On 03.06.20 18:11, Miles Chen wrote: > max_pfn is uesd to get the highest pfn in the system. Drivers like > drivers/iommu/mtk_iommu.c checks max_pfn to see if it should enable > its "4GB mode". > > This patch exports the max_pfn symbol, so we can build the driver as > a kernel module. Please add that change to the respective user patch (and cc MM-people for that patch), so we have the actual user right along the change and can figure out if this is the right thing to do. > > Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx> > --- > mm/memblock.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/memblock.c b/mm/memblock.c > index c79ba6f9920c..3b2b21ecebb6 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -99,6 +99,7 @@ EXPORT_SYMBOL(contig_page_data); > unsigned long max_low_pfn; > unsigned long min_low_pfn; > unsigned long max_pfn; > +EXPORT_SYMBOL(max_pfn); > unsigned long long max_possible_pfn; > > static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock; > -- Thanks, David / dhildenb