Re: [PATCH] powerpc/kasan: KASAN is not supported on RELOCATABLE && FSL_BOOKE

[Christophe Leroy]

Le 29/11/2019 Ã 08:46, Christophe Leroy a ÃcritÂ:
> Le 29/11/2019 Ã 08:04, Lexi Shao a ÃcritÂ:
> > CONFIG_RELOCATABLE and CONFIG_KASAN cannot be enabled at the same time
> > on ppce500 fsl_booke. All functions called before kasan_early_init()
> > should be disabled with kasan check. When CONFIG_RELOCATABLE is enabled
> > on ppce500 fsl_booke, relocate_init() is called before kasan_early_init()
> > which triggers kasan check and results in boot failure.
> > Call trace and functions which triggers kasan check(*):
> > ÂÂ - _start
> > ÂÂÂ - set_ivor
> > ÂÂÂÂ - relocate_init(*)
> > ÂÂÂÂÂ - early_get_first_memblock_info(*)
> > ÂÂÂÂÂÂ - of_scan_flat_dt(*)
> > ÂÂÂÂ...
> > ÂÂÂÂ - kasan_early_init
> >
> > Potential solutions could be 1. implement relocate_init and all its 
> > children
> > function in a seperate file or 2. introduce a global vairable in 
> > KASAN, only
> > enable KASAN check when init is done.
>
> Solution 1 seems uneasy. of_scan_flat_dt() and children are general 
> functions that can't be set aside.
> Solution 2 would destroy performance, and would anyway not work with 
> inline instrumentation.
>
> Have you tried moving the call to kasan_early_init() before the call of 
> relocate_init() ?

I just tried it with QEMU, it works. I'll send a patch out soon.

Christophe


> On other PPC32, kasan_early_init() is the first thing done after 
> activating the MMU. But AFAIU, MMU is always active on BOOKE though.
>
> Christophe
>
> > Disable KASAN when RELOCATABLE is selected on fsl_booke for now until
> > it is supported.
> >
> > Signed-off-by: Lexi Shao <shaolexi@xxxxxxxxxx>
> > ---
> > Â arch/powerpc/Kconfig | 2 +-
> > Â 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > index 3e56c9c2f16e..14f3da63c088 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -171,7 +171,7 @@ config PPC
> > ÂÂÂÂÂ select HAVE_ARCH_AUDITSYSCALL
> > ÂÂÂÂÂ select HAVE_ARCH_HUGE_VMAPÂÂÂÂÂÂÂ if PPC_BOOK3S_64 && PPC_RADIX_MMU
> > ÂÂÂÂÂ select HAVE_ARCH_JUMP_LABEL
> > -ÂÂÂ select HAVE_ARCH_KASANÂÂÂÂÂÂÂÂÂÂÂ if PPC32
> > +ÂÂÂ select HAVE_ARCH_KASANÂÂÂÂÂÂÂÂÂÂÂ if PPC32 && !(RELOCATABLE && 
> > FSL_BOOKE)
> > ÂÂÂÂÂ select HAVE_ARCH_KGDB
> > ÂÂÂÂÂ select HAVE_ARCH_MMAP_RND_BITS
> > ÂÂÂÂÂ select HAVE_ARCH_MMAP_RND_COMPAT_BITSÂÂÂ if COMPAT