qemu /
qemu /
097d68ac2fd9bd40d0b6a3b3992c86a1f79d7187 target/arm: Forbid return to AArch32 when CPU is AArch64-only
In the Arm ARM, rule R_TYTWB states that returning to AArch32
is an illegal exception return if:
* AArch32 is not supported at any exception level
* the target EL is configured for AArch64 via SCR_EL3.RW
or HCR_EL2.RW or via CPU state at reset
We check the second of these, but not the first (which can only be
relevant for the case of a return to EL0, because if AArch32 is not
supported at one of the higher ELs then the RW bits will have an
effective value of 1 and the the "configured for AArch64" condition
will hold also).
Add the missing condition. Although this is technically a bug
(because we have one AArch64-only CPU: a64fx) it isn't worth
backporting to stable because no sensible guest code will
deliberately try to return to a nonexistent execution state
to check that it gets an illegal exception return.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
1 file changed
