[Qemu-devel] OpenBios in Sparc can't handle long kernel command lines.

[Qemu-devel] OpenBios in Sparc can't handle long kernel command lines.

[Rob Landley]

If I do this:

qemu-system-sparc -nographic -no-reboot -kernel image -hda hda.sqf  
-append 'root=/dev/sda rw init=/sbin/init.sh panic=1  
PATH=/usr/distcc:/bin:/sbin console=ttyS0 HOST=sparc CPUS=1  
DISTCC_HOSTS=10.0.2.2:31322/1 FTP_SERVER=10.0.2.2 FTP_PORT=31307  
NATIVE_BUILD=lfs-bootstrap ' -hdb hdb.img -hdc lfs-bootstrap.hdc -m 256

qemu goes:

^[[H^[[JConfiguration device id QEMU version 1 machine id 32
CPUs: 1 x FMI,MB86904
Unhandled Exception 0x00000007
PC = 0xffd07d28 NPC = 0xffd07d2c
Stopping execution

And then hangs. I've never figured out why it clears the screen first  
(none of the other targets do), but I _have_ figured out that the  
unhandled exception is "kernel command line too long". Because 197  
bytes is just too much data for Sparc to cope with.

Rob

Re: [Qemu-devel] OpenBios in Sparc can't handle long kernel command lines.

[Mark Cave-Ayland]

On 22/03/13 05:19, Rob Landley wrote:

> If I do this:
>
> qemu-system-sparc -nographic -no-reboot -kernel image -hda hda.sqf
> -append 'root=/dev/sda rw init=/sbin/init.sh panic=1
> PATH=/usr/distcc:/bin:/sbin console=ttyS0 HOST=sparc CPUS=1
> DISTCC_HOSTS=10.0.2.2:31322/1 FTP_SERVER=10.0.2.2 FTP_PORT=31307
> NATIVE_BUILD=lfs-bootstrap ' -hdb hdb.img -hdc lfs-bootstrap.hdc -m 256
>
> qemu goes:
>
> ^[[H^[[JConfiguration device id QEMU version 1 machine id 32
> CPUs: 1 x FMI,MB86904
> Unhandled Exception 0x00000007
> PC = 0xffd07d28 NPC = 0xffd07d2c
> Stopping execution
>
> And then hangs. I've never figured out why it clears the screen first
> (none of the other targets do), but I _have_ figured out that the
> unhandled exception is "kernel command line too long". Because 197 bytes
> is just too much data for Sparc to cope with.

This is actually a bug in OpenBIOS which declares the command line 
storage like this:

static void
arch_init( void )
{
         static char cmdline[128];

         ....

         kernel_cmdline = (const char *) 
fw_cfg_read_i32(FW_CFG_KERNEL_CMDLINE);
         if (kernel_cmdline) {
             size = strlen(kernel_cmdline);
             memcpy(cmdline, kernel_cmdline, size);
             obp_arg.argv[1] = cmdline;
         }
         cmdline[size] = '\0';

         ....
}

Would increasing it to 256 bytes be enough? I can't say I've ever come 
across command lines in a normal environment with more than about 80 
characters, but I don't see an issue with increasing it.


ATB,

Mark.

Re: [Qemu-devel] [OpenBIOS] OpenBios in Sparc can't handle long kernel command lines.

[Blue Swirl]

On Thu, Mar 28, 2013 at 7:20 PM, Mark Cave-Ayland
<mark.cave-ayland@ilande.co.uk> wrote:
> On 22/03/13 05:19, Rob Landley wrote:
>
>> If I do this:
>>
>> qemu-system-sparc -nographic -no-reboot -kernel image -hda hda.sqf
>> -append 'root=/dev/sda rw init=/sbin/init.sh panic=1
>> PATH=/usr/distcc:/bin:/sbin console=ttyS0 HOST=sparc CPUS=1
>> DISTCC_HOSTS=10.0.2.2:31322/1 FTP_SERVER=10.0.2.2 FTP_PORT=31307
>> NATIVE_BUILD=lfs-bootstrap ' -hdb hdb.img -hdc lfs-bootstrap.hdc -m 256
>>
>> qemu goes:
>>
>> ^[[H^[[JConfiguration device id QEMU version 1 machine id 32
>> CPUs: 1 x FMI,MB86904
>> Unhandled Exception 0x00000007
>> PC = 0xffd07d28 NPC = 0xffd07d2c
>> Stopping execution
>>
>> And then hangs. I've never figured out why it clears the screen first
>> (none of the other targets do), but I _have_ figured out that the
>> unhandled exception is "kernel command line too long". Because 197 bytes
>> is just too much data for Sparc to cope with.
>
>
> This is actually a bug in OpenBIOS which declares the command line storage
> like this:
>
> static void
> arch_init( void )
> {
>         static char cmdline[128];
>
>         ....
>
>         kernel_cmdline = (const char *)
> fw_cfg_read_i32(FW_CFG_KERNEL_CMDLINE);
>         if (kernel_cmdline) {
>             size = strlen(kernel_cmdline);
>             memcpy(cmdline, kernel_cmdline, size);
>             obp_arg.argv[1] = cmdline;
>         }
>         cmdline[size] = '\0';
>
>         ....
> }
>
> Would increasing it to 256 bytes be enough? I can't say I've ever come
> across command lines in a normal environment with more than about 80
> characters, but I don't see an issue with increasing it.

Isn't strdup() (or memory allocation subsystem) available at that time?

>
>
> ATB,
>
> Mark.
>
> --
> OpenBIOS                 http://openbios.org/
> Mailinglist:  http://lists.openbios.org/mailman/listinfo
> Free your System - May the Forth be with you

Re: [Qemu-devel] OpenBios in Sparc can't handle long kernel command lines.

[Mark Cave-Ayland]

On 22/03/13 05:19, Rob Landley wrote:

> If I do this:
>
> qemu-system-sparc -nographic -no-reboot -kernel image -hda hda.sqf
> -append 'root=/dev/sda rw init=/sbin/init.sh panic=1
> PATH=/usr/distcc:/bin:/sbin console=ttyS0 HOST=sparc CPUS=1
> DISTCC_HOSTS=10.0.2.2:31322/1 FTP_SERVER=10.0.2.2 FTP_PORT=31307
> NATIVE_BUILD=lfs-bootstrap ' -hdb hdb.img -hdc lfs-bootstrap.hdc -m 256
>
> qemu goes:
>
> ^[[H^[[JConfiguration device id QEMU version 1 machine id 32
> CPUs: 1 x FMI,MB86904
> Unhandled Exception 0x00000007
> PC = 0xffd07d28 NPC = 0xffd07d2c
> Stopping execution
>
> And then hangs. I've never figured out why it clears the screen first
> (none of the other targets do), but I _have_ figured out that the
> unhandled exception is "kernel command line too long". Because 197 bytes
> is just too much data for Sparc to cope with.
>
> Rob

This is now fixed in OpenBIOS SVN trunk, and so should be included in 
QEMU 1.5 when we update the images in git master. Thanks for the report!


ATB,

Mark.

Re: [Qemu-devel] OpenBios in Sparc can't handle long kernel command lines.

[Rob Landley]

On 04/19/2013 05:27:55 AM, Mark Cave-Ayland wrote:
> On 22/03/13 05:19, Rob Landley wrote:
> 
>> If I do this:
>> 
>> qemu-system-sparc -nographic -no-reboot -kernel image -hda hda.sqf
>> -append 'root=/dev/sda rw init=/sbin/init.sh panic=1
>> PATH=/usr/distcc:/bin:/sbin console=ttyS0 HOST=sparc CPUS=1
>> DISTCC_HOSTS=10.0.2.2:31322/1 FTP_SERVER=10.0.2.2 FTP_PORT=31307
>> NATIVE_BUILD=lfs-bootstrap ' -hdb hdb.img -hdc lfs-bootstrap.hdc -m  
>> 256
>> 
>> qemu goes:
>> 
>> ^[[H^[[JConfiguration device id QEMU version 1 machine id 32
>> CPUs: 1 x FMI,MB86904
>> Unhandled Exception 0x00000007
>> PC = 0xffd07d28 NPC = 0xffd07d2c
>> Stopping execution
>> 
>> And then hangs. I've never figured out why it clears the screen first
>> (none of the other targets do), but I _have_ figured out that the
>> unhandled exception is "kernel command line too long". Because 197  
>> bytes
>> is just too much data for Sparc to cope with.
>> 
>> Rob
> 
> This is now fixed in OpenBIOS SVN trunk, and so should be included in  
> QEMU 1.5
> when we update the images in git master. Thanks for the report!

Yay! Thank you. I look forward to trying it out when QEMU refreshes.

Rob