![Bernhard Walle](/assets/img/avatar_default.png)
This patch adds /sys/firmware/memmap interface that represents the BIOS (or Firmware) provided memory map. The tree looks like: /sys/firmware/memmap/0/start (hex number) end (hex number) type (string) ... /1/start end type With the following shell snippet one can print the memory map in the same form the kernel prints itself when booting on x86 (the E820 map). --------- 8< -------------------------- #!/bin/sh cd /sys/firmware/memmap for dir in * ; do start=$(cat $dir/start) end=$(cat $dir/end) type=$(cat $dir/type) printf "%016x-%016x (%s)\n" $start $[ $end +1] "$type" done --------- >8 -------------------------- That patch only provides the needed interface: 1. The sysfs interface. 2. The structure and enumeration definition. 3. The function firmware_map_add() and firmware_map_add_early() that should be called from architecture code (E820/EFI, for example) to add the contents to the interface. If the kernel is compiled without CONFIG_FIRMWARE_MEMMAP, the interface does nothing without cluttering the architecture-specific code with #ifdef's. The purpose of the new interface is kexec: While /proc/iomem represents the *used* memory map (e.g. modified via kernel parameters like 'memmap' and 'mem'), the /sys/firmware/memmap tree represents the unmodified memory map provided via the firmware. So kexec can: - use the original memory map for rebooting, - use the /proc/iomem for setting up the ELF core headers for kdump case that should only represent the memory of the system. The patch has been tested on i386 and x86_64. Signed-off-by: Bernhard Walle <bwalle@suse.de> Acked-by: Greg KH <gregkh@suse.de> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: kexec@lists.infradead.org Cc: yhlu.kernel@gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
75 lines
2.1 KiB
C
75 lines
2.1 KiB
C
/*
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* include/linux/firmware-map.h:
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* Copyright (C) 2008 SUSE LINUX Products GmbH
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* by Bernhard Walle <bwalle@suse.de>
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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 v2.0 as published by
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* 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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*/
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#ifndef _LINUX_FIRMWARE_MAP_H
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#define _LINUX_FIRMWARE_MAP_H
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#include <linux/list.h>
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#include <linux/kobject.h>
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/*
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* provide a dummy interface if CONFIG_FIRMWARE_MEMMAP is disabled
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*/
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#ifdef CONFIG_FIRMWARE_MEMMAP
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/**
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* Adds a firmware mapping entry. This function uses kmalloc() for memory
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* allocation. Use firmware_map_add_early() if you want to use the bootmem
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* allocator.
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*
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* That function must be called before late_initcall.
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*
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* @start: Start of the memory range.
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* @end: End of the memory range (inclusive).
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* @type: Type of the memory range.
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*
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* Returns 0 on success, or -ENOMEM if no memory could be allocated.
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*/
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int firmware_map_add(resource_size_t start, resource_size_t end,
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const char *type);
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/**
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* Adds a firmware mapping entry. This function uses the bootmem allocator
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* for memory allocation. Use firmware_map_add() if you want to use kmalloc().
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*
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* That function must be called before late_initcall.
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*
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* @start: Start of the memory range.
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* @end: End of the memory range (inclusive).
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* @type: Type of the memory range.
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*
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* Returns 0 on success, or -ENOMEM if no memory could be allocated.
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*/
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int firmware_map_add_early(resource_size_t start, resource_size_t end,
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const char *type);
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#else /* CONFIG_FIRMWARE_MEMMAP */
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static inline int firmware_map_add(resource_size_t start, resource_size_t end,
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const char *type)
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{
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return 0;
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}
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static inline int firmware_map_add_early(resource_size_t start,
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resource_size_t end, const char *type)
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{
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return 0;
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}
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#endif /* CONFIG_FIRMWARE_MEMMAP */
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#endif /* _LINUX_FIRMWARE_MAP_H */
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