[PATCH] x86_64 built-in command line

[PATCH] x86_64 built-in command line

[Matt Mackall]

Allow setting a command line at build time on x86_64. Compiled but not
tested.

Signed-off-by: Matt Mackall <mpm@selenic.com>

Index: linux/arch/x86_64/Kconfig
===================================================================
--- linux.orig/arch/x86_64/Kconfig	2006-07-26 18:08:29.000000000 -0500
+++ linux/arch/x86_64/Kconfig	2006-07-27 17:19:50.000000000 -0500
@@ -558,6 +558,20 @@ config K8_NB
 	def_bool y
 	depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
 
+config CMDLINE_BOOL
+	bool "Default bootloader kernel arguments" if EMBEDDED
+
+config CMDLINE
+	string "Initial kernel command string" if EMBEDDED
+	depends on CMDLINE_BOOL
+	default "root=/dev/hda1 ro"
+	help
+	  On some systems, there is no way for the boot loader to pass
+	  arguments to the kernel. For these platforms, you can supply
+	  some command-line options at build time by entering them
+	  here. In most cases you will need to specify the root device
+	  here.
+
 endmenu
 
 #
Index: linux/arch/x86_64/kernel/setup.c
===================================================================
--- linux.orig/arch/x86_64/kernel/setup.c	2006-07-26 18:08:29.000000000 -0500
+++ linux/arch/x86_64/kernel/setup.c	2006-07-27 17:26:51.000000000 -0500
@@ -289,6 +289,10 @@ static __init void parse_cmdline_early (
 	int len = 0;
 	int userdef = 0;
 
+#ifdef CONFIG_CMDLINE_BOOL
+	strlcpy(saved_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#endif
+
 	for (;;) {
 		if (c != ' ') 
 			goto next_char; 

-- 
Mathematics is the supreme nostalgia of our time.

Re: [PATCH] x86_64 built-in command line

[linux-os (Dick Johnson)]

On Mon, 31 Jul 2006, Matt Mackall wrote:

> Allow setting a command line at build time on x86_64. Compiled but not
> tested.
>
> Signed-off-by: Matt Mackall <mpm@selenic.com>
>
> Index: linux/arch/x86_64/Kconfig
> ===================================================================
> --- linux.orig/arch/x86_64/Kconfig	2006-07-26 18:08:29.000000000 -0500
> +++ linux/arch/x86_64/Kconfig	2006-07-27 17:19:50.000000000 -0500
> @@ -558,6 +558,20 @@ config K8_NB
> 	def_bool y
> 	depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
>
> +config CMDLINE_BOOL
> +	bool "Default bootloader kernel arguments" if EMBEDDED
> +
> +config CMDLINE
> +	string "Initial kernel command string" if EMBEDDED
> +	depends on CMDLINE_BOOL
> +	default "root=/dev/hda1 ro"
> +	help
> +	  On some systems, there is no way for the boot loader to pass
> +	  arguments to the kernel. For these platforms, you can supply
> +	  some command-line options at build time by entering them
> +	  here. In most cases you will need to specify the root device
> +	  here.
> +
> endmenu
>
> #
> Index: linux/arch/x86_64/kernel/setup.c
> ===================================================================
> --- linux.orig/arch/x86_64/kernel/setup.c	2006-07-26 18:08:29.000000000 -0500
> +++ linux/arch/x86_64/kernel/setup.c	2006-07-27 17:26:51.000000000 -0500
> @@ -289,6 +289,10 @@ static __init void parse_cmdline_early (
> 	int len = 0;
> 	int userdef = 0;
>
> +#ifdef CONFIG_CMDLINE_BOOL
> +	strlcpy(saved_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> +#endif
> +
> 	for (;;) {
> 		if (c != ' ')
> 			goto next_char;
>
> --
> Mathematics is the supreme nostalgia of our time.
> -

But this just makes it nice for __your__ embedded system. I suggest you
use:
> +	default "root=/dev/root ro"

The boot setup code makes a symlink to whatever your specific
setup requires.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.62 BogoMips).
New book: http://www.AbominableFirebug.com/
_
\x1a\x04

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Re: [PATCH] x86_64 built-in command line

[Andi Kleen]

  
> +#ifdef CONFIG_CMDLINE_BOOL
> +	strlcpy(saved_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> +#endif

I think I would prefer a strcat.

Also you should describe the exact behaviour (override/append) in Kconfig help.

-Andi

Re: [PATCH] x86_64 built-in command line

[H. Peter Anvin]

Andi Kleen wrote:
>   
>> +#ifdef CONFIG_CMDLINE_BOOL
>> +	strlcpy(saved_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
>> +#endif
> 
> I think I would prefer a strcat.
> 
> Also you should describe the exact behaviour (override/append) in Kconfig help.
> 

In the i386 thread, Matt described having a firmware bootloader which 
passes bogus parameters.  For that case, it would make sense to have a 
non-default CONFIG option to have override rather than conjoined (and I 
maintain that the built-in command line should be prepended.)

	-hpa

Re: [PATCH] x86_64 built-in command line

[Andi Kleen]

On Monday 31 July 2006 22:41, H. Peter Anvin wrote:
> Andi Kleen wrote:
> >   
> >> +#ifdef CONFIG_CMDLINE_BOOL
> >> +	strlcpy(saved_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> >> +#endif
> > 
> > I think I would prefer a strcat.
> > 
> > Also you should describe the exact behaviour (override/append) in Kconfig help.
> > 
> 
> In the i386 thread, Matt described having a firmware bootloader which 
> passes bogus parameters.  For that case, it would make sense to have a 
> non-default CONFIG option to have override rather than conjoined (and I 
> maintain that the built-in command line should be prepended.)

Is that boot loader common? What's its name? 
If not I would prefer that he keeps the one liner patch to deal
with that private.

For generic semantics strcat (or possible prepend) is probably better.

-Andi

Re: [PATCH] x86_64 built-in command line

[Matt Mackall]

On Tue, Aug 01, 2006 at 12:17:00AM +0200, Andi Kleen wrote:
> On Monday 31 July 2006 22:41, H. Peter Anvin wrote:
> > Andi Kleen wrote:
> > >   
> > >> +#ifdef CONFIG_CMDLINE_BOOL
> > >> +	strlcpy(saved_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> > >> +#endif
> > > 
> > > I think I would prefer a strcat.
> > > 
> > > Also you should describe the exact behaviour (override/append) in Kconfig help.
> > > 
> > 
> > In the i386 thread, Matt described having a firmware bootloader which 
> > passes bogus parameters.  For that case, it would make sense to have a 
> > non-default CONFIG option to have override rather than conjoined (and I 
> > maintain that the built-in command line should be prepended.)
> 
> Is that boot loader common? What's its name? 
> If not I would prefer that he keeps the one liner patch to deal
> with that private.
> 
> For generic semantics strcat (or possible prepend) is probably better.

No, it doesn't work for numerous kernel options that can't be negated.

-- 
Mathematics is the supreme nostalgia of our time.

Re: [PATCH] x86_64 built-in command line

[H. Peter Anvin]

Matt Mackall wrote:
> On Tue, Aug 01, 2006 at 12:17:00AM +0200, Andi Kleen wrote:
>> On Monday 31 July 2006 22:41, H. Peter Anvin wrote:
>>> Andi Kleen wrote:
>>>>   
>>>>> +#ifdef CONFIG_CMDLINE_BOOL
>>>>> +	strlcpy(saved_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
>>>>> +#endif
>>>> I think I would prefer a strcat.
>>>>
>>>> Also you should describe the exact behaviour (override/append) in Kconfig help.
>>>>
>>> In the i386 thread, Matt described having a firmware bootloader which 
>>> passes bogus parameters.  For that case, it would make sense to have a 
>>> non-default CONFIG option to have override rather than conjoined (and I 
>>> maintain that the built-in command line should be prepended.)
>> Is that boot loader common? What's its name? 
>> If not I would prefer that he keeps the one liner patch to deal
>> with that private.
>>
>> For generic semantics strcat (or possible prepend) is probably better.
> 
> No, it doesn't work for numerous kernel options that can't be negated.
> 

How about we fix the real problem, then?

	-hpa

Re: [PATCH] x86_64 built-in command line

[H. Peter Anvin]

Matt Mackall wrote:
>>
>> For generic semantics strcat (or possible prepend) is probably better.
> 
> No, it doesn't work for numerous kernel options that can't be negated.
> 

Anyway, there are four possible behaviours: builtin only, bootloader 
only, buildin+bootloader, and bootloader+builtin.  I believe the last is 
the most appropriate default, but there really is no reason why this 
can't be a four-way configuration option.

	-hpa

Re: [PATCH] x86_64 built-in command line

[H. Peter Anvin]

Actually, the best thing to do might be to designate a symbol (say &, 
like in automount) as "insert the boot loader command line here."

That way you can specify things in the builtin command line that are 
both prepended and appended to the boot loader command, and if you wish, 
you can emit it completely.

The default would be just "&".

	-hpa

Re: [PATCH] x86_64 built-in command line

[Matt Mackall]

On Mon, Jul 31, 2006 at 07:38:39PM -0700, H. Peter Anvin wrote:
> Actually, the best thing to do might be to designate a symbol (say &, 
> like in automount) as "insert the boot loader command line here."
> 
> That way you can specify things in the builtin command line that are 
> both prepended and appended to the boot loader command, and if you wish, 
> you can emit it completely.
> 
> The default would be just "&".

That idea doesn't suck. I'll take a look at it.

We still have a problem with overriding things like console=tty, for
which there's no obvious fix that doesn't break the world.

-- 
Mathematics is the supreme nostalgia of our time.

Re: [PATCH] x86_64 built-in command line

[Andi Kleen]

On Tuesday 01 August 2006 04:41, Matt Mackall wrote:
> On Mon, Jul 31, 2006 at 07:38:39PM -0700, H. Peter Anvin wrote:
> > Actually, the best thing to do might be to designate a symbol (say &, 
> > like in automount) as "insert the boot loader command line here."
> > 
> > That way you can specify things in the builtin command line that are 
> > both prepended and appended to the boot loader command, and if you wish, 
> > you can emit it completely.
> > 
> > The default would be just "&".
> 
> That idea doesn't suck. I'll take a look at it.

With %s it would be much less code to write.

-Andi

Re: [PATCH] x86_64 built-in command line

[H. Peter Anvin]

Andi Kleen wrote:
> On Tuesday 01 August 2006 04:41, Matt Mackall wrote:
>> On Mon, Jul 31, 2006 at 07:38:39PM -0700, H. Peter Anvin wrote:
>>> Actually, the best thing to do might be to designate a symbol (say &, 
>>> like in automount) as "insert the boot loader command line here."
>>>
>>> That way you can specify things in the builtin command line that are 
>>> both prepended and appended to the boot loader command, and if you wish, 
>>> you can emit it completely.
>>>
>>> The default would be just "&".
>> That idea doesn't suck. I'll take a look at it.
> 
> With %s it would be much less code to write.
> 

True; it would just mean that the buildin command line would have to 
double %'s, but that's not really a problem.

On the other hand, a single-character substitution loop is hardly complex.

	-hpa

Re: [PATCH] x86_64 built-in command line

[Andi Kleen]

> True; it would just mean that the buildin command line would have to 
> double %'s, but that's not really a problem.

Similar for &s

-Andi

Re: [PATCH] x86_64 built-in command line

[H. Peter Anvin]

Matt Mackall wrote:
> 
> That idea doesn't suck. I'll take a look at it.
> 
> We still have a problem with overriding things like console=tty, for
> which there's no obvious fix that doesn't break the world.
> 

One could define "console=" (empty argument) as a command to reset the 
list.  It probably would be useful.

	-hpa

Re: [PATCH] x86_64 built-in command line

[Andrew Morton]

On Mon, 31 Jul 2006 20:43:19 -0500
Matt Mackall <mpm@selenic.com> wrote:

> On Tue, Aug 01, 2006 at 12:17:00AM +0200, Andi Kleen wrote:
> > On Monday 31 July 2006 22:41, H. Peter Anvin wrote:
> > > Andi Kleen wrote:
> > > >   
> > > >> +#ifdef CONFIG_CMDLINE_BOOL
> > > >> +	strlcpy(saved_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> > > >> +#endif
> > > > 
> > > > I think I would prefer a strcat.
> > > > 
> > > > Also you should describe the exact behaviour (override/append) in Kconfig help.
> > > > 
> > > 
> > > In the i386 thread, Matt described having a firmware bootloader which 
> > > passes bogus parameters.  For that case, it would make sense to have a 
> > > non-default CONFIG option to have override rather than conjoined (and I 
> > > maintain that the built-in command line should be prepended.)
> > 
> > Is that boot loader common? What's its name? 
> > If not I would prefer that he keeps the one liner patch to deal
> > with that private.
> > 
> > For generic semantics strcat (or possible prepend) is probably better.
> 
> No, it doesn't work for numerous kernel options that can't be negated.

I think what I'm hearing is that we need three options: append, prepend or replace.

Re: [PATCH] x86_64 built-in command line

[Deepak Saxena]

On Jul 31 2006, at 12:14, Matt Mackall was caught saying:
> Allow setting a command line at build time on x86_64. Compiled but not
> tested.

Can we just make this into a generic option and put the relevant strcpy
(strcat) in init/main.c. We've supported a default in-kernel command line
on ARM for sometime now and I think it would be best to just have a single
implementation.

~Deepak

-- 
Deepak Saxena - dsaxena@plexity.net - http://www.plexity.net

"An open heart has no possessions, only experiences" - Matt Bibbeau

Re: [PATCH] x86_64 built-in command line

[Andi Kleen]

On Tuesday 01 August 2006 03:06, Deepak Saxena wrote:
> On Jul 31 2006, at 12:14, Matt Mackall was caught saying:
> > Allow setting a command line at build time on x86_64. Compiled but not
> > tested.
> 
> Can we just make this into a generic option and put the relevant strcpy
> (strcat) in init/main.c. We've supported a default in-kernel command line
> on ARM for sometime now and I think it would be best to just have a single
> implementation.

One problem is that some architectures (like i386/x86-64) have early 
boot arguments that are processed before init/main

-Andi

Re: [PATCH] x86_64 built-in command line

[H. Peter Anvin]

Deepak Saxena wrote:
> On Jul 31 2006, at 12:14, Matt Mackall was caught saying:
>> Allow setting a command line at build time on x86_64. Compiled but not
>> tested.
> 
> Can we just make this into a generic option and put the relevant strcpy
> (strcat) in init/main.c. We've supported a default in-kernel command line
> on ARM for sometime now and I think it would be best to just have a single
> implementation.
> 

Yes on the generic option, no on putting it in init/main.c... on a lot 
of architectures, some parsing of the command line happens *very* early, 
sometimes even before the C code is invoked.

	-hpa