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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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8b81576c16
Add HIGHMEM (High Memory) support for LoongArch, mostly needed by 32BIT kernel because the size of kernel virtual memory space is only 512MB and the size of usable physical memory is only 256MB in this case. HIGHMEM adds permanent kernel mapping (PKMAP) and fixed kernel mapping (FIX_KMAP), which increase usable physical memory up to 2.25GB (2304MB). We can just use the generic copy_user_highpage(), so remove the custom version. Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
43 lines
927 B
C
43 lines
927 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* fixmap.h: compile-time virtual memory allocation
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*
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* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
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*/
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#ifndef _ASM_FIXMAP_H
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#define _ASM_FIXMAP_H
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#ifdef CONFIG_HIGHMEM
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#include <linux/threads.h>
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#include <asm/kmap_size.h>
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#endif
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#define NR_FIX_BTMAPS 64
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enum fixed_addresses {
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FIX_HOLE,
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#ifdef CONFIG_HIGHMEM
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FIX_KMAP_BEGIN,
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FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
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#endif
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FIX_EARLYCON_MEM_BASE,
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__end_of_fixed_addresses
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};
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#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
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#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
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#define FIXMAP_PAGE_IO PAGE_KERNEL_SUC
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extern void __set_fixmap(enum fixed_addresses idx,
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phys_addr_t phys, pgprot_t flags);
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#include <asm-generic/fixmap.h>
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/*
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* Called from pagetable_init()
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*/
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extern void fixrange_init(unsigned long start, unsigned long end, pgd_t *pgd_base);
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#endif
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