On Tue, 11 Feb 2025 at 12:01, Deepak Gupta <debug@xxxxxxxxxxxx> wrote: > > On Tue, Feb 11, 2025 at 09:20:22AM +0800, Chunyan Zhang wrote: > >On Thu, 30 Jan 2025 at 16:42, Björn Töpel <bjorn@xxxxxxxxxx> wrote: > >> > >> Chunyan Zhang <zhangchunyan@xxxxxxxxxxx> writes: > >> > >> > The PTE bit(9) on RISC-V is reserved for software, it is used by devmap > >> > now which has to be disabled if we want to use bit(9) for other features, > >> > since there's no more free PTE bit on RISC-V now. > >> > > >> > So to make ARCH_HAS_PTE_DEVMAP selectable, this patch uses it as > >> > the build condition of devmap definitions. > >> > >> Heads-up: It seems like Alistair's series [1] that removes the devmap > >> PTE bit will most likely land in 6.15. > > > >Yes, I've been keeping an eye on Alistair's series, intended to update > >this patchset after Alistair's patch that removes the devmap PTE bit > >got merged. > > Please keep in mind that even after claiming back devmap PTE SW bit, a compile > time decision to select between uffd-wp and soft-dirty is not desirable. Yes, I agree. I've read your aother email. I also hope we can have more RSW bits to use. So should we add uffd-wp and soft-dirty support on RISC-V until we have two RSW bits for these two functions? Is an undesirable solution better than no solution for now? I can optimize the code when we have more free RSW bits, that's not hard. Thanks, Chunyan
