[patch 0/2] ARM: Disable outer cache before kexec call -V3

[patch 0/2] ARM: Disable outer cache before kexec call -V3

[Thomas Gleixner]

The following patch series addresses the problem that the kexec code
does not disable the outer cache before disabling the inner cache and
jumping into the new kernel. This results in random crashes of the new
kernel.

Changes since version 2:

 - Use CLEAN_INV_WAY in l2x0_flush_all according to Catalin

 - Rename outer_cache_disable() to outer_disable()

 - Added a  BUG_ON() when l2x0_inv_all() is called with L2 enabled.

Thanks,

	tglx

[patch 1/2] arm: Disable outer (L2) cache in kexec

[Thomas Gleixner]

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[patch 1/2] arm: Disable outer (L2) cache in kexec

[Catalin Marinas]

On Mon, 2010-07-05 at 12:52 +0100, Thomas Gleixner wrote:
> kexec does not disable the outer cache before disabling the inner
> caches in cpu_proc_fin(). So L2 is enabled across the kexec jump. When
> the new kernel enables chaches again, it randomly crashes.
> 
> Disabling L2 before calling cpu_proc_fin() cures the problem.
> 
> Disabling L2 requires the following new functions: flush_all(),
> inv_all() and disable(). Add them to outer_cache_fns and call them
> from the kexec code.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

-- 
Catalin

[patch 2/2] arm: Implement l2x0 cache disable functions

[Thomas Gleixner]

An embedded and charset-unspecified text was scrubbed...
Name: arm-l2x0-cache-disable.patch
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[patch 2/2] arm: Implement l2x0 cache disable functions

[Catalin Marinas]

On Mon, 2010-07-05 at 12:52 +0100, Thomas Gleixner wrote:
> Add flush_all, inv_all and disable functions to the l2x0 code. These
> functions are called from kexec code to prevent random crashes in the
> new kernel.
> 
> Platforms like OMAP which control L2 enable/disable via SMI mode can
> override the outer_cache.disable() function to implement their own.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[...]
> -static inline void l2x0_inv_all(void)
> +static void l2x0_flush_all(void)
> +{
> +       unsigned long flags;
> +
> +       /* clean all ways */

Minor point - /* clean and invalidate all ways */

But the patch looks good to me:

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

-- 
Catalin

[patch 2/2] arm: Implement l2x0 cache disable functions

[Linus Walleij]

2010/7/5 Thomas Gleixner <tglx@linutronix.de>:

> Add flush_all, inv_all and disable functions to the l2x0 code. These
> functions are called from kexec code to prevent random crashes in the
> new kernel.
> (...)
> +static void l2x0_disable(void)
> +{
> + ? ? ? unsigned long flags;
> +
> + ? ? ? spin_lock_irqsave(&l2x0_lock, flags);
> + ? ? ? writel(0, l2x0_base + L2X0_CTRL);
> + ? ? ? spin_unlock_irqrestore(&l2x0_lock, flags);
> +}
> +

Does this take into account this comment from Srinidhi:

[Srinidhi KASAGAR wrote]
> I think it's a problem for PL310 controller where the access to
> L2X0_CTRL is secure, accessing this in non-secure mode will fault.

I'm worried that a writel() into the CTRL register like that will cause
a bus error on platforms that have L2x0 in Trusted World (TrustZone)?
Or that it may be ignored simply on such platforms causing
trouble that way?

Yours,
Linus Walleij

[patch 0/2] ARM: Disable outer cache before kexec call -V3

[Andrea Paterniani]

Hi,
     I have applied your patches to kernel 2.6.35-rc4 running on my 
beagleboard.
I'm using kexec-tools-2.0.1.

My u-boot bootargs is:
     console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 
rootwait ip=192.168.2.13::255.255.255.0

To restart the system I type:
 > sync
 > kexec -l /boot/zImage --append="console=ttyS2,115200n8 
root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait 
ip=192.168.2.13::255.255.255.0"
 > kexec -e

Not every time the system restart.
In some cases no output on the console after the following:
     Bye!
     Uncompressing Linux... done, booting the kernel.

Any idea?

Regards,
Andrea



Il 05/07/2010 13.52, Thomas Gleixner ha scritto:
> The following patch series addresses the problem that the kexec code
> does not disable the outer cache before disabling the inner cache and
> jumping into the new kernel. This results in random crashes of the new
> kernel.
>
> Changes since version 2:
>
>   - Use CLEAN_INV_WAY in l2x0_flush_all according to Catalin
>
>   - Rename outer_cache_disable() to outer_disable()
>
>   - Added a  BUG_ON() when l2x0_inv_all() is called with L2 enabled.
>
> Thanks,
>
> 	tglx
>
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
>    

-- 

[patch 0/2] ARM: Disable outer cache before kexec call -V3

[Gadiyar, Anand]

Andrea Paterniani wrote:
> Hi,
>      I have applied your patches to kernel 2.6.35-rc4 running on my beagleboard.
> I'm using kexec-tools-2.0.1.
> 
> My u-boot bootargs is:
>      console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait ip=192.168.2.13::255.255.255.0
> 
> To restart the system I type:
>  > sync
>  > kexec -l /boot/zImage --append="console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait ip=192.168.2.13::255.255.255.0"
>  > kexec -e
> 
> Not every time the system restart.
> In some cases no output on the console after the following:
>      Bye!
>      Uncompressing Linux... done, booting the kernel.
> 
> Any idea?
> 

Can you try building your kernel with CONFIG_EARLY_PRINTK,
and add the word "earlyprintk" to your bootargs?



> Il 05/07/2010 13.52, Thomas Gleixner ha scritto:
> > The following patch series addresses the problem that the kexec code
> > does not disable the outer cache before disabling the inner cache and
> > jumping into the new kernel. This results in random crashes of the new
> > kernel.
> >
> > Changes since version 2:
> >
> >   - Use CLEAN_INV_WAY in l2x0_flush_all according to Catalin
> >
> >   - Rename outer_cache_disable() to outer_disable()
> >
> >   - Added a  BUG_ON() when l2x0_inv_all() is called with L2 enabled.
> >
> > Thanks,
> >
> >       tglx
> >
> >
> >

[patch 0/2] ARM: Disable outer cache before kexec call -V3

[Andrea Paterniani]

Il 03/08/2010 19.36, Gadiyar, Anand ha scritto:
> Andrea Paterniani wrote:
>    
>> Hi,
>>       I have applied your patches to kernel 2.6.35-rc4 running on my beagleboard.
>> I'm using kexec-tools-2.0.1.
>>
>> My u-boot bootargs is:
>>       console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait ip=192.168.2.13::255.255.255.0
>>
>> To restart the system I type:
>>   >  sync
>>   >  kexec -l /boot/zImage --append="console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait ip=192.168.2.13::255.255.255.0"
>>   >  kexec -e
>>
>> Not every time the system restart.
>> In some cases no output on the console after the following:
>>       Bye!
>>       Uncompressing Linux... done, booting the kernel.
>>
>> Any idea?
>>
>>      
> Can you try building your kernel with CONFIG_EARLY_PRINTK,
> and add the word "earlyprintk" to your bootargs?
>
>    
How to enable EARLY_PRINTK for ARM architecture?
Browsing kernel source I find arch/arm/kernel/early_printk.c but no way 
to enable CONFIG_EARLY_PRINTK from make menuconfig.
Is there any patch to have this config option for ARM?

- Andrea
>
>    
>> Il 05/07/2010 13.52, Thomas Gleixner ha scritto:
>>      
>>> The following patch series addresses the problem that the kexec code
>>> does not disable the outer cache before disabling the inner cache and
>>> jumping into the new kernel. This results in random crashes of the new
>>> kernel.
>>>
>>> Changes since version 2:
>>>
>>>    - Use CLEAN_INV_WAY in l2x0_flush_all according to Catalin
>>>
>>>    - Rename outer_cache_disable() to outer_disable()
>>>
>>>    - Added a  BUG_ON() when l2x0_inv_all() is called with L2 enabled.
>>>
>>> Thanks,
>>>
>>>        tglx
>>>
>>>
>>>
>>>        
>    

-- 

[patch 0/2] ARM: Disable outer cache before kexec call -V3

[Shilimkar, Santosh]

> -----Original Message-----
> From: Andrea Paterniani [mailto:a.paterniani at swapp-eng.it]
> Sent: Wednesday, August 04, 2010 12:16 PM
> To: Gadiyar, Anand
> Cc: linux-arm-kernel at lists.infradead.org; Thomas Gleixner;
> catalin.marinas at arm.com; Shilimkar, Santosh
> Subject: Re: [patch 0/2] ARM: Disable outer cache before kexec call -V3
> 
> Il 03/08/2010 19.36, Gadiyar, Anand ha scritto:
> > Andrea Paterniani wrote:
> >
> >> Hi,
> >>       I have applied your patches to kernel 2.6.35-rc4 running on my
> beagleboard.
> >> I'm using kexec-tools-2.0.1.
> >>
> >> My u-boot bootargs is:
> >>       console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3
> rootwait ip=192.168.2.13::255.255.255.0
> >>
> >> To restart the system I type:
> >>   >  sync
> >>   >  kexec -l /boot/zImage --append="console=ttyS2,115200n8
> root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait
> ip=192.168.2.13::255.255.255.0"
> >>   >  kexec -e
> >>
> >> Not every time the system restart.
> >> In some cases no output on the console after the following:
> >>       Bye!
> >>       Uncompressing Linux... done, booting the kernel.
> >>
> >> Any idea?
> >>
> >>
> > Can you try building your kernel with CONFIG_EARLY_PRINTK,
> > and add the word "earlyprintk" to your bootargs?
> >
> >
> How to enable EARLY_PRINTK for ARM architecture?
> Browsing kernel source I find arch/arm/kernel/early_printk.c but no way
> to enable CONFIG_EARLY_PRINTK from make menuconfig.
> Is there any patch to have this config option for ARM?
>
Menuconfig >
	 Kernel hacking -> 
		Kernel low-level debugging functions 
			-->Early printk (NEW)

[patch 0/2] ARM: Disable outer cache before kexec call -V3

[Baruch Siach]

Hi Andrea,

On Wed, Aug 04, 2010 at 08:46:21AM +0200, Andrea Paterniani wrote:
> Il 03/08/2010 19.36, Gadiyar, Anand ha scritto:
> >Andrea Paterniani wrote:
> >>Hi,
> >>      I have applied your patches to kernel 2.6.35-rc4 running on my beagleboard.
> >>I'm using kexec-tools-2.0.1.
> >>
> >>My u-boot bootargs is:
> >>      console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait ip=192.168.2.13::255.255.255.0
> >>
> >>To restart the system I type:
> >>  >  sync
> >>  >  kexec -l /boot/zImage --append="console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait ip=192.168.2.13::255.255.255.0"
> >>  >  kexec -e
> >>
> >>Not every time the system restart.
> >>In some cases no output on the console after the following:
> >>      Bye!
> >>      Uncompressing Linux... done, booting the kernel.
> >>
> >>Any idea?
> >>
> >Can you try building your kernel with CONFIG_EARLY_PRINTK,
> >and add the word "earlyprintk" to your bootargs?
> >
> How to enable EARLY_PRINTK for ARM architecture?
> Browsing kernel source I find arch/arm/kernel/early_printk.c but no
> way to enable CONFIG_EARLY_PRINTK from make menuconfig.
> Is there any patch to have this config option for ARM?

EARLY_PRINTK is in arch/arm/Kconfig.debug. It depends on DEBUG_LL, though. So 
you must enable DEBUG_LL to make EARLY_PRINTK visible.

baruch

> 
> - Andrea
> >
> >>Il 05/07/2010 13.52, Thomas Gleixner ha scritto:
> >>>The following patch series addresses the problem that the kexec code
> >>>does not disable the outer cache before disabling the inner cache and
> >>>jumping into the new kernel. This results in random crashes of the new
> >>>kernel.
> >>>
> >>>Changes since version 2:
> >>>
> >>>   - Use CLEAN_INV_WAY in l2x0_flush_all according to Catalin
> >>>
> >>>   - Rename outer_cache_disable() to outer_disable()
> >>>
> >>>   - Added a  BUG_ON() when l2x0_inv_all() is called with L2 enabled.
> >>>
> >>>Thanks,
> >>>
> >>>       tglx

-- 
                                                     ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

[patch 0/2] ARM: Disable outer cache before kexec call -V3

[Andrea Paterniani]

Il 03/08/2010 19.36, Gadiyar, Anand ha scritto:
> Andrea Paterniani wrote:
>    
>> Hi,
>>       I have applied your patches to kernel 2.6.35-rc4 running on my beagleboard.
>> I'm using kexec-tools-2.0.1.
>>
>> My u-boot bootargs is:
>>       console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait ip=192.168.2.13::255.255.255.0
>>
>> To restart the system I type:
>>   >  sync
>>   >  kexec -l /boot/zImage --append="console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait ip=192.168.2.13::255.255.255.0"
>>   >  kexec -e
>>
>> Not every time the system restart.
>> In some cases no output on the console after the following:
>>       Bye!
>>       Uncompressing Linux... done, booting the kernel.
>>
>> Any idea?
>>
>>      
> Can you try building your kernel with CONFIG_EARLY_PRINTK,
> and add the word "earlyprintk" to your bootargs?
>
>    
I built the kernel with (also verified via zcat /proc/config.gz | grep 
... after succesfull kexec):

CONFIG_EARLY_PRINTK=y
CONFIG_DEBUG_LL=y

I load new kernel zImage via:
kexec -l /boot/zImage --append="earlyprintk console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait ip=192.168.2.13::255.255.255.0"

but when kexec fails I got only the following:
	Bye!
	Uncompressing Linux... done, booting the kernel.

What do I miss whith earlyprintk?

Perhaps I did not enough tests, but at the moment it seems that system boot with nfs rootfs followed by kexec with mmc rootfs works.
Problems arise with system boot and kexec both with mmc rootfs.

Regards,
- Andrea

>
>    
>> Il 05/07/2010 13.52, Thomas Gleixner ha scritto:
>>      
>>> The following patch series addresses the problem that the kexec code
>>> does not disable the outer cache before disabling the inner cache and
>>> jumping into the new kernel. This results in random crashes of the new
>>> kernel.
>>>
>>> Changes since version 2:
>>>
>>>    - Use CLEAN_INV_WAY in l2x0_flush_all according to Catalin
>>>
>>>    - Rename outer_cache_disable() to outer_disable()
>>>
>>>    - Added a  BUG_ON() when l2x0_inv_all() is called with L2 enabled.
>>>
>>> Thanks,
>>>
>>>        tglx
>>>
>>>
>>>
>>>        
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
>    

-- 

[patch 0/2] ARM: Disable outer cache before kexec call -V3

[Andrea Paterniani]

Any other suggestion?

Thanks
- Andrea

Il 04/08/2010 11.19, Andrea Paterniani ha scritto:
> Il 03/08/2010 19.36, Gadiyar, Anand ha scritto:
>> Andrea Paterniani wrote:
>>> Hi,
>>>       I have applied your patches to kernel 2.6.35-rc4 running on my 
>>> beagleboard.
>>> I'm using kexec-tools-2.0.1.
>>>
>>> My u-boot bootargs is:
>>>       console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext3 
>>> rootwait ip=192.168.2.13::255.255.255.0
>>>
>>> To restart the system I type:
>>> >  sync
>>> >  kexec -l /boot/zImage --append="console=ttyS2,115200n8 
>>> root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait 
>>> ip=192.168.2.13::255.255.255.0"
>>> >  kexec -e
>>>
>>> Not every time the system restart.
>>> In some cases no output on the console after the following:
>>>       Bye!
>>>       Uncompressing Linux... done, booting the kernel.
>>>
>>> Any idea?
>>>
>> Can you try building your kernel with CONFIG_EARLY_PRINTK,
>> and add the word "earlyprintk" to your bootargs?
>>
> I built the kernel with (also verified via zcat /proc/config.gz | grep 
> ... after succesfull kexec):
>
> CONFIG_EARLY_PRINTK=y
> CONFIG_DEBUG_LL=y
>
> I load new kernel zImage via:
> kexec -l /boot/zImage --append="earlyprintk console=ttyS2,115200n8 
> root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait 
> ip=192.168.2.13::255.255.255.0"
>
> but when kexec fails I got only the following:
>     Bye!
>     Uncompressing Linux... done, booting the kernel.
>
> What do I miss whith earlyprintk?
>
> Perhaps I did not enough tests, but at the moment it seems that system 
> boot with nfs rootfs followed by kexec with mmc rootfs works.
> Problems arise with system boot and kexec both with mmc rootfs.
>
> Regards,
> - Andrea
>
>>
>>> Il 05/07/2010 13.52, Thomas Gleixner ha scritto:
>>>> The following patch series addresses the problem that the kexec code
>>>> does not disable the outer cache before disabling the inner cache and
>>>> jumping into the new kernel. This results in random crashes of the new
>>>> kernel.
>>>>
>>>> Changes since version 2:
>>>>
>>>>    - Use CLEAN_INV_WAY in l2x0_flush_all according to Catalin
>>>>
>>>>    - Rename outer_cache_disable() to outer_disable()
>>>>
>>>>    - Added a  BUG_ON() when l2x0_inv_all() is called with L2 enabled.
>>>>
>>>> Thanks,
>>>>
>>>>        tglx
>>>>
>>>>
>>>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
>

--