[PATCH v2] m68k: Fix WARNING splat in pmac_zilog driver

[Geert Uytterhoeven]

On Sun, Nov 22, 2020 at 12:40 AM Finn Thain <fthain at telegraphics.com.au> wrote:
> Don't add platform resources that won't be used. This avoids a
> recently-added warning from the driver core, that can show up on a
> multi-platform kernel when !MACH_IS_MAC.
>
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 0 at drivers/base/platform.c:224 platform_get_irq_optional+0x8e/0xce
> 0 is an invalid IRQ number
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper Not tainted 5.9.0-multi #1
> Stack from 004b3f04:
>         004b3f04 00462c2f 00462c2f 004b3f20 0002e128 004754db 004b6ad4 004b3f4c
>         0002e19c 004754f7 000000e0 00285ba0 00000009 00000000 004b3f44 ffffffff
>         004754db 004b3f64 004b3f74 00285ba0 004754f7 000000e0 00000009 004754db
>         004fdf0c 005269e2 004fdf0c 00000000 004b3f88 00285cae 004b6964 00000000
>         004fdf0c 004b3fac 0051cc68 004b6964 00000000 004b6964 00000200 00000000
>         0051cc3e 0023c18a 004b3fc0 0051cd8a 004fdf0c 00000002 0052b43c 004b3fc8
> Call Trace: [<0002e128>] __warn+0xa6/0xd6
>  [<0002e19c>] warn_slowpath_fmt+0x44/0x76
>  [<00285ba0>] platform_get_irq_optional+0x8e/0xce
>  [<00285ba0>] platform_get_irq_optional+0x8e/0xce
>  [<00285cae>] platform_get_irq+0x12/0x4c
>  [<0051cc68>] pmz_init_port+0x2a/0xa6
>  [<0051cc3e>] pmz_init_port+0x0/0xa6
>  [<0023c18a>] strlen+0x0/0x22
>  [<0051cd8a>] pmz_probe+0x34/0x88
>  [<0051cde6>] pmz_console_init+0x8/0x28
>  [<00511776>] console_init+0x1e/0x28
>  [<0005a3bc>] printk+0x0/0x16
>  [<0050a8a6>] start_kernel+0x368/0x4ce
>  [<005094f8>] _sinittext+0x4f8/0xc48
> random: get_random_bytes called from print_oops_end_marker+0x56/0x80 with crng_init=0
> ---[ end trace 392d8e82eed68d6c ]---
>
> Commit a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is invalid"),
> which introduced the WARNING, suggests that testing for irq == 0 is
> undesirable. Instead of that comparison, just test for resource existence.
>
> Cc: Michael Ellerman <mpe at ellerman.id.au>
> Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Cc: Paul Mackerras <paulus at samba.org>
> Cc: Joshua Thompson <funaho at jurai.org>
> Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> Cc: Jiri Slaby <jirislaby at kernel.org>
> Cc: stable at vger.kernel.org # v5.8+
> References: commit a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is invalid")
> Reported-by: Laurent Vivier <laurent at vivier.eu>
> Signed-off-by: Finn Thain <fthain at telegraphics.com.au>

Reviewed-by: Geert Uytterhoeven <geert at linux-m68k.org>
i.e. will queue in the m68k for-v5.11 branch.

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