Hi Khalid, On Thu, May 23, 2019 at 11:51:40AM -0600, Khalid Aziz wrote: > On 5/21/19 6:04 PM, Kees Cook wrote: > > As an aside: I think Sparc ADI support in Linux actually side-stepped > > this[1] (i.e. chose "solution 1"): "All addresses passed to kernel must > > be non-ADI tagged addresses." (And sadly, "Kernel does not enable ADI > > for kernel code.") I think this was a mistake we should not repeat for > > arm64 (we do seem to be at least in agreement about this, I think). > > > > [1] https://lore.kernel.org/patchwork/patch/654481/ > > That is a very early version of the sparc ADI patch. Support for tagged > addresses in syscalls was added in later versions and is in the patch > that is in the kernel. I tried to figure out but I'm not familiar with the sparc port. How did you solve the tagged address going into various syscall implementations in the kernel (e.g. sys_write)? Is the tag removed on kernel entry or it ends up deeper in the core code? Thanks. -- Catalin
