forked from mirrors/linux
6c359eb1dc
On systems where physical memory begins at a non-zero address, defining PHYS_OFFSET (which influences ARCH_PFN_OFFSET) can save us time & memory by avoiding book-keeping for pages from address zero to the start of memory. Some MIPS platforms already make use of this, but with the definition of PHYS_OFFSET being compile-time constant it hasn't been possible to enable this optimization for a kernel which may run on systems with varying physical memory base addresses. Introduce a new Kconfig option CONFIG_MIPS_AUTO_PFN_OFFSET which, when enabled, makes ARCH_PFN_OFFSET a variable & detects it from the boot memory map (which for example may have been populated from DT). The relationship with PHYS_OFFSET is reversed, with PHYS_OFFSET now being based on ARCH_PFN_OFFSET. This is because ARCH_PFN_OFFSET is used far more often, so avoiding the need for runtime calculation gives us a smaller impact on kernel text size (0.1% rather than 0.15% for 64r6el_defconfig). Signed-off-by: Paul Burton <paul.burton@mips.com> Suggested-by: Vladimir Kondratiev <vladimir.kondratiev@intel.com> Patchwork: https://patchwork.linux-mips.org/patch/20048/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
106 lines
2.4 KiB
C
106 lines
2.4 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1994 - 1999, 2000, 03, 04 Ralf Baechle
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* Copyright (C) 2000, 2002 Maciej W. Rozycki
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* Copyright (C) 1990, 1999, 2000 Silicon Graphics, Inc.
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*/
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#ifndef _ASM_MACH_GENERIC_SPACES_H
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#define _ASM_MACH_GENERIC_SPACES_H
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#include <linux/const.h>
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#include <asm/mipsregs.h>
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/*
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* This gives the physical RAM offset.
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*/
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#ifndef __ASSEMBLY__
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# if defined(CONFIG_MIPS_AUTO_PFN_OFFSET)
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# define PHYS_OFFSET ((unsigned long)PFN_PHYS(ARCH_PFN_OFFSET))
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# elif !defined(PHYS_OFFSET)
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# define PHYS_OFFSET _AC(0, UL)
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# endif
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#endif /* __ASSEMBLY__ */
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#ifdef CONFIG_32BIT
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#ifdef CONFIG_KVM_GUEST
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#define CAC_BASE _AC(0x40000000, UL)
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#else
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#define CAC_BASE _AC(0x80000000, UL)
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#endif
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#ifndef IO_BASE
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#define IO_BASE _AC(0xa0000000, UL)
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#endif
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#ifndef UNCAC_BASE
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#define UNCAC_BASE _AC(0xa0000000, UL)
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#endif
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#ifndef MAP_BASE
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#ifdef CONFIG_KVM_GUEST
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#define MAP_BASE _AC(0x60000000, UL)
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#else
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#define MAP_BASE _AC(0xc0000000, UL)
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#endif
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#endif
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/*
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* Memory above this physical address will be considered highmem.
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*/
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#ifndef HIGHMEM_START
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#define HIGHMEM_START _AC(0x20000000, UL)
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#endif
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#endif /* CONFIG_32BIT */
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#ifdef CONFIG_64BIT
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#ifndef CAC_BASE
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#define CAC_BASE PHYS_TO_XKPHYS(read_c0_config() & CONF_CM_CMASK, 0)
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#endif
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#ifndef IO_BASE
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#define IO_BASE _AC(0x9000000000000000, UL)
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#endif
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#ifndef UNCAC_BASE
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#define UNCAC_BASE _AC(0x9000000000000000, UL)
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#endif
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#ifndef MAP_BASE
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#define MAP_BASE _AC(0xc000000000000000, UL)
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#endif
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/*
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* Memory above this physical address will be considered highmem.
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* Fixme: 59 bits is a fictive number and makes assumptions about processors
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* in the distant future. Nobody will care for a few years :-)
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*/
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#ifndef HIGHMEM_START
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#define HIGHMEM_START (_AC(1, UL) << _AC(59, UL))
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#endif
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#define TO_PHYS(x) ( ((x) & TO_PHYS_MASK))
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#define TO_CAC(x) (CAC_BASE | ((x) & TO_PHYS_MASK))
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#define TO_UNCAC(x) (UNCAC_BASE | ((x) & TO_PHYS_MASK))
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#endif /* CONFIG_64BIT */
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/*
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* This handles the memory map.
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*/
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#ifndef PAGE_OFFSET
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#define PAGE_OFFSET (CAC_BASE + PHYS_OFFSET)
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#endif
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#ifndef FIXADDR_TOP
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#ifdef CONFIG_KVM_GUEST
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#define FIXADDR_TOP ((unsigned long)(long)(int)0x7ffe0000)
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#else
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#define FIXADDR_TOP ((unsigned long)(long)(int)0xfffe0000)
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#endif
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#endif
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#endif /* __ASM_MACH_GENERIC_SPACES_H */
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