[PATCH v5 1/8] mm: enhance region_is_ram() to region_intersects()

region_is_ram() is used to prevent the establishment of aliased mappings to physical "System RAM" with incompatible cache settings. However, it uses "-1" to indicate both "unknown" memory ranges (ranges not described by platform firmware) and "mixed" ranges (where the parameters describe a range

[PATCH v5 1/8] mm: enhance region_is_ram() to region_intersects()

region_is_ram() is used to prevent the establishment of aliased mappings to physical System RAM with incompatible cache settings. However, it uses -1 to indicate both unknown memory ranges (ranges not described by platform firmware) and mixed ranges (where the parameters describe a range that