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From: "Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
To: Suraj Jitindar Singh <sjitindarsingh@gmail•com>,
	linuxppc-dev@lists•ozlabs.org
Cc: sjitindarsingh@gmail•com, benh@kernel•crashing.org,
	paulus@samba•org, mpe@ellerman•id.au, bsingharora@gmail•com
Subject: Re: [PATCH] powerpc/mm: Correct process and partition table max size
Date: Thu, 10 Nov 2016 15:06:51 +0530	[thread overview]
Message-ID: <87eg2j1xsc.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <1478669793-15074-1-git-send-email-sjitindarsingh@gmail.com>

Suraj Jitindar Singh <sjitindarsingh@gmail•com> writes:

> Version 3.00 of the ISA states that the PATS (partition table size) field
> of the PTCR (partition table control register) and the PRTS (process table
> size) field of the partition table entry must both be less than or equal
> to 24. However the actual size of the partition and process tables is equal
> to 2 to the power of 12 plus the PATS and PRTS fields, respectively. This
> means that the max allowable size of each of these tables is 2^36 or 64GB
> for both.
>
> Thus when checking the size shift for each we should be checking for values
> of greater than 36 instead of the current check for shifts larger than 24
> and 23.
>
> Fixes: 2bfd65e45e877fb5704730244da67c748d28a1b8
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail•com>

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux•vnet.ibm.com>

> ---
>  arch/powerpc/mm/pgtable-radix.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
> index ed7bddc..80f3479 100644
> --- a/arch/powerpc/mm/pgtable-radix.c
> +++ b/arch/powerpc/mm/pgtable-radix.c
> @@ -159,7 +159,7 @@ static void __init radix_init_pgtable(void)
>  	 * Allocate Partition table and process table for the
>  	 * host.
>  	 */
> -	BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 23), "Process table size too large.");
> +	BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 36), "Process table size too large.");
>  	process_tb = early_alloc_pgtable(1UL << PRTB_SIZE_SHIFT);
>  	/*
>  	 * Fill in the process table.
> @@ -181,7 +181,7 @@ static void __init radix_init_partition_table(void)
>
>  	rts_field = radix__get_tree_size();
>
> -	BUILD_BUG_ON_MSG((PATB_SIZE_SHIFT > 24), "Partition table size too large.");
> +	BUILD_BUG_ON_MSG((PATB_SIZE_SHIFT > 36), "Partition table size too large.");
>  	partition_tb = early_alloc_pgtable(1UL << PATB_SIZE_SHIFT);
>  	partition_tb->patb0 = cpu_to_be64(rts_field | __pa(init_mm.pgd) |
>  					  RADIX_PGD_INDEX_SIZE | PATB_HR);
> -- 
> 2.5.5

  parent reply	other threads:[~2016-11-10  9:36 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-09  5:36 [PATCH] powerpc/mm: Correct process and partition table max size Suraj Jitindar Singh
2016-11-10  0:30 ` Balbir Singh
2016-11-10  9:36 ` Aneesh Kumar K.V [this message]
2016-11-17 12:04 ` Michael Ellerman

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