linux.git/Documentation/features/debug/KASAN, branch v6.6.132

LoongArch: Add KASAN (Kernel Address Sanitizer) support

2023-09-06T14:54:16+00:00

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 
Signed-off-by: Huacai Chen

Documentation/features: Use loongarch instead of loong

2022-12-05T09:50:12+00:00

The official arch name is LoongArch [1], we should use small letter
loongarch instead of loong in Documentation/features, just use the
features-refresh.sh to refresh all the related files.

[1] https://www.kernel.org/doc/html/latest/loongarch/index.html

Fixes: 5860800e8696 ("Documentation/features: Update the arch support status files")
Signed-off-by: Tiezhu Yang 
Link: https://lore.kernel.org/r/1670156327-9631-3-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Jonathan Corbet

Documentation/features: Update feature lists for 6.1

2022-12-03T10:54:20+00:00

Run the refresh script to document the recent feature additions
on loong, um and csky as of v6.1-rc7.

Signed-off-by: Wei Li 
Link: https://lore.kernel.org/r/20221203093750.4145802-1-liwei391@huawei.com
Signed-off-by: Jonathan Corbet

Documentation/features: Update the arch support status files

2022-06-09T15:35:57+00:00

The arch support status files don't match reality as of v5.19-rc1,
use the features-refresh.sh to refresh all the arch-support.txt files
in place.  The main effect is to add entries for the new loong
architecture.

Signed-off-by: Zheng Zengkai 
Link: https://lore.kernel.org/r/20220609025656.143460-1-zhengzengkai@huawei.com
Signed-off-by: Jonathan Corbet

Merge branch 'remove-h8300' of git://git.infradead.org/users/hch/misc into asm-generic

2022-04-04T12:42:49+00:00

* 'remove-h8300' of git://git.infradead.org/users/hch/misc:
  remove the h8300 architecture

This is clearly the least actively maintained architecture we have at
the moment, and probably the least useful. It is now the only one that
does not support MMUs at all, and most of the boards only support 4MB
of RAM, out of which the defconfig kernel needs more than half just
for .text/.data.

Guenter Roeck did the original patch to remove the architecture in 2013
after it had already been obsolete for a while, and Yoshinori Sato brought
it back in a much more modern form in 2015. Looking at the git history
since the reinstantiation, it's clear that almost all commits in the tree
are build fixes or cross-architecture cleanups:

$ git log --no-merges --format=%an v4.5.. arch/h8300/  | sort | uniq
-c | sort -rn | head -n 12
     25 Masahiro Yamada
     18 Christoph Hellwig
     14 Mike Rapoport
      9 Arnd Bergmann
      8 Mark Rutland
      7 Peter Zijlstra
      6 Kees Cook
      6 Ingo Molnar
      6 Al Viro
      5 Randy Dunlap
      4 Yury Norov

Signed-off-by: Arnd Bergmann

nds32: Remove the architecture

2022-03-07T12:54:59+00:00

The nds32 architecture, also known as AndeStar V3, is a custom 32-bit
RISC target designed by Andes Technologies. Support was added to the
kernel in 2016 as the replacement RISC-V based V5 processors were
already announced, and maintained by (current or former) Andes
employees.

As explained by Alan Kao, new customers are now all using RISC-V,
and all known nds32 users are already on longterm stable kernels
provided by Andes, with no development work going into mainline
support any more.

While the port is still in a reasonably good shape, it only gets
worse over time without active maintainers, so it seems best
to remove it before it becomes unusable. As always, if it turns
out that there are mainline users after all, and they volunteer
to maintain the port in the future, the removal can be reverted.

Link: https://lore.kernel.org/linux-mm/YhdWNLUhk+x9RAzU@yamatobi.andestech.com/
Link: https://lore.kernel.org/lkml/20220302065213.82702-1-alankao@andestech.com/
Link: https://www.andestech.com/en/products-solutions/andestar-architecture/
Signed-off-by: Alan Kao 
[arnd: rewrite changelog to provide more background]
Signed-off-by: Arnd Bergmann

remove the h8300 architecture

2022-02-23T07:52:50+00:00

Signed-off-by: Christoph Hellwig

Documentation: features: remove c6x references

2021-02-25T18:25:57+00:00

The references to arch/c6x are obsolete now that the architecture
is gone. Remove them.

Signed-off-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20210225142841.3385428-1-arnd@kernel.org
Signed-off-by: Jonathan Corbet

ARM: 9017/2: Enable KASan for ARM

2020-10-27T12:11:11+00:00

This patch enables the kernel address sanitizer for ARM. XIP_KERNEL
has not been tested and is therefore not allowed for now.

Cc: Andrey Ryabinin 
Cc: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: kasan-dev@googlegroups.com
Acked-by: Dmitry Vyukov 
Reviewed-by: Ard Biesheuvel 
Tested-by: Ard Biesheuvel  # QEMU/KVM/mach-virt/LPAE/8G
Tested-by: Florian Fainelli  # Brahma SoCs
Tested-by: Ahmad Fatoum  # i.MX6Q
Signed-off-by: Abbott Liu 
Signed-off-by: Florian Fainelli 
Signed-off-by: Linus Walleij 
Signed-off-by: Russell King

arch: remove unicore32 port

2020-07-01T09:09:13+00:00

The unicore32 port do not seem maintained for a long time now, there is no
upstream toolchain that can create unicore32 binaries and all the links to
prebuilt toolchains for unicore32 are dead. Even compilers that were
available are not supported by the kernel anymore.

Guenter Roeck says:

  I have stopped building unicore32 images since v4.19 since there is no
  available compiler that is still supported by the kernel. I am surprised
  that support for it has not been removed from the kernel.

Remove unicore32 port.

Signed-off-by: Mike Rapoport 
Acked-by: Arnd Bergmann 
Acked-by: Guenter Roeck