Commit ef7f0d6a authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by Linus Torvalds
Browse files

x86_64: add KASan support 



This patch adds arch specific code for kernel address sanitizer.

16TB of virtual addressed used for shadow memory.  It's located in range
[ffffec0000000000 - fffffc0000000000] between vmemmap and %esp fixup
stacks.

At early stage we map whole shadow region with zero page.  Latter, after
pages mapped to direct mapping address range we unmap zero pages from
corresponding shadow (see kasan_map_shadow()) and allocate and map a real
shadow memory reusing vmemmap_populate() function.

Also replace __pa with __pa_nodebug before shadow initialized.  __pa with
CONFIG_DEBUG_VIRTUAL=y make external function call (__phys_addr)
__phys_addr is instrumented, so __asan_load could be called before shadow
area initialized.

Signed-off-by: default avatarAndrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: default avatarAndrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Jim Davis <jim.epost@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 786a8959

Documentation/x86/x86_64/mm.txt

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space 
ffffe90000000000 - ffffe9ffffffffff (=40 bits) hole

ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)

... unused hole ...

ffffec0000000000 - fffffc0000000000 (=44 bits) kasan shadow memory (16TB)

... unused hole ...

ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks

... unused hole ...

ffffffff80000000 - ffffffffa0000000 (=512 MB)  kernel text mapping, from phys 0

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -85,6 +85,7 @@ config X86 
	select HAVE_CMPXCHG_LOCAL

	select HAVE_CMPXCHG_DOUBLE

	select HAVE_ARCH_KMEMCHECK

	select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP

	select HAVE_USER_RETURN_NOTIFIER

	select ARCH_BINFMT_ELF_RANDOMIZE_PIE

	select HAVE_ARCH_JUMP_LABEL

arch/x86/boot/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
# Set it to -DSVGA_MODE=NORMAL_VGA if you just want the EGA/VGA mode.

# The number is the same as you would ordinarily press at bootup.



KASAN_SANITIZE := n



SVGA_MODE	:= -DSVGA_MODE=NORMAL_VGA



targets		:= vmlinux.bin setup.bin setup.elf bzImage

arch/x86/boot/compressed/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 
#	(see scripts/Makefile.lib size_append)

#	compressed vmlinux.bin.all + u32 size of vmlinux.bin.all



KASAN_SANITIZE := n



targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \

	vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4

arch/x86/include/asm/kasan.h

0 → 100644
+31 −0
Original line number Diff line number Diff line 
#ifndef _ASM_X86_KASAN_H

#define _ASM_X86_KASAN_H



/*

 * Compiler uses shadow offset assuming that addresses start

 * from 0. Kernel addresses don't start from 0, so shadow

 * for kernel really starts from compiler's shadow offset +

 * 'kernel address space start' >> KASAN_SHADOW_SCALE_SHIFT

 */

#define KASAN_SHADOW_START      (KASAN_SHADOW_OFFSET + \

					(0xffff800000000000ULL >> 3))

/* 47 bits for kernel address -> (47 - 3) bits for shadow */

#define KASAN_SHADOW_END        (KASAN_SHADOW_START + (1ULL << (47 - 3)))



#ifndef __ASSEMBLY__



extern pte_t kasan_zero_pte[];

extern pte_t kasan_zero_pmd[];

extern pte_t kasan_zero_pud[];



#ifdef CONFIG_KASAN

void __init kasan_map_early_shadow(pgd_t *pgd);

void __init kasan_init(void);

#else

static inline void kasan_map_early_shadow(pgd_t *pgd) { }

static inline void kasan_init(void) { }

#endif



#endif



#endif

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