Messages in this thread | | | From | Sami Tolvanen <> | Date | Tue, 10 Nov 2020 10:59:55 -0800 | Subject | Re: [PATCH v6 22/25] x86/asm: annotate indirect jumps |
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On Tue, Nov 10, 2020 at 9:46 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > On Mon, Nov 09, 2020 at 08:29:24PM -0600, Josh Poimboeuf wrote: > > On Mon, Nov 09, 2020 at 03:11:41PM -0800, Sami Tolvanen wrote: > > > CONFIG_XEN > > > > > > __switch_to_asm()+0x0: undefined stack state > > > xen_hypercall_set_trap_table()+0x0: <=== (sym) > > With your branch + GCC 9 I can recreate all the warnings except this > one.
In a gcc build this warning is replaced with a different one:
vmlinux.o: warning: objtool: __startup_secondary_64()+0x7: return with modified stack frame
This just seems to depend on which function is placed right after the code in xen-head.S. With gcc, the disassembly looks like this:
0000000000000000 <asm_cpu_bringup_and_idle>: 0: e8 00 00 00 00 callq 5 <asm_cpu_bringup_and_idle+0x5> 1: R_X86_64_PLT32 cpu_bringup_and_idle-0x4 5: e9 f6 0f 00 00 jmpq 1000 <xen_hypercall_set_trap_table> ... 0000000000001000 <xen_hypercall_set_trap_table>: ... ... 0000000000002000 <__startup_secondary_64>:
With Clang+LTO, we end up with __switch_to_asm here instead of __startup_secondary_64.
> Will do some digging on the others...
Thanks!
Sami
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