From: Christophe Leroy Date: Tue, 19 May 2020 05:48:44 +0000 (+0000) Subject: powerpc/kasan: Fix issues by lowering KASAN_SHADOW_END X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=3a66a24f6060e6775f8c02ac52329ea0152d7e58;p=linux.git powerpc/kasan: Fix issues by lowering KASAN_SHADOW_END At the time being, KASAN_SHADOW_END is 0x100000000, which is 0 in 32 bits representation. This leads to a couple of issues: - kasan_remap_early_shadow_ro() does nothing because the comparison k_cur < k_end is always false. - In ptdump, address comparison for markers display fails and the marker's name is printed at the start of the KASAN area instead of being printed at the end. However, there is no need to shadow the KASAN shadow area itself, so the KASAN shadow area can stop shadowing memory at the start of itself. With a PAGE_OFFSET set to 0xc0000000, KASAN shadow area is then going from 0xf8000000 to 0xff000000. Fixes: cbd18991e24f ("powerpc/mm: Fix an Oops in kasan_mmu_init()") Cc: stable@vger.kernel.org Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/ae1a3c0d19a37410c209c3fc453634cfcc0ee318.1589866984.git.christophe.leroy@csgroup.eu --- diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h index fbff9ff9032eb..fc900937f6534 100644 --- a/arch/powerpc/include/asm/kasan.h +++ b/arch/powerpc/include/asm/kasan.h @@ -23,9 +23,7 @@ #define KASAN_SHADOW_OFFSET ASM_CONST(CONFIG_KASAN_SHADOW_OFFSET) -#define KASAN_SHADOW_END 0UL - -#define KASAN_SHADOW_SIZE (KASAN_SHADOW_END - KASAN_SHADOW_START) +#define KASAN_SHADOW_END (-(-KASAN_SHADOW_START >> KASAN_SHADOW_SCALE_SHIFT)) #ifdef CONFIG_KASAN void kasan_early_init(void);