e8a62cc26d
By adding a new 4th level of page table, give the possibility to 64bit kernel to address 2^48 bytes of virtual address: in practice, that offers 128TB of virtual address space to userspace and allows up to 64TB of physical memory. If the underlying hardware does not support sv48, we will automatically fallback to a standard 3-level page table by folding the new PUD level into PGDIR level. In order to detect HW capabilities at runtime, we use SATP feature that ignores writes with an unsupported mode. Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
61 lines
1.5 KiB
C
61 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2019 Western Digital Corporation or its affiliates.
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*/
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#ifndef _ASM_RISCV_FIXMAP_H
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#define _ASM_RISCV_FIXMAP_H
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#include <linux/kernel.h>
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#include <linux/sizes.h>
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#include <linux/pgtable.h>
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#include <asm/page.h>
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#ifdef CONFIG_MMU
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/*
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* Here we define all the compile-time 'special' virtual addresses.
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* The point is to have a constant address at compile time, but to
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* set the physical address only in the boot process.
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*
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* These 'compile-time allocated' memory buffers are page-sized. Use
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* set_fixmap(idx,phys) to associate physical memory with fixmap indices.
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*/
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enum fixed_addresses {
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FIX_HOLE,
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FIX_PTE,
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FIX_PMD,
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FIX_PUD,
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FIX_TEXT_POKE1,
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FIX_TEXT_POKE0,
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FIX_EARLYCON_MEM_BASE,
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__end_of_permanent_fixed_addresses,
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/*
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* Temporary boot-time mappings, used by early_ioremap(),
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* before ioremap() is functional.
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*/
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#define NR_FIX_BTMAPS (SZ_256K / PAGE_SIZE)
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#define FIX_BTMAPS_SLOTS 7
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#define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
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FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
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FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
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__end_of_fixed_addresses
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};
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#define FIXMAP_PAGE_IO PAGE_KERNEL
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#define __early_set_fixmap __set_fixmap
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#define __late_set_fixmap __set_fixmap
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#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
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extern void __set_fixmap(enum fixed_addresses idx,
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phys_addr_t phys, pgprot_t prot);
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#include <asm-generic/fixmap.h>
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#endif /* CONFIG_MMU */
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#endif /* _ASM_RISCV_FIXMAP_H */
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