Patch Set 1:

How does FSP use the region near _car_stack_start? For something else than a stack? Since active stack is already within _car_stack_start to _car_stack_end, FSP should not and cannot zero-fill that entire region either, so what does FSP do with it?

Why do we even pass _car_stack_start and DCACHE_BSP_STACK_SIZE to FSP, like done in setup_fsp_stack_frame? On entry to FSP, %esp is what FSP will have to cope with and it's the configurations fault if we have not reserved enough space for the stack.

This is further convoluted as configurations with FSP_USES_CB_STACK=n will place their FSP stack below _car_region_end. While allocation is dynamically checked, it really should have been accounted for in the linker scripts instead.

Since the logged errors are now just annoyance and not boot regression, I suggest we revisit CB:34882 with this new information and see what can be achieved here.

All great questions. I was searching around for FSP 2.1 spec, but it doesn't seem to be published. 2.1 has support for utilizing the stack that's already being used. Empirically it sure seems that FSP is using the whole thing and for uses other than a 'stack'. The interpretation of StackBase and StackSize in FSP is dependent on the spec version. They have different meanings.

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