On 09/03/18 20:44, Baoquan He wrote: > > 1) in arch/x86/kernel/relocate_kernel_64.S, we set X86_CR4_LA57 into cr4 > if the 1st kernel is in 5-level mode. Then in > arch/x86/boot/compressed/head_64.S, paging_prepare() is called to decide > if 5-level mode will be enabled, and prepare the trampoline. If > kexec/kdump kernel is expected to be in 4-level, e.g with 'nolv5' > specified, it still can handle well. But for the old kernel w/o these > 5-level codes, it will ignore the fact that X86_CR4_LA57 has been set > in CR4 and proceed anyway, then #GP is triggered. That's why XLF_5LEVEL > is used to mark. > That's what I'm saying, don't do that. Always jump into the second kernel in 4-level mode, i.e. X86_CR4_LA57 unset. That's the only sane thing. -hpa _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
