1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * highmem.h: virtual kernel memory mappings for high memory 4 * 5 * PowerPC version, stolen from the i386 version. 6 * 7 * Used in CONFIG_HIGHMEM systems for memory pages which 8 * are not addressable by direct kernel virtual addresses. 9 * 10 * Copyright (C) 1999 Gerhard Wichert, Siemens AG 11 * Gerhard.Wichert@pdb.siemens.de 12 * 13 * 14 * Redesigned the x86 32-bit VM architecture to deal with 15 * up to 16 Terrabyte physical memory. With current x86 CPUs 16 * we now support up to 64 Gigabytes physical RAM. 17 * 18 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> 19 */ 20 21 #ifndef _ASM_HIGHMEM_H 22 #define _ASM_HIGHMEM_H 23 24 #ifdef __KERNEL__ 25 26 #include <linux/interrupt.h> 27 #include <asm/kmap_types.h> 28 #include <asm/cacheflush.h> 29 #include <asm/page.h> 30 #include <asm/fixmap.h> 31 32 extern pte_t *kmap_pte; 33 extern pte_t *pkmap_page_table; 34 35 /* 36 * Right now we initialize only a single pte table. It can be extended 37 * easily, subsequent pte tables have to be allocated in one physical 38 * chunk of RAM. 39 */ 40 /* 41 * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte 42 * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP 43 * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP 44 * in case of 16K/64K/256K page sizes. 45 */ 46 #ifdef CONFIG_PPC_4K_PAGES 47 #define PKMAP_ORDER PTE_SHIFT 48 #else 49 #define PKMAP_ORDER 9 50 #endif 51 #define LAST_PKMAP (1 << PKMAP_ORDER) 52 #ifndef CONFIG_PPC_4K_PAGES 53 #define PKMAP_BASE (FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) 54 #else 55 #define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK) 56 #endif 57 #define LAST_PKMAP_MASK (LAST_PKMAP-1) 58 #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) 59 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) 60 61 #define flush_cache_kmaps() flush_cache_all() 62 63 #endif /* __KERNEL__ */ 64 65 #endif /* _ASM_HIGHMEM_H */ 66