linux-kernel - Re: [PATCH 1/3] powerpc/mm: Initialize the HPTE encoding values

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Date:   Fri, 13 Sep 2019 12:56:16 +0200
From:   Laurent Dufour <ldufour@...ux.ibm.com>
To:     "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
        mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
        npiggin@...il.com
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] powerpc/mm: Initialize the HPTE encoding values

Le 12/09/2019 à 15:37, Aneesh Kumar K.V a écrit :
> On 8/30/19 5:37 PM, Laurent Dufour wrote:
>> Before reading the HPTE encoding values we initialize all of them to -1 (an
>> invalid value) to later being able to detect the initialized ones.
>>
>> Signed-off-by: Laurent Dufour <ldufour@...ux.ibm.com>
>> ---
>>   arch/powerpc/mm/book3s64/hash_utils.c | 8 ++++++--
>>   1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/powerpc/mm/book3s64/hash_utils.c 
>> b/arch/powerpc/mm/book3s64/hash_utils.c
>> index c3bfef08dcf8..2039bc315459 100644
>> --- a/arch/powerpc/mm/book3s64/hash_utils.c
>> +++ b/arch/powerpc/mm/book3s64/hash_utils.c
>> @@ -408,7 +408,7 @@ static int __init htab_dt_scan_page_sizes(unsigned 
>> long node,
>>   {
>>       const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
>>       const __be32 *prop;
>> -    int size = 0;
>> +    int size = 0, idx, base_idx;
>>       /* We are scanning "cpu" nodes only */
>>       if (type == NULL || strcmp(type, "cpu") != 0)
>> @@ -418,6 +418,11 @@ static int __init htab_dt_scan_page_sizes(unsigned 
>> long node,
>>       if (!prop)
>>           return 0;
>> +    /* Set all the penc values to invalid */
>> +    for (base_idx = 0; base_idx < MMU_PAGE_COUNT; base_idx++)
>> +        for (idx = 0; idx < MMU_PAGE_COUNT; idx++)
>> +            mmu_psize_defs[base_idx].penc[idx] = -1;
>> +
>>       pr_info("Page sizes from device-tree:\n");
>>       size /= 4;
>>       cur_cpu_spec->mmu_features &= ~(MMU_FTR_16M_PAGE);
>> @@ -426,7 +431,6 @@ static int __init htab_dt_scan_page_sizes(unsigned 
>> long node,
>>           unsigned int slbenc = be32_to_cpu(prop[1]);
>>           unsigned int lpnum = be32_to_cpu(prop[2]);
>>           struct mmu_psize_def *def;
>> -        int idx, base_idx;
>>           size -= 3; prop += 3;
>>           base_idx = get_idx_from_shift(base_shift);
>>
> 
> We already do this in mmu_psize_set_default_penc() ?

Correct, I missed that, then this patch is no more needed.