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
s

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>

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docs/zh_CN: Update the translation of kasan to 6.1-rc8

Update to commit cd36d84d2571 ("kasan: allow sampling
page_alloc allocations for HW_TAGS")

Commit 80b92bfe3bb7 ("kasan: dynamically allocate
s

docs/zh_CN: Update the translation of kasan to 6.1-rc8

Update to commit cd36d84d2571 ("kasan: allow sampling
page_alloc allocations for HW_TAGS")

Commit 80b92bfe3bb7 ("kasan: dynamically allocate
stack ring entries")
Commit 7ebfce331251 ("kasan: support kasan.stacktrace
for SW_TAGS")
Commit ca89f2a2e66d ("kasan: move boot parameters
section in documentation")

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Wu XiangCheng <bobwxc@email.cn>
Link: https://lore.kernel.org/r/824d1cea864dac3ef78c0911c2c5a238f36c55ad.1670642548.git.siyanteng@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

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Docs/zh_CN: Update the translation of kasan to 5.19-rc8

update to commit 3ff16d30f593 ("kasan: test:
improve failure message in KUNIT_EXPECT_KASAN_FAIL()")

c9d1af2b780a ("mm/kasan: move kasan.fault

Docs/zh_CN: Update the translation of kasan to 5.19-rc8

update to commit 3ff16d30f593 ("kasan: test:
improve failure message in KUNIT_EXPECT_KASAN_FAIL()")

c9d1af2b780a ("mm/kasan: move kasan.fault to mm/kasan/report.c")
2d27e5851473 ("kasan: Extend KASAN mode kernel parameter")
8479d7b5be2f ("kasan: documentation updates")
c2ec0c8f6877 ("kasan: update documentation")

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/abbb6c5cc5a7daf0720a9cb0a8255472d4ac69b4.1658983157.git.siyanteng@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

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docs/zh_CN: add translations in zh_CN/dev-tools/kasan

Add new zh translations
* zh_CN/dev-tools/kasan.rst
and link it to zh_CN/dev-tools/index.rst

Reviewed-by: Fangrui Song <maskray@google.com>
Sig

docs/zh_CN: add translations in zh_CN/dev-tools/kasan

Add new zh translations
* zh_CN/dev-tools/kasan.rst
and link it to zh_CN/dev-tools/index.rst

Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/20210603141127.101689-1-wanjiabing@vivo.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

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