patch to make 2.4.32 work on i486 again

patch to make 2.4.32 work on i486 again

[Jacek Lipkowski]

Booting the 2.4.32 kernel compiled for a i486 on an i486 box fails,
because "Kernel compiled for Pentium+, requires TSC feature!" (printed
from check_config() include/asm-i386/bugs.h). To reproduce, select 486 in
the kernel configuration and grep CONFIG_X86_TSC .config

Seems strange that no one noticed this, am i the only one still using 486
boxes? :)

Jacek

Simple patch against vanilla 2.4.32:

--- arch/i386/config.in.old	2006-01-30 22:57:21.000000000 +0100
+++ arch/i386/config.in	2006-01-30 23:00:55.000000000 +0100
@@ -65,6 +65,7 @@
    define_bool CONFIG_X86_POPAD_OK y
    define_bool CONFIG_RWSEM_GENERIC_SPINLOCK n
    define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM y
+   define_bool CONFIG_X86_TSC n
 fi
 if [ "$CONFIG_M486" = "y" ]; then
    define_int  CONFIG_X86_L1_CACHE_SHIFT 4
@@ -72,6 +73,7 @@
    define_bool CONFIG_X86_ALIGNMENT_16 y
    define_bool CONFIG_X86_PPRO_FENCE y
    define_bool CONFIG_X86_F00F_WORKS_OK n
+   define_bool CONFIG_X86_TSC n
 fi
 if [ "$CONFIG_M586" = "y" ]; then
    define_int  CONFIG_X86_L1_CACHE_SHIFT 5

Re: patch to make 2.4.32 work on i486 again

[Grant Coady]

On 2/1/06, Jacek Lipkowski <sq5bpf@acid.ch.pw.edu.pl> wrote:
> Booting the 2.4.32 kernel compiled for a i486 on an i486 box fails,
> because "Kernel compiled for Pentium+, requires TSC feature!" (printed
> from check_config() include/asm-i386/bugs.h). To reproduce, select 486 in
> the kernel configuration and grep CONFIG_X86_TSC .config
>
> Seems strange that no one noticed this, am i the only one still using 486
> boxes? :)

I keep old stuff going, but no i486 mobo's here :(

Grant.

Re: patch to make 2.4.32 work on i486 again

[Willy Tarreau]

Hi,

On Tue, Jan 31, 2006 at 11:29:05PM +0100, Jacek Lipkowski wrote:
> Booting the 2.4.32 kernel compiled for a i486 on an i486 box fails,
> because "Kernel compiled for Pentium+, requires TSC feature!" (printed
> from check_config() include/asm-i386/bugs.h). To reproduce, select 486 in
> the kernel configuration and grep CONFIG_X86_TSC .config
> 
> Seems strange that no one noticed this, am i the only one still using 486
> boxes? :)

perhaps :-)
It's been more than one year since I last booted mine. However, I believe
I came through this bug by accident while compiling a kernel of a VIA Eden
CPU, then I realized it should be compiled as i586 and forgot about the
bug.

> Jacek
> 
> Simple patch against vanilla 2.4.32:

Thanks. I've queued it for the next hotfix.
Marcelo, I've put it in -upstream if you want.

Regards,
Willy

Re: patch to make 2.4.32 work on i486 again

[Marcelo Tosatti]

On Wed, Feb 01, 2006 at 06:20:06AM +0100, Willy Tarreau wrote:
> Hi,
> 
> On Tue, Jan 31, 2006 at 11:29:05PM +0100, Jacek Lipkowski wrote:
> > Booting the 2.4.32 kernel compiled for a i486 on an i486 box fails,
> > because "Kernel compiled for Pentium+, requires TSC feature!" (printed
> > from check_config() include/asm-i386/bugs.h). To reproduce, select 486 in
> > the kernel configuration and grep CONFIG_X86_TSC .config
> > 
> > Seems strange that no one noticed this, am i the only one still using 486
> > boxes? :)
> 
> perhaps :-)
> It's been more than one year since I last booted mine. However, I believe
> I came through this bug by accident while compiling a kernel of a VIA Eden
> CPU, then I realized it should be compiled as i586 and forgot about the
> bug.
> 
> > Jacek
> > 
> > Simple patch against vanilla 2.4.32:
> 
> Thanks. I've queued it for the next hotfix.
> Marcelo, I've put it in -upstream if you want.

Patch is correct indeed - thanks Willy.

Re: patch to make 2.4.32 work on i486 again

[Mikael Pettersson]

Jacek Lipkowski writes:
 > Booting the 2.4.32 kernel compiled for a i486 on an i486 box fails,
 > because "Kernel compiled for Pentium+, requires TSC feature!" (printed
 > from check_config() include/asm-i386/bugs.h). To reproduce, select 486 in
 > the kernel configuration and grep CONFIG_X86_TSC .config
 > 
 > Seems strange that no one noticed this, am i the only one still using 486
 > boxes? :)
 > 
 > Jacek
 > 
 > Simple patch against vanilla 2.4.32:
 > 
 > --- arch/i386/config.in.old	2006-01-30 22:57:21.000000000 +0100
 > +++ arch/i386/config.in	2006-01-30 23:00:55.000000000 +0100
 > @@ -65,6 +65,7 @@
 >     define_bool CONFIG_X86_POPAD_OK y
 >     define_bool CONFIG_RWSEM_GENERIC_SPINLOCK n
 >     define_bool CONFIG_RWSEM_XCHGADD_ALGORITHM y
 > +   define_bool CONFIG_X86_TSC n
 >  fi
 >  if [ "$CONFIG_M486" = "y" ]; then
 >     define_int  CONFIG_X86_L1_CACHE_SHIFT 4
 > @@ -72,6 +73,7 @@
 >     define_bool CONFIG_X86_ALIGNMENT_16 y
 >     define_bool CONFIG_X86_PPRO_FENCE y
 >     define_bool CONFIG_X86_F00F_WORKS_OK n
 > +   define_bool CONFIG_X86_TSC n
 >  fi
 >  if [ "$CONFIG_M586" = "y" ]; then
 >     define_int  CONFIG_X86_L1_CACHE_SHIFT 5

This is a known limitation of the 2.4 kernel's configuration system:
a single round of make ${foo}config doesn't always reach a fixpoint
with regard to the derived options. CONFIG_X86_TSC is the standard
example of this: switching from a stable .config with TSC (say i686)
to one without (say i486) leaves a stray definition of CONFIG_X86_TSC
behind in .config. Solution: run 'make oldconfig' after flipping the
user-selectatable options.

Your patch may fix the TSC case, but there are probably more cases
like this in 2.4.

/Mikael