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authorQing Zhang <zhangqing@loongson.cn>2023-09-06 22:54:16 +0800
committerHuacai Chen <chenhuacai@loongson.cn>2023-09-06 22:54:16 +0800
commit5aa4ac64e6add3e40d5049e31275b2822daf885d (patch)
tree84a7ec4d51784b69c8af20f376eb16ebd72eeac5 /arch/loongarch/Makefile
parent9fbcc076798ead2af28c854a265d9da83bec8429 (diff)
LoongArch: Add KASAN (Kernel Address Sanitizer) support
1/8 of kernel addresses reserved for shadow memory. But for LoongArch, There are a lot of holes between different segments and valid address space (256T available) is insufficient to map all these segments to kasan shadow memory with the common formula provided by kasan core, saying (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET So LoongArch has a arch-specific mapping formula, different segments are mapped individually, and only limited space lengths of these specific segments are mapped to shadow. At early boot stage the whole shadow region populated with just one physical page (kasan_early_shadow_page). Later, this page is reused as readonly zero shadow for some memory that kasan currently don't track. After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset()/memcpy()/memmove() do a lot of memory accesses. If bad pointer passed to one of these function it is important to be caught. 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 names, so we could call non-instrumented variant if needed. Signed-off-by: Qing Zhang <zhangqing@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch/loongarch/Makefile')
-rw-r--r--arch/loongarch/Makefile3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index ef87bab46754..fb0fada43197 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -84,7 +84,10 @@ LDFLAGS_vmlinux += -static -pie --no-dynamic-linker -z notext
endif
cflags-y += $(call cc-option, -mno-check-zero-division)
+
+ifndef CONFIG_KASAN
cflags-y += -fno-builtin-memcpy -fno-builtin-memmove -fno-builtin-memset
+endif
load-y = 0x9000000000200000
bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y)