Since the framework of KASAN_VMALLOC is well-developed,
It's easy to support for ARM that simply not to map shadow of VMALLOC
area on kasan_init.

Since the virtual address of vmalloc for Arm is also between
MODULE_VADDR and 0x100000000 (ZONE_HIGHMEM), which means the shadow
address has already included between KASAN_SHADOW_START and
KASAN_SHADOW_END.
Thus we need to change nothing for memory map of Arm.

This can fix ARM_MODULE_PLTS with KASan, support KASan for higmem
and support CONFIG_VMAP_STACK with KASan.
    

Test on
1. Qemu with memory 2G and vmalloc=500M for 3G/1G mapping.
2. Qemu with memory 2G and vmalloc=500M for 3G/1G mapping + LPAE.
3. Qemu with memory 2G and vmalloc=500M for 2G/2G mapping.


v5:
    rebase on 5.18-rc4
    
v4:
    rebase on 5.17-rc8.
    remove simple doc for "arm: kasan: support CONFIG_KASAN_VMALLOC"
    rewrite the description for VMAP_STACK

https://lore.kernel.org/lkml/20220315090157.27001-1-lecopzer.chen@mediatek.com/

v3:
    rebase on 5.17-rc5.
    Add simple doc for "arm: kasan: support CONFIG_KASAN_VMALLOC"
    Tweak commit message.

https://lore.kernel.org/lkml/20220227134726.27584-1-lecopzer.chen@mediatek.com/

v2:
    rebase on 5.17-rc3


Lecopzer Chen (2):
  arm: kasan: support CONFIG_KASAN_VMALLOC
  arm: kconfig: fix MODULE_PLTS for KASAN with KASAN_VMALLOC

 arch/arm/Kconfig         | 2 ++
 arch/arm/mm/kasan_init.c | 6 +++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

-- 
2.18.0

On Wed, Apr 27, 2022 at 11:59 AM Lecopzer Chen
<lecopzer.chen@mediatek.com> wrote:

> Since the framework of KASAN_VMALLOC is well-developed,
> It's easy to support for ARM that simply not to map shadow of VMALLOC
> area on kasan_init.
>
> Since the virtual address of vmalloc for Arm is also between
> MODULE_VADDR and 0x100000000 (ZONE_HIGHMEM), which means the shadow
> address has already included between KASAN_SHADOW_START and
> KASAN_SHADOW_END.
> Thus we need to change nothing for memory map of Arm.
>
> This can fix ARM_MODULE_PLTS with KASan, support KASan for higmem
> and support CONFIG_VMAP_STACK with KASan.

Excellent Lecopzer,

can you put these patches into Russell's patch tracker so he can pick them?
https://www.armlinux.org.uk/developer/patches/

Yours,
Linus Walleij

> On Wed, Apr 27, 2022 at 11:59 AM Lecopzer Chen
> <lecopzer.chen@mediatek.com> wrote:
> 
> > Since the framework of KASAN_VMALLOC is well-developed,
> > It's easy to support for ARM that simply not to map shadow of VMALLOC
> > area on kasan_init.
> >
> > Since the virtual address of vmalloc for Arm is also between
> > MODULE_VADDR and 0x100000000 (ZONE_HIGHMEM), which means the shadow
> > address has already included between KASAN_SHADOW_START and
> > KASAN_SHADOW_END.
> > Thus we need to change nothing for memory map of Arm.
> >
> > This can fix ARM_MODULE_PLTS with KASan, support KASan for higmem
> > and support CONFIG_VMAP_STACK with KASan.
> 
> Excellent Lecopzer,
> 
> can you put these patches into Russell's patch tracker so he can pick them?
> https://www.armlinux.org.uk/developer/patches/
> 
> Yours,
> Linus Walleij


I've added
9202/1 	kasan: support CONFIG_KASAN_VMALLOC
9203/1 	kconfig: fix MODULE_PLTS for KASAN with KASAN_VMALLOC

Thank you very much

BRs,
Lecopzer