[PATCH v2 02/14] arm: add initjmp()

[Heinrich Schuchardt]

On 28.02.25 14:21, Jerome Forissier wrote:
>
>
> On 2/28/25 14:05, Heinrich Schuchardt wrote:
>> On 25.02.25 17:34, Jerome Forissier wrote:
>>> Implement initjmp() for 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);
>>> +int initjmp(jmp_buf jmp, void __noreturn (*func)(void), void *stack_top);
>>
>> As this is not a standard function we cannot expect developers to know
>> what it does and how to use it.
>>
>> Please, provide Sphinx style documentation with the necessary information.
>
> I agree on principle, but if I add documentation here then I should add the
> same for all architectures. That being said the prototypes are already
> duplicated so maybe consolidation is a question for another time.  I will
> add Shpinx style doc to all 3 commits "{arm,riscv,sandbox}: add initjmp()".

Yes, this was not designed correctly:

We should move setjmp.h to include/asm-generic and include an
architecture specific setjmp_bits.h from there.

setjmp_bits.h would provide the struct jmp_buf_data definition.

>
> As for usage, I think the best documentation is test/lib/initjmp.c added
> by "test: lib: add initjmp() test".

Example code is valuable but does not replace documentation.

Best regards

Heinrich