[PATCH V2 1/2] powerpc/kexec: Reset secondary cpu endianess before kexec

[Scott Wood]

On Wed, 2015-07-08 at 14:37 +1000, Samuel Mendoza-Jonas wrote:
> If the target kernel does not inlcude the FIXUP_ENDIAN check, coming
> from a different-endian kernel will cause the target kernel to panic.
> All ppc64 kernels can handle starting in big-endian mode, so return to
> big-endian before branching into the target kernel.
> 
> This mainly affects pseries as secondaries on powernv are returned to
> OPAL.
> 
> Signed-off-by: Samuel Mendoza-Jonas <sam.mj at au1.ibm.com>
> ---
> v2: Add an #ifdef for subarch-specific code
>     Neaten the endian check (and extra call to mfmsr!) by modifying the msr 
> and
>     branching to the target kernel in the same call to rfid.
>  arch/powerpc/kernel/misc_64.S | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
> index 4e314b9..89f0600 100644
> --- a/arch/powerpc/kernel/misc_64.S
> +++ b/arch/powerpc/kernel/misc_64.S
> @@ -475,9 +475,18 @@ _GLOBAL(kexec_wait)
>  #ifdef CONFIG_KEXEC          /* use no memory without kexec */
>       lwz     r4,0(r5)
>       cmpwi   0,r4,0
> -     bnea    0x60
> +     beq     99b
> +#ifdef CONFIG_PPC_BOOK3S_64
> +     li      r10,0x60
> +     mfmsr   r11
> +     clrrdi  r11,r11,1       /* Clear MSR_LE */
> +     mtsrr0  r10
> +     mtsrr1  r11
> +     rfid
> +#else
> +     b       0x60
> +#endif
>  #endif
> -     b       99b

"b 0x60" needs to be "ba 0x60".

-Scott