kernel.git/drivers/firmware/efi/Kconfig, branch linux-5.6.y

efi: Allow disabling PCI busmastering on bridges during boot

2020-01-10T17:55:04Z

Add an option to disable the busmaster bit in the control register on all PCI bridges before calling ExitBootServices() and passing control to the runtime kernel. System firmware may configure the IOMMU to prevent malicious PCI devices from being able to attack the OS via DMA. However, since firmware can't guarantee that the OS is IOMMU-aware, it will tear down IOMMU configuration when ExitBootServices() is called. This leaves a window between where a hostile device could still cause damage before Linux configures the IOMMU again. If CONFIG_EFI_DISABLE_PCI_DMA is enabled or "efi=disable_early_pci_dma" is passed on the command line, the EFI stub will clear the busmaster bit on all PCI bridges before ExitBootServices() is called. This will prevent any malicious PCI devices from being able to perform DMA until the kernel reenables busmastering after configuring the IOMMU. This option may cause failures with some poorly behaved hardware and should not be enabled without testing. The kernel commandline options "efi=disable_early_pci_dma" or "efi=no_disable_early_pci_dma" may be used to override the default. Note that PCI devices downstream from PCI bridges are disconnected from their drivers first, using the UEFI driver model API, so that DMA can be disabled safely at the bridge level. [ardb: disconnect PCI I/O handles first, as suggested by Arvind] Co-developed-by: Matthew Garrett Signed-off-by: Matthew Garrett Signed-off-by: Ard Biesheuvel Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Arvind Sankar Cc: Matthew Garrett Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20200103113953.9571-18-ardb@kernel.org Signed-off-by: Ingo Molnar

efi: Common enable/disable infrastructure for EFI soft reservation

2019-11-07T14:44:08Z

UEFI 2.8 defines an EFI_MEMORY_SP attribute bit to augment the interpretation of the EFI Memory Types as "reserved for a specific purpose". The proposed Linux behavior for specific purpose memory is that it is reserved for direct-access (device-dax) by default and not available for any kernel usage, not even as an OOM fallback. Later, through udev scripts or another init mechanism, these device-dax claimed ranges can be reconfigured and hot-added to the available System-RAM with a unique node identifier. This device-dax management scheme implements "soft" in the "soft reserved" designation by allowing some or all of the reservation to be recovered as typical memory. This policy can be disabled at compile-time with CONFIG_EFI_SOFT_RESERVE=n, or runtime with efi=nosoftreserve. As for this patch, define the common helpers to determine if the EFI_MEMORY_SP attribute should be honored. The determination needs to be made early to prevent the kernel from being loaded into soft-reserved memory, or otherwise allowing early allocations to land there. Follow-on changes are needed per architecture to leverage these helpers in their respective mem-init paths. Reviewed-by: Ard Biesheuvel Signed-off-by: Dan Williams Acked-by: Thomas Gleixner Signed-off-by: Rafael J. Wysocki

efi: Make CONFIG_EFI_RCI2_TABLE selectable on x86 only

2019-10-31T08:40:16Z

For the EFI_RCI2_TABLE Kconfig option, 'make oldconfig' asks the user for input on platforms where the option may not be applicable. This patch modifies the Kconfig option to ask the user for input only when CONFIG_X86 or CONFIG_COMPILE_TEST is set to y. Suggested-by: Geert Uytterhoeven Reported-by: Geert Uytterhoeven Tested-by: Geert Uytterhoeven Signed-off-by: Narendra K Signed-off-by: Ard Biesheuvel Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191029173755.27149-2-ardb@kernel.org Signed-off-by: Ingo Molnar

efi: Export Runtime Configuration Interface table to sysfs

2019-08-08T08:10:25Z

System firmware advertises the address of the 'Runtime Configuration Interface table version 2 (RCI2)' via an EFI Configuration Table entry. This code retrieves the RCI2 table from the address and exports it to sysfs as a binary attribute 'rci2' under /sys/firmware/efi/tables directory. The approach adopted is similar to the attribute 'DMI' under /sys/firmware/dmi/tables. RCI2 table contains BIOS HII in XML format and is used to populate BIOS setup page in Dell EMC OpenManage Server Administrator tool. The BIOS setup page contains BIOS tokens which can be configured. Signed-off-by: Narendra K Reviewed-by: Mario Limonciello Signed-off-by: Ard Biesheuvel

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46Z

Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation

2019-02-04T07:27:30Z

Move the x86 EFI earlyprintk implementation to a shared location under drivers/firmware and tweak it slightly so we can expose it as an earlycon implementation (which is generic) rather than earlyprintk (which is only implemented for a few architectures) This also involves switching to write-combine mappings by default (which is required on ARM since device mappings lack memory semantics, and so memcpy/memset may not be used on them), and adding support for shared memory framebuffers on cache coherent non-x86 systems (which do not tolerate mismatched attributes). Note that 32-bit ARM does not populate its struct screen_info early enough for earlycon=efifb to work, so it is disabled there. Signed-off-by: Ard Biesheuvel Reviewed-by: Alexander Graf Cc: AKASHI Takahiro Cc: Bjorn Andersson Cc: Borislav Petkov Cc: Heinrich Schuchardt Cc: Jeffrey Hugo Cc: Lee Jones Cc: Leif Lindholm Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Jones Cc: Peter Zijlstra Cc: Sai Praneeth Prakhya Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20190202094119.13230-10-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar

efi/libstub/arm: default EFI_ARMSTUB_DTB_LOADER to y

2018-09-12T14:41:41Z

Default EFI_ARMSTUB_DTB_LOADER to y to allow the dtb= command line parameter to function with efi loader. Required for development purposes and to boot on existing bootloaders that do not support devicetree provided by the firmware or by the bootloader. Fixes: 3d7ee348aa41 ("efi/libstub/arm: Add opt-in Kconfig option ...") Signed-off-by: Scott Branden Signed-off-by: Ard Biesheuvel

efi/libstub/arm: Add opt-in Kconfig option for the DTB loader

2018-07-15T22:43:12Z

There are various ways a platform can provide a device tree binary to the kernel, with different levels of sophistication: - ideally, the UEFI firmware, which is tightly coupled with the platform, provides a device tree image directly as a UEFI configuration table, and typically permits the contents to be manipulated either via menu options or via UEFI environment variables that specify a replacement image, - GRUB for ARM has a 'devicetree' directive which allows a device tree image to be loaded from any location accessible to GRUB, and supersede the one provided by the firmware, - the EFI stub implements a dtb= command line option that allows a device tree image to be loaded from a file residing in the same file system as the one the kernel image was loaded from. The dtb= command line option was never intended to be more than a development feature, to allow the other options to be implemented in parallel. So let's make it an opt-in feature that is disabled by default, but can be re-enabled at will. Note that we already disable the dtb= command line option when we detect that we are running with UEFI Secure Boot enabled. Signed-off-by: Ard Biesheuvel Reviewed-by: Alexander Graf Acked-by: Leif Lindholm Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20180711094040.12506-7-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar

efi: Decode IA32/X64 Processor Error Section

2018-05-14T06:57:47Z

Recognize the IA32/X64 Processor Error Section. Do the section decoding in a new "cper-x86.c" file and add this to the Makefile depending on a new "UEFI_CPER_X86" config option. Print the Local APIC ID and CPUID info from the Processor Error Record. The "Processor Error Info" and "Processor Context" fields will be decoded in following patches. Based on UEFI 2.7 Table 252. Processor Error Record. Signed-off-by: Yazen Ghannam Signed-off-by: Ard Biesheuvel Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20180504060003.19618-5-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar

Merge tag 'kconfig-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2018-02-01T19:45:49Z

Pull Kconfig updates from Masahiro Yamada: "A pretty big batch of Kconfig updates. I have to mention the lexer and parser of Kconfig are now built from real .l and .y sources. So, flex and bison are the requirement for building the kernel. Both of them (unlike gperf) have been stable for a long time. This change has been tested several weeks in linux-next, and I did not receive any problem report about this. Summary: - add checks for mistakes, like the choice default is not in choice, help is doubled - document data structure and complex code - fix various memory leaks - change Makefile to build lexer and parser instead of using pre-generated C files - drop 'boolean' keyword, which is equivalent to 'bool' - use default 'yy' prefix and remove unneeded Make variables - fix gettext() check for xconfig - announce that oldnoconfig will be finally removed - make 'Selected by:' and 'Implied by' readable in help and search result - hide silentoldconfig from 'make help' to stop confusing people - fix misc things and cleanups" * tag 'kconfig-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (37 commits) kconfig: Remove silentoldconfig from help and docs; fix kconfig/conf's help kconfig: make "Selected by:" and "Implied by:" readable kconfig: announce removal of oldnoconfig if used kconfig: fix make xconfig when gettext is missing kconfig: Clarify menu and 'if' dependency propagation kconfig: Document 'if' flattening logic kconfig: Clarify choice dependency propagation kconfig: Document SYMBOL_OPTIONAL logic kbuild: remove unnecessary LEX_PREFIX and YACC_PREFIX kconfig: use default 'yy' prefix for lexer and parser kconfig: make conf_unsaved a local variable of conf_read() kconfig: make xfgets() really static kconfig: make input_mode static kconfig: Warn if there is more than one help text kconfig: drop 'boolean' keyword kconfig: use bool instead of boolean for type definition attributes, again kconfig: Remove menu_end_entry() kconfig: Document important expression functions kconfig: Document automatic submenu creation code kconfig: Fix choice symbol expression leak ...