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authorAndrey Konovalov <andreyknvl@google.com>2018-12-28 00:30:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 12:11:43 -0800
commit3c9e3aa11094e821aff4a8f6812a6e032293dbc0 (patch)
tree6d4b0baeb13a2f51dc3b5dd2019b0133b0456ca2 /arch
parent9c23f84723d2bb5611a973f56f0952fa74f048f3 (diff)
downloadlinux-3c9e3aa11094e821aff4a8f6812a6e032293dbc0.tar.gz
kasan: add tag related helper functions
This commit adds a few helper functions, that are meant to be used to work with tags embedded in the top byte of kernel pointers: to set, to get or to reset the top byte. Link: http://lkml.kernel.org/r/f6c6437bb8e143bc44f42c3c259c62e734be7935.1544099024.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/kasan.h8
-rw-r--r--arch/arm64/include/asm/memory.h12
-rw-r--r--arch/arm64/mm/kasan_init.c2
3 files changed, 20 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/kasan.h b/arch/arm64/include/asm/kasan.h
index 8758bb008436..b52aacd2c526 100644
--- a/arch/arm64/include/asm/kasan.h
+++ b/arch/arm64/include/asm/kasan.h
@@ -4,12 +4,16 @@
#ifndef __ASSEMBLY__
-#ifdef CONFIG_KASAN
-
#include <linux/linkage.h>
#include <asm/memory.h>
#include <asm/pgtable-types.h>
+#define arch_kasan_set_tag(addr, tag) __tag_set(addr, tag)
+#define arch_kasan_reset_tag(addr) __tag_reset(addr)
+#define arch_kasan_get_tag(addr) __tag_get(addr)
+
+#ifdef CONFIG_KASAN
+
/*
* KASAN_SHADOW_START: beginning of the kernel virtual addresses.
* KASAN_SHADOW_END: KASAN_SHADOW_START + 1/N of kernel virtual addresses,
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index e73bb89d6141..25b46f88726c 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -226,6 +226,18 @@ extern u64 vabits_user;
#define untagged_addr(addr) \
((__typeof__(addr))sign_extend64((u64)(addr), 55))
+#ifdef CONFIG_KASAN_SW_TAGS
+#define __tag_shifted(tag) ((u64)(tag) << 56)
+#define __tag_set(addr, tag) (__typeof__(addr))( \
+ ((u64)(addr) & ~__tag_shifted(0xff)) | __tag_shifted(tag))
+#define __tag_reset(addr) untagged_addr(addr)
+#define __tag_get(addr) (__u8)((u64)(addr) >> 56)
+#else
+#define __tag_set(addr, tag) (addr)
+#define __tag_reset(addr) (addr)
+#define __tag_get(addr) 0
+#endif
+
/*
* Physical vs virtual RAM address space conversion. These are
* private definitions which should NOT be used outside memory.h
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 38fa4bba9279..3e142add890b 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -252,6 +252,8 @@ void __init kasan_init(void)
memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+ kasan_init_tags();
+
/* At this point kasan is fully initialized. Enable error messages */
init_task.kasan_depth = 0;
pr_info("KernelAddressSanitizer initialized\n");