Fix stack pointer in core dumps

[arbrauns]

The register set in the coredump contains the register values from just before the trap (these are pushed by hardware as the exception stack frame/ESF). Thus, the SP register also needs to point to the stack location from before the ESF was pushed; this is simply the location of the ESF plus the size of the ESF.

[arbrauns]

Marking as draft because it needs more logic - the size of the Exception Stack Frame depends on whether or not floating-point instructions were used by the faulting thread: https://developer.arm.com/documentation/107706/0100/Floating-point-and-MVE-support/Floating-point-context-handling-mechanisms?lang=en

Bit 4 of EXC_CAUSE (stored in lr on exception entry) tells us whether it's a Basic or Extended stack frame. This is easy enough to check in z_arm_fault(), which already gets exc_cause as an arument, but z_do_kernel_oops() is shared between Cortex-M and Cortex-A/R, the latter of which don't even have a concept of exception stack frames. How can I sneak this in there without too many hacks?

[arbrauns]

I don't understand the C++ errors (invalid application of 'sizeof' to incomplete type 'z_arm_get_hw_esf_size(uint32_t)::__basic_sf').

[mrkhldn]

I believe I'm trying to address the same issue here - #73189

[arbrauns]

Hah, indeed, left a review there.

[MaureenHelm]

@ithinuel please take a look

[kartben]

@arbrauns this needs rebasing. Thanks!

[arbrauns]

Fixed by #79622.