[PATCH] char: Drop bogus dependency of DEVPORT on !M68K

[PATCH] char: Drop bogus dependency of DEVPORT on !M68K

[Geert Uytterhoeven]

According to full-history-linux commit d3794f4fa7c3edc3 ("[PATCH] M68k
update (part 25)"), port operations are allowed on m68k if CONFIG_ISA is
defined.

However, commit 153dcc54df826d2f ("[PATCH] mem driver: fix conditional
on isa i/o support") accidentally changed an "||" into an "&&",
disabling it completely on m68k. This logic was retained when
introducing the DEVPORT symbol in commit 4f911d64e04a44c4 ("Make
/dev/port conditional on config symbol").

Drop the bogus dependency on !M68K to fix this.

Fixes: 153dcc54df826d2f ("[PATCH] mem driver: fix conditional on isa i/o support")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 drivers/char/Kconfig | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index d3b8ddc6241cac2d..fa56bc757fe98fd1 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -585,7 +585,6 @@ config TELCLOCK
 
 config DEVPORT
 	bool
-	depends on !M68K
 	depends on ISA || PCI
 	default y
 
-- 
1.9.1

Re: [PATCH] char: Drop bogus dependency of DEVPORT on !M68K

[Al Stone]

On 04/11/2016 02:40 AM, Geert Uytterhoeven wrote:
> According to full-history-linux commit d3794f4fa7c3edc3 ("[PATCH] M68k
> update (part 25)"), port operations are allowed on m68k if CONFIG_ISA is
> defined.
> 
> However, commit 153dcc54df826d2f ("[PATCH] mem driver: fix conditional
> on isa i/o support") accidentally changed an "||" into an "&&",
> disabling it completely on m68k. This logic was retained when
> introducing the DEVPORT symbol in commit 4f911d64e04a44c4 ("Make
> /dev/port conditional on config symbol").
> 
> Drop the bogus dependency on !M68K to fix this.
> 
> Fixes: 153dcc54df826d2f ("[PATCH] mem driver: fix conditional on isa i/o support")
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> ---
>  drivers/char/Kconfig | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
> index d3b8ddc6241cac2d..fa56bc757fe98fd1 100644
> --- a/drivers/char/Kconfig
> +++ b/drivers/char/Kconfig
> @@ -585,7 +585,6 @@ config TELCLOCK
>  
>  config DEVPORT
>  	bool
> -	depends on !M68K
>  	depends on ISA || PCI
>  	default y
>  
> 

This solves the particular problem I was running into on an arm64 AMD Seattle
system.  Thanks!

Tested-by: Al Stone <ahs3@redhat.com>

-- 
ciao,
al
-----------------------------------
Al Stone
Software Engineer
Red Hat, Inc.
ahs3@redhat.com
-----------------------------------

Re: [PATCH] char: Drop bogus dependency of DEVPORT on !M68K

[Paul Bolle]

On wo, 2016-04-20 at 13:43 -0600, Al Stone wrote:
> On 04/11/2016 02:40 AM, Geert Uytterhoeven wrote:
> > --- a/drivers/char/Kconfig
> > +++ b/drivers/char/Kconfig

> > config DEVPORT
> >  	bool
> > -	depends on !M68K
> >  	depends on ISA || PCI
> >  	default y

> This solves the particular problem I was running into on an arm64 AMD Seattle
> system.  Thanks!

That problem must be 
lkml.kernel.org/g/1459978040-2226-1-git-send-email-ahs3@redhat.com . Ie,
the fact that CONFIG_DEVPORT "cannot really be used and it allows us to
crash a kernel from user space" on arm64. 

> Tested-by: Al Stone <ahs3@redhat.com>

I fail to see how this patch helps your problem. And if one applies this
patch on top of v4.6-rc4 and does
    make ARCH=arm64 defconfig

one gets a .config that still has
    CONFIG_DEVPORT=y

So my guess is that it wasn't this patch that solved that arm64 problem.

Thanks,


Paul Bolle