Re: [PATCH] objtool: Fix STACK_FRAME_NON_STANDARD reloc type

From: Josh Poimboeuf
Date: Fri Apr 29 2022 - 16:13:40 EST


On Fri, Apr 29, 2022 at 11:20:24AM +0200, Peter Zijlstra wrote:
>
> STACK_FRAME_NON_STANDARD results in inconsistent relocation types
> depending on .c or .S usage:
>
> Relocation section '.rela.discard.func_stack_frame_non_standard' at offset 0x3c01090 contains 5 entries:
> Offset Info Type Symbol's Value Symbol's Name + Addend
> 0000000000000000 00020c2200000002 R_X86_64_PC32 0000000000047b40 do_suspend_lowlevel + 0
> 0000000000000008 0002461e00000001 R_X86_64_64 00000000000480a0 machine_real_restart + 0
> 0000000000000010 0000001400000001 R_X86_64_64 0000000000000000 .rodata + b3d4
> 0000000000000018 0002444600000002 R_X86_64_PC32 00000000000678a0 __efi64_thunk + 0
> 0000000000000020 0002659d00000001 R_X86_64_64 0000000000113160 __crash_kexec + 0
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> ---
> include/linux/objtool.h | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> --- a/include/linux/objtool.h
> +++ b/include/linux/objtool.h
> @@ -137,7 +137,11 @@ struct unwind_hint {
>
> .macro STACK_FRAME_NON_STANDARD func:req
> .pushsection .discard.func_stack_frame_non_standard, "aw"
> - .long \func - .
> +#ifdef CONFIG_64BIT
> + .quad \func
> +#else
> + .long \func
> +#endif
> .popsection
> .endm

Can use _ASM_PTR here, and objtool.h needs synced to tools.

--
Josh