Re: [PATCH v3 2/8] arm64, unwind: build kernel with sframe V3 info

[Randy Dunlap <rdunlap@infradead.org>]

On 4/6/26 11:49 AM, Dylan Hatch wrote:
> Build with -Wa,--gsframe-3 flags to generate a .sframe section. This
> will be used for in-kernel reliable stacktrace in cases where the frame
> pointer alone is insufficient.
> 
> Currently, the sframe format only supports arm64, x86_64 and s390x
> architectures.
> 
> Signed-off-by: Weinan Liu <wnliu@google.com>
> Signed-off-by: Dylan Hatch <dylanbhatch@google.com>
> Reviewed-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
> ---
>  MAINTAINERS                            |  1 +
>  Makefile                               |  8 ++++++++
>  arch/Kconfig                           |  7 +++++++
>  arch/arm64/Kconfig                     |  1 +
>  arch/arm64/Kconfig.debug               | 13 +++++++++++++
>  arch/arm64/include/asm/unwind_sframe.h | 12 ++++++++++++
>  arch/arm64/kernel/vdso/Makefile        |  2 +-
>  include/asm-generic/vmlinux.lds.h      | 15 +++++++++++++++
>  8 files changed, 58 insertions(+), 1 deletion(-)
>  create mode 100644 arch/arm64/include/asm/unwind_sframe.h
> 


> diff --git a/arch/Kconfig b/arch/Kconfig
> index 6695c222c728..c87e489fa978 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -520,6 +520,13 @@ config SFRAME_VALIDATION
>  
>  	  If unsure, say N.
>  
> +config ARCH_SUPPORTS_SFRAME_UNWINDER
> +	bool
> +	help
> +	  An architecture can select this if it  enables the sframe (Simple

	                         drop one space^^    (if it)
	
> +	  Frame) unwinder for unwinding kernel stack traces. It uses unwind

	                                                             an unwind

> +	  table that is directly generatedby toolchain based on DWARF CFI information.

	                         generated by the toolchain

> +
>  config HAVE_PERF_REGS
>  	bool
>  	help


> index 265c4461031f..df291d64812f 100644
> --- a/arch/arm64/Kconfig.debug
> +++ b/arch/arm64/Kconfig.debug
> @@ -20,4 +20,17 @@ config ARM64_RELOC_TEST
>  	depends on m
>  	tristate "Relocation testing module"
>  
> +config SFRAME_UNWINDER
> +	bool "Sframe unwinder"
> +	depends on AS_SFRAME3
> +	depends on 64BIT
> +	depends on ARCH_SUPPORTS_SFRAME_UNWINDER
> +	select SFRAME_LOOKUP
> +	help
> +	  This option enables the sframe (Simple Frame) unwinder for unwinding
> +	  kernel stack traces. It uses unwind table that is directly generated

	                          uses an unwind table

> +	  by toolchain based on DWARF CFI information. In, practice this can

	  by the toolchain

> +	  provide more reliable stacktrace results than unwinding with frame
> +	  pointers alone.
> +
>  source "drivers/hwtracing/coresight/Kconfig"


-- 
~Randy