This replaces the somewhat opaque preprocessor based stack/unstack macros
with open coded ldp/stp sequences to preserve the interrupted context
before handing over to the exception handler in C.
This removes various arithmetic operations on the stack pointer, and
reduces the exception return critical section to its minimum size (i.e.,
the bare minimum required to populate the ELR and SPSR registers and invoke
the eret).
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Eugene Cohen <eugene@hp.com>
If we are using the vector table in place, there is no need to make an
indirect call to the common handler routine from the vector table entries,
so just use a straight branch instruction in that case.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Eugene Cohen <eugene@hp.com>
ESR and FAR are populated by the hardware upon exception entry, and
describe the exception, not the interrupted context. So there is no point
in restoring their values before returning from the exception.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Eugene Cohen <eugene@hp.com>
We have three code paths to stack/unstack the exception context, one for
each of EL3, EL2 and EL1. However, they all access the same copy of FPSR
so move that access to the common path.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Eugene Cohen <eugene@hp.com>
Unlike the AArch32 vector table, which has room for a single instruction
for each exception type, the AArch64 exception table has 128 byte slots,
which can easily hold the shared prologues that are emitted out of line.
So refactor this code into a single macro, and expand it into each vector
table slot. Since the address of the command handler entry point is no
longer patched in by the C code, we can just emit the literal into each
vector entry directly.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Eugene Cohen <eugene@hp.com>
Introduce ARM and AArch64 instances of the CpuExceptionHandlerLib which
provides exception handling and registration of handlers regardless of
execution phase.
Two variants of the ArmExceptionLib are provided: one where exception
handlers reside within the module (meeting appropriate architectural
alignment requirements for the vector table) and another one that will
relocate a copy of thee xception handlers to an address specified by
PcdCpuVectorBaseAddress. The ArmRelocateExceptionLib is intended for use
in cases where ArmExceptionLib is too large for the application
(uncompressed XIP images) as driven by the vector table alignment padding.
The AArch64 build of this library supports execution at EL1, EL2, and EL3
exception levels.
Tested on ARM, and AArch64 with SEC, DXE Core, and CpuDxe modules.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Eugene Cohen <eugene@hp.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Ard Biesheuvel
Cohen, Eugene