From 69ac9cd629ca96e59f34eb4ccd12d00b2c8276a7 Mon Sep 17 00:00:00 2001 From: Bernhard Walle Date: Fri, 27 Jun 2008 13:12:54 +0200 Subject: sysfs: add /sys/firmware/memmap 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 Acked-by: Greg KH Acked-by: Vivek Goyal Cc: kexec@lists.infradead.org Cc: yhlu.kernel@gmail.com Signed-off-by: Ingo Molnar --- include/linux/firmware-map.h | 74 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 include/linux/firmware-map.h (limited to 'include/linux/firmware-map.h') diff --git a/include/linux/firmware-map.h b/include/linux/firmware-map.h new file mode 100644 index 00000000000..acbdbcc1605 --- /dev/null +++ b/include/linux/firmware-map.h @@ -0,0 +1,74 @@ +/* + * include/linux/firmware-map.h: + * Copyright (C) 2008 SUSE LINUX Products GmbH + * by Bernhard Walle + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License v2.0 as published by + * the Free Software Foundation + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ +#ifndef _LINUX_FIRMWARE_MAP_H +#define _LINUX_FIRMWARE_MAP_H + +#include +#include + +/* + * provide a dummy interface if CONFIG_FIRMWARE_MEMMAP is disabled + */ +#ifdef CONFIG_FIRMWARE_MEMMAP + +/** + * Adds a firmware mapping entry. This function uses kmalloc() for memory + * allocation. Use firmware_map_add_early() if you want to use the bootmem + * allocator. + * + * That function must be called before late_initcall. + * + * @start: Start of the memory range. + * @end: End of the memory range (inclusive). + * @type: Type of the memory range. + * + * Returns 0 on success, or -ENOMEM if no memory could be allocated. + */ +int firmware_map_add(resource_size_t start, resource_size_t end, + const char *type); + +/** + * Adds a firmware mapping entry. This function uses the bootmem allocator + * for memory allocation. Use firmware_map_add() if you want to use kmalloc(). + * + * That function must be called before late_initcall. + * + * @start: Start of the memory range. + * @end: End of the memory range (inclusive). + * @type: Type of the memory range. + * + * Returns 0 on success, or -ENOMEM if no memory could be allocated. + */ +int firmware_map_add_early(resource_size_t start, resource_size_t end, + const char *type); + +#else /* CONFIG_FIRMWARE_MEMMAP */ + +static inline int firmware_map_add(resource_size_t start, resource_size_t end, + const char *type) +{ + return 0; +} + +static inline int firmware_map_add_early(resource_size_t start, + resource_size_t end, const char *type) +{ + return 0; +} + +#endif /* CONFIG_FIRMWARE_MEMMAP */ + +#endif /* _LINUX_FIRMWARE_MAP_H */ -- cgit v1.2.3-70-g09d2