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In-Reply-To: <096906ff06c532bbd0e9bda53bcba2ba0a1da873.1605046192.git.andreyknvl@google.com>
From:   Alexander Potapenko <glider@google.com>
Date:   Wed, 11 Nov 2020 17:15:46 +0100
Message-ID: <CAG_fn=U5bs8U8uw1765wDXuWg+0uGWkxUw4THjmW5cgVv3rrVw@mail.gmail.com>
Subject: Re: [PATCH v9 37/44] kasan, x86, s390: update undef CONFIG_KASAN
To:     Andrey Konovalov <andreyknvl@google.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Marco Elver <elver@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Vasily Gorbik <gor@linux.ibm.com>
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On Tue, Nov 10, 2020 at 11:12 PM Andrey Konovalov <andreyknvl@google.com> w=
rote:
>
> With the intoduction of hardware tag-based KASAN some kernel checks of
> this kind:
>
>   ifdef CONFIG_KASAN
>
> will be updated to:
>
>   if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
>
> x86 and s390 use a trick to #undef CONFIG_KASAN for some of the code
> that isn't linked with KASAN runtime and shouldn't have any KASAN
> annotations.
>
> Also #undef CONFIG_KASAN_GENERIC with CONFIG_KASAN.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> Reviewed-by: Marco Elver <elver@google.com>
> Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>

> ---
> Change-Id: I2a622db0cb86a8feb60c30d8cb09190075be2a90
> ---
>  arch/s390/boot/string.c         | 1 +
>  arch/x86/boot/compressed/misc.h | 1 +
>  2 files changed, 2 insertions(+)
>
> diff --git a/arch/s390/boot/string.c b/arch/s390/boot/string.c
> index b11e8108773a..faccb33b462c 100644
> --- a/arch/s390/boot/string.c
> +++ b/arch/s390/boot/string.c
> @@ -3,6 +3,7 @@
>  #include <linux/kernel.h>
>  #include <linux/errno.h>
>  #undef CONFIG_KASAN
> +#undef CONFIG_KASAN_GENERIC
>  #include "../lib/string.c"
>
>  int strncmp(const char *cs, const char *ct, size_t count)
> diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/m=
isc.h
> index d9a631c5973c..901ea5ebec22 100644
> --- a/arch/x86/boot/compressed/misc.h
> +++ b/arch/x86/boot/compressed/misc.h
> @@ -12,6 +12,7 @@
>  #undef CONFIG_PARAVIRT_XXL
>  #undef CONFIG_PARAVIRT_SPINLOCKS
>  #undef CONFIG_KASAN
> +#undef CONFIG_KASAN_GENERIC
>
>  /* cpu_feature_enabled() cannot be used this early */
>  #define USE_EARLY_PGTABLE_L5
> --
> 2.29.2.222.g5d2a92d10f8-goog
>


--=20
Alexander Potapenko
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