From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: kasan, vmalloc, arm64: mark vmalloc mappings as pgprot_tagged HW_TAGS KASAN relies on ARM Memory Tagging Extension (MTE). With MTE, a memory region must be mapped as MT_NORMAL_TAGGED to allow setting memory tags via MTE-specific instructions. Add proper protection bits to vmalloc() allocations. These allocations are always backed by page_alloc pages, so the tags will actually be getting set on the corresponding physical memory. Link: https://lkml.kernel.org/r/983fc33542db2f6b1e77b34ca23448d4640bbb9e.1643047180.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Co-developed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Acked-by: Marco Elver <elver@xxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Peter Collingbourne <pcc@xxxxxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm64/include/asm/vmalloc.h | 6 ++++++ include/linux/vmalloc.h | 7 +++++++ mm/vmalloc.c | 9 +++++++++ 3 files changed, 22 insertions(+) --- a/arch/arm64/include/asm/vmalloc.h~kasan-vmalloc-arm64-mark-vmalloc-mappings-as-pgprot_tagged +++ a/arch/arm64/include/asm/vmalloc.h @@ -25,4 +25,10 @@ static inline bool arch_vmap_pmd_support #endif +#define arch_vmap_pgprot_tagged arch_vmap_pgprot_tagged +static inline pgprot_t arch_vmap_pgprot_tagged(pgprot_t prot) +{ + return pgprot_tagged(prot); +} + #endif /* _ASM_ARM64_VMALLOC_H */ --- a/include/linux/vmalloc.h~kasan-vmalloc-arm64-mark-vmalloc-mappings-as-pgprot_tagged +++ a/include/linux/vmalloc.h @@ -115,6 +115,13 @@ static inline int arch_vmap_pte_supporte } #endif +#ifndef arch_vmap_pgprot_tagged +static inline pgprot_t arch_vmap_pgprot_tagged(pgprot_t prot) +{ + return prot; +} +#endif + /* * Highlevel APIs for driver use */ --- a/mm/vmalloc.c~kasan-vmalloc-arm64-mark-vmalloc-mappings-as-pgprot_tagged +++ a/mm/vmalloc.c @@ -3128,6 +3128,15 @@ again: goto fail; } + /* + * Modify protection bits to allow tagging. + * This must be done before mapping by __vmalloc_area_node(). + */ + if (kasan_hw_tags_enabled() && + pgprot_val(prot) == pgprot_val(PAGE_KERNEL)) + prot = arch_vmap_pgprot_tagged(prot); + + /* Allocate physical pages and map them into vmalloc space. */ addr = __vmalloc_area_node(area, gfp_mask, prot, shift, node); if (!addr) goto fail; _
