Laurent Vivier [off-list ref] writes:

Le 20/10/2020 à 20:32, Greg KH a écrit :

quoted

On Tue, Oct 20, 2020 at 08:19:26PM +0200, Laurent Vivier wrote:

quoted

Le 20/10/2020 à 19:37, Greg KH a écrit :

quoted

On Tue, Oct 20, 2020 at 06:37:41PM +0200, Laurent Vivier wrote:

quoted

Le 20/10/2020 à 18:28, Greg KH a écrit :

quoted

On Tue, Oct 20, 2020 at 06:23:03PM +0200, Laurent Vivier wrote:

quoted

We can avoid to probe for the Zilog device (and generate ugly kernel warning)
if kernel is built for Mac but not on a Mac.

Signed-off-by: Laurent Vivier <redacted>
---
 drivers/tty/serial/pmac_zilog.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/tty/serial/pmac_zilog.c b/drivers/tty/serial/pmac_zilog.c
index 063484b22523..d1d2e55983c3 100644
--- a/drivers/tty/serial/pmac_zilog.c
+++ b/drivers/tty/serial/pmac_zilog.c

@@ -1867,6 +1867,12 @@ static struct platform_driver pmz_driver = {
 static int __init init_pmz(void)
 {
 	int rc, i;
+
+#ifdef CONFIG_MAC
+	if (!MACH_IS_MAC)
+		return -ENODEV;
+#endif

Why is the #ifdef needed?

We don't like putting #ifdef in .c files for good reasons.  Can you make
the api check for this work with and without that #ifdef needed?

The #ifdef is needed because this file can be compiled for PowerMac and
m68k Mac. For PowerMac, the MACH_IS_MAC is not defined, so we need the
#ifdef.

We need the MAC_IS_MAC because the same kernel can be used with several
m68k machines, so the init_pmz can be called on a m68k machine without
the zilog device (it's a multi-targets kernel).

You can check it's the good way to do by looking inside:

    drivers/video/fbdev/valkyriefb.c +317
    drivers/macintosh/adb.c +316

That are two files used by both, mac and pmac.

Why not fix it to work properly like other arch checks are done

I would be happy to do the same.

quoted

Put it in a .h file and do the #ifdef there.  Why is this "special"?

I don't know.

Do you mean something like:

drivers/tty/serial/pmac_zilog.h
...
#ifndef MACH_IS_MAC
#define MACH_IS_MAC (0)
#endif
...

drivers/tty/serial/pmac_zilog.c
...
static int __init pmz_console_init(void)
{
        if (!MACH_IS_MAC)
                return -ENODEV;
...

Yup, that would be a good start, but why is the pmac_zilog.h file
responsible for this?  Shouldn't this be in some arch-specific file
somewhere?

For m68k, MACH_IS_MAC is defined in arch/m68k/include/asm/setup.h

If I want to define it for any other archs I don't know in which file we
can put it.

But as m68k mac is only sharing drivers with pmac perhaps we can put
this in arch/powerpc/include/asm/setup.h?

It doesn't really belong in there.

I'd accept a patch to create arch/powerpc/include/asm/macintosh.h, with
MACH_IS_MAC defined in there.

cheers