[RFC PATCH 02/10] arm: add initjmp()

[Heinrich Schuchardt]

On 14.02.25 15:00, Jerome Forissier wrote:
> Implement initjmp() for Arm.

Could you, please, describe in the commit message what initjmp() good
for and why it is needed and why it would not be needed for any other
architectures but ARM.

>
> Signed-off-by: Jerome Forissier <jerome.forissier at linaro.org>
> ---
>   arch/Kconfig                  |  1 +
>   arch/arm/include/asm/setjmp.h |  1 +
>   arch/arm/lib/setjmp.S         | 11 +++++++++++
>   arch/arm/lib/setjmp_aarch64.S |  9 +++++++++
>   4 files changed, 22 insertions(+)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 8d5b54031b3..57695fada8d 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -94,6 +94,7 @@ config ARC
>   config ARM
>   	bool "ARM architecture"
>   	select HAVE_SETJMP
> +	select HAVE_INITJMP
>   	select ARCH_SUPPORTS_LTO
>   	select CREATE_ARCH_SYMLINK
>   	select HAVE_PRIVATE_LIBGCC if !ARM64
> diff --git a/arch/arm/include/asm/setjmp.h b/arch/arm/include/asm/setjmp.h
> index 662bec86321..1ad5b500f2a 100644
> --- a/arch/arm/include/asm/setjmp.h
> +++ b/arch/arm/include/asm/setjmp.h
> @@ -23,5 +23,6 @@ typedef struct jmp_buf_data jmp_buf[1];
>
>   int setjmp(jmp_buf jmp);
>   void longjmp(jmp_buf jmp, int ret);

Please, always provide a Sphinx description for any new function.

Best regards

Heinrich

> +int initjmp(jmp_buf jmp, void __noreturn (*func)(void), void *stack_top);
>
>   #endif /* _SETJMP_H_ */
> diff --git a/arch/arm/lib/setjmp.S b/arch/arm/lib/setjmp.S
> index 2f041aeef01..320ddea85f9 100644
> --- a/arch/arm/lib/setjmp.S
> +++ b/arch/arm/lib/setjmp.S
> @@ -34,3 +34,14 @@ ENTRY(longjmp)
>   	ret  lr
>   ENDPROC(longjmp)
>   .popsection
> +
> +.pushsection .text.initjmp, "ax"
> +ENTRY(initjmp)
> +	stm  a1, {v1-v8}
> +	/* a2: entry point address, a3: stack top */
> +	str  a3, [a1, #32]  /* where setjmp would save sp */
> +	str  a2, [a1, #36]  /* where setjmp would save lr */
> +	mov  a1, #0
> +	ret  lr
> +ENDPROC(initjmp)
> +.popsection
> diff --git a/arch/arm/lib/setjmp_aarch64.S b/arch/arm/lib/setjmp_aarch64.S
> index 1b8d000eb48..074320d25fb 100644
> --- a/arch/arm/lib/setjmp_aarch64.S
> +++ b/arch/arm/lib/setjmp_aarch64.S
> @@ -39,3 +39,12 @@ ENTRY(longjmp)
>   	ret
>   ENDPROC(longjmp)
>   .popsection
> +
> +.pushsection .text.initjmp, "ax"
> +ENTRY(initjmp)
> +	/* x1: entry point address, x2: stack top */
> +	stp x1, x2, [x0,#88]
> +	mov  x0, #0
> +	ret
> +ENDPROC(initjmp)
> +.popsection