| From | Josh Poimboeuf <> | Subject | [PATCH 14/21] x86/xen: Support objtool vmlinux.o validation in xen-head.S | Date | Thu, 14 Jan 2021 13:40:10 -0600 |
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The Xen hypercall page is filled with zeros, causing objtool to fall through all the empty hypercall functions until it reaches a real function, resulting in a stack state mismatch.
The build-time contents of the hypercall page don't matter, since it gets mapped to the hypervisor. Make it more palatable to objtool by making each hypervisor function a true empty function, with nops and a return.
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> --- arch/x86/xen/xen-head.S | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index 2d7c8f34f56c..cb6538ae2fe0 100644 --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -68,8 +68,9 @@ SYM_CODE_END(asm_cpu_bringup_and_idle) .balign PAGE_SIZE SYM_CODE_START(hypercall_page) .rept (PAGE_SIZE / 32) - UNWIND_HINT_EMPTY - .skip 32 + UNWIND_HINT_FUNC + .skip 31, 0x90 + ret .endr #define HYPERCALL(n) \ -- 2.29.2
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