target/arm: Support CP_ACCESS_TRAP_EL1 as a CPAccessResult

target/arm: Support CP_ACCESS_TRAP_EL1 as a CPAccessResult

In the CPAccessResult enum, the CP_ACCESS_TRAP* values indicate the
equivalent of the pseudocode AArch64.SystemAccessTrap(..., 0x18),
causing a trap to a specified exception level with a syndrome value
giving information about the failing instructions.  In the
pseudocode, such traps are always taken to a specified target EL.  We
support that for target EL of 2 or 3 via CP_ACCESS_TRAP_EL2 and
CP_ACCESS_TRAP_EL3, but the only way to take the access trap to EL1
currently is to use CP_ACCESS_TRAP, which takes the trap to the
"usual target EL" (EL1 if in EL0, otherwise to the current EL).

Add CP_ACCESS_TRAP_EL1 so that access functions can follow the
pseudocode more closely.

(Note that for the common case in the pseudocode of "trap to
EL2 if HCR_EL2.TGE is set, otherwise trap to EL1", we handle
this in raise_exception(), so access functions don't need to
special case it and can use CP_ACCESS_TRAP_EL1.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250130182309.717346-10-peter.maydell@linaro.org