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authorAndrey Ryabinin <ryabinin.a.a@gmail.com>2015-10-12 18:52:58 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2015-10-12 17:46:36 +0100
commit39d114ddc68223022c12ae3a1573912bc4b585e5 (patch)
tree738d0566a0b66a8fec44b04fa1480f258e00a248 /arch/arm64/include/asm/pgtable.h
parentarm64: move PGD_SIZE definition to pgalloc.h (diff)
downloadlinux-dev-39d114ddc68223022c12ae3a1573912bc4b585e5.tar.xz
linux-dev-39d114ddc68223022c12ae3a1573912bc4b585e5.zip
arm64: add KASAN support
This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to '')
-rw-r--r--arch/arm64/include/asm/pgtable.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 3f481ef42c07..e3b515fbf0c2 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -41,7 +41,14 @@
* fixed mappings and modules
*/
#define VMEMMAP_SIZE ALIGN((1UL << (VA_BITS - PAGE_SHIFT)) * sizeof(struct page), PUD_SIZE)
+
+#ifndef CONFIG_KASAN
#define VMALLOC_START (VA_START)
+#else
+#include <asm/kasan.h>
+#define VMALLOC_START (KASAN_SHADOW_END + SZ_64K)
+#endif
+
#define VMALLOC_END (PAGE_OFFSET - PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
#define vmemmap ((struct page *)(VMALLOC_END + SZ_64K))