MAX_LOW_PFN 30 arch/xtensa/include/asm/page.h #define MAX_LOW_PFN (PHYS_PFN(XCHAL_KSEG_PADDR) + \ MAX_LOW_PFN 35 arch/xtensa/include/asm/page.h #define MAX_LOW_PFN PHYS_PFN(0xfffffffful)