* LEROY Christophe <christophe.leroy2@xxxxxxxxxxxxxxxxxx> [240710 17:02]:
>
>
> Le 10/07/2024 à 21:22, Liam R. Howlett a écrit :
> > From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
> >
> > The arch_unmap call was previously moved above the rbtree modifications
> > in commit 5a28fc94c914 ("x86/mpx, mm/core: Fix recursive munmap()
> > corruption"). The move was motivated by an issue with calling
> > arch_unmap() after the rbtree was modified.
> >
> > Since the above commit, mpx was dropped from the kernel in 45fc24e89b7c
> > ("x86/mpx: remove MPX from arch/x86"), so the motivation for calling
> > arch_unmap() prior to modifying the vma tree no longer exists
> > (regardless of rbtree or maple tree implementations).
> >
> > Furthermore, the powerpc implementation is also no longer needed as per
> > [1] and [2]. So the arch_unmap() function can be completely removed.
>
> I'm not sure to understand. Is it replaced by something else ?
> We wanted to get rid of arch_unmap() but it was supposed to be replaced
> by some core function because the functionnality itself is still
> required and indeed all the discussion around [2] demonstrated that not
> only powerpc but at least arm and probably others needed to properly
> clean-up reference to VDSO mappings on unmapping.
>
> So as mentioned by Michael you can't just drop that without replacing it
> by something else. We need the VDSO signal handling to properly fallback
> on stack-based trampoline when the VDSO trampoline gets mapped out.
I'll address this after the part I missed..
>
> Or did I miss something ?
>
I think I missed something in regards to what you need in ppc.
