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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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69ac9cd629
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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