On Sat Nov 5, 2022 at 6:00 PM AEST, Christophe Leroy wrote:
Le 04/11/2022 à 18:27, Andrew Donnellan a écrit :
quoted
powerpc unfortunately has too many places where we run stuff in real mode.
With CONFIG_VMAP_STACK enabled, this means we need to be able to swap the
stack pointer to use the linear mapping when we enter a real mode section,
and back afterwards.
Store the top bits of the stack pointer in both the linear map and the
vmalloc space in the PACA, and add some helper macros/functions to swap
between them.
That may work when pagesize is 64k because stack is on a single page,
but I doubt is works with 4k pages, because vmalloc may allocate non
contiguous pages.
Yeah. This could be a first-stage though, and depend on 64k page size
and stack size, or !KVM or whatever. When the real-mode code is solved,
that could be relaxed.
Thanks,
Nick