39d114ddc6
This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
96 lines
3.1 KiB
C
96 lines
3.1 KiB
C
/*
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* Linker script macros to generate Image header fields.
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*
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* Copyright (C) 2014 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ASM_IMAGE_H
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#define __ASM_IMAGE_H
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#ifndef LINKER_SCRIPT
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#error This file should only be included in vmlinux.lds.S
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#endif
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/*
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* There aren't any ELF relocations we can use to endian-swap values known only
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* at link time (e.g. the subtraction of two symbol addresses), so we must get
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* the linker to endian-swap certain values before emitting them.
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*/
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#ifdef CONFIG_CPU_BIG_ENDIAN
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#define DATA_LE64(data) \
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((((data) & 0x00000000000000ff) << 56) | \
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(((data) & 0x000000000000ff00) << 40) | \
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(((data) & 0x0000000000ff0000) << 24) | \
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(((data) & 0x00000000ff000000) << 8) | \
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(((data) & 0x000000ff00000000) >> 8) | \
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(((data) & 0x0000ff0000000000) >> 24) | \
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(((data) & 0x00ff000000000000) >> 40) | \
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(((data) & 0xff00000000000000) >> 56))
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#else
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#define DATA_LE64(data) ((data) & 0xffffffffffffffff)
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#endif
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#ifdef CONFIG_CPU_BIG_ENDIAN
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#define __HEAD_FLAG_BE 1
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#else
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#define __HEAD_FLAG_BE 0
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#endif
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#define __HEAD_FLAGS (__HEAD_FLAG_BE << 0)
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/*
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* These will output as part of the Image header, which should be little-endian
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* regardless of the endianness of the kernel. While constant values could be
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* endian swapped in head.S, all are done here for consistency.
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*/
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#define HEAD_SYMBOLS \
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_kernel_size_le = DATA_LE64(_end - _text); \
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_kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
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_kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
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#ifdef CONFIG_EFI
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/*
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* The EFI stub has its own symbol namespace prefixed by __efistub_, to
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* isolate it from the kernel proper. The following symbols are legally
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* accessed by the stub, so provide some aliases to make them accessible.
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* Only include data symbols here, or text symbols of functions that are
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* guaranteed to be safe when executed at another offset than they were
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* linked at. The routines below are all implemented in assembler in a
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* position independent manner
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*/
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__efistub_memcmp = __pi_memcmp;
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__efistub_memchr = __pi_memchr;
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__efistub_memcpy = __pi_memcpy;
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__efistub_memmove = __pi_memmove;
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__efistub_memset = __pi_memset;
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__efistub_strlen = __pi_strlen;
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__efistub_strcmp = __pi_strcmp;
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__efistub_strncmp = __pi_strncmp;
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__efistub___flush_dcache_area = __pi___flush_dcache_area;
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#ifdef CONFIG_KASAN
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__efistub___memcpy = __pi_memcpy;
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__efistub___memmove = __pi_memmove;
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__efistub___memset = __pi_memset;
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#endif
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__efistub__text = _text;
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__efistub__end = _end;
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__efistub__edata = _edata;
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#endif
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#endif /* __ASM_IMAGE_H */
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