where/how arm start first jump from svc to user in kernel

[vichy]

 hi Mark:
2014-10-21 20:41 GMT+08:00 Mark Rutland <mark.rutland at arm.com>:
> There is no movs pc, lr equivalent in AArch64. The eret instruction is
> the only mechanism for dropping to a lower privileged exception level
> (e.g. to EL0 userspace from an EL1 kernel).
>
> The A32 eret instruction was only added with the ARMv7 virtualization
Per your explanation, EL0/EL1/EL3 of A32 are still using movs pc, lr, right?
> extensions (and in PL1 behaves as movs pc, lr if present). So it's
Is here a type? (PL1 should be EL1?)

> necessary to us movs pc, lr to function across a wide variety of CPUs,
> and there's no benefit to using eret.
thanks for your kind help,