Messages in this thread Patch in this message | | | Date | Tue, 17 Mar 2020 18:02:38 +0100 | From | Peter Zijlstra <> | Subject | [PATCH v2 04/19] x86/kexec: Use RIP relative addressing |
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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> --- arch/x86/kernel/relocate_kernel_64.S | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
--- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -196,10 +196,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_ma /* get the re-entry point of the peer system */ movq 0(%rsp), %rbp - call 1f -1: - popq %r8 - subq $(1b - relocate_kernel), %r8 + leaq relocate_kernel(%rip), %r8 movq CP_PA_SWAP_PAGE(%r8), %r10 movq CP_PA_BACKUP_PAGES_MAP(%r8), %rdi movq CP_PA_TABLE_PAGE(%r8), %rax
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