1*4882a593SmuzhiyunWhat: /sys/firmware/efi/runtime-map/ 2*4882a593SmuzhiyunDate: December 2013 3*4882a593SmuzhiyunContact: Dave Young <dyoung@redhat.com> 4*4882a593SmuzhiyunDescription: Switching efi runtime services to virtual mode requires 5*4882a593Smuzhiyun that all efi memory ranges which have the runtime attribute 6*4882a593Smuzhiyun bit set to be mapped to virtual addresses. 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun The efi runtime services can only be switched to virtual 9*4882a593Smuzhiyun mode once without rebooting. The kexec kernel must maintain 10*4882a593Smuzhiyun the same physical to virtual address mappings as the first 11*4882a593Smuzhiyun kernel. The mappings are exported to sysfs so userspace tools 12*4882a593Smuzhiyun can reassemble them and pass them into the kexec kernel. 13*4882a593Smuzhiyun 14*4882a593Smuzhiyun /sys/firmware/efi/runtime-map/ is the directory the kernel 15*4882a593Smuzhiyun exports that information in. 16*4882a593Smuzhiyun 17*4882a593Smuzhiyun subdirectories are named with the number of the memory range:: 18*4882a593Smuzhiyun 19*4882a593Smuzhiyun /sys/firmware/efi/runtime-map/0 20*4882a593Smuzhiyun /sys/firmware/efi/runtime-map/1 21*4882a593Smuzhiyun /sys/firmware/efi/runtime-map/2 22*4882a593Smuzhiyun /sys/firmware/efi/runtime-map/3 23*4882a593Smuzhiyun ... 24*4882a593Smuzhiyun 25*4882a593Smuzhiyun Each subdirectory contains five files: 26*4882a593Smuzhiyun 27*4882a593Smuzhiyun ========= ========================================= 28*4882a593Smuzhiyun attribute The attributes of the memory range. 29*4882a593Smuzhiyun num_pages The size of the memory range in pages. 30*4882a593Smuzhiyun phys_addr The physical address of the memory range. 31*4882a593Smuzhiyun type The type of the memory range. 32*4882a593Smuzhiyun virt_addr The virtual address of the memory range. 33*4882a593Smuzhiyun ========= ========================================= 34*4882a593Smuzhiyun 35*4882a593Smuzhiyun Above values are all hexadecimal numbers with the '0x' prefix. 36*4882a593SmuzhiyunUsers: Kexec 37