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Subject: Re: [PATCH v11 09/13] powerpc: disable KASAN instrumentation on
 early/critical files.
From:   Christophe Leroy <christophe.leroy@c-s.fr>
To:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Daniel Axtens <dja@axtens.net>
Cc:     linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com
References: <cover.1556295459.git.christophe.leroy@c-s.fr>
 <867c149e77f80e855a9310a490fb15ca03ffd63d.1556295461.git.christophe.leroy@c-s.fr>
Message-ID: <5cff9551-e0ce-a2a4-989c-6b55825fa171@c-s.fr>
Date:   Fri, 3 May 2019 09:38:06 +0200
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Le 26/04/2019 à 18:23, Christophe Leroy a écrit :
> All files containing functions run before kasan_early_init() is called
> must have KASAN instrumentation disabled.
> 
> For those file, branch profiling also have to be disabled otherwise
> each if () generates a call to ftrace_likely_update().
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
>   arch/powerpc/kernel/Makefile             | 12 ++++++++++++
>   arch/powerpc/lib/Makefile                |  8 ++++++++
>   arch/powerpc/mm/Makefile                 |  6 ++++++
>   arch/powerpc/platforms/powermac/Makefile |  6 ++++++
>   arch/powerpc/purgatory/Makefile          |  3 +++
>   arch/powerpc/xmon/Makefile               |  1 +
>   6 files changed, 36 insertions(+)
> 

[...]

> diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
> index 3c1bd9fa23cd..dd945ca869b2 100644
> --- a/arch/powerpc/mm/Makefile
> +++ b/arch/powerpc/mm/Makefile
> @@ -7,6 +7,12 @@ ccflags-$(CONFIG_PPC64)	:= $(NO_MINIMAL_TOC)
>   
>   CFLAGS_REMOVE_slb.o = $(CC_FLAGS_FTRACE)
>   
> +KASAN_SANITIZE_ppc_mmu_32.o := n
> +
> +ifdef CONFIG_KASAN
> +CFLAGS_ppc_mmu_32.o  		+= -DDISABLE_BRANCH_PROFILING
> +endif
> +

The above is missing in powerpc/next (should now be in 
arch/powerpc/mm/book3s32/Makefile )

Christophe