Commit 4ca8cc8d authored by Alexander Potapenko's avatar Alexander Potapenko Committed by Andrew Morton
Browse files

x86: kmsan: enable KMSAN builds for x86 

Make KMSAN usable by adding the necessary Kconfig bits.

Also declare x86-specific functions checking address validity in
arch/x86/include/asm/kmsan.h.

Link: https://lkml.kernel.org/r/20220915150417.722975-44-glider@google.com


Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 1468c6f4

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -169,6 +169,7 @@ config X86 
	select HAVE_ARCH_KASAN			if X86_64

	select HAVE_ARCH_KASAN_VMALLOC		if X86_64

	select HAVE_ARCH_KFENCE

	select HAVE_ARCH_KMSAN			if X86_64

	select HAVE_ARCH_KGDB

	select HAVE_ARCH_MMAP_RND_BITS		if MMU

	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT

arch/x86/include/asm/kmsan.h

0 → 100644
+55 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/*

 * x86 KMSAN support.

 *

 * Copyright (C) 2022, Google LLC

 * Author: Alexander Potapenko <glider@google.com>

 */



#ifndef _ASM_X86_KMSAN_H

#define _ASM_X86_KMSAN_H



#ifndef MODULE



#include <asm/processor.h>

#include <linux/mmzone.h>



/*

 * Taken from arch/x86/mm/physaddr.h to avoid using an instrumented version.

 */

static inline bool kmsan_phys_addr_valid(unsigned long addr)

{

	if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT))

		return !(addr >> boot_cpu_data.x86_phys_bits);

	else

		return true;

}



/*

 * Taken from arch/x86/mm/physaddr.c to avoid using an instrumented version.

 */

static inline bool kmsan_virt_addr_valid(void *addr)

{

	unsigned long x = (unsigned long)addr;

	unsigned long y = x - __START_KERNEL_map;



	/* use the carry flag to determine if x was < __START_KERNEL_map */

	if (unlikely(x > y)) {

		x = y + phys_base;



		if (y >= KERNEL_IMAGE_SIZE)

			return false;

	} else {

		x = y + (__START_KERNEL_map - PAGE_OFFSET);



		/* carry flag will be set if starting x was >= PAGE_OFFSET */

		if ((x > y) || !kmsan_phys_addr_valid(x))

			return false;

	}



	return pfn_valid(x >> PAGE_SHIFT);

}



#endif /* !MODULE */



#endif /* _ASM_X86_KMSAN_H */