Commit 01d92c7f authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds
Browse files

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@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Co-developed-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: default avatarMarco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1d96320f

arch/arm64/include/asm/vmalloc.h

+6 −0
Original line number Diff line number Diff line
@@ -25,4 +25,10 @@ static inline bool arch_vmap_pmd_supported(pgprot_t prot) 


#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 */

include/linux/vmalloc.h

+7 −0
Original line number Diff line number Diff line
@@ -115,6 +115,13 @@ static inline int arch_vmap_pte_supported_shift(unsigned long size) 
}

#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

 */

mm/vmalloc.c

+9 −0
Original line number Diff line number Diff line
@@ -3128,6 +3128,15 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, 
		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;