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

[Josh Boyer]

On Wed, Jul 13, 2011 at 12:28:36AM -0500, 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 <suzuki@xxxxxxxxxx>
>> Cc:	Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
>> ---
>> 
>> 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?

It's a different MMU type (again), that is similar to 44x but not exact.
We can't run a single kernel image on both yet, for example.

Also, they aren't widely available so testing on them is difficult.

josh
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