Re: [PATCH] parisc: check hardcoded value of SHMLBA against value reported by firmware

[Helge Deller <deller@gmx.de>]

On 10/29/2013 10:10 PM, John David Anglin wrote:
> I seem to recall the aliasing boundary value returned by my rp3440 is "unknown".

Even better, then it would be interesting to see what this patch reports on
your machine....


> 
> On 10/29/2013 5:05 PM, Helge Deller wrote:
>> Our value of SHMLBA is hardcoded to 4MB on parisc due to aliasing restrictions
>> of the platform. The firmware function PDC_CACHE does return the machine
>> dependend value of this aliasing requirement.
>> So, if there is a difference between those two - which we don't expect - let's
>> report it at least.
>>
>> Signed-off-by: Helge Deller <deller@gmx.de>
>>
>> diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
>> index c035673..3523e20 100644
>> --- a/arch/parisc/kernel/cache.c
>> +++ b/arch/parisc/kernel/cache.c
>> @@ -142,6 +142,15 @@ parisc_cache_init(void)
>>       if (pdc_cache_info(&cache_info) < 0)
>>           panic("parisc_cache_init: pdc_cache_info failed");
>>   +    /*
>> +     * The alias field returned by PDC_CACHE specifies the aliasing
>> +     * boundaries for virtual addresses.  So, let's verify if our hardcoded
>> +     * value of SHMLBA (4 MB) is correct for this machine.
>> +     */
>> +    if ((4096UL << (cache_info.dc_conf.cc_alias-1)) != SHMLBA)
>> +        pr_warn("WARNING: PDC_CACHE returns aliasing of %lu kB.\n",
>> +            (4UL << (cache_info.dc_conf.cc_alias-1)));
>> +
>>   #if 0
>>       printk("ic_size %lx dc_size %lx it_size %lx\n",
>>           cache_info.ic_size,
>> -- 
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>>
> 
>