[PATCH] ARM: shmobile: smp: Enforce shmobile_smp_* alignment

[Geert Uytterhoeven]

Hi Prabhakar,

On Tue, 11 Mar 2025 at 16:11, Lad, Prabhakar <prabhakar.csengg at gmail.com> wrote:
> On Mon, Mar 10, 2025 at 1:14 PM Geert Uytterhoeven
> > When the addresses of the shmobile_smp_mpidr, shmobile_smp_fn, and
> > shmobile_smp_arg variables are not multiples of 4 bytes, secondary CPU
> > bring-up fails:
> >
> >     smp: Bringing up secondary CPUs ...
> >     CPU1: failed to come online
> >     CPU2: failed to come online
> >     CPU3: failed to come online
> >     smp: Brought up 1 node, 1 CPU
> >
> > Fix this by adding the missing alignment directive.
> >
> > Fixes: 4e960f52fce16a3b ("ARM: shmobile: Move shmobile_smp_{mpidr, fn, arg}[] from .text to .bss")
>
> I wonder if this fixes tag should go back a bit far as I was able to
> reproduce this on 5.10-cip BSP kernel on RZ/G1E this was only seen
> when CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE was enabled,

4e960f52fce16a3b is in v4.5, so it covers 5.10-cip.

> RZ/G1E failure logs:
> --------------------------
> [    0.006719] smp: Bringing up secondary CPUs ...
> [    1.040749] CPU1: failed to come online

> c154d5fd B shmobile_smp_mpidr
> c154d61d B shmobile_smp_fn
> c154d63d B shmobile_smp_arg

Bang!

> > Closes: https://lore.kernel.org/r/CAMuHMdU=QR-JLgEHKWpsr6SbaZRc-Hz9r91JfpP8c3n2G-OjqA@mail.gmail.com
> > Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
> > ---
> > To be queued in renesas-fixes-for-v6.14.
> > ---
> >  arch/arm/mach-shmobile/headsmp.S | 1 +
> >  1 file changed, 1 insertion(+)
> >
> Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>

Thanks!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds