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:
vmlinux.o: warning: objtool: .text+0x4c0f1: unsupported intra-function call
Replace the (i386 inspired) pattern:
call 1f
1: popq %r8
subq $(1b - relocate_kernel), %r8
With a x86_64 RIP-relative LEA:
leaq relocate_kernel(%rip), %r8
Suggested-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200324160924.143334345@infradead.org
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