Subject: Re: [PATCH v2] powerpc32: Kexec support for PPC440X chipsets

From: Suzuki Poulose <[email-masked]>
Date: Wed, 13 Jul 2011 11:31:47 +0530

On 07/13/11 10:58, Kumar Gala wrote:
>
> On Jul 12, 2011, at 1:44 AM, Suzuki K. Poulose wrote:
>
>> Changes from V1: Uses a tmp mapping in the other address space to setup
>> 		 the 1:1 mapping (suggested by Sebastian Andrzej Siewior).
>>
>> Note: Should we do the same for kernel entry code for PPC44x ?
>>
>> This patch adds kexec support for PPC440 based chipsets.This work is based
>> on the KEXEC patches for FSL BookE.
>>
>> The FSL BookE patch and the code flow could be found at the link below:
>>
>> 	http://patchwork.ozlabs.org/patch/49359/
>>
>> Steps:
>>
>> 1) Invalidate all the TLB entries except the one this code is run from
>> 2) Create a tmp mapping for our code in the other address space and jump to it
>> 3) Invalidate the entry we used
>> 4) Create a 1:1 mapping for 0-2GiB in blocks of 256M
>> 5) Jump to the new 1:1 mapping and invalidate the tmp mapping
>>
>> I have tested this patches on Ebony, Sequoia boards and Virtex on QEMU.
>> It would be great if somebody could test this on the other boards.
>>
>> Signed-off-by: 	Suzuki Poulose<[email-masked]>
>> Cc:	Sebastian Andrzej Siewior<[email-masked]>
>> ---
>>
>> arch/powerpc/Kconfig             |    2
>> arch/powerpc/include/asm/kexec.h |    2
>> arch/powerpc/kernel/misc_32.S    |  170 ++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 172 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> index 423145a6..d04fae0 100644
>> --- a/arch/powerpc/Kconfig
>> +++ b/arch/powerpc/Kconfig
>> @@ -349,7 +349,7 @@ config ARCH_ENABLE_MEMORY_HOTREMOVE
>>
>> config KEXEC
>> 	bool "kexec system call (EXPERIMENTAL)"
>> -	depends on (PPC_BOOK3S || FSL_BOOKE)&&  EXPERIMENTAL
>> +	depends on (PPC_BOOK3S || FSL_BOOKE || (44x&&  !SMP&&  !47x))&&  EXPERIMENTAL
>
> Is there something special about 47x that its not supported?

At the moment, I have not written the code for doing the 47x TLB setup which
is slightly different from 44x.

It is in my TODO list. I don't have access to a 47x yet. I will work on it
once I get access to the board.

Thanks
Suzuki

>
>> 	help
>> 	  kexec is a system call that implements the ability to shutdown your
>> 	  current kernel, and to start another kernel.  It is like a reboot
>
> - k
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