HIGHMEM_START
#ifndef HIGHMEM_START
max_low_pfn = min(PFN_DOWN(HIGHMEM_START), max_pfn);
max_low_pfn = min(PFN_DOWN(HIGHMEM_START), max_pfn);
max_low_pfn = min(PFN_DOWN(HIGHMEM_START), max_pfn);
#ifndef HIGHMEM_START
#ifndef HIGHMEM_START
if (start >= PFN_DOWN(HIGHMEM_START))
if (end > PFN_DOWN(HIGHMEM_START))
end = PFN_DOWN(HIGHMEM_START);
if (max_pfn > PFN_DOWN(HIGHMEM_START)) {
max_low_pfn = PFN_DOWN(HIGHMEM_START);