On Fri, Jun 21, 2024 at 09:11:56AM -0700, Dave Hansen wrote: > It's in the "Determination of Access Rights" section. > > A linear address is a shadow-stack address if the following are > true of the translation of the linear address: (1) the R/W flag > (bit 1) is 0 and the dirty flag (bit 6) is 1 in the paging- > structure entry that maps the page containing the linear > address; and (2) the R/W flag is 1 in every other paging- > structure entry controlling the translation of the linear > address.
Thanks. It'll be nice if this can be referenced in the pgtable definitions too in some way. [...] > One big thing I did in this review was make sure that the PMD and PUD > helpers were doing the same thing. Would you mind circling back and > double-checking the same before you repost this? Sure, I'll make sure I'll at least add a comment if it doesn't match and explain why. I actually did it already e.g. in the _modify path for shadow stack, but I failed this spot. The page table check thing is really rare that I overlooked, could be relevant to what I used to hit a bug but fixed around this area, so I forgot to add it back, but I really can't remember. I'll keep an extra eye on that. Thanks, -- Peter Xu
