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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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a7f8de168a
This relaxes the kernel Image placement requirements, so that it may be placed at any 2 MB aligned offset in physical memory. This is accomplished by ignoring PHYS_OFFSET when installing memblocks, and accounting for the apparent virtual offset of the kernel Image. As a result, virtual address references below PAGE_OFFSET are correctly mapped onto physical references into the kernel Image regardless of where it sits in memory. Special care needs to be taken for dealing with memory limits passed via mem=, since the generic implementation clips memory top down, which may clip the kernel image itself if it is loaded high up in memory. To deal with this case, we simply add back the memory covering the kernel image, which may result in more memory to be retained than was passed as a mem= parameter. Since mem= should not be considered a production feature, a panic notifier handler is installed that dumps the memory limit at panic time if one was set. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
112 lines
3.9 KiB
C
112 lines
3.9 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_FLAG_PAGE_SIZE ((PAGE_SHIFT - 10) / 2)
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#define __HEAD_FLAG_PHYS_BASE 1
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#define __HEAD_FLAGS ((__HEAD_FLAG_BE << 0) | \
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(__HEAD_FLAG_PAGE_SIZE << 1) | \
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(__HEAD_FLAG_PHYS_BASE << 3))
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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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* Prevent the symbol aliases below from being emitted into the kallsyms
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* table, by forcing them to be absolute symbols (which are conveniently
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* ignored by scripts/kallsyms) rather than section relative symbols.
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* The distinction is only relevant for partial linking, and only for symbols
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* that are defined within a section declaration (which is not the case for
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* the definitions below) so the resulting values will be identical.
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*/
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#define KALLSYMS_HIDE(sym) ABSOLUTE(sym)
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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 = KALLSYMS_HIDE(__pi_memcmp);
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__efistub_memchr = KALLSYMS_HIDE(__pi_memchr);
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__efistub_memcpy = KALLSYMS_HIDE(__pi_memcpy);
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__efistub_memmove = KALLSYMS_HIDE(__pi_memmove);
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__efistub_memset = KALLSYMS_HIDE(__pi_memset);
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__efistub_strlen = KALLSYMS_HIDE(__pi_strlen);
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__efistub_strcmp = KALLSYMS_HIDE(__pi_strcmp);
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__efistub_strncmp = KALLSYMS_HIDE(__pi_strncmp);
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__efistub___flush_dcache_area = KALLSYMS_HIDE(__pi___flush_dcache_area);
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#ifdef CONFIG_KASAN
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__efistub___memcpy = KALLSYMS_HIDE(__pi_memcpy);
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__efistub___memmove = KALLSYMS_HIDE(__pi_memmove);
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__efistub___memset = KALLSYMS_HIDE(__pi_memset);
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#endif
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__efistub__text = KALLSYMS_HIDE(_text);
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__efistub__end = KALLSYMS_HIDE(_end);
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__efistub__edata = KALLSYMS_HIDE(_edata);
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#endif
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#endif /* __ASM_IMAGE_H */
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