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? > +#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. > +#endif > }
