On 9/9/20 3:08 PM, Yu, Yu-cheng wrote: > After looking at this more, I found the changes are more similar to > mprotect() than madvise(). We are going to change an anonymous mapping > to a read-only mapping, and add the VM_SHSTK flag to it. Would an > x86-specific mprotect(PROT_SHSTK) make more sense? > > One alternative would be requiring a read-only mapping for > madvise(MADV_SHSTK). But that is inconvenient for the application. Why? It's just: mmap()/malloc(); mprotect(PROT_READ); madvise(MADV_SHSTK); vs. mmap()/malloc(); mprotect(PROT_SHSTK); I'm not sure a single syscall counts as inconvenient. I don't quite think we should use a PROT_ bit for this. It seems like the kind of thing that could be fragile and break existing expectations. I don't care _that_ strongly though.
