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As Linus suggested, kasan_mem_to_shadow()/kasan_shadow_to_mem() are not
performance-critical and too big to inline. This is simply wrong so just
define them out-of-line.
If they really need to be inlined in future, such as the objtool / SMAP
issue for X86, we should mark them __always_inline.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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As Linus suggested, __HAVE_ARCH_XYZ is "stupid" and "having historical
uses of it doesn't make it good". So migrate __HAVE_ARCH_SHADOW_MAP to
separate macros named after the respective functions.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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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>
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