Merge branch 'x86-efi-kexec-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 EFI changes from Ingo Molnar: "This consists of two main parts: - New static EFI runtime services virtual mapping layout which is groundwork for kexec support on EFI (Borislav Petkov) - EFI kexec support itself (Dave Young)" * 'x86-efi-kexec-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) x86/efi: parse_efi_setup() build fix x86: ksysfs.c build fix x86/efi: Delete superfluous global variables x86: Reserve setup_data ranges late after parsing memmap cmdline x86: Export x86 boot_params to sysfs x86: Add xloadflags bit for EFI runtime support on kexec x86/efi: Pass necessary EFI data for kexec via setup_data efi: Export EFI runtime memory mapping to sysfs efi: Export more EFI table variables to sysfs x86/efi: Cleanup efi_enter_virtual_mode() function x86/efi: Fix off-by-one bug in EFI Boot Services reservation x86/efi: Add a wrapper function efi_map_region_fixed() x86/efi: Remove unused variables in __map_region() x86/efi: Check krealloc return value x86/efi: Runtime services virtual mapping x86/mm/cpa: Map in an arbitrary pgd x86/mm/pageattr: Add last levels of error path x86/mm/pageattr: Add a PUD error unwinding path x86/mm/pageattr: Add a PTE pagetable populating function x86/mm/pageattr: Add a PMD pagetable populating function ...
2026-05-01 15:00:59 -07:00 · 2014-01-20 12:05:30 -08:00
parent 5d4863e4cc ef0b8b9a52
commit 972d5e7e5b
23 changed files with 1693 additions and 120 deletions
@@ -0,0 +1,20 @@
+What:		/sys/firmware/efi/fw_vendor
+Date:		December 2013
+Contact:	Dave Young <dyoung@redhat.com>
+Description:	It shows the physical address of firmware vendor field in the
+		EFI system table.
+Users:		Kexec
+
+What:		/sys/firmware/efi/runtime
+Date:		December 2013
+Contact:	Dave Young <dyoung@redhat.com>
+Description:	It shows the physical address of runtime service table entry in
+		the EFI system table.
+Users:		Kexec
+
+What:		/sys/firmware/efi/config_table
+Date:		December 2013
+Contact:	Dave Young <dyoung@redhat.com>
+Description:	It shows the physical address of config table entry in the EFI
+		system table.
+Users:		Kexec
@@ -0,0 +1,34 @@
+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
@@ -0,0 +1,38 @@
+What:		/sys/kernel/boot_params
+Date:		December 2013
+Contact:	Dave Young <dyoung@redhat.com>
+Description:	The /sys/kernel/boot_params directory contains two
+		files: "data" and "version" and one subdirectory "setup_data".
+		It is used to export the kernel boot parameters of an x86
+		platform to userspace for kexec and debugging purpose.
+
+		If there's no setup_data in boot_params the subdirectory will
+		not be created.
+
+		"data" file is the binary representation of struct boot_params.
+
+		"version" file is the string representation of boot
+		protocol version.
+
+		"setup_data" subdirectory contains the setup_data data
+		structure in boot_params. setup_data is maintained in kernel
+		as a link list. In "setup_data" subdirectory there's one
+		subdirectory for each link list node named with the number
+		of the list nodes. The list node subdirectory contains two
+		files "type" and "data". "type" file is the string
+		representation of setup_data type. "data" file is the binary
+		representation of setup_data payload.
+
+		The whole boot_params directory structure is like below:
+		/sys/kernel/boot_params
+		|__ data
+		|__ setup_data
+		|   |__ 0
+		|   |   |__ data
+		|   |   |__ type
+		|   |__ 1
+		|       |__ data
+		|       |__ type
+		|__ version
+
+Users:		Kexec
@@ -899,6 +899,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	edd=		[EDD]
 			Format: {"off" | "on" | "skip[mbr]"}

+	efi=		[EFI]
+			Format: { "old_map" }
+			old_map [X86-64]: switch to the old ioremap-based EFI
+			runtime services mapping. 32-bit still uses this one by
+			default.
+
 	efi_no_storage_paranoia [EFI; X86]
 			Using this parameter you can use more than 50% of
 			your efi variable storage. Use this parameter only if
@@ -608,6 +608,9 @@ Protocol:       2.12+
 	- If 1, the kernel supports the 64-bit EFI handoff entry point
          given at handover_offset + 0x200.

+  Bit 4 (read): XLF_EFI_KEXEC
+	- If 1, the kernel supports kexec EFI boot with EFI runtime support.
+
 Field name:	cmdline_size
 Type:		read
 Offset/size:	0x238/4
@@ -28,4 +28,11 @@ reference.
 Current X86-64 implementations only support 40 bits of address space,
 but we support up to 46 bits. This expands into MBZ space in the page tables.

+->trampoline_pgd:
+
+We map EFI runtime services in the aforementioned PGD in the virtual
+range of 64Gb (arbitrarily set, can be raised if needed)
+
+0xffffffef00000000 - 0xffffffff00000000
+
 -Andi Kleen, Jul 2004