Re: [PATCH v2 31/37] kasan, x86, s390: update undef CONFIG_KASAN

From: Marco Elver
Date: Fri Sep 18 2020 - 06:52:16 EST


On Tue, Sep 15, 2020 at 11:16PM +0200, Andrey Konovalov wrote:
[...]
> 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

Is CONFIG_KASAN still used to guard instrumented versions of functions?

It looks like #undef CONFIG_KASAN is no longer needed -- at least
<linux/string.h> no longer mentions it.

> #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/misc.h
> index 726e264410ff..2ac973983a8e 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

Similar here; although it seems a little harder to check if CONFIG_KASAN
is still needed. (Maybe could check the preprocessed output diffs?)

>
> /* cpu_feature_enabled() cannot be used this early */
> #define USE_EARLY_PGTABLE_L5
> --
> 2.28.0.618.gf4bc123cb7-goog
>