastermain-cg-testing-releaseandroid-s-beta-5android-s-beta-4
Original change: https://android-review.googlesource.com/c/platform/external/arm-trusted-firmware/+/1589611
MUST ONLY BE SUBMITTED BY AUTOMERGER
Change-Id: I3a25534ceed4f8e188510641080d8b8ed49b8f62
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diff --git a/docs/components/secure-partition-manager-design.rst b/docs/components/secure-partition-manager-design.rst deleted file mode 100644 index 52b1c03e8..000000000 --- a/docs/components/secure-partition-manager-design.rst +++ /dev/null @@ -1,819 +0,0 @@ -Secure Partition Manager -************************ - -Background -========== - -In some market segments that primarily deal with client-side devices like mobile -phones, tablets, STBs and embedded devices, a Trusted OS instantiates trusted -applications to provide security services like DRM, secure payment and -authentication. The Global Platform TEE Client API specification defines the API -used by Non-secure world applications to access these services. A Trusted OS -fulfils the requirements of a security service as described above. - -Management services are typically implemented at the highest level of privilege -in the system, i.e. EL3 in Trusted Firmware-A (TF-A). The service requirements are -fulfilled by the execution environment provided by TF-A. - -The following diagram illustrates the corresponding software stack: - -|Image 1| - -In other market segments that primarily deal with server-side devices (e.g. data -centres and enterprise servers) the secure software stack typically does not -include a Global Platform Trusted OS. Security functions are accessed through -other interfaces (e.g. ACPI TCG TPM interface, UEFI runtime variable service). - -Placement of management and security functions with diverse requirements in a -privileged Exception Level (i.e. EL3 or S-EL1) makes security auditing of -firmware more difficult and does not allow isolation of unrelated services from -each other either. - -Introduction -============ - -A **Secure Partition** is a software execution environment instantiated in -S-EL0 that can be used to implement simple management and security services. -Since S-EL0 is an unprivileged Exception Level, a Secure Partition relies on -privileged firmware (i.e. TF-A) to be granted access to system and processor -resources. Essentially, it is a software sandbox in the Secure world that runs -under the control of privileged software, provides one or more services and -accesses the following system resources: - -- Memory and device regions in the system address map. - -- PE system registers. - -- A range of synchronous exceptions (e.g. SMC function identifiers). - -Note that currently TF-A only supports handling one Secure Partition. - -A Secure Partition enables TF-A to implement only the essential secure -services in EL3 and instantiate the rest in a partition in S-EL0. -Furthermore, multiple Secure Partitions can be used to isolate unrelated -services from each other. - -The following diagram illustrates the place of a Secure Partition in a typical -Armv8-A software stack. A single or multiple Secure Partitions provide secure -services to software components in the Non-secure world and other Secure -Partitions. - -|Image 2| - -The TF-A build system is responsible for including the Secure Partition image -in the FIP. During boot, BL2 includes support to authenticate and load the -Secure Partition image. A BL31 component called **Secure Partition Manager -(SPM)** is responsible for managing the partition. This is semantically -similar to a hypervisor managing a virtual machine. - -The SPM is responsible for the following actions during boot: - -- Allocate resources requested by the Secure Partition. - -- Perform architectural and system setup required by the Secure Partition to - fulfil a service request. - -- Implement a standard interface that is used for initialising a Secure - Partition. - -The SPM is responsible for the following actions during runtime: - -- Implement a standard interface that is used by a Secure Partition to fulfil - service requests. - -- Implement a standard interface that is used by the Non-secure world for - accessing the services exported by a Secure Partition. A service can be - invoked through a SMC. - -Alternatively, a partition can be viewed as a thread of execution running under -the control of the SPM. Hence common programming concepts described below are -applicable to a partition. - -Description -=========== - -The previous section introduced some general aspects of the software -architecture of a Secure Partition. This section describes the specific choices -made in the current implementation of this software architecture. Subsequent -revisions of the implementation will include a richer set of features that -enable a more flexible architecture. - -Building TF-A with Secure Partition support -------------------------------------------- - -SPM is supported on the Arm FVP exclusively at the moment. The current -implementation supports inclusion of only a single Secure Partition in which a -service always runs to completion (e.g. the requested services cannot be -preempted to give control back to the Normal world). - -It is not currently possible for BL31 to integrate SPM support and a Secure -Payload Dispatcher (SPD) at the same time; they are mutually exclusive. In the -SPM bootflow, a Secure Partition image executing at S-EL0 replaces the Secure -Payload image executing at S-EL1 (e.g. a Trusted OS). Both are referred to as -BL32. - -A working prototype of a SP has been implemented by re-purposing the EDK2 code -and tools, leveraging the concept of the *Standalone Management Mode (MM)* in -the UEFI specification (see the PI v1.6 Volume 4: Management Mode Core -Interface). This will be referred to as the *Standalone MM Secure Partition* in -the rest of this document. - -To enable SPM support in TF-A, the source code must be compiled with the build -flag ``SPM_MM=1``, along with ``EL3_EXCEPTION_HANDLING=1``. On Arm -platforms the build option ``ARM_BL31_IN_DRAM`` must be set to 1. Also, the -location of the binary that contains the BL32 image -(``BL32=path/to/image.bin``) must be specified. - -First, build the Standalone MM Secure Partition. To build it, refer to the -`instructions in the EDK2 repository`_. - -Then build TF-A with SPM support and include the Standalone MM Secure Partition -image in the FIP: - -.. code:: shell - - BL32=path/to/standalone/mm/sp BL33=path/to/bl33.bin \ - make PLAT=fvp SPM_MM=1 EL3_EXCEPTION_HANDLING=1 ARM_BL31_IN_DRAM=1 all fip - -Describing Secure Partition resources -------------------------------------- - -TF-A exports a porting interface that enables a platform to specify the system -resources required by the Secure Partition. Some instructions are given below. -However, this interface is under development and it may change as new features -are implemented. - -- A Secure Partition is considered a BL32 image, so the same defines that apply - to BL32 images apply to a Secure Partition: ``BL32_BASE`` and ``BL32_LIMIT``. - -- The following defines are needed to allocate space for the translation tables - used by the Secure Partition: ``PLAT_SP_IMAGE_MMAP_REGIONS`` and - ``PLAT_SP_IMAGE_MAX_XLAT_TABLES``. - -- The functions ``plat_get_secure_partition_mmap()`` and - ``plat_get_secure_partition_boot_info()`` have to be implemented. The file - ``plat/arm/board/fvp/fvp_common.c`` can be used as an example. It uses the - defines in ``include/plat/arm/common/arm_spm_def.h``. - - - ``plat_get_secure_partition_mmap()`` returns an array of mmap regions that - describe the memory regions that the SPM needs to allocate for a Secure - Partition. - - - ``plat_get_secure_partition_boot_info()`` returns a - ``spm_mm_boot_info_t`` struct that is populated by the platform - with information about the memory map of the Secure Partition. - -For an example of all the changes in context, you may refer to commit -``e29efeb1b4``, in which the port for FVP was introduced. - -Accessing Secure Partition services ------------------------------------ - -The `SMC Calling Convention`_ (*Arm DEN 0028B*) describes SMCs as a conduit for -accessing services implemented in the Secure world. The ``MM_COMMUNICATE`` -interface defined in the `Management Mode Interface Specification`_ (*Arm DEN -0060A*) is used to invoke a Secure Partition service as a Fast Call. - -The mechanism used to identify a service within the partition depends on the -service implementation. It is assumed that the caller of the service will be -able to discover this mechanism through standard platform discovery mechanisms -like ACPI and Device Trees. For example, *Volume 4: Platform Initialisation -Specification v1.6. Management Mode Core Interface* specifies that a GUID is -used to identify a management mode service. A client populates the GUID in the -``EFI_MM_COMMUNICATE_HEADER``. The header is populated in the communication -buffer shared with the Secure Partition. - -A Fast Call appears to be atomic from the perspective of the caller and returns -when the requested operation has completed. A service invoked through the -``MM_COMMUNICATE`` SMC will run to completion in the partition on a given CPU. -The SPM is responsible for guaranteeing this behaviour. This means that there -can only be a single outstanding Fast Call in a partition on a given CPU. - -Exchanging data with the Secure Partition ------------------------------------------ - -The exchange of data between the Non-secure world and the partition takes place -through a shared memory region. The location of data in the shared memory area -is passed as a parameter to the ``MM_COMMUNICATE`` SMC. The shared memory area -is statically allocated by the SPM and is expected to be either implicitly known -to the Non-secure world or discovered through a platform discovery mechanism -e.g. ACPI table or device tree. It is possible for the Non-secure world to -exchange data with a partition only if it has been populated in this shared -memory area. The shared memory area is implemented as per the guidelines -specified in Section 3.2.3 of the `Management Mode Interface Specification`_ -(*Arm DEN 0060A*). - -The format of data structures used to encapsulate data in the shared memory is -agreed between the Non-secure world and the Secure Partition. For example, in -the `Management Mode Interface specification`_ (*Arm DEN 0060A*), Section 4 -describes that the communication buffer shared between the Non-secure world and -the Management Mode (MM) in the Secure world must be of the type -``EFI_MM_COMMUNICATE_HEADER``. This data structure is defined in *Volume 4: -Platform Initialisation Specification v1.6. Management Mode Core Interface*. -Any caller of a MM service will have to use the ``EFI_MM_COMMUNICATE_HEADER`` -data structure. - -Runtime model of the Secure Partition -===================================== - -This section describes how the Secure Partition interfaces with the SPM. - -Interface with SPM ------------------- - -In order to instantiate one or more secure services in the Secure Partition in -S-EL0, the SPM should define the following types of interfaces: - -- Interfaces that enable access to privileged operations from S-EL0. These - operations typically require access to system resources that are either shared - amongst multiple software components in the Secure world or cannot be directly - accessed from an unprivileged Exception Level. - -- Interfaces that establish the control path between the SPM and the Secure - Partition. - -This section describes the APIs currently exported by the SPM that enable a -Secure Partition to initialise itself and export its services in S-EL0. These -interfaces are not accessible from the Non-secure world. - -Conduit -^^^^^^^ - -The `SMC Calling Convention`_ (*Arm DEN 0028B*) specification describes the SMC -and HVC conduits for accessing firmware services and their availability -depending on the implemented Exception levels. In S-EL0, the Supervisor Call -exception (SVC) is the only architectural mechanism available for unprivileged -software to make a request for an operation implemented in privileged software. -Hence, the SVC conduit must be used by the Secure Partition to access interfaces -implemented by the SPM. - -A SVC causes an exception to be taken to S-EL1. TF-A assumes ownership of S-EL1 -and installs a simple exception vector table in S-EL1 that relays a SVC request -from a Secure Partition as a SMC request to the SPM in EL3. Upon servicing the -SMC request, Trusted Firmware-A returns control directly to S-EL0 through an -ERET instruction. - -Calling conventions -^^^^^^^^^^^^^^^^^^^ - -The `SMC Calling Convention`_ (*Arm DEN 0028B*) specification describes the -32-bit and 64-bit calling conventions for the SMC and HVC conduits. The SVC -conduit introduces the concept of SVC32 and SVC64 calling conventions. The SVC32 -and SVC64 calling conventions are equivalent to the 32-bit (SMC32) and the -64-bit (SMC64) calling conventions respectively. - -Communication initiated by SPM -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -A service request is initiated from the SPM through an exception return -instruction (ERET) to S-EL0. Later, the Secure Partition issues an SVC -instruction to signal completion of the request. Some example use cases are -given below: - -- A request to initialise the Secure Partition during system boot. - -- A request to handle a runtime service request. - -Communication initiated by Secure Partition -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -A request is initiated from the Secure Partition by executing a SVC instruction. -An ERET instruction is used by TF-A to return to S-EL0 with the result of the -request. - -For instance, a request to perform privileged operations on behalf of a -partition (e.g. management of memory attributes in the translation tables for -the Secure EL1&0 translation regime). - -Interfaces -^^^^^^^^^^ - -The current implementation reserves function IDs for Fast Calls in the Standard -Secure Service calls range (see `SMC Calling Convention`_ (*Arm DEN 0028B*) -specification) for each API exported by the SPM. This section defines the -function prototypes for each function ID. The function IDs specify whether one -or both of the SVC32 and SVC64 calling conventions can be used to invoke the -corresponding interface. - -Secure Partition Event Management -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -The Secure Partition provides an Event Management interface that is used by the -SPM to delegate service requests to the Secure Partition. The interface also -allows the Secure Partition to: - -- Register with the SPM a service that it provides. -- Indicate completion of a service request delegated by the SPM - -Miscellaneous interfaces ------------------------- - -``SPM_MM_VERSION_AARCH32`` -^^^^^^^^^^^^^^^^^^^^^^^^^^ - -- Description - - Returns the version of the interface exported by SPM. - -- Parameters - - - **uint32** - Function ID - - - SVC32 Version: **0x84000060** - -- Return parameters - - - **int32** - Status - - On success, the format of the value is as follows: - - - Bit [31]: Must be 0 - - Bits [30:16]: Major Version. Must be 0 for this revision of the SPM - interface. - - Bits [15:0]: Minor Version. Must be 1 for this revision of the SPM - interface. - - On error, the format of the value is as follows: - - - ``NOT_SUPPORTED``: SPM interface is not supported or not available for the - client. - -- Usage - - This function returns the version of the Secure Partition Manager - implementation. The major version is 0 and the minor version is 1. The version - number is a 31-bit unsigned integer, with the upper 15 bits denoting the major - revision, and the lower 16 bits denoting the minor revision. The following - rules apply to the version numbering: - - - Different major revision values indicate possibly incompatible functions. - - - For two revisions, A and B, for which the major revision values are - identical, if the minor revision value of revision B is greater than the - minor revision value of revision A, then every function in revision A must - work in a compatible way with revision B. However, it is possible for - revision B to have a higher function count than revision A. - -- Implementation responsibilities - - If this function returns a valid version number, all the functions that are - described subsequently must be implemented, unless it is explicitly stated - that a function is optional. - -See `Error Codes`_ for integer values that are associated with each return -code. - -Secure Partition Initialisation -------------------------------- - -The SPM is responsible for initialising the architectural execution context to -enable initialisation of a service in S-EL0. The responsibilities of the SPM are -listed below. At the end of initialisation, the partition issues a -``MM_SP_EVENT_COMPLETE_AARCH64`` call (described later) to signal readiness for -handling requests for services implemented by the Secure Partition. The -initialisation event is executed as a Fast Call. - -Entry point invocation -^^^^^^^^^^^^^^^^^^^^^^ - -The entry point for service requests that should be handled as Fast Calls is -used as the target of the ERET instruction to start initialisation of the Secure -Partition. - -Architectural Setup -^^^^^^^^^^^^^^^^^^^ - -At cold boot, system registers accessible from S-EL0 will be in their reset -state unless otherwise specified. The SPM will perform the following -architectural setup to enable execution in S-EL0 - -MMU setup -^^^^^^^^^ - -The platform port of a Secure Partition specifies to the SPM a list of regions -that it needs access to and their attributes. The SPM validates this resource -description and initialises the Secure EL1&0 translation regime as follows. - -1. Device regions are mapped with nGnRE attributes and Execute Never - instruction access permissions. - -2. Code memory regions are mapped with RO data and Executable instruction access - permissions. - -3. Read Only data memory regions are mapped with RO data and Execute Never - instruction access permissions. - -4. Read Write data memory regions are mapped with RW data and Execute Never - instruction access permissions. - -5. If the resource description does not explicitly describe the type of memory - regions then all memory regions will be marked with Code memory region - attributes. - -6. The ``UXN`` and ``PXN`` bits are set for regions that are not executable by - S-EL0 or S-EL1. - -System Register Setup -^^^^^^^^^^^^^^^^^^^^^ - -System registers that influence software execution in S-EL0 are setup by the SPM -as follows: - -1. ``SCTLR_EL1`` - - - ``UCI=1`` - - ``EOE=0`` - - ``WXN=1`` - - ``nTWE=1`` - - ``nTWI=1`` - - ``UCT=1`` - - ``DZE=1`` - - ``I=1`` - - ``UMA=0`` - - ``SA0=1`` - - ``C=1`` - - ``A=1`` - - ``M=1`` - -2. ``CPACR_EL1`` - - - ``FPEN=b'11`` - -3. ``PSTATE`` - - - ``D,A,I,F=1`` - - ``CurrentEL=0`` (EL0) - - ``SpSel=0`` (Thread mode) - - ``NRW=0`` (AArch64) - -General Purpose Register Setup -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -SPM will invoke the entry point of a service by executing an ERET instruction. -This transition into S-EL0 is special since it is not in response to a previous -request through a SVC instruction. This is the first entry into S-EL0. The -general purpose register usage at the time of entry will be as specified in the -"Return State" column of Table 3-1 in Section 3.1 "Register use in AArch64 SMC -calls" of the `SMC Calling Convention`_ (*Arm DEN 0028B*) specification. In -addition, certain other restrictions will be applied as described below. - -1. ``SP_EL0`` - - A non-zero value will indicate that the SPM has initialised the stack pointer - for the current CPU. - - The value will be 0 otherwise. - -2. ``X4-X30`` - - The values of these registers will be 0. - -3. ``X0-X3`` - - Parameters passed by the SPM. - - - ``X0``: Virtual address of a buffer shared between EL3 and S-EL0. The - buffer will be mapped in the Secure EL1&0 translation regime with read-only - memory attributes described earlier. - - - ``X1``: Size of the buffer in bytes. - - - ``X2``: Cookie value (*IMPLEMENTATION DEFINED*). - - - ``X3``: Cookie value (*IMPLEMENTATION DEFINED*). - -Runtime Event Delegation ------------------------- - -The SPM receives requests for Secure Partition services through a synchronous -invocation (i.e. a SMC from the Non-secure world). These requests are delegated -to the partition by programming a return from the last -``MM_SP_EVENT_COMPLETE_AARCH64`` call received from the partition. The last call -was made to signal either completion of Secure Partition initialisation or -completion of a partition service request. - -``MM_SP_EVENT_COMPLETE_AARCH64`` -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -- Description - - Signal completion of the last SP service request. - -- Parameters - - - **uint32** - Function ID - - - SVC64 Version: **0xC4000061** - - - **int32** - Event Status Code - - Zero or a positive value indicates that the event was handled successfully. - The values depend upon the original event that was delegated to the Secure - partition. They are described as follows. - - - ``SUCCESS`` : Used to indicate that the Secure Partition was initialised - or a runtime request was handled successfully. - - - Any other value greater than 0 is used to pass a specific Event Status - code in response to a runtime event. - - A negative value indicates an error. The values of Event Status code depend - on the original event. - -- Return parameters - - - **int32** - Event ID/Return Code - - Zero or a positive value specifies the unique ID of the event being - delegated to the partition by the SPM. - - In the current implementation, this parameter contains the function ID of - the ``MM_COMMUNICATE`` SMC. This value indicates to the partition that an - event has been delegated to it in response to an ``MM_COMMUNICATE`` request - from the Non-secure world. - - A negative value indicates an error. The format of the value is as follows: - - - ``NOT_SUPPORTED``: Function was called from the Non-secure world. - - See `Error Codes`_ for integer values that are associated with each return - code. - - - **uint32** - Event Context Address - - Address of a buffer shared between the SPM and Secure Partition to pass - event specific information. The format of the data populated in the buffer - is implementation defined. - - The buffer is mapped in the Secure EL1&0 translation regime with read-only - memory attributes described earlier. - - For the SVC64 version, this parameter is a 64-bit Virtual Address (VA). - - For the SVC32 version, this parameter is a 32-bit Virtual Address (VA). - - - **uint32** - Event context size - - Size of the memory starting at Event Address. - - - **uint32/uint64** - Event Cookie - - This is an optional parameter. If unused its value is SBZ. - -- Usage - - This function signals to the SPM that the handling of the last event delegated - to a partition has completed. The partition is ready to handle its next event. - A return from this function is in response to the next event that will be - delegated to the partition. The return parameters describe the next event. - -- Caller responsibilities - - A Secure Partition must only call ``MM_SP_EVENT_COMPLETE_AARCH64`` to signal - completion of a request that was delegated to it by the SPM. - -- Callee responsibilities - - When the SPM receives this call from a Secure Partition, the corresponding - syndrome information can be used to return control through an ERET - instruction, to the instruction immediately after the call in the Secure - Partition context. This syndrome information comprises of general purpose and - system register values when the call was made. - - The SPM must save this syndrome information and use it to delegate the next - event to the Secure Partition. The return parameters of this interface must - specify the properties of the event and be populated in ``X0-X3/W0-W3`` - registers. - -Secure Partition Memory Management ----------------------------------- - -A Secure Partition executes at S-EL0, which is an unprivileged Exception Level. -The SPM is responsible for enabling access to regions of memory in the system -address map from a Secure Partition. This is done by mapping these regions in -the Secure EL1&0 Translation regime with appropriate memory attributes. -Attributes refer to memory type, permission, cacheability and shareability -attributes used in the Translation tables. The definitions of these attributes -and their usage can be found in the `Armv8-A ARM`_ (*Arm DDI 0487*). - -All memory required by the Secure Partition is allocated upfront in the SPM, -even before handing over to the Secure Partition for the first time. The initial -access permissions of the memory regions are statically provided by the platform -port and should allow the Secure Partition to run its initialisation code. - -However, they might not suit the final needs of the Secure Partition because its -final memory layout might not be known until the Secure Partition initialises -itself. As the Secure Partition initialises its runtime environment it might, -for example, load dynamically some modules. For instance, a Secure Partition -could implement a loader for a standard executable file format (e.g. an PE-COFF -loader for loading executable files at runtime). These executable files will be -a part of the Secure Partition image. The location of various sections in an -executable file and their permission attributes (e.g. read-write data, read-only -data and code) will be known only when the file is loaded into memory. - -In this case, the Secure Partition needs a way to change the access permissions -of its memory regions. The SPM provides this feature through the -``MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64`` SVC interface. This interface is -available to the Secure Partition during a specific time window: from the first -entry into the Secure Partition up to the first ``SP_EVENT_COMPLETE`` call that -signals the Secure Partition has finished its initialisation. Once the -initialisation is complete, the SPM does not allow changes to the memory -attributes. - -This section describes the standard SVC interface that is implemented by the SPM -to determine and change permission attributes of memory regions that belong to a -Secure Partition. - -``MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64`` -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -- Description - - Request the permission attributes of a memory region from S-EL0. - -- Parameters - - - **uint32** Function ID - - - SVC64 Version: **0xC4000064** - - - **uint64** Base Address - - This parameter is a 64-bit Virtual Address (VA). - - There are no alignment restrictions on the Base Address. The permission - attributes of the translation granule it lies in are returned. - -- Return parameters - - - **int32** - Memory Attributes/Return Code - - On success the format of the Return Code is as follows: - - - Bits[1:0] : Data access permission - - - b'00 : No access - - b'01 : Read-Write access - - b'10 : Reserved - - b'11 : Read-only access - - - Bit[2]: Instruction access permission - - - b'0 : Executable - - b'1 : Non-executable - - - Bit[30:3] : Reserved. SBZ. - - - Bit[31] : Must be 0 - - On failure the following error codes are returned: - - - ``INVALID_PARAMETERS``: The Secure Partition is not allowed to access the - memory region the Base Address lies in. - - - ``NOT_SUPPORTED`` : The SPM does not support retrieval of attributes of - any memory page that is accessible by the Secure Partition, or the - function was called from the Non-secure world. Also returned if it is - used after ``MM_SP_EVENT_COMPLETE_AARCH64``. - - See `Error Codes`_ for integer values that are associated with each return - code. - -- Usage - - This function is used to request the permission attributes for S-EL0 on a - memory region accessible from a Secure Partition. The size of the memory - region is equal to the Translation Granule size used in the Secure EL1&0 - translation regime. Requests to retrieve other memory region attributes are - not currently supported. - -- Caller responsibilities - - The caller must obtain the Translation Granule Size of the Secure EL1&0 - translation regime from the SPM through an implementation defined method. - -- Callee responsibilities - - The SPM must not return the memory access controls for a page of memory that - is not accessible from a Secure Partition. - -``MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64`` -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -- Description - - Set the permission attributes of a memory region from S-EL0. - -- Parameters - - - **uint32** - Function ID - - - SVC64 Version: **0xC4000065** - - - **uint64** - Base Address - - This parameter is a 64-bit Virtual Address (VA). - - The alignment of the Base Address must be greater than or equal to the size - of the Translation Granule Size used in the Secure EL1&0 translation - regime. - - - **uint32** - Page count - - Number of pages starting from the Base Address whose memory attributes - should be changed. The page size is equal to the Translation Granule Size. - - - **uint32** - Memory Access Controls - - - Bits[1:0] : Data access permission - - - b'00 : No access - - b'01 : Read-Write access - - b'10 : Reserved - - b'11 : Read-only access - - - Bit[2] : Instruction access permission - - - b'0 : Executable - - b'1 : Non-executable - - - Bits[31:3] : Reserved. SBZ. - - A combination of attributes that mark the region with RW and Executable - permissions is prohibited. A request to mark a device memory region with - Executable permissions is prohibited. - -- Return parameters - - - **int32** - Return Code - - - ``SUCCESS``: The Memory Access Controls were changed successfully. - - - ``DENIED``: The SPM is servicing a request to change the attributes of a - memory region that overlaps with the region specified in this request. - - - ``INVALID_PARAMETER``: An invalid combination of Memory Access Controls - has been specified. The Base Address is not correctly aligned. The Secure - Partition is not allowed to access part or all of the memory region - specified in the call. - - - ``NO_MEMORY``: The SPM does not have memory resources to change the - attributes of the memory region in the translation tables. - - - ``NOT_SUPPORTED``: The SPM does not permit change of attributes of any - memory region that is accessible by the Secure Partition. Function was - called from the Non-secure world. Also returned if it is used after - ``MM_SP_EVENT_COMPLETE_AARCH64``. - - See `Error Codes`_ for integer values that are associated with each return - code. - -- Usage - - This function is used to change the permission attributes for S-EL0 on a - memory region accessible from a Secure Partition. The size of the memory - region is equal to the Translation Granule size used in the Secure EL1&0 - translation regime. Requests to change other memory region attributes are not - currently supported. - - This function is only available at boot time. This interface is revoked after - the Secure Partition sends the first ``MM_SP_EVENT_COMPLETE_AARCH64`` to - signal that it is initialised and ready to receive run-time requests. - -- Caller responsibilities - - The caller must obtain the Translation Granule Size of the Secure EL1&0 - translation regime from the SPM through an implementation defined method. - -- Callee responsibilities - - The SPM must preserve the original memory access controls of the region of - memory in case of an unsuccessful call. The SPM must preserve the consistency - of the S-EL1 translation regime if this function is called on different PEs - concurrently and the memory regions specified overlap. - -Error Codes ------------ - -.. csv-table:: - :header: "Name", "Value" - - ``SUCCESS``,0 - ``NOT_SUPPORTED``,-1 - ``INVALID_PARAMETER``,-2 - ``DENIED``,-3 - ``NO_MEMORY``,-5 - ``NOT_PRESENT``,-7 - --------------- - -*Copyright (c) 2017-2019, Arm Limited and Contributors. All rights reserved.* - -.. _Armv8-A ARM: https://developer.arm.com/docs/ddi0487/latest/arm-architecture-reference-manual-armv8-for-armv8-a-architecture-profile -.. _instructions in the EDK2 repository: https://github.com/tianocore/edk2-staging/blob/AArch64StandaloneMm/HowtoBuild.MD -.. _Management Mode Interface Specification: http://infocenter.arm.com/help/topic/com.arm.doc.den0060a/DEN0060A_ARM_MM_Interface_Specification.pdf -.. _SDEI Specification: http://infocenter.arm.com/help/topic/com.arm.doc.den0054a/ARM_DEN0054A_Software_Delegated_Exception_Interface.pdf -.. _SMC Calling Convention: http://infocenter.arm.com/help/topic/com.arm.doc.den0028b/ARM_DEN0028B_SMC_Calling_Convention.pdf - -.. |Image 1| image:: ../resources/diagrams/secure_sw_stack_tos.png -.. |Image 2| image:: ../resources/diagrams/secure_sw_stack_sp.png |