Re: [RFC PATCH v4 08/17] powerpc/ftrace: Move ftrace stub used for init text before _einittext

Nicholas Piggin
2024-07-15T06:52:37Z

On Sun Jul 14, 2024 at 6:27 PM AEST, Naveen N Rao wrote:
> Move the ftrace stub used to cover inittext before _einittext so that it
> is within kernel text, as seen through core_kernel_text(). This is
> required for a subsequent change to ftrace.

Hmm, is there a reason it was outside einittext anyway?

Does it do anything else? Other than symbols, on some 32-bit platforms
it looks like it could change some of the initial mapping/pinning. Maybe
they jut get lucky and always map it before the change anyway?

It looks like the right thing to do even without the subsequent ftrace
change though.

Thanks,
Nick

>
> Signed-off-by: Naveen N Rao <naveen@kernel.org>
> ---
> arch/powerpc/kernel/vmlinux.lds.S | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
> index f420df7888a7..0aef9959f2cd 100644
> --- a/arch/powerpc/kernel/vmlinux.lds.S
> +++ b/arch/powerpc/kernel/vmlinux.lds.S
> @@ -267,14 +267,13 @@ SECTIONS
> .init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
> _sinittext = .;
> INIT_TEXT
> -
> + *(.tramp.ftrace.init);
> /*
> *.init.text might be RO so we must ensure this section ends on
> * a page boundary.
> */
> . = ALIGN(PAGE_SIZE);
> _einittext = .;
> - *(.tramp.ftrace.init);
> } :text
>
> /* .exit.text is discarded at runtime, not link time,