From: Mark Rutland <mark.rutland@arm.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Christoph Lameter <cl@linux.com>,
Andrew Morton <akpm@linux-foundation.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Dave Martin <dave.martin@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Ingo Molnar <mingo@kernel.org>,
Paul Lawrence <paullawrence@google.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Arnd Bergmann <arnd@arndb.de>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
kasan-dev@googlegroups.com, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-sparse@vger.kernel.org, linux-mm@kvack.org,
linux-kbuild@vger.kernel.org, Kostya Serebryany <kcc@google.com>,
Evgeniy Stepanov <eugenis@google.com>,
Lee Smith <Lee.Smith@arm.com>,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
Jacob Bramley <Jacob.Bramley@arm.com>,
Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
Jann Horn <jannh@google.com>, Mark Brand <markbrand@google.com>,
Chintan Pandya <cpandya@codeaurora.org>,
Vishwath Mohan <vishwath@google.com>
Subject: Re: [PATCH v10 06/22] kasan, arm64: adjust shadow size for tag-based mode
Date: Wed, 7 Nov 2018 16:54:38 +0000 [thread overview]
Message-ID: <20181107165438.34kb5ufoe5ve2f6i@lakrids.cambridge.arm.com> (raw)
In-Reply-To: <86d1b17c755d8bfd6e44e6869a16f4a409e7bd06.1541525354.git.andreyknvl@google.com>
Hi Andrey,
On Tue, Nov 06, 2018 at 06:30:21PM +0100, Andrey Konovalov wrote:
> Tag-based KASAN uses 1 shadow byte for 16 bytes of kernel memory, so it
> requires 1/16th of the kernel virtual address space for the shadow memory.
>
> This commit sets KASAN_SHADOW_SCALE_SHIFT to 4 when the tag-based KASAN
> mode is enabled.
>
> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---
> arch/arm64/Makefile | 2 +-
> arch/arm64/include/asm/memory.h | 13 +++++++++----
> 2 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> index 6cb9fc7e9382..9887492381d9 100644
> --- a/arch/arm64/Makefile
> +++ b/arch/arm64/Makefile
> @@ -94,7 +94,7 @@ endif
> # KASAN_SHADOW_OFFSET = VA_START + (1 << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT))
> # - (1 << (64 - KASAN_SHADOW_SCALE_SHIFT))
> # in 32-bit arithmetic
> -KASAN_SHADOW_SCALE_SHIFT := 3
> +KASAN_SHADOW_SCALE_SHIFT := $(if $(CONFIG_KASAN_SW_TAGS), 4, 3)
We could make this something like:
ifeq ($(CONFIG_KASAN_SW_TAGS), y)
KASAN_SHADOW_SCALE_SHIFT := 4
else
KASAN_SHADOW_SCALE_SHIFT := 3
endif
KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
> KASAN_SHADOW_OFFSET := $(shell printf "0x%08x00000000\n" $$(( \
> (0xffffffff & (-1 << ($(CONFIG_ARM64_VA_BITS) - 32))) \
> + (1 << ($(CONFIG_ARM64_VA_BITS) - 32 - $(KASAN_SHADOW_SCALE_SHIFT))) \
> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index b96442960aea..0f1e024a951f 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -74,12 +74,17 @@
> #define KERNEL_END _end
>
> /*
> - * KASAN requires 1/8th of the kernel virtual address space for the shadow
> - * region. KASAN can bloat the stack significantly, so double the (minimum)
> - * stack size when KASAN is in use.
> + * Generic and tag-based KASAN require 1/8th and 1/16th of the kernel virtual
> + * address space for the shadow region respectively. They can bloat the stack
> + * significantly, so double the (minimum) stack size when they are in use.
> */
> -#ifdef CONFIG_KASAN
> +#ifdef CONFIG_KASAN_GENERIC
> #define KASAN_SHADOW_SCALE_SHIFT 3
> +#endif
> +#ifdef CONFIG_KASAN_SW_TAGS
> +#define KASAN_SHADOW_SCALE_SHIFT 4
> +#endif
> +#ifdef CONFIG_KASAN
... and remove the constant entirely here, avoiding duplication.
Maybe factor that into a Makefile.kasan if things are going to get much
more complicated.
Thanks,
Mark.
> #define KASAN_SHADOW_SIZE (UL(1) << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT))
> #define KASAN_THREAD_SHIFT 1
> #else
> --
> 2.19.1.930.g4563a0d9d0-goog
>
next prev parent reply other threads:[~2018-11-07 16:54 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-06 17:30 [PATCH v10 00/22] kasan: add software tag-based mode for arm64 Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 01/22] kasan, mm: change hooks signatures Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 02/22] kasan, slub: handle pointer tags in early_kmem_cache_node_alloc Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 03/22] kasan: move common generic and tag-based code to common.c Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 04/22] kasan: rename source files to reflect the new naming scheme Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 05/22] kasan: add CONFIG_KASAN_GENERIC and CONFIG_KASAN_SW_TAGS Andrey Konovalov
2018-11-07 17:04 ` Mark Rutland
2018-11-12 18:21 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 06/22] kasan, arm64: adjust shadow size for tag-based mode Andrey Konovalov
2018-11-07 16:54 ` Mark Rutland [this message]
2018-11-12 17:50 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 07/22] kasan: initialize shadow to 0xff " Andrey Konovalov
2018-11-07 17:08 ` Mark Rutland
2018-11-13 14:13 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 08/22] kasan, arm64: untag address in __kimg_to_phys and _virt_addr_is_linear Andrey Konovalov
2018-11-07 16:52 ` Mark Rutland
2018-11-14 19:23 ` Andrey Konovalov
2018-11-15 13:43 ` Andrey Konovalov
2018-11-07 18:10 ` Catalin Marinas
2018-11-14 19:52 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 09/22] kasan: add tag related helper functions Andrey Konovalov
2018-11-07 17:23 ` Mark Rutland
2018-11-14 19:19 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 10/22] kasan: preassign tags to objects with ctors or SLAB_TYPESAFE_BY_RCU Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 11/22] mm: move obj_to_index to include/linux/slab_def.h Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 12/22] kasan, arm64: fix up fault handling logic Andrey Konovalov
2018-11-07 18:26 ` Catalin Marinas
2018-11-08 12:22 ` Mark Rutland
2018-11-13 15:01 ` Andrey Konovalov
2018-11-13 22:07 ` Mark Rutland
2018-11-14 20:06 ` Andrey Konovalov
2018-11-14 20:17 ` Mark Rutland
2018-11-15 13:33 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 13/22] kasan, arm64: enable top byte ignore for the kernel Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 14/22] kasan, mm: perform untagged pointers comparison in krealloc Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 15/22] kasan: split out generic_report.c from report.c Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 16/22] kasan: add bug reporting routines for tag-based mode Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 17/22] kasan: add hooks implementation " Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 18/22] kasan, arm64: add brk handler for inline instrumentation Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 19/22] kasan, mm, arm64: tag non slab memory allocated via pagealloc Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 20/22] kasan: add __must_check annotations to kasan hooks Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 21/22] kasan: update documentation Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 22/22] kasan: add SPDX-License-Identifier mark to source files Andrey Konovalov
2018-11-07 14:56 ` [PATCH v10 00/22] kasan: add software tag-based mode for arm64 Andrey Konovalov
2018-11-07 14:59 ` Will Deacon
2018-11-07 15:11 ` Andrey Konovalov
2018-11-07 15:34 ` Will Deacon
2018-11-07 15:54 ` Andrey Konovalov
2018-11-07 15:56 ` Andrey Konovalov
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