Re: [Xen-devel] [PATCH v2 05/41] acpi : add helper function for mapping memory

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 20/05/15 17:03, Jan Beulich wrote:
>>>> On 17.05.15 at 22:03, <parth.dixit@xxxxxxxxxx> wrote:
>> --- a/xen/drivers/acpi/osl.c
>> +++ b/xen/drivers/acpi/osl.c
>> @@ -87,16 +87,7 @@ acpi_physical_address __init 
>> acpi_os_get_root_pointer(void)
>>  void __iomem *
>>  acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
>>  {
>> -    if (system_state >= SYS_STATE_active) {
>> -            unsigned long pfn = PFN_DOWN(phys);
>> -            unsigned int offs = phys & (PAGE_SIZE - 1);
>> -
>> -            /* The low first Mb is always mapped. */
>> -            if ( !((phys + size - 1) >> 20) )
>> -                    return __va(phys);
>> -            return __vmap(&pfn, PFN_UP(offs + size), 1, 1, 
>> PAGE_HYPERVISOR_NOCACHE) + offs;
>> -    }
>> -    return __acpi_map_table(phys, size);
>> +    return acpi_os_map_iomem(phys, size);
>>  }
> 
> I think ioremap() (or maybe ioremap_cache()) should be used here,
> and tweaked suitably on x86 if need be.

ioremap_cache is most suitable for ARM.

ioremap (i.e ioremap_nocache) is mapping the region with device
attribute. Any unaligned access will result to a data abort.

Regards,

-- 
Julien Grall

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