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authorLinus Torvalds <torvalds@linux-foundation.org>2008-07-15 00:43:24 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-15 00:43:24 +0400
commita3da5bf84a97d48cfaf66c6842470fc403da5121 (patch)
treecdf66c0cff8c61eedd60601fc9dffdd1ed39b880 /Documentation/ABI/testing
parent3b23e665b68387f5ee7b21f7b75ceea4d9acae4a (diff)
parentd59fdcf2ac501de99c3dfb452af5e254d4342886 (diff)
downloadlinux-a3da5bf84a97d48cfaf66c6842470fc403da5121.tar.xz
Merge branch 'x86/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (821 commits) x86: make 64bit hpet_set_mapping to use ioremap too, v2 x86: get x86_phys_bits early x86: max_low_pfn_mapped fix #4 x86: change _node_to_cpumask_ptr to return const ptr x86: I/O APIC: remove an IRQ2-mask hack x86: fix numaq_tsc_disable calling x86, e820: remove end_user_pfn x86: max_low_pfn_mapped fix, #3 x86: max_low_pfn_mapped fix, #2 x86: max_low_pfn_mapped fix, #1 x86_64: fix delayed signals x86: remove conflicting nx6325 and nx6125 quirks x86: Recover timer_ack lost in the merge of the NMI watchdog x86: I/O APIC: Never configure IRQ2 x86: L-APIC: Always fully configure IRQ0 x86: L-APIC: Set IRQ0 as edge-triggered x86: merge dwarf2 headers x86: use AS_CFI instead of UNWIND_INFO x86: use ignore macro instead of hash comment x86: use matching CFI_ENDPROC ...
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+What: /sys/firmware/memmap/
+Date: June 2008
+Contact: Bernhard Walle <bwalle@suse.de>
+Description:
+ On all platforms, the firmware provides a memory map which the
+ kernel reads. The resources from that memory map are registered
+ in the kernel resource tree and exposed to userspace via
+ /proc/iomem (together with other resources).
+
+ However, on most architectures that firmware-provided memory
+ map is modified afterwards by the kernel itself, either because
+ the kernel merges that memory map with other information or
+ just because the user overwrites that memory map via command
+ line.
+
+ kexec needs the raw firmware-provided memory map to setup the
+ parameter segment of the kernel that should be booted with
+ kexec. Also, the raw memory map is useful for debugging. For
+ that reason, /sys/firmware/memmap is an interface that provides
+ the raw memory map to userspace.
+
+ The structure is as follows: Under /sys/firmware/memmap there
+ are subdirectories with the number of the entry as their name:
+
+ /sys/firmware/memmap/0
+ /sys/firmware/memmap/1
+ /sys/firmware/memmap/2
+ /sys/firmware/memmap/3
+ ...
+
+ The maximum depends on the number of memory map entries provided
+ by the firmware. The order is just the order that the firmware
+ provides.
+
+ Each directory contains three files:
+
+ start : The start address (as hexadecimal number with the
+ '0x' prefix).
+ end : The end address, inclusive (regardless whether the
+ firmware provides inclusive or exclusive ranges).
+ type : Type of the entry as string. See below for a list of
+ valid types.
+
+ So, for example:
+
+ /sys/firmware/memmap/0/start
+ /sys/firmware/memmap/0/end
+ /sys/firmware/memmap/0/type
+ /sys/firmware/memmap/1/start
+ ...
+
+ Currently following types exist:
+
+ - System RAM
+ - ACPI Tables
+ - ACPI Non-volatile Storage
+ - reserved
+
+ Following shell snippet can be used to display that memory
+ map in a human-readable format:
+
+ -------------------- 8< ----------------------------------------
+ #!/bin/bash
+ 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 ----------------------------------------