aout support almost working now

aout support almost working now

[walt]

With Bean's last two commits I can almost replace legacy with grub2
at least on x86.  I have still one problem with the aout support that
Bean posted as a patch on Jan 27.

Using legacy, which loads the FreeBSD /boot/loader as the 'kernel',
loader then reads its config files from the /boot directory so it
knows what parameters to pass to the real kernel and also what menu
items to show the user.

Using grub2 with Bean's aout patch,  I can load /boot/loader and
then boot it successfully, but it seems that 'loader' can't find
its config files in the /boot directory.  This is what it prints:

Can't work out which disk we are booting from.
Guessed BIOS device 0xffffffff not found by probes,
defaulting to disk0:  can't load "kernel".

At least on my machine, disk0 is the floppy drive and loader does
actually go to try to read it before printing the error messages
I listed, and then it drops to its interactive prompt.

By examining the loader's variables it's clear that it never found
its usual config files in /boot.

BTW, I did set 'root' and 'prefix' to point at the correct partition
before booting the loader.

Any ideas what else to try?

Re: aout support almost working now

[Bean]

On Feb 7, 2008 3:23 AM, walt <wa1ter@myrealbox.com> wrote:
> With Bean's last two commits I can almost replace legacy with grub2
> at least on x86.  I have still one problem with the aout support that
> Bean posted as a patch on Jan 27.
>
> Using legacy, which loads the FreeBSD /boot/loader as the 'kernel',
> loader then reads its config files from the /boot directory so it
> knows what parameters to pass to the real kernel and also what menu
> items to show the user.
>
> Using grub2 with Bean's aout patch,  I can load /boot/loader and
> then boot it successfully, but it seems that 'loader' can't find
> its config files in the /boot directory.  This is what it prints:
>
> Can't work out which disk we are booting from.
> Guessed BIOS device 0xffffffff not found by probes,
> defaulting to disk0:  can't load "kernel".
>
> At least on my machine, disk0 is the floppy drive and loader does
> actually go to try to read it before printing the error messages
> I listed, and then it drops to its interactive prompt.
>
> By examining the loader's variables it's clear that it never found
> its usual config files in /boot.
>
> BTW, I did set 'root' and 'prefix' to point at the correct partition
> before booting the loader.
>
> Any ideas what else to try?

i think the %edx should be set before jumping to code, try this patch:

diff --git a/kern/i386/loader.S b/kern/i386/loader.S
index 266f4ef..88f3045 100644
--- a/kern/i386/loader.S
+++ b/kern/i386/loader.S
@@ -137,6 +137,7 @@ FUNCTION(grub_multiboot_real_boot)
 	cli
 	
 	/* Move the magic value into eax and jump to the kernel.  */
+	movl	$0x80, %edx
 	movl	$MULTIBOOT_MAGIC2,%eax
 	popl	%ecx
 	jmp 	*%ecx
@@ -159,6 +160,7 @@ FUNCTION(grub_multiboot2_real_boot)
         cli

         /* Move the magic value into eax and jump to the kernel.  */
+	movl	$0x80, %edx
         movl    $MULTIBOOT2_BOOTLOADER_MAGIC,%eax
         popl    %ecx
         jmp     *%ecx

Please note that this is not a proper patch, it assume booting from
the (hd0,0,a). you can adjust the value of %edx if you boot from other
partition.

-- 
Bean

Re: aout support almost working now

[walt]

Bean wrote:
> On Feb 7, 2008 3:23 AM, walt<wa1ter@myrealbox.com>  wrote:
>> With Bean's last two commits I can almost replace legacy with grub2
>> at least on x86.  I have still one problem with the aout support that
>> Bean posted as a patch on Jan 27.
>>
>> Using legacy, which loads the FreeBSD /boot/loader as the 'kernel',
>> loader then reads its config files from the /boot directory so it
>> knows what parameters to pass to the real kernel and also what menu
>> items to show the user.
>>
>> Using grub2 with Bean's aout patch,  I can load /boot/loader and
>> then boot it successfully, but it seems that 'loader' can't find
>> its config files in the /boot directory.  This is what it prints:
>>
>> Can't work out which disk we are booting from.
>> Guessed BIOS device 0xffffffff not found by probes,
>> defaulting to disk0:  can't load "kernel".
>>
>> At least on my machine, disk0 is the floppy drive and loader does
>> actually go to try to read it before printing the error messages
>> I listed, and then it drops to its interactive prompt.
>>
>> By examining the loader's variables it's clear that it never found
>> its usual config files in /boot.
>>
>> BTW, I did set 'root' and 'prefix' to point at the correct partition
>> before booting the loader.
>>
>> Any ideas what else to try?
>
> i think the %edx should be set before jumping to code, try this patch:
>
> diff --git a/kern/i386/loader.S b/kern/i386/loader.S
> index 266f4ef..88f3045 100644
> --- a/kern/i386/loader.S
> +++ b/kern/i386/loader.S
> @@ -137,6 +137,7 @@ FUNCTION(grub_multiboot_real_boot)
>   	cli
>   	
>   	/* Move the magic value into eax and jump to the kernel.  */
> +	movl	$0x80, %edx
>   	movl	$MULTIBOOT_MAGIC2,%eax
>   	popl	%ecx
>   	jmp 	*%ecx
> @@ -159,6 +160,7 @@ FUNCTION(grub_multiboot2_real_boot)
>           cli
>
>           /* Move the magic value into eax and jump to the kernel.  */
> +	movl	$0x80, %edx
>           movl    $MULTIBOOT2_BOOTLOADER_MAGIC,%eax
>           popl    %ecx
>           jmp     *%ecx
>
> Please note that this is not a proper patch, it assume booting from
> the (hd0,0,a). you can adjust the value of %edx if you boot from other
> partition.

Sorry, I don't know what adjustment to make.  I did find a macro for
MULTIBOOT_INFO_DISK_INFO but it's never actually used anywhere :o/

I'm trying to load (hd0,3,a) -- can you show me the right value for %edx ?

Thanks.

Re: aout support almost working now

[Robert Millan]

On Wed, Feb 06, 2008 at 04:26:15PM -0800, walt wrote:
> >diff --git a/kern/i386/loader.S b/kern/i386/loader.S
> >index 266f4ef..88f3045 100644
> >--- a/kern/i386/loader.S
> >+++ b/kern/i386/loader.S
> >@@ -137,6 +137,7 @@ FUNCTION(grub_multiboot_real_boot)
> >  	cli
> >  	
> >  	/* Move the magic value into eax and jump to the kernel.  */
> >+	movl	$0x80, %edx
> >  	movl	$MULTIBOOT_MAGIC2,%eax
> >  	popl	%ecx
> >  	jmp 	*%ecx
> >@@ -159,6 +160,7 @@ FUNCTION(grub_multiboot2_real_boot)
> >          cli
> >
> >          /* Move the magic value into eax and jump to the kernel.  */
> >+	movl	$0x80, %edx
> >          movl    $MULTIBOOT2_BOOTLOADER_MAGIC,%eax
> >          popl    %ecx
> >          jmp     *%ecx
> >
> >Please note that this is not a proper patch, it assume booting from
> >the (hd0,0,a). you can adjust the value of %edx if you boot from other
> >partition.
> 
> Sorry, I don't know what adjustment to make.  I did find a macro for
> MULTIBOOT_INFO_DISK_INFO but it's never actually used anywhere :o/
> 
> I'm trying to load (hd0,3,a) -- can you show me the right value for %edx ?

If he guessed right, you don't need to do anything special, and 0x80 will
work for you.

The patch is not correct because it breaks setups in which boot disk is not
the first one.  But that doesn't seem to affect you.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)

Re: aout support almost working now

[walt]

On Thu, 2008-02-07 at 01:32 +0100, Robert Millan wrote:
> On Wed, Feb 06, 2008 at 04:26:15PM -0800, walt wrote:
> > >diff --git a/kern/i386/loader.S b/kern/i386/loader.S
> > >index 266f4ef..88f3045 100644
> > >--- a/kern/i386/loader.S
> > >+++ b/kern/i386/loader.S
> > >@@ -137,6 +137,7 @@ FUNCTION(grub_multiboot_real_boot)
> > >  	cli
> > >  	
> > >  	/* Move the magic value into eax and jump to the kernel.  */
> > >+	movl	$0x80, %edx
> > >  	movl	$MULTIBOOT_MAGIC2,%eax
> > >  	popl	%ecx
> > >  	jmp 	*%ecx
> > >@@ -159,6 +160,7 @@ FUNCTION(grub_multiboot2_real_boot)
> > >          cli
> > >
> > >          /* Move the magic value into eax and jump to the kernel.  */
> > >+	movl	$0x80, %edx
> > >          movl    $MULTIBOOT2_BOOTLOADER_MAGIC,%eax
> > >          popl    %ecx
> > >          jmp     *%ecx
> > >
> > >Please note that this is not a proper patch, it assume booting from
> > >the (hd0,0,a). you can adjust the value of %edx if you boot from other
> > >partition.
> > 
> > Sorry, I don't know what adjustment to make.  I did find a macro for
> > MULTIBOOT_INFO_DISK_INFO but it's never actually used anywhere :o/
> > 
> > I'm trying to load (hd0,3,a) -- can you show me the right value for %edx ?
> 
> If he guessed right, you don't need to do anything special, and 0x80
> will work for you.
> 
> The patch is not correct because it breaks setups in which boot disk is not
> the first one.  But that doesn't seem to affect you.

Sorry to report that this patch changes nothing :o(  Behavior is exactly
the same.

However, that particular section of code seems to be for multiboot
kernels, and the FreeBSD kernel is not multiboot (yet).  Could that
be the problem?