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Date: Tue, 23 Nov 2004 15:41:01 -0800
From: Manish Lachwani <mlachwani@mvista.com>
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To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>,
	Thiemo Seufer <ica2_ts@csv.ica.uni-stuttgart.de>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Linux/MIPS Development <linux-mips@linux-mips.org>
Subject: Re: [PATCH] Synthesize TLB refill handler at runtime
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Hi Maciej,

Maciej W. Rozycki wrote:
> On Mon, 22 Nov 2004, Manish Lachwani wrote:
> 
> 
>>However, the crash still occurs. I dont think your patch was intended to 
>>fix the problem that I see below (resulting in crash).
> 
> 
>  Certainly, it wasn't, but it couldn't have hurt, either.

I never said that your patch could have hurt ;)

> 
> 
>>Data bus error, epc == 801f83b8, ra == 80323f04
> 
> 
>  The reason are cp0 hazards, likely leading to an incorrect mapping.  Try
> the following patch; already applied to the mainline as obviously correct.


I did sync with the latest CVS sometime back and have been trying it out 
on the MIPS Malta 24Kc. Looks stable upto now ...

Thanks
Manish Lachwani



> 
>   Maciej
> 
> patch-mips-2.6.10-rc1-20041112-mips-tlb-ehb-0
> diff -up --recursive --new-file linux-mips-2.6.10-rc1-20041112.macro/arch/mips/mm/tlbex.c linux-mips-2.6.10-rc1-20041112/arch/mips/mm/tlbex.c
> --- linux-mips-2.6.10-rc1-20041112.macro/arch/mips/mm/tlbex.c	2004-11-23 19:52:53.000000000 +0000
> +++ linux-mips-2.6.10-rc1-20041112/arch/mips/mm/tlbex.c	2004-11-23 19:58:31.000000000 +0000
> @@ -448,7 +448,8 @@ L_LA(_split)
>  #define i_bnez(buf, rs, off) i_bne(buf, rs, 0, off)
>  #define i_move(buf, a, b) i_ADDU(buf, a, 0, b)
>  #define i_nop(buf) i_sll(buf, 0, 0, 0)
> -#define i_ssnop(buf) i_sll(buf, 0, 2, 1)
> +#define i_ssnop(buf) i_sll(buf, 0, 0, 1)
> +#define i_ehb(buf) i_sll(buf, 0, 0, 3)
>  
>  #if CONFIG_MIPS64
>  static __init int in_compat_space_p(long addr)
> @@ -799,12 +800,12 @@ static __init void build_tlb_write_rando
>  	default:
>  		/*
>  		 * Others are assumed to have one cycle mtc0 hazard,
> -		 * and one cycle tlbwr hazard.
> +		 * and one cycle tlbwr hazard or to understand ehb.
>  		 * XXX: This might be overly general.
>  		 */
> -		i_nop(p);
> +		i_ehb(p);
>  		i_tlbwr(p);
> -		i_nop(p);
> +		i_ehb(p);
>  		break;
>  	}
>  }