1*926172d4SDave YoungWhat: /sys/firmware/efi/runtime-map/ 2*926172d4SDave YoungDate: December 2013 3*926172d4SDave YoungContact: Dave Young <dyoung@redhat.com> 4*926172d4SDave YoungDescription: Switching efi runtime services to virtual mode requires 5*926172d4SDave Young that all efi memory ranges which have the runtime attribute 6*926172d4SDave Young bit set to be mapped to virtual addresses. 7*926172d4SDave Young 8*926172d4SDave Young The efi runtime services can only be switched to virtual 9*926172d4SDave Young mode once without rebooting. The kexec kernel must maintain 10*926172d4SDave Young the same physical to virtual address mappings as the first 11*926172d4SDave Young kernel. The mappings are exported to sysfs so userspace tools 12*926172d4SDave Young can reassemble them and pass them into the kexec kernel. 13*926172d4SDave Young 14*926172d4SDave Young /sys/firmware/efi/runtime-map/ is the directory the kernel 15*926172d4SDave Young exports that information in. 16*926172d4SDave Young 17*926172d4SDave Young subdirectories are named with the number of the memory range: 18*926172d4SDave Young 19*926172d4SDave Young /sys/firmware/efi/runtime-map/0 20*926172d4SDave Young /sys/firmware/efi/runtime-map/1 21*926172d4SDave Young /sys/firmware/efi/runtime-map/2 22*926172d4SDave Young /sys/firmware/efi/runtime-map/3 23*926172d4SDave Young ... 24*926172d4SDave Young 25*926172d4SDave Young Each subdirectory contains five files: 26*926172d4SDave Young 27*926172d4SDave Young attribute : The attributes of the memory range. 28*926172d4SDave Young num_pages : The size of the memory range in pages. 29*926172d4SDave Young phys_addr : The physical address of the memory range. 30*926172d4SDave Young type : The type of the memory range. 31*926172d4SDave Young virt_addr : The virtual address of the memory range. 32*926172d4SDave Young 33*926172d4SDave Young Above values are all hexadecimal numbers with the '0x' prefix. 34*926172d4SDave YoungUsers: Kexec 35