user_p4d 420 arch/x86/mm/pti.c p4d_t *kernel_p4d, *user_p4d; user_p4d 423 arch/x86/mm/pti.c user_p4d = pti_user_pagetable_walk_p4d(addr); user_p4d 424 arch/x86/mm/pti.c if (!user_p4d) user_p4d 429 arch/x86/mm/pti.c *user_p4d = *kernel_p4d;