Re: [PATCH] powerpc/mm/hash: Always clear UPRT and Host Radix bits when setting up CPU

[Balbir Singh <bsingharora@gmail.com>]

On Wed, Feb 22, 2017 at 10:42:02AM +0530, Aneesh Kumar K.V wrote:
> We will set LPCR with correct value for radix during int. This make sure we
> start with a sanitized value of LPCR. In case of kexec, cpus can have LPCR
> value based on the previous translation mode we were running.
> 
> Fixes: fe036a0605d60 ("powerpc/64/kexec: Fix MMU cleanup on radix")
> Cc: stable@vger.kernel.org # v4.9+
> Acked-by: Michael Neuling <mikey@neuling.org>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
>  arch/powerpc/kernel/cpu_setup_power.S | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/powerpc/kernel/cpu_setup_power.S b/arch/powerpc/kernel/cpu_setup_power.S
> index 917188615bf5..7fe8c79e6937 100644
> --- a/arch/powerpc/kernel/cpu_setup_power.S
> +++ b/arch/powerpc/kernel/cpu_setup_power.S
> @@ -101,6 +101,8 @@ _GLOBAL(__setup_cpu_power9)
>  	mfspr	r3,SPRN_LPCR
>  	LOAD_REG_IMMEDIATE(r4, LPCR_PECEDH | LPCR_PECE_HVEE | LPCR_HVICE)
>  	or	r3, r3, r4
> +	LOAD_REG_IMMEDIATE(r4, LPCR_UPRT | LPCR_HR)
> +	andc	r3, r3, r4
>  	bl	__init_LPCR
>  	bl	__init_HFSCR
>  	bl	__init_tlb_power9
> @@ -122,6 +124,8 @@ _GLOBAL(__restore_cpu_power9)
>  	mfspr   r3,SPRN_LPCR
>  	LOAD_REG_IMMEDIATE(r4, LPCR_PECEDH | LPCR_PECE_HVEE | LPCR_HVICE)
>  	or	r3, r3, r4
> +	LOAD_REG_IMMEDIATE(r4, LPCR_UPRT | LPCR_HR)
> +	andc	r3, r3, r4
>  	bl	__init_LPCR
>  	bl	__init_HFSCR
>  	bl	__init_tlb_power9

My previous comment mentions GTSE, but really we should be clearing
LPCR to 0 and setting it to sane values in __init_LPCR

Balbir