docs/components/ras.rst

30 EA’s and Error interrupts corresponding to NS nodes are handled first in firmware
40 FFH works in conjunction with `Exception Handling Framework`. Exceptions resulting from
41 errors in Non-secure world are routed to and handled in EL3. Said errors are Synchronous
44 RAS Framework in TF-A allows the platform to define an external abort handler and to
59 EA's originating/attributed to NS world are handled first in NS and Kernel navigates
64    to lower EL. This happens when there is an error (EA) in the system which is not yet
72 reflected back to lower EL (KFH) or handled in EL3 itself (FFH).
76 Limitation in KFH Mode
79 When handling asynchronous External Aborts (EAs) synchronized at EL3 entry in Kernel First Handling
80 (KFH) mode, there is a limitation in the current implementation:
98 Once this capability is supported in TF-A, EL3 will be able to handle the original exception
100 eliminating the need for panic handling in this scenario.
103 in KFH mode.
126 RAS functionality is regularly tested in TF-A CI using `RAS test group`_ which has multiple
129 All the tests are written in TF-A tests which runs as NS-EL2 payload.
135    Couple of tests, one each for sync EA and async EA from lower EL which gets handled in El3.
136    Inject External aborts(sync/async) which traps in EL3, FVP has a handler which gracefully
147     Inject an unrecoverable RAS error, which gets handled in EL3.
155     Test nested exception handling at El3 for synchronized async EAs. Inject an SError in lower EL
161   Couple of tests in the group :
165     Inject and handle RAS errors in TF-A tests (no El3 involvement)
170     in IRQ and SMC path.
190 RAS nodes are components in the system capable of signalling errors to PEs
194 error records are implemented in the Standard Error Record format. The RAS
202 -  For memory-mapped error record, its base address and size in KB; for a system
257 must be used in the same file where the array is defined.
273 When the platform enumerates error records, for those records in the Standard
277 -  Return non-zero value when an error is detected in a Standard Error Record;
299 macro must be used in the same file where the array is defined.
301 The array of ``struct ras_interrupt`` must be sorted in the increasing order of
302 interrupt number. This allows for fast look of handlers in order to service RAS
317 masked—meaning, in such systems, External Aborts/SErrors are not immediately
322 thus is able to detect a Double Fault conditions in software, without needing
333 The RAS support in |TF-A| introduces a default implementation of
334 ``plat_ea_handler``, the External Abort handler in EL3. When ``ENABLE_FEAT_RAS``
340 not be called if ``FEAT_RAS`` is not present in hardware. The checks to do so
357 As mentioned in earlier sections, RAS framework interacts with the |EHF| to
366 <non-interrupt-flow>` exceptions follow the sequences outlined in the |EHF|