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Commit 1a640687 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Alistair Delva
Browse files

BACKPORT: kasan, arm64: enable top byte ignore for the kernel 

(Upstream commit 21696c1613244f2ad4e9216c4f6e7804831a992c).

Tag-based KASAN uses the Top Byte Ignore feature of arm64 CPUs to store a
pointer tag in the top byte of each pointer.  This commit enables the
TCR_TBI1 bit, which enables Top Byte Ignore for the kernel, when tag-based
KASAN is used.

Link: http://lkml.kernel.org/r/f51eca084c8cdb2f3a55195fe342dc8953b7aead.1544099024.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: default avatarDmitry Vyukov <dvyukov@google.com>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Change-Id: Ia31aff11e6b8b80fbbd0be7580f83ee1f5e4db72
Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Bug: 128674696
parent 479d328d

arch/arm64/include/asm/pgtable-hwdef.h

+1 −0
Original line number Diff line number Diff line
@@ -289,6 +289,7 @@ 
#define TCR_A1			(UL(1) << 22)

#define TCR_ASID16		(UL(1) << 36)

#define TCR_TBI0		(UL(1) << 37)

#define TCR_TBI1		(UL(1) << 38)

#define TCR_HA			(UL(1) << 39)

#define TCR_HD			(UL(1) << 40)

#define TCR_NFD1		(UL(1) << 54)

arch/arm64/mm/proc.S

+7 −1
Original line number Diff line number Diff line
@@ -47,6 +47,12 @@ 
/* PTWs cacheable, inner/outer WBWA */

#define TCR_CACHE_FLAGS	TCR_IRGN_WBWA | TCR_ORGN_WBWA



#ifdef CONFIG_KASAN_SW_TAGS

#define TCR_KASAN_FLAGS TCR_TBI1

#else

#define TCR_KASAN_FLAGS 0

#endif



#define MAIR(attr, mt)	((attr) << ((mt) * 8))



/*
@@ -442,7 +448,7 @@ ENTRY(__cpu_setup) 
	 */

	ldr	x10, =TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \

			TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \

			TCR_TBI0 | TCR_A1

			TCR_TBI0 | TCR_A1 | TCR_KASAN_FLAGS

	tcr_set_idmap_t0sz	x10, x9



	/*