1926172d4SDave YoungWhat: /sys/firmware/efi/runtime-map/ 2926172d4SDave YoungDate: December 2013 3926172d4SDave YoungContact: Dave Young <dyoung@redhat.com> 4926172d4SDave YoungDescription: Switching efi runtime services to virtual mode requires 5926172d4SDave Young that all efi memory ranges which have the runtime attribute 6926172d4SDave Young bit set to be mapped to virtual addresses. 7926172d4SDave Young 8926172d4SDave Young The efi runtime services can only be switched to virtual 9926172d4SDave Young mode once without rebooting. The kexec kernel must maintain 10926172d4SDave Young the same physical to virtual address mappings as the first 11926172d4SDave Young kernel. The mappings are exported to sysfs so userspace tools 12926172d4SDave Young can reassemble them and pass them into the kexec kernel. 13926172d4SDave Young 14926172d4SDave Young /sys/firmware/efi/runtime-map/ is the directory the kernel 15926172d4SDave Young exports that information in. 16926172d4SDave Young 17*54a19b4dSMauro Carvalho Chehab subdirectories are named with the number of the memory range:: 18926172d4SDave Young 19926172d4SDave Young /sys/firmware/efi/runtime-map/0 20926172d4SDave Young /sys/firmware/efi/runtime-map/1 21926172d4SDave Young /sys/firmware/efi/runtime-map/2 22926172d4SDave Young /sys/firmware/efi/runtime-map/3 23926172d4SDave Young ... 24926172d4SDave Young 25926172d4SDave Young Each subdirectory contains five files: 26926172d4SDave Young 27*54a19b4dSMauro Carvalho Chehab ========= ========================================= 28*54a19b4dSMauro Carvalho Chehab attribute The attributes of the memory range. 29*54a19b4dSMauro Carvalho Chehab num_pages The size of the memory range in pages. 30*54a19b4dSMauro Carvalho Chehab phys_addr The physical address of the memory range. 31*54a19b4dSMauro Carvalho Chehab type The type of the memory range. 32*54a19b4dSMauro Carvalho Chehab virt_addr The virtual address of the memory range. 33*54a19b4dSMauro Carvalho Chehab ========= ========================================= 34926172d4SDave Young 35926172d4SDave Young Above values are all hexadecimal numbers with the '0x' prefix. 36926172d4SDave YoungUsers: Kexec 37