forked from Minki/linux
bb86bf28ae
Commit 351336929c (kernel.org) rsp.
b3594a089f1c17ff919f8f78505c3f20e1f6f8ce (linux-mips.org):
> From: Chris Dearman <chris@mips.com>
> Date: Wed, 19 Sep 2007 00:58:24 +0100
> Subject: [PATCH] [MIPS] Allow setting of the cache attribute at run time.
>
> Slightly tacky, but there is a precedent in the sparc archirecture code.
introduces the variable _page_cachable_default, which defaults to zero and.
is used to create the prototype PTE for __kmap_atomic in
arch/mips/mm/init.c:kmap_init before initialization in
arch/mips/mm/c-r4k.c:coherency_setup, so the default value of 0 will be
used as the CCA of kmap atomic pages which on many processors is not a
defined CCA value and may result in writes to kmap_atomic pages getting
corrupted. Debugged by Jon Fraser (jfraser@broadcom.com).
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
70 lines
1.9 KiB
C
70 lines
1.9 KiB
C
/*
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* highmem.h: virtual kernel memory mappings for high memory
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*
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* Used in CONFIG_HIGHMEM systems for memory pages which
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* are not addressable by direct kernel virtual addresses.
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*
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* Copyright (C) 1999 Gerhard Wichert, Siemens AG
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* Gerhard.Wichert@pdb.siemens.de
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*
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*
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* Redesigned the x86 32-bit VM architecture to deal with
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* up to 16 Terabyte physical memory. With current x86 CPUs
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* we now support up to 64 Gigabytes physical RAM.
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*
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* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
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*/
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#ifndef _ASM_HIGHMEM_H
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#define _ASM_HIGHMEM_H
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#ifdef __KERNEL__
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/uaccess.h>
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#include <asm/kmap_types.h>
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/* undef for production */
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#define HIGHMEM_DEBUG 1
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/* declarations for highmem.c */
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extern unsigned long highstart_pfn, highend_pfn;
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extern pte_t *pkmap_page_table;
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/*
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* Right now we initialize only a single pte table. It can be extended
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* easily, subsequent pte tables have to be allocated in one physical
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* chunk of RAM.
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*/
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#define LAST_PKMAP 1024
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#define LAST_PKMAP_MASK (LAST_PKMAP-1)
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#define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
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#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
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extern void * kmap_high(struct page *page);
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extern void kunmap_high(struct page *page);
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extern void *__kmap(struct page *page);
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extern void __kunmap(struct page *page);
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extern void *__kmap_atomic(struct page *page, enum km_type type);
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extern void __kunmap_atomic(void *kvaddr, enum km_type type);
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extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
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extern struct page *__kmap_atomic_to_page(void *ptr);
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#define kmap __kmap
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#define kunmap __kunmap
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#define kmap_atomic __kmap_atomic
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#define kunmap_atomic __kunmap_atomic
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#define kmap_atomic_to_page __kmap_atomic_to_page
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#define flush_cache_kmaps() flush_cache_all()
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extern void kmap_init(void);
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#define kmap_prot PAGE_KERNEL
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#endif /* __KERNEL__ */
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#endif /* _ASM_HIGHMEM_H */
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