On Tue, Jul 12, 2022 at 2:21 PM Marco Elver <elver@xxxxxxxxxx> wrote: > > On Fri, 1 Jul 2022 at 16:23, Alexander Potapenko <glider@xxxxxxxxxx> wrote: > > > > Insert KMSAN hooks that make the necessary bookkeeping changes: > > - poison page shadow and origins in alloc_pages()/free_page(); > > - clear page shadow and origins in clear_page(), copy_user_highpage(); > > - copy page metadata in copy_highpage(), wp_page_copy(); > > - handle vmap()/vunmap()/iounmap(); > > > > Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> > > --- > > v2: > > -- move page metadata hooks implementation here > > -- remove call to kmsan_memblock_free_pages() > > > > v3: > > -- use PAGE_SHIFT in kmsan_ioremap_page_range() > > > > v4: > > -- change sizeof(type) to sizeof(*ptr) > > -- replace occurrences of |var| with @var > > -- swap mm: and kmsan: in the subject > > -- drop __no_sanitize_memory from clear_page() > > > > Link: https://linux-review.googlesource.com/id/I6d4f53a0e7eab46fa29f0348f3095d9f2e326850 > > --- > > arch/x86/include/asm/page_64.h | 12 ++++ > > arch/x86/mm/ioremap.c | 3 + > > include/linux/highmem.h | 3 + > > include/linux/kmsan.h | 123 +++++++++++++++++++++++++++++++++ > > mm/internal.h | 6 ++ > > mm/kmsan/hooks.c | 87 +++++++++++++++++++++++ > > mm/kmsan/shadow.c | 114 ++++++++++++++++++++++++++++++ > > mm/memory.c | 2 + > > mm/page_alloc.c | 11 +++ > > mm/vmalloc.c | 20 +++++- > > 10 files changed, 379 insertions(+), 2 deletions(-) > > > > diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h > > index baa70451b8df5..227dd33eb4efb 100644 > > --- a/arch/x86/include/asm/page_64.h > > +++ b/arch/x86/include/asm/page_64.h > > @@ -45,14 +45,26 @@ void clear_page_orig(void *page); > > void clear_page_rep(void *page); > > void clear_page_erms(void *page); > > > > +/* This is an assembly header, avoid including too much of kmsan.h */ > > All of this code is under an "#ifndef __ASSEMBLY__" guard, does it matter? Actually, the comment is a bit outdated. kmsan-checks.h doesn't introduce any unnecessary declarations and can be used here. > > +#ifdef CONFIG_KMSAN > > +void kmsan_unpoison_memory(const void *addr, size_t size); > > +#endif > > static inline void clear_page(void *page) > > { > > +#ifdef CONFIG_KMSAN > > + /* alternative_call_2() changes @page. */ > > + void *page_copy = page; > > +#endif > > alternative_call_2(clear_page_orig, > > clear_page_rep, X86_FEATURE_REP_GOOD, > > clear_page_erms, X86_FEATURE_ERMS, > > "=D" (page), > > "0" (page) > > : "cc", "memory", "rax", "rcx"); > > +#ifdef CONFIG_KMSAN > > + /* Clear KMSAN shadow for the pages that have it. */ > > + kmsan_unpoison_memory(page_copy, PAGE_SIZE); > > What happens if this is called before the alternative-call? Could this > (in the interest of simplicity) be moved above it? And if you used the > kmsan-checks.h header, it also doesn't need any "ifdef CONFIG_KMSAN" > anymore. Good idea, that'll work. > > +#endif > > } -- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Paul Manicle, Liana Sebastian Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg
