This series addresses an issue related to kexec/kdump when SME is active. The SME support uses a workarea located after the end of the kernel to perform "in-place" encryption of the kernel. When kexec/kdump is used, it is possible that some other data used by kexec/kdump could be in this area of memory which would cause the kexec/kdump of the kernel to fail.
Create a workarea section for use by SME in vmlinux.lds.S that is positioned after "_end", so that the memory it occupies will be reclaimed after its use during boot. Since it is part of the kernel image, there is no worry now that kexec/kdump will place data in the SME workarea when installing the kexec/kdump kernel. As part of this fix, clarify what occupied kernel memory is reserved and what parts of the kernel memory are discarded. The following patches are included: - Identify and document what parts of the kernel image are reserved (saved) and what is discarded. - Create a new section that lives outside of the kernel proper, so that it will be reclaimed as available memory during boot, thus allowing it to be used as a workarea by SME for kernel in-place encryption during early boot.. This patch series is based on tip/master. --- Changes from v2: - Grammar fixes - A more generic naming of the scratch/workarea section to indicate it is not restricted to SME usage Changes from v1: - Clarify how and where the kernel sections/memory is reserved. - Add an explicit symbol, __end_of_kernel_reserve, for reserving the kernel memory rather than using __bss_stop. Tom Lendacky (2): x86/mm: Identify the end of the kernel area to be reserved x86/mm: Create a workarea in the kernel for SME early encryption arch/x86/include/asm/sections.h | 2 ++ arch/x86/kernel/setup.c | 8 ++++++- arch/x86/kernel/vmlinux.lds.S | 34 +++++++++++++++++++++++++++++- arch/x86/mm/mem_encrypt_identity.c | 22 +++++++++++++++++-- 4 files changed, 62 insertions(+), 4 deletions(-) -- 2.17.1
