Subject: Re: BDI2000 and Linux 2.6 kernel

From: Guillaume Autran <[email-masked]>
Date: Mon, 14 Nov 2005 18:42:11 -0500

Hi Marcelo,

Despite your patch, I'm still having trouble getting my BDI2000 to translate 
kernel virtual address to physical address on a 2.6.13 kernel.

What should I look for to make sure I set it up properly ?

Regards,
Guillaume.

Marcelo Tosatti wrote:
> Hi,
> 
> Currently gdb over BDI (and I've seen other reports on this list) fails to
> translate virtual->physical addresses on PPC 8xx:
> 
> *** MMU: address translation for 0xC000C66C failed
> *** MMU: address translation for 0xC000C66C failed
> 
> Thats because the v2.6 kernel was changed to use physical addresses on the
> first level page.
> 
> Dan informed me there might be a firmware update available to address 
> this problem. Is this true?
> 
> With the following the kernel stores the virtual address on the PMD 
> getting the BDI "to work".
> 
> A newer firmware would be much better though.
> 
> --- linux-2.6.14-rc4.orig/arch/ppc/kernel/head_8xx.S	2005-10-18 16:59:34.000000000 -0500
> +++ linux-2.6.14-rc4/arch/ppc/kernel/head_8xx.S	2005-11-01 05:45:00.000000000 -0600
> @@ -320,11 +320,12 @@ InstructionTLBMiss:
>  	lwz	r11, 0(r10)	/* Get the level 1 entry */
>  	rlwinm.	r10, r11,0,0,19	/* Extract page descriptor page address */
>  	beq	2f		/* If zero, don't try to find a pte */
> +	tophys(r11,r11)
>  
>  	/* We have a pte table, so load the MI_TWC with the attributes
>  	 * for this "segment."
>  	 */
> -	ori	r11,r11,1		/* Set valid bit */
> +	/*ori	r11,r11,1		 Set valid bit */
>  	DO_8xx_CPU6(0x2b80, r3)
>  	mtspr	SPRN_MI_TWC, r11	/* Set segment attributes */
>  	DO_8xx_CPU6(0x3b80, r3)
> @@ -379,6 +380,7 @@ DataStoreTLBMiss:
>  	lwz	r11, 0(r10)	/* Get the level 1 entry */
>  	rlwinm.	r10, r11,0,0,19	/* Extract page descriptor page address */
>  	beq	2f		/* If zero, don't try to find a pte */
> +	tophys(r11,r11)
>  
>  	/* We have a pte table, so load fetch the pte from the table.
>  	 */
> @@ -493,6 +495,7 @@ DataTLBError:
>  	lwz	r11, 0(r10)	/* Get the level 1 entry */
>  	rlwinm.	r10, r11,0,0,19	/* Extract page descriptor page address */
>  	beq	2f		/* If zero, bail */
> +	tophys(r11,r11)
>  
>  	/* We have a pte table, so fetch the pte from the table.
>  	 */
> diff -Nur -p --exclude-from=linux-2.6.14-rc4/Documentation/dontdiff linux-2.6.14-rc4.orig/include/asm-ppc/pgalloc.h linux-2.6.14-rc4/include/asm-ppc/pgalloc.h
> --- linux-2.6.14-rc4.orig/include/asm-ppc/pgalloc.h	2005-10-18 17:00:09.000000000 -0500
> +++ linux-2.6.14-rc4/include/asm-ppc/pgalloc.h	2005-11-01 08:02:08.000000000 -0600
> @@ -19,16 +19,16 @@ extern void pgd_free(pgd_t *pgd);
>  #define __pmd_free_tlb(tlb,x)		do { } while (0)
>  #define pgd_populate(mm, pmd, pte)      BUG()
>  
> -#ifndef CONFIG_BOOKE
> +#if defined(CONFIG_BOOKE) || defined(CONFIG_8xx)
>  #define pmd_populate_kernel(mm, pmd, pte)	\
> -		(pmd_val(*(pmd)) = __pa(pte) | _PMD_PRESENT)
> +		(pmd_val(*(pmd)) = (unsigned long)pte | _PMD_PRESENT)
>  #define pmd_populate(mm, pmd, pte)	\
> -		(pmd_val(*(pmd)) = (page_to_pfn(pte) << PAGE_SHIFT) | _PMD_PRESENT)
> +		(pmd_val(*(pmd)) = (unsigned long)page_to_virt(pte) | _PMD_PRESENT)
>  #else
>  #define pmd_populate_kernel(mm, pmd, pte)	\
> -		(pmd_val(*(pmd)) = (unsigned long)pte | _PMD_PRESENT)
> +		(pmd_val(*(pmd)) = __pa(pte) | _PMD_PRESENT)
>  #define pmd_populate(mm, pmd, pte)	\
> -		(pmd_val(*(pmd)) = (unsigned long)page_to_virt(pte) | _PMD_PRESENT)
> +		(pmd_val(*(pmd)) = (page_to_pfn(pte) << PAGE_SHIFT) | _PMD_PRESENT)
>  #endif
>  
>  extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr);
> diff -Nur -p --exclude-from=linux-2.6.14-rc4/Documentation/dontdiff linux-2.6.14-rc4.orig/include/asm-ppc/pgtable.h linux-2.6.14-rc4/include/asm-ppc/pgtable.h
> --- linux-2.6.14-rc4.orig/include/asm-ppc/pgtable.h	2005-10-18 17:00:09.000000000 -0500
> +++ linux-2.6.14-rc4/include/asm-ppc/pgtable.h	2005-11-01 08:01:34.000000000 -0600
> @@ -719,16 +719,16 @@ extern pgprot_t phys_mem_access_prot(str
>   * handler).  On everything else the pmd contains the physical address
>   * of the pte page.  -- paulus
>   */
> -#ifndef CONFIG_BOOKE
> +#if defined (CONFIG_BOOKE) || defined CONFIG_8xx
>  #define pmd_page_kernel(pmd)	\
> -	((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
> +	((unsigned long) (pmd_val(pmd) & PAGE_MASK))
>  #define pmd_page(pmd)		\
> -	(mem_map + (pmd_val(pmd) >> PAGE_SHIFT))
> +	(mem_map + (__pa(pmd_val(pmd)) >> PAGE_SHIFT))
>  #else
>  #define pmd_page_kernel(pmd)	\
> -	((unsigned long) (pmd_val(pmd) & PAGE_MASK))
> +	((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
>  #define pmd_page(pmd)		\
> -	(mem_map + (__pa(pmd_val(pmd)) >> PAGE_SHIFT))
> +	(mem_map + (pmd_val(pmd) >> PAGE_SHIFT))
>  #endif
>  
>  /* to find an entry in a kernel page-table-directory */
> 
> 
> 
> 
> 
> 
> 
> 
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> Linuxppc-embedded mailing list
> [email-masked]
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
> 

-- 
=======================================
Guillaume Autran
Senior Software Engineer
MRV Communications, Inc.
Tel: (978) 952-4932 office
=======================================