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authorLinus Torvalds <torvalds@linux-foundation.org>2008-07-14 16:43:24 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-14 16:43:24 -0400
commita3da5bf84a97d48cfaf66c6842470fc403da5121 (patch)
treecdf66c0cff8c61eedd60601fc9dffdd1ed39b880 /Documentation/ABI
parent3b23e665b68387f5ee7b21f7b75ceea4d9acae4a (diff)
parentd59fdcf2ac501de99c3dfb452af5e254d4342886 (diff)
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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1What: /sys/firmware/memmap/
2Date: June 2008
3Contact: Bernhard Walle <bwalle@suse.de>
4Description:
5 On all platforms, the firmware provides a memory map which the
6 kernel reads. The resources from that memory map are registered
7 in the kernel resource tree and exposed to userspace via
8 /proc/iomem (together with other resources).
9
10 However, on most architectures that firmware-provided memory
11 map is modified afterwards by the kernel itself, either because
12 the kernel merges that memory map with other information or
13 just because the user overwrites that memory map via command
14 line.
15
16 kexec needs the raw firmware-provided memory map to setup the
17 parameter segment of the kernel that should be booted with
18 kexec. Also, the raw memory map is useful for debugging. For
19 that reason, /sys/firmware/memmap is an interface that provides
20 the raw memory map to userspace.
21
22 The structure is as follows: Under /sys/firmware/memmap there
23 are subdirectories with the number of the entry as their name:
24
25 /sys/firmware/memmap/0
26 /sys/firmware/memmap/1
27 /sys/firmware/memmap/2
28 /sys/firmware/memmap/3
29 ...
30
31 The maximum depends on the number of memory map entries provided
32 by the firmware. The order is just the order that the firmware
33 provides.
34
35 Each directory contains three files:
36
37 start : The start address (as hexadecimal number with the
38 '0x' prefix).
39 end : The end address, inclusive (regardless whether the
40 firmware provides inclusive or exclusive ranges).
41 type : Type of the entry as string. See below for a list of
42 valid types.
43
44 So, for example:
45
46 /sys/firmware/memmap/0/start
47 /sys/firmware/memmap/0/end
48 /sys/firmware/memmap/0/type
49 /sys/firmware/memmap/1/start
50 ...
51
52 Currently following types exist:
53
54 - System RAM
55 - ACPI Tables
56 - ACPI Non-volatile Storage
57 - reserved
58
59 Following shell snippet can be used to display that memory
60 map in a human-readable format:
61
62 -------------------- 8< ----------------------------------------
63 #!/bin/bash
64 cd /sys/firmware/memmap
65 for dir in * ; do
66 start=$(cat $dir/start)
67 end=$(cat $dir/end)
68 type=$(cat $dir/type)
69 printf "%016x-%016x (%s)\n" $start $[ $end +1] "$type"
70 done
71 -------------------- >8 ----------------------------------------