1b2441318SGreg Kroah-Hartman /* SPDX-License-Identifier: GPL-2.0 */ 22f2f371fSMichal Simek /* 32f2f371fSMichal Simek * highmem.h: virtual kernel memory mappings for high memory 42f2f371fSMichal Simek * 52f2f371fSMichal Simek * Used in CONFIG_HIGHMEM systems for memory pages which 62f2f371fSMichal Simek * are not addressable by direct kernel virtual addresses. 72f2f371fSMichal Simek * 82f2f371fSMichal Simek * Copyright (C) 1999 Gerhard Wichert, Siemens AG 92f2f371fSMichal Simek * Gerhard.Wichert@pdb.siemens.de 102f2f371fSMichal Simek * 112f2f371fSMichal Simek * 122f2f371fSMichal Simek * Redesigned the x86 32-bit VM architecture to deal with 132f2f371fSMichal Simek * up to 16 Terabyte physical memory. With current x86 CPUs 142f2f371fSMichal Simek * we now support up to 64 Gigabytes physical RAM. 152f2f371fSMichal Simek * 162f2f371fSMichal Simek * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> 172f2f371fSMichal Simek */ 182f2f371fSMichal Simek #ifndef _ASM_HIGHMEM_H 192f2f371fSMichal Simek #define _ASM_HIGHMEM_H 202f2f371fSMichal Simek 212f2f371fSMichal Simek #ifdef __KERNEL__ 222f2f371fSMichal Simek 232f2f371fSMichal Simek #include <linux/init.h> 242f2f371fSMichal Simek #include <linux/interrupt.h> 252f2f371fSMichal Simek #include <linux/uaccess.h> 262f2f371fSMichal Simek #include <asm/fixmap.h> 272f2f371fSMichal Simek 282f2f371fSMichal Simek extern pte_t *kmap_pte; 292f2f371fSMichal Simek extern pgprot_t kmap_prot; 302f2f371fSMichal Simek extern pte_t *pkmap_page_table; 312f2f371fSMichal Simek 322f2f371fSMichal Simek /* 332f2f371fSMichal Simek * Right now we initialize only a single pte table. It can be extended 342f2f371fSMichal Simek * easily, subsequent pte tables have to be allocated in one physical 352f2f371fSMichal Simek * chunk of RAM. 362f2f371fSMichal Simek */ 372f2f371fSMichal Simek /* 382f2f371fSMichal Simek * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte 392f2f371fSMichal Simek * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP 402f2f371fSMichal Simek * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP 412f2f371fSMichal Simek * in case of 16K/64K/256K page sizes. 422f2f371fSMichal Simek */ 432f2f371fSMichal Simek 442f2f371fSMichal Simek #define PKMAP_ORDER PTE_SHIFT 452f2f371fSMichal Simek #define LAST_PKMAP (1 << PKMAP_ORDER) 462f2f371fSMichal Simek 472f2f371fSMichal Simek #define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \ 482f2f371fSMichal Simek & PMD_MASK) 492f2f371fSMichal Simek 502f2f371fSMichal Simek #define LAST_PKMAP_MASK (LAST_PKMAP - 1) 512f2f371fSMichal Simek #define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT) 522f2f371fSMichal Simek #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) 532f2f371fSMichal Simek 542f2f371fSMichal Simek extern void *kmap_high(struct page *page); 552f2f371fSMichal Simek extern void kunmap_high(struct page *page); 562f2f371fSMichal Simek extern void *kmap_atomic_prot(struct page *page, pgprot_t prot); 572f2f371fSMichal Simek extern void __kunmap_atomic(void *kvaddr); 582f2f371fSMichal Simek 592f2f371fSMichal Simek static inline void *kmap(struct page *page) 602f2f371fSMichal Simek { 612f2f371fSMichal Simek might_sleep(); 622f2f371fSMichal Simek if (!PageHighMem(page)) 632f2f371fSMichal Simek return page_address(page); 642f2f371fSMichal Simek return kmap_high(page); 652f2f371fSMichal Simek } 662f2f371fSMichal Simek 672f2f371fSMichal Simek static inline void kunmap(struct page *page) 682f2f371fSMichal Simek { 692f2f371fSMichal Simek BUG_ON(in_interrupt()); 702f2f371fSMichal Simek if (!PageHighMem(page)) 712f2f371fSMichal Simek return; 722f2f371fSMichal Simek kunmap_high(page); 732f2f371fSMichal Simek } 742f2f371fSMichal Simek 75ffed2b4fSMichal Simek static inline void *kmap_atomic(struct page *page) 762f2f371fSMichal Simek { 772f2f371fSMichal Simek return kmap_atomic_prot(page, kmap_prot); 782f2f371fSMichal Simek } 792f2f371fSMichal Simek 802f2f371fSMichal Simek #define flush_cache_kmaps() { flush_icache(); flush_dcache(); } 812f2f371fSMichal Simek 822f2f371fSMichal Simek #endif /* __KERNEL__ */ 832f2f371fSMichal Simek 842f2f371fSMichal Simek #endif /* _ASM_HIGHMEM_H */ 85