On Fri, Nov 13, 2020 at 2:34 PM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > > On Fri, Nov 13, 2020 at 12:24:32PM -0800, Sami Tolvanen wrote: > > > I still don't see this warning for some reason. > > > > Do you have CONFIG_XEN enabled? I can reproduce this on ToT master as follows: > > > > $ git rev-parse HEAD > > 585e5b17b92dead8a3aca4e3c9876fbca5f7e0ba > > $ make defconfig && \ > > ./scripts/config -e HYPERVISOR_GUEST -e PARAVIRT -e XEN && \ > > make olddefconfig && \ > > make -j110 > > ... > > $ ./tools/objtool/objtool check -arfld vmlinux.o 2>&1 | grep secondary > > vmlinux.o: warning: objtool: __startup_secondary_64()+0x2: return with > > modified stack frame > > > > > Is it fixed by adding cpu_bringup_and_idle() to global_noreturns[] in > > > tools/objtool/check.c? > > > > No, that didn't fix the warning. Here's what I tested: > > I think this fixes it: > > From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > Subject: [PATCH] x86/xen: Fix objtool vmlinux.o validation of xen hypercalls > > Objtool vmlinux.o validation is showing warnings like the following: > > # tools/objtool/objtool check -barfld vmlinux.o > vmlinux.o: warning: objtool: __startup_secondary_64()+0x2: return with modified stack frame > vmlinux.o: warning: objtool: xen_hypercall_set_trap_table()+0x0: <=== (sym) > > Objtool falls through all the empty hypercall text and gets confused > when it encounters the first real function afterwards. The empty unwind > hints in the hypercalls aren't working for some reason. Replace them > with a more straightforward use of STACK_FRAME_NON_STANDARD. > > Reported-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> > Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > --- > arch/x86/xen/xen-head.S | 9 ++++----- > include/linux/objtool.h | 8 ++++++++ > 2 files changed, 12 insertions(+), 5 deletions(-) Confirmed, this fixes the warning, also in LTO builds. Thanks! Tested-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Sami
