Hi, Here is the V4 resend for supporting kexec kernel efi runtime. Per pervious discussion I pass the 1st kernel efi runtime mapping via setup_data to 2nd kernel. Besides of the runtime mapping info I also pass the fw_vendor, runtime, config table, smbios physical address in setup_data. EFI spec mentioned fw_vendor, runtime, config table addresses will be converted to virt address after entering virtual mode, but we will use it as physical address in efi_init. For smbios EFI spec did not mention about the address updating, but during my test on a HP workstation, the bios will convert it to Virt addr, thus pass it in setup_data as well. For fw_vendor, runtime, config table, I export them in /sys/firmware/ efi/, smbios is already in /sys/firmware/efi/systab. For efi runtime mapping I add a new directory /sys/firmware/efi/ runtime-map/ like below [dave at darkstar ~]$ tree /sys/firmware/efi/runtime-map/ /sys/firmware/efi/runtime-map/ ??? 0 ? ??? attribute ? ??? num_pages ? ??? phys_addr ? ??? type ? ??? virt_addr ??? 1 ? ??? attribute ? ??? num_pages ? ??? phys_addr ? ??? type ? ??? virt_addr [snip] kexec-tools will assemble them as setup_data and pass to 2nd kernel. I will send userspace patches as well. Limitation is I only write support for x86_64, test on below machines: Lenovo thinkpad t420 Dell inspiron 14 - 3421 HP Z420 workstation Qemu + OVMF Please help to review the patches. The patches are based on matt's efi master tree Changes from v1: add one flag in xloadflags, so kexec-tools can safely load old kernel without efi support. coding style fixes function name for map phys_addr to fixed virt_addr Add ABI documentation for sysfs files Changes from v2: 01/09: a new patch to remove unused variables in __map_region function catched by Toshi Kani 09/09: a new patch to export x86 boot_params to sysfs instead of use debugfs files Matt: reuse __map_region instead do same thing in another function. add a wrapper function efi_map_region_fixed [02/09] check return value of krealloc sysfs dir name s/efi-runtime-map/runtime-map [06/09] use desc_size in efi_runtime_map for the xloadflags defination: +&& defined(CONFIG_KEXEC) Greg: sysfs : one file one value for fw_vendor, runtime, tables. [05/09] Document them in ABI testing HPA: Document the new xloadflag Also there's other function cleanup and improvement for error handling. Changes from v3: Greg: sysfs code move to use __ATTR_RO and attr_group Boris: comments and code alignment Added 3 new patches below 10-print-efi-runtime-memmap.patch - 10/12: print only runtime ranges in case EFI_DEBUG printing 11-reserve-setup-data-late.patch - fix a bug of kdump kernel, move function for reserving setup data ranges late after parsing memmap= cmdline params because kdump kernel will pass exact memmap late. 12-x86-kdebugfs-use-ioremap.patch - fix a bug of x86/kernel/kdebugfs.c, use ioremap instead of __va for low mem because __va does not work for exact memmap= Dave Young (12): efi: remove unused variables in __map_region efi: add a wrapper function efi_map_region_fixed efi: reserve boot service fix efi: cleanup efi_enter_virtual_mode function efi: export more efi table variable to sysfs efi: export efi runtime memory mapping to sysfs efi: passing kexec necessary efi data via setup_data efi: only print saved efi runtime maps instead of all memmap ranges for kexec x86: add xloadflags bit for efi runtime support on kexec x86: export x86 boot_params to sysfs x86: reserve setup_data ranges late after parsing memmap cmdline x86: kdebugfs do not use __va for getting setup_data virt addr Documentation/ABI/testing/sysfs-firmware-efi | 26 ++ .../ABI/testing/sysfs-firmware-efi-runtime-map | 45 +++ Documentation/ABI/testing/sysfs-kernel-boot_params | 40 +++ Documentation/x86/boot.txt | 3 + arch/x86/boot/header.S | 9 +- arch/x86/include/asm/efi.h | 13 + arch/x86/include/uapi/asm/bootparam.h | 2 + arch/x86/kernel/Makefile | 2 +- arch/x86/kernel/kdebugfs.c | 35 +-- arch/x86/kernel/ksysfs.c | 339 +++++++++++++++++++++ arch/x86/kernel/setup.c | 7 +- arch/x86/platform/efi/efi.c | 313 +++++++++++++++---- arch/x86/platform/efi/efi_32.c | 2 + arch/x86/platform/efi/efi_64.c | 16 +- drivers/firmware/efi/Kconfig | 10 + drivers/firmware/efi/Makefile | 1 + drivers/firmware/efi/efi.c | 47 ++- drivers/firmware/efi/runtime-map.c | 199 ++++++++++++ include/linux/efi.h | 9 + 19 files changed, 1028 insertions(+), 90 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-firmware-efi create mode 100644 Documentation/ABI/testing/sysfs-firmware-efi-runtime-map create mode 100644 Documentation/ABI/testing/sysfs-kernel-boot_params create mode 100644 arch/x86/kernel/ksysfs.c create mode 100644 drivers/firmware/efi/runtime-map.c -- 1.8.3.1