On 2025-09-15 09:11:12+0200, Benjamin Berg wrote:
> From: Benjamin Berg <benjamin.b...@intel.com>
>
> In principle, it is possible to use nolibc for only some object files in
> a program. In that case, the startup code in _start and _start_c is not
> going to be used. Add the NOLIBC_NO_STARTCODE compile time option to
> disable it entirely and also remove anything that depends on it.
Not a big fan of the naming. More than only _start()/_start_c() are
disabled. Maybe NOLIBC_NO_RUNTIME? I'm horrible at naming...
> Doing this avoids warnings from modpost for UML as the _start_c code
> references the main function from the .init.text section while it is not
> inside .init itself.
>
> Signed-off-by: Benjamin Berg <benjamin.b...@intel.com>
> ---
> tools/include/nolibc/arch-arm.h | 2 ++
> tools/include/nolibc/arch-arm64.h | 2 ++
> tools/include/nolibc/arch-loongarch.h | 2 ++
> tools/include/nolibc/arch-m68k.h | 2 ++
> tools/include/nolibc/arch-mips.h | 2 ++
> tools/include/nolibc/arch-powerpc.h | 2 ++
> tools/include/nolibc/arch-riscv.h | 2 ++
> tools/include/nolibc/arch-s390.h | 2 ++
> tools/include/nolibc/arch-sh.h | 2 ++
> tools/include/nolibc/arch-sparc.h | 2 ++
> tools/include/nolibc/arch-x86.h | 4 ++++
> tools/include/nolibc/crt.h | 3 +++
> tools/include/nolibc/stackprotector.h | 2 ++
> tools/include/nolibc/stdlib.h | 2 ++
> tools/include/nolibc/sys.h | 3 ++-
> tools/include/nolibc/sys/auxv.h | 3 +++
> 16 files changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h
> index 1f66e7e5a444..24ad348cc1e8 100644
> --- a/tools/include/nolibc/arch-arm.h
> +++ b/tools/include/nolibc/arch-arm.h
> @@ -185,6 +185,7 @@
> })
>
> /* startup code */
> +#ifndef NOLIBC_NO_STARTCODE
I'd prefer the ifdef around the comments.
> void __attribute__((weak, noreturn)) __nolibc_entrypoint
> __no_stack_protector _start(void)
> {
> __asm__ volatile (
> @@ -193,5 +194,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint
> __no_stack_protector _s
> );
> __nolibc_entrypoint_epilogue();
> }
> +#endif /* NOLIBC_NO_STARTCODE */
(...)
