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Subject: Re: [PATCH v6 4/4] powerpc: Book3S 64-bit "heavyweight" KASAN support
To:     Daniel Axtens <dja@axtens.net>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
        kasan-dev@googlegroups.com, aneesh.kumar@linux.ibm.com,
        bsingharora@gmail.com
Cc:     Michael Ellerman <mpe@ellerman.id.au>
References: <20200212054724.7708-1-dja@axtens.net>
 <20200212054724.7708-5-dja@axtens.net>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Message-ID: <224745f3-db66-fe46-1459-d1d41867b4f3@c-s.fr>
Date:   Wed, 12 Feb 2020 07:35:32 +0100
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Le 12/02/2020 à 06:47, Daniel Axtens a écrit :
> diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
> index fbff9ff9032e..2911fdd3a6a0 100644
> --- a/arch/powerpc/include/asm/kasan.h
> +++ b/arch/powerpc/include/asm/kasan.h
> @@ -2,6 +2,8 @@
>   #ifndef __ASM_KASAN_H
>   #define __ASM_KASAN_H
>   
> +#include <asm/page.h>
> +
>   #ifdef CONFIG_KASAN
>   #define _GLOBAL_KASAN(fn)	_GLOBAL(__##fn)
>   #define _GLOBAL_TOC_KASAN(fn)	_GLOBAL_TOC(__##fn)
> @@ -14,29 +16,41 @@
>   
>   #ifndef __ASSEMBLY__
>   
> -#include <asm/page.h>
> -
>   #define KASAN_SHADOW_SCALE_SHIFT	3
>   
>   #define KASAN_SHADOW_START	(KASAN_SHADOW_OFFSET + \
>   				 (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT))
>   
> +#ifdef CONFIG_KASAN_SHADOW_OFFSET
>   #define KASAN_SHADOW_OFFSET	ASM_CONST(CONFIG_KASAN_SHADOW_OFFSET)
> +#endif
>   
> +#ifdef CONFIG_PPC32
>   #define KASAN_SHADOW_END	0UL
>   
> -#define KASAN_SHADOW_SIZE	(KASAN_SHADOW_END - KASAN_SHADOW_START)
> +#ifdef CONFIG_KASAN
> +void kasan_late_init(void);
> +#else
> +static inline void kasan_late_init(void) { }
> +#endif
> +
> +#endif
> +
> +#ifdef CONFIG_PPC_BOOK3S_64
> +#define KASAN_SHADOW_END	(KASAN_SHADOW_OFFSET + \
> +				 (RADIX_VMEMMAP_END >> KASAN_SHADOW_SCALE_SHIFT))
> +
> +static inline void kasan_late_init(void) { }
> +#endif
>   
>   #ifdef CONFIG_KASAN
>   void kasan_early_init(void);
>   void kasan_mmu_init(void);
>   void kasan_init(void);
> -void kasan_late_init(void);
>   #else
>   static inline void kasan_init(void) { }
>   static inline void kasan_mmu_init(void) { }
> -static inline void kasan_late_init(void) { }
>   #endif

Why modify all this kasan_late_init() stuff ?

This function is only called from kasan init_32.c, it is never called by 
PPC64, so you should not need to modify anything at all.

Christophe