From 840b239863449f27bf7522deb81e6746fbfbfeaf Mon Sep 17 00:00:00 2001 From: Marco Elver Date: Thu, 25 Feb 2021 17:19:03 -0800 Subject: arm64, kfence: enable KFENCE for ARM64 Add architecture specific implementation details for KFENCE and enable KFENCE for the arm64 architecture. In particular, this implements the required interface in . KFENCE requires that attributes for pages from its memory pool can individually be set. Therefore, force the entire linear map to be mapped at page granularity. Doing so may result in extra memory allocated for page tables in case rodata=full is not set; however, currently CONFIG_RODATA_FULL_DEFAULT_ENABLED=y is the default, and the common case is therefore not affected by this change. [elver@google.com: add missing copyright and description header] Link: https://lkml.kernel.org/r/20210118092159.145934-3-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-4-elver@google.com Signed-off-by: Alexander Potapenko Signed-off-by: Marco Elver Reviewed-by: Dmitry Vyukov Co-developed-by: Alexander Potapenko Reviewed-by: Jann Horn Reviewed-by: Mark Rutland Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christopher Lameter Cc: Dave Hansen Cc: David Rientjes Cc: Eric Dumazet Cc: Greg Kroah-Hartman Cc: Hillf Danton Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Joern Engel Cc: Jonathan Corbet Cc: Joonsoo Kim Cc: Kees Cook Cc: Paul E. McKenney Cc: Pekka Enberg Cc: Peter Zijlstra Cc: SeongJae Park Cc: Thomas Gleixner Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/arm64/mm/mmu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/arm64/mm/mmu.c') diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index d0758d24a42d..ef7698c4e2f0 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1465,7 +1465,13 @@ int arch_add_memory(int nid, u64 start, u64 size, int ret, flags = 0; VM_BUG_ON(!mhp_range_allowed(start, size, true)); - if (rodata_full || debug_pagealloc_enabled()) + + /* + * KFENCE requires linear map to be mapped at page granularity, so that + * it is possible to protect/unprotect single pages in the KFENCE pool. + */ + if (rodata_full || debug_pagealloc_enabled() || + IS_ENABLED(CONFIG_KFENCE)) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), -- cgit v1.2.3-59-g8ed1b