1 What: /sys/firmware/efi/runtime-map/ 1 What: /sys/firmware/efi/runtime-map/
2 Date: December 2013 2 Date: December 2013
3 Contact: Dave Young <dyoung@redhat.com> 3 Contact: Dave Young <dyoung@redhat.com>
4 Description: Switching efi runtime services 4 Description: Switching efi runtime services to virtual mode requires
5 that all efi memory ranges whi 5 that all efi memory ranges which have the runtime attribute
6 bit set to be mapped to virtua 6 bit set to be mapped to virtual addresses.
7 7
8 The efi runtime services can o 8 The efi runtime services can only be switched to virtual
9 mode once without rebooting. T 9 mode once without rebooting. The kexec kernel must maintain
10 the same physical to virtual a 10 the same physical to virtual address mappings as the first
11 kernel. The mappings are expor 11 kernel. The mappings are exported to sysfs so userspace tools
12 can reassemble them and pass t 12 can reassemble them and pass them into the kexec kernel.
13 13
14 /sys/firmware/efi/runtime-map/ 14 /sys/firmware/efi/runtime-map/ is the directory the kernel
15 exports that information in. 15 exports that information in.
16 16
17 subdirectories are named with 17 subdirectories are named with the number of the memory range::
18 18
19 /sys/firmware/efi/runt 19 /sys/firmware/efi/runtime-map/0
20 /sys/firmware/efi/runt 20 /sys/firmware/efi/runtime-map/1
21 /sys/firmware/efi/runt 21 /sys/firmware/efi/runtime-map/2
22 /sys/firmware/efi/runt 22 /sys/firmware/efi/runtime-map/3
23 ... 23 ...
24 24
25 Each subdirectory contains fiv 25 Each subdirectory contains five files:
26 26
27 ========= ================== 27 ========= =========================================
28 attribute The attributes of 28 attribute The attributes of the memory range.
29 num_pages The size of the me 29 num_pages The size of the memory range in pages.
30 phys_addr The physical addre 30 phys_addr The physical address of the memory range.
31 type The type of the me 31 type The type of the memory range.
32 virt_addr The virtual addres 32 virt_addr The virtual address of the memory range.
33 ========= ================== 33 ========= =========================================
34 34
35 Above values are all hexadecim 35 Above values are all hexadecimal numbers with the '0x' prefix.
36 Users: Kexec 36 Users: Kexec
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