[-mm patch] always enable regparm on i386

[-mm patch] always enable regparm on i386

[Adrian Bunk]

The patch below always enables regparm on i386 (with gcc >= 3.0).

With this patch, it should get a better testing coverage in -mm.

This patch should help to find bugs that show up with regparm enabled.


Signed-off-by: Adrian Bunk <bunk@stusta.de>

--- linux-2.6.10-mm2-full/arch/i386/Kconfig.old	2005-01-08 17:41:49.000000000 +0100
+++ linux-2.6.10-mm2-full/arch/i386/Kconfig	2005-01-08 17:42:10.000000000 +0100
@@ -877,9 +877,8 @@
 	default y
 
 config REGPARM
-	bool "Use register arguments (EXPERIMENTAL)"
-	depends on EXPERIMENTAL
-	default n
+	bool
+	default y
 	help
 	Compile the kernel with -mregparm=3. This uses an different ABI
 	and passes the first three arguments of a function call in registers.

Re: [-mm patch] always enable regparm on i386

[Andrew Morton]

Adrian Bunk <bunk@stusta.de> wrote:
>
>  The patch below always enables regparm on i386 (with gcc >= 3.0).

I'd prefer to keep the config option so that people can diagnose compiler
and kernel bugs by disabling it.  This has proved useful in the past.

[-mm patch] always enable regparm on i386

[Adrian Bunk]

The patch below always enables regparm on i386 (with gcc >= 3.0).

With this patch, it should get a better testing coverage in -mm.

If this doesn't cause any problems, I plan to send a patch to completely 
remove the CONFIG_REGPARM option after 2.6.11 will be released.


Signed-off-by: Adrian Bunk <bunk@stusta.de>

--- linux-2.6.10-mm2-full/arch/i386/Kconfig.old	2005-01-08 17:41:49.000000000 +0100
+++ linux-2.6.10-mm2-full/arch/i386/Kconfig	2005-01-08 17:42:10.000000000 +0100
@@ -877,9 +877,8 @@
 	default y
 
 config REGPARM
-	bool "Use register arguments (EXPERIMENTAL)"
-	depends on EXPERIMENTAL
-	default n
+	bool
+	default y
 	help
 	Compile the kernel with -mregparm=3. This uses an different ABI
 	and passes the first three arguments of a function call in registers.

Re: [-mm patch] always enable regparm on i386

[Andrew Morton]

Adrian Bunk <bunk@stusta.de> wrote:
>
> The patch below always enables regparm on i386 (with gcc >= 3.0).
> 
>  With this patch, it should get a better testing coverage in -mm.
> 
>  If this doesn't cause any problems, I plan to send a patch to completely 
>  remove the CONFIG_REGPARM option after 2.6.11 will be released.

-mregparm has revealed at least two kernel bugs thus far.  The ability to
disable -mregparm is a useful diagnostic tool.

Re: [-mm patch] always enable regparm on i386

[Adrian Bunk]

On Sat, Jan 08, 2005 at 03:52:48PM -0800, Andrew Morton wrote:
> Adrian Bunk <bunk@stusta.de> wrote:
> >
> > The patch below always enables regparm on i386 (with gcc >= 3.0).
> > 
> >  With this patch, it should get a better testing coverage in -mm.
> > 
> >  If this doesn't cause any problems, I plan to send a patch to completely 
> >  remove the CONFIG_REGPARM option after 2.6.11 will be released.
> 
> -mregparm has revealed at least two kernel bugs thus far.  The ability to
> disable -mregparm is a useful diagnostic tool.

You are still able to disable it by editing the Kconfig file.

And even if the option will no longer be present at some time in the 
future, it will be trivial to disable it in the Makefile.

But currently (an option depending on EXPERIMENTAL) the testing coverage 
isn't that big, and with this -mm patch, most people using -mm [1] will 
have it enabled and notice if other problems pop up.

cu
Adrian

[1] except for those with gcc < 3.0 or !i386

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed