On Tue, 2020-02-25 at 12:59 -0800, Kees Cook wrote: > On Wed, Feb 05, 2020 at 10:19:23AM -0800, Yu-cheng Yu wrote: > > This patch implements THP Shadow Stack (SHSTK) copying in the same way as > > in the previous patch for regular PTE. > > > > In copy_huge_pmd(), clear the dirty bit from the PMD to cause a page fault > > upon the next SHSTK access to the PMD. At that time, fix the PMD and > > copy/re-use the page. > > Now is as good a time as any to ask: do you have selftests for all this? > It seems like it would be really nice to have a way to verify SHSTK is > working correctly. Yes, I have some simple tests at https://github.com/yyu168/cet-smoke-test. I also run Linux/tools/testing/selftests/x86 and GLIBC tests with CET and THP combinations. Yu-cheng
