On a GICv2 system, interrupts that should be handled in the secure world are
typically signalled as FIQs. On a GICv3 system, these interrupts are signalled
as IRQs instead. The mechanism for handling both types of interrupts is the same
in both cases. This patch enables the TSP to run on a GICv3 system by:
1. adding support for handling IRQs in the exception handling code.
2. removing use of "fiq" in the names of data structures, macros and functions.
The build option TSPD_ROUTE_IRQ_TO_EL3 is deprecated and is replaced with a
new build flag TSP_NS_INTR_ASYNC_PREEMPT. For compatibility reasons, if the
former build flag is defined, it will be used to define the value for the
new build flag. The documentation is also updated accordingly.
Change-Id: I1807d371f41c3656322dd259340a57649833065e
The TSP is expected to pass control back to EL3 if it gets preempted due to
an interrupt while handling a Standard SMC in the following scenarios:
1. An FIQ preempts Standard SMC execution and that FIQ is not a TSP Secure
timer interrupt or is preempted by a higher priority interrupt by the time
the TSP acknowledges it. In this case, the TSP issues an SMC with the ID
as `TSP_EL3_FIQ`. Currently this case is never expected to happen as only
the TSP Secure Timer is expected to generate FIQ.
2. An IRQ preempts Standard SMC execution and in this case the TSP issues
an SMC with the ID as `TSP_PREEMPTED`.
In both the cases, the TSPD hands control back to the normal world and returns
returns an error code to the normal world to indicate that the standard SMC it
had issued has been preempted but not completed.
This patch unifies the handling of these two cases in the TSPD and ensures that
the TSP only uses TSP_PREEMPTED instead of separate SMC IDs. Also instead of 2
separate error codes, SMC_PREEMPTED and TSP_EL3_FIQ, only SMC_PREEMPTED is
returned as error code back to the normal world.
Background information: On a GICv3 system, when the secure world has affinity
routing enabled, in 2. an FIQ will preempt TSP execution instead of an IRQ. The
FIQ could be a result of a Group 0 or a Group 1 NS interrupt. In both case, the
TSPD passes control back to the normal world upon receipt of the TSP_PREEMPTED
SMC. A Group 0 interrupt will immediately preempt execution to EL3 where it
will be handled. This allows for unified interrupt handling in TSP for both
GICv3 and GICv2 systems.
Change-Id: I9895344db74b188021e3f6a694701ad272fb40d4
This patch disables routing of external aborts from lower exception levels to
EL3 and ensures that a SError interrupt generated as a result of execution in
EL3 is taken locally instead of a lower exception level.
The SError interrupt is enabled in the TSP code only when the operation has not
been directly initiated by the normal world. This is to prevent the possibility
of an asynchronous external abort which originated in normal world from being
taken when execution is in S-EL1.
FixesARM-software/tf-issues#153
Change-Id: I157b996c75996d12fd86d27e98bc73dd8bce6cd5
Implements support for Non Secure Interrupts preempting the
Standard SMC call in EL1. Whenever an IRQ is trapped in the
Secure world we securely handover to the Normal world
to process the interrupt. The normal world then issues
"resume" smc call to resume the previous interrupted SMC call.
FixesARM-software/tf-issues#105
Change-Id: I72b760617dee27438754cdfc9fe9bcf4cc024858
This patch adds support in the TSP to handle FIQ interrupts that are
generated when execution is in the TSP. S-EL1 interrupt are handled
normally and execution resumes at the instruction where the exception
was originally taken. S-EL3 interrupts i.e. any interrupt not
recognized by the TSP are handed to the TSPD. Execution resumes
normally once such an interrupt has been handled at EL3.
Change-Id: Ia3ada9a4fb15670afcc12538a6456f21efe58a8f
Soby Mathew
Achin Gupta