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Diffstat (limited to 'arch/powerpc/include/asm/highmem.h')
-rw-r--r-- | arch/powerpc/include/asm/highmem.h | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/highmem.h b/arch/powerpc/include/asm/highmem.h new file mode 100644 index 000000000..104026f7d --- /dev/null +++ b/arch/powerpc/include/asm/highmem.h @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * highmem.h: virtual kernel memory mappings for high memory + * + * PowerPC version, stolen from the i386 version. + * + * Used in CONFIG_HIGHMEM systems for memory pages which + * are not addressable by direct kernel virtual addresses. + * + * Copyright (C) 1999 Gerhard Wichert, Siemens AG + * Gerhard.Wichert@pdb.siemens.de + * + * + * Redesigned the x86 32-bit VM architecture to deal with + * up to 16 Terrabyte physical memory. With current x86 CPUs + * we now support up to 64 Gigabytes physical RAM. + * + * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> + */ + +#ifndef _ASM_HIGHMEM_H +#define _ASM_HIGHMEM_H + +#ifdef __KERNEL__ + +#include <linux/interrupt.h> +#include <asm/kmap_types.h> +#include <asm/cacheflush.h> +#include <asm/page.h> +#include <asm/fixmap.h> + +extern pte_t *kmap_pte; +extern pte_t *pkmap_page_table; + +/* + * Right now we initialize only a single pte table. It can be extended + * easily, subsequent pte tables have to be allocated in one physical + * chunk of RAM. + */ +/* + * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte + * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP + * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP + * in case of 16K/64K/256K page sizes. + */ +#ifdef CONFIG_PPC_4K_PAGES +#define PKMAP_ORDER PTE_SHIFT +#else +#define PKMAP_ORDER 9 +#endif +#define LAST_PKMAP (1 << PKMAP_ORDER) +#ifndef CONFIG_PPC_4K_PAGES +#define PKMAP_BASE (FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) +#else +#define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK) +#endif +#define LAST_PKMAP_MASK (LAST_PKMAP-1) +#define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) +#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) + +#define flush_cache_kmaps() flush_cache_all() + +#endif /* __KERNEL__ */ + +#endif /* _ASM_HIGHMEM_H */ |