Commit | Line | Data |
---|---|---|
926172d4 DY |
1 | What: /sys/firmware/efi/runtime-map/ |
2 | Date: December 2013 | |
3 | Contact: Dave Young <dyoung@redhat.com> | |
4 | Description: Switching efi runtime services to virtual mode requires | |
5 | that all efi memory ranges which have the runtime attribute | |
6 | bit set to be mapped to virtual addresses. | |
7 | ||
8 | The efi runtime services can only be switched to virtual | |
9 | mode once without rebooting. The kexec kernel must maintain | |
10 | the same physical to virtual address mappings as the first | |
11 | kernel. The mappings are exported to sysfs so userspace tools | |
12 | can reassemble them and pass them into the kexec kernel. | |
13 | ||
14 | /sys/firmware/efi/runtime-map/ is the directory the kernel | |
15 | exports that information in. | |
16 | ||
17 | subdirectories are named with the number of the memory range: | |
18 | ||
19 | /sys/firmware/efi/runtime-map/0 | |
20 | /sys/firmware/efi/runtime-map/1 | |
21 | /sys/firmware/efi/runtime-map/2 | |
22 | /sys/firmware/efi/runtime-map/3 | |
23 | ... | |
24 | ||
25 | Each subdirectory contains five files: | |
26 | ||
27 | attribute : The attributes of the memory range. | |
28 | num_pages : The size of the memory range in pages. | |
29 | phys_addr : The physical address of the memory range. | |
30 | type : The type of the memory range. | |
31 | virt_addr : The virtual address of the memory range. | |
32 | ||
33 | Above values are all hexadecimal numbers with the '0x' prefix. | |
34 | Users: Kexec |