Re: [PATCH] arm64: fix CONFIG_KASAN_SW_TAGS && CONFIG_KASAN_INLINE (was: Re: [PATCH V5 03/12] arm64: kasan: Switch to using) KASAN_SHADOW_OFFSET
From: Will Deacon <will@kernel.org>
Date: 2019-08-14 15:57:22
On Wed, Aug 14, 2019 at 04:20:18PM +0100, Mark Rutland wrote:
On Wed, Aug 07, 2019 at 04:55:15PM +0100, Steve Capper wrote:quoted
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index b2400f9c1213..2b7db0d41498 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile@@ -126,14 +126,6 @@ KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT) KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT) KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT) -# KASAN_SHADOW_OFFSET = VA_START + (1 << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT)) -# - (1 << (64 - KASAN_SHADOW_SCALE_SHIFT)) -# in 32-bit arithmetic -KASAN_SHADOW_OFFSET := $(shell printf "0x%08x00000000\n" $$(( \ - (0xffffffff & (-1 << ($(CONFIG_ARM64_VA_BITS) - 1 - 32))) \ - + (1 << ($(CONFIG_ARM64_VA_BITS) - 32 - $(KASAN_SHADOW_SCALE_SHIFT))) \ - - (1 << (64 - 32 - $(KASAN_SHADOW_SCALE_SHIFT))) )) ) - export TEXT_OFFSET GZFLAGS core-y += arch/arm64/kernel/ arch/arm64/mm/I've just spotted this breaks build using CONFIG_KASAN_SW_TAGS && CONFIG_KASAN_INLINE, as scripts/Makefile.kasan only propagates CONFIG_KASAN_SHADOW_OFFSET into KASAN_SHADOW_OFFSET when CONFIG_KASAN_GENERIC is selected, but consumes KASAN_SHADOW_OFFSET regardless. I think that's by accident rather than by design, but to minimize/localize the fixup, how about the below? I can send a cleanup patch for scripts/Makefile.kasan later.
How much work is that? I've dropped this stuff from -next for now, so we have time to fix it properly as long as it's not going to take weeks.
quoted hunk ↗ jump to hunk
---->8---- From b1a6f2dd5aa30d874c4bd97a20ea1330607da624 Mon Sep 17 00:00:00 2001 From: Mark Rutland <mark.rutland@arm.com> Date: Wed, 14 Aug 2019 15:51:14 +0100 Subject: [PATCH] arm64: fix CONFIG_KASAN_SW_TAGS && CONFIG_KASAN_INLINE Since commit: 6bd1d0be0e97936d ("arm64: kasan: Switch to using KASAN_SHADOW_OFFSET") ... attempting to build with CONFIG_KASAN_SW_TAGS && CONFIG_KASAN_INLINE results ins splat: | [mark@lakrids:~/src/linux]% usellvm 8.0.1 usekorg 8.1.0 make ARCH=arm64 CROSS_COMPILE=aarch64-linux- CC=clang | scripts/kconfig/conf --syncconfig Kconfig | CC scripts/mod/empty.o | clang (LLVM option parsing): for the -hwasan-mapping-offset option: '' value invalid for uint argument! | scripts/Makefile.build:273: recipe for target 'scripts/mod/empty.o' failed | make[1]: *** [scripts/mod/empty.o] Error 1 | Makefile:1123: recipe for target 'prepare0' failed | make: *** [prepare0] Error 2 ... since Makefile.kasan only consumes CONFIG_KASAN_SHADOW_OFFSET when CONFIG_KASAN_GENERIC is selected, and for CONFIG_KASAN_SW_TAGS it consumes KASAN_SHADOW_OFFSET (without a CONFIG_ prefix). For the moment, let's always propagate CONFIG_KASAN_SHADOW_OFFSET into KASAN_SHADOW_OFFSET via the arm64 Makefile. We can clean up the generic kasan Makefile later down the line. Fixes: 6bd1d0be0e97936d ("arm64: kasan: Switch to using KASAN_SHADOW_OFFSET") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Steve Capper <redacted> Cc: Will Deacon <will@kernel.org> --- arch/arm64/Makefile | 2 ++ 1 file changed, 2 insertions(+)diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index a8d2a241ac58..a0c733f93b5b 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile@@ -126,6 +126,8 @@ KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT) KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT) KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT) +KASAN_SHADOW_OFFSET := $(CONFIG_KASAN_SHADOW_OFFSET)
This needs a comment explaining what it's doing and that it's a dirty, temporary hack. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel