linux-kernel - Re: [PATCH] MIPS: tlb-r4k: panic if the MMU doesn't support PAGE

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Date:	Wed, 10 Feb 2016 14:10:49 -0800
From:	Paul Burton <paul.burton@...tec.com>
To:	Ralf Baechle <ralf@...ux-mips.org>
CC:	<linux-mips@...ux-mips.org>,
	"Steven J. Hill" <Steven.Hill@...tec.com>,
	Joshua Kinard <kumba@...too.org>,
	<linux-kernel@...r.kernel.org>,
	Rafał Miłecki <zajec5@...il.com>,
	James Hogan <james.hogan@...tec.com>,
	Markos Chandras <markos.chandras@...tec.com>
Subject: Re: [PATCH] MIPS: tlb-r4k: panic if the MMU doesn't support PAGE_SIZE

On Mon, Jul 13, 2015 at 05:12:44PM +0100, Paul Burton wrote:
> After writing the appropriate mask to the cop0 PageMask register, read
> the register back & check it matches what we want. If it doesn't then
> the MMU does not support the page size the kernel is configured for and
> we're better off bailing than continuing to do odd things with TLB
> exceptions.
> 
> Signed-off-by: Paul Burton <paul.burton@...tec.com>
> ---

Hi Ralf,

This patch is marked as accepted in patchwork[1] but is not present in
upstream. Did you lose it somehow? Could you please merge it?

Thanks,
    Paul

[1] http://patchwork.linux-mips.org/patch/10691/

>  arch/mips/mm/tlb-r4k.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
> index 08318ec..4330315 100644
> --- a/arch/mips/mm/tlb-r4k.c
> +++ b/arch/mips/mm/tlb-r4k.c
> @@ -19,6 +19,7 @@
>  #include <asm/cpu.h>
>  #include <asm/cpu-type.h>
>  #include <asm/bootinfo.h>
> +#include <asm/hazards.h>
>  #include <asm/mmu_context.h>
>  #include <asm/pgtable.h>
>  #include <asm/tlb.h>
> @@ -486,6 +487,10 @@ static void r4k_tlb_configure(void)
>  	 *     be set to fixed-size pages.
>  	 */
>  	write_c0_pagemask(PM_DEFAULT_MASK);
> +	back_to_back_c0_hazard();
> +	if (read_c0_pagemask() != PM_DEFAULT_MASK)
> +		panic("MMU doesn't support PAGE_SIZE=0x%lx", PAGE_SIZE);
> +
>  	write_c0_wired(0);
>  	if (current_cpu_type() == CPU_R10000 ||
>  	    current_cpu_type() == CPU_R12000 ||
> -- 
> 2.4.5
>