Some platform have firmware that violates the UEFI spec and access boot service code or data segments after the system has called ExitBootServices(). The call to efi_reserve_boot_services in setup_arch is a workaround to avoid using boot service memory until after the kernel has done SetVirtualAddressMap. However, this reservation fragments memory which can cause large allocations early in boot (e.g. crash kernel) to fail. This patch set creates a quirk list that governs whether efi_reserve_boot_services is called. A new kernel parameter is added that overrides the quirk list and allows engineers developing new platforms to test whether they need to have the quirk applied or not. With this information, setup_arch avoids calling efi_reserve_boot_services when it doesn't need to, thus avoiding fragmenting memory. ChangeLog V1 => v2) In version 1 the control of the workaround was only by command line argument. In version 2, the quirk list is the primary control of the whether the workaround is applied. This allows for seamless integration with tools and doesn't require any special knowledge from the user. The command line argument is retained for platform developers to be able to test whether their platforms require the workaround. Jerry Hoemann (2): efi: Early use of boot service memory x86, efi: Early use of boot service memory Documentation/kernel-parameters.txt | 5 +++ arch/x86/kernel/setup.c | 5 ++- arch/x86/platform/efi/efi.c | 77 ++++++++++++++++++++++++++++++++++++- include/linux/efi.h | 2 + 4 files changed, 86 insertions(+), 3 deletions(-) -- 1.7.11.3 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
