Messages in this thread | | | Date | Fri, 13 Mar 2020 18:22:57 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH 04/16] objtool: Annotate identity_mapped() |
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On Fri, Mar 13, 2020 at 12:46:05PM -0400, Brian Gerst wrote: > On Thu, Mar 12, 2020 at 9:53 AM Peter Zijlstra <peterz@infradead.org> wrote: > > > > Normally identity_mapped is not visible to objtool, due to: > > > > arch/x86/kernel/Makefile:OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o := y > > > > However, when we want to run objtool on vmlinux.o there is no hiding > > it. Without the annotation we'll get complaints about the: > > > call 1f > 1: popq %r8 > subq $(1b - relocate_kernel), %r8 > > It looks to me that this code is simply trying to get the virtual > address of relocate_kernel using the old 32-bit method of PIC address > calculation. On 64-bit can be done with leaq relocate_kernel(%rip), > %r8.
Indeed. Objtool would be happy with that. And it seems I can still kexec a kernel too.
Thanks!
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