Re: [PATCH v4 09/39] x86/vdso: Enable sframe generation in VDSO

Jens Remus
2025-01-24T16:01:04Z

On 22.01.2025 03:31, Josh Poimboeuf wrote:
> Enable sframe generation in the VDSO library so kernel and user space
> can unwind through it.
>
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

...

> diff --git a/arch/x86/include/asm/dwarf2.h b/arch/x86/include/asm/dwarf2.h
> index b195b3c8677e..1c354f648505 100644
> --- a/arch/x86/include/asm/dwarf2.h
> +++ b/arch/x86/include/asm/dwarf2.h
> @@ -12,8 +12,11 @@
> * For the vDSO, emit both runtime unwind information and debug
> * symbols for the .dbg file.
> */
> -

Nit: Deleted blank line you introduced in "[PATCH v4 05/39] x86/asm:
Avoid emitting DWARF CFI for non-VDSO".

> +#ifdef __x86_64__

#if defined(__x86_64__) && defined(CONFIG_AS_SFRAME)

AFAIK the kernel has a minimum binutils requirement of 2.25 [1]
and assembler option "--gsframe" as well as directive
".cfi_sections .sframe" were introduced with 2.40.

> + .cfi_sections .eh_frame, .debug_frame, .sframe
> +#else
> .cfi_sections .eh_frame, .debug_frame
> +#endif
>
> #define CFI_STARTPROC .cfi_startproc
> #define CFI_ENDPROC .cfi_endproc

[1]: https://docs.kernel.org/process/changes.html

Regards,
Jens
--
Jens Remus
Linux on Z Development (D3303)
+49-7031-16-1128 Office
jremus@de.ibm.com

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