From f4b4bc10b0b85ec66f1a9bf5dddf475e6695b6d2 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 21 Jan 2021 15:29:29 -0600 Subject: [PATCH] x86/xen: Support objtool vmlinux.o validation in xen-head.S 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 because the page gets rewritten by the hypervisor. Make it more palatable to objtool by making each hypervisor function a true empty function, with nops and a return. Cc: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/0883bde1d7a1fb3b6a4c952bc0200e873752f609.1611263462.git.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) \ -- 2.34.1