arm64: entry: move ARM64_ERRATUM_845719 workaround to C
To make the entry code less of a rats nest of overlapping labels and
shared state, and to make the code easier to debug and maintain, let's
move the workaround for ARM64_ERRATUM_845719 to C.
The workaround requires us to perform a write to CONTEXTIDR_EL1 at
AArch64 EL1 before retuning to an AArch32 EL0 task. There are no
additional requirements on the state of the CPU, or on subsequent
instructions prior to the ERET, so this can safely be performed in C
code.
As with the assembly version, we preserve the value of CONTEXTIDR if
CONFIG_PID_IN_CONTEXTIDR is selected.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
2 files changed
