On the ARMv8 architecture, cache maintenance operations by set/way on the last
level of integrated cache do not affect the system cache. This means that such a
flush or clean operation could result in the data being pushed out to the system
cache rather than main memory. Another CPU could access this data before it
enables its data cache or MMU. Such accesses could be serviced from the main
memory instead of the system cache. If the data in the sysem cache has not yet
been flushed or evicted to main memory then there could be a loss of
coherency. The only mechanism to guarantee that the main memory will be updated
is to use cache maintenance operations to the PoC by MVA(See section D3.4.11
(System level caches) of ARMv8-A Reference Manual (Issue A.g/ARM DDI0487A.G).
This patch removes the reliance of Trusted Firmware on the flush by set/way
operation to ensure visibility of data in the main memory. Cache maintenance
operations by MVA are now used instead. The following are the broad category of
changes:
1. The RW areas of BL2/BL31/BL32 are invalidated by MVA before the C runtime is
initialised. This ensures that any stale cache lines at any level of cache
are removed.
2. Updates to global data in runtime firmware (BL31) by the primary CPU are made
visible to secondary CPUs using a cache clean operation by MVA.
3. Cache maintenance by set/way operations are only used prior to power down.
NOTE: NON-UPSTREAM TRUSTED FIRMWARE CODE SHOULD MAKE EQUIVALENT CHANGES IN
ORDER TO FUNCTION CORRECTLY ON PLATFORMS WITH SUPPORT FOR SYSTEM CACHES.
FixesARM-software/tf-issues#205
Change-Id: I64f1b398de0432813a0e0881d70f8337681f6e9a
In certain Trusted OS implementations it is a requirement to pass them the
highest power level which will enter a power down state during a PSCI
CPU_SUSPEND or SYSTEM_SUSPEND API invocation. This patch passes this power level
to the SPD in the "max_off_pwrlvl" parameter of the svc_suspend() hook.
Currently, the highest power level which was requested to be placed in a low
power state (retention or power down) is passed to the SPD svc_suspend_finish()
hook. This hook is called after emerging from the low power state. It is more
useful to pass the highest power level which was powered down instead. This
patch does this by changing the semantics of the parameter passed to an SPD's
svc_suspend_finish() hook. The name of the parameter has been changed from
"suspend_level" to "max_off_pwrlvl" as well. Same changes have been made to the
parameter passed to the tsp_cpu_resume_main() function.
NOTE: THIS PATCH CHANGES THE SEMANTICS OF THE EXISTING "svc_suspend_finish()"
API BETWEEN THE PSCI AND SPD/SP IMPLEMENTATIONS. THE LATTER MIGHT NEED
UPDATES TO ENSURE CORRECT BEHAVIOUR.
Change-Id: If3a9d39b13119bbb6281f508a91f78a2f46a8b90
This patch reworks the PSCI generic implementation to conform to ARM
Trusted Firmware coding guidelines as described here:
https://github.com/ARM-software/arm-trusted-firmware/wiki
This patch also reviews the use of signed data types within PSCI
Generic code and replaces them with their unsigned counterparts wherever
they are not appropriate. The PSCI_INVALID_DATA macro which was defined
to -1 is now replaced with PSCI_INVALID_PWR_LVL macro which is defined
to PLAT_MAX_PWR_LVL + 1.
Change-Id: Iaea422d0e46fc314e0b173c2b4c16e0d56b2515a
This commit does the switch to the new PSCI framework implementation replacing
the existing files in PSCI folder with the ones in PSCI1.0 folder. The
corresponding makefiles are modified as required for the new implementation.
The platform.h header file is also is switched to the new one
as required by the new frameworks. The build flag ENABLE_PLAT_COMPAT defaults
to 1 to enable compatibility layer which let the existing platform ports to
continue to build and run with minimal changes.
The default weak implementation of platform_get_core_pos() is now removed from
platform_helpers.S and is provided by the compatibility layer.
Note: The Secure Payloads and their dispatchers still use the old platform
and framework APIs and hence it is expected that the ENABLE_PLAT_COMPAT build
flag will remain enabled in subsequent patch. The compatibility for SPDs using
the older APIs on platforms migrated to the new APIs will be added in the
following patch.
Change-Id: I18c51b3a085b564aa05fdd98d11c9f3335712719
Achin Gupta
Soby Mathew