34 lines
1.2 KiB
Text
34 lines
1.2 KiB
Text
What: /sys/firmware/efi/runtime-map/
|
|
Date: December 2013
|
|
Contact: Dave Young <dyoung@redhat.com>
|
|
Description: Switching efi runtime services to virtual mode requires
|
|
that all efi memory ranges which have the runtime attribute
|
|
bit set to be mapped to virtual addresses.
|
|
|
|
The efi runtime services can only be switched to virtual
|
|
mode once without rebooting. The kexec kernel must maintain
|
|
the same physical to virtual address mappings as the first
|
|
kernel. The mappings are exported to sysfs so userspace tools
|
|
can reassemble them and pass them into the kexec kernel.
|
|
|
|
/sys/firmware/efi/runtime-map/ is the directory the kernel
|
|
exports that information in.
|
|
|
|
subdirectories are named with the number of the memory range:
|
|
|
|
/sys/firmware/efi/runtime-map/0
|
|
/sys/firmware/efi/runtime-map/1
|
|
/sys/firmware/efi/runtime-map/2
|
|
/sys/firmware/efi/runtime-map/3
|
|
...
|
|
|
|
Each subdirectory contains five files:
|
|
|
|
attribute : The attributes of the memory range.
|
|
num_pages : The size of the memory range in pages.
|
|
phys_addr : The physical address of the memory range.
|
|
type : The type of the memory range.
|
|
virt_addr : The virtual address of the memory range.
|
|
|
|
Above values are all hexadecimal numbers with the '0x' prefix.
|
|
Users: Kexec
|