Re: lang/sbcl will not work with x-only

On Fri, Jan 27, 2023 at 05:02:33PM +0100, Christian Weisgerber wrote:
> lang/sbcl will not work with x-only.
>
> I took another look at the warnings about data directives in .text.
> In runtime/x86-64-assem.S we have snippets like these:
>
> GNAME(fun_end_breakpoint_trap):
> TRAP
> .byte trap_FunEndBreakpoint
> hlt # We should never return here.
>
> GNAME(do_pending_interrupt):
> TRAP
> .byte trap_PendingInterrupt
> ret
>
> GNAME(memory_fault_emulation_trap):
> TRAP
> .byte trap_MemoryFaultEmulation
>
> Where TRAP is defined to int3, and trap_* are consecutively numbered
> constants. The other half of this is sigtrap_handler() in
> runtime/x86-64-arch.c, which reads the byte after the int3 instruction
>
> trap = *(unsigned char *)OS_CONTEXT_PC(context);
>
> and then dispatches accordingly.
>
> ... And this brief analysis marks the end of my own involvement
> with this port.

Unfortunately I don't have a new enough CPU to test xonly, so someone
should probably mark it USE_NOEXECONLY