ef22d8abd8
The Motorola 68xxx MMUs, 040 (and later) have a fixed 7,7,{5,6}
page-table setup, where the last depends on the page-size selected (8k
vs 4k resp.), and head.S selects 4K pages. For 030 (and earlier) we
explicitly program 7,7,6 and 4K pages in %tc.
However, the current code implements this mightily weird. What it does
is group 16 of those (6 bit) pte tables into one 4k page to not waste
space. The down-side is that that forces pmd_t to be a 16-tuple
pointing to consecutive pte tables.
This breaks the generic code which assumes READ_ONCE(*pmd) will be
word sized.
Therefore implement a straight forward 7,7,6 3 level page-table setup,
with the addition (for 020/030) of (partial) large-page support. For
now this increases the memory footprint for pte-tables 15 fold.
Tested with ARAnyM/68040 emulation.
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.711478295@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _M68K_PAGE_H
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#define _M68K_PAGE_H
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#include <linux/const.h>
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#include <asm/setup.h>
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#include <asm/page_offset.h>
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/* PAGE_SHIFT determines the page size */
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#if defined(CONFIG_SUN3) || defined(CONFIG_COLDFIRE)
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#define PAGE_SHIFT 13
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#else
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#define PAGE_SHIFT 12
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#endif
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#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT)
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#define PAGE_MASK (~(PAGE_SIZE-1))
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#define PAGE_OFFSET (PAGE_OFFSET_RAW)
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#ifndef __ASSEMBLY__
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/*
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* These are used to make use of C type-checking..
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*/
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#if !defined(CONFIG_MMU) || CONFIG_PGTABLE_LEVELS == 3
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typedef struct { unsigned long pmd; } pmd_t;
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#define pmd_val(x) ((&x)->pmd)
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#define __pmd(x) ((pmd_t) { (x) } )
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#endif
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typedef struct { unsigned long pte; } pte_t;
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typedef struct { unsigned long pgd; } pgd_t;
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typedef struct { unsigned long pgprot; } pgprot_t;
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typedef struct page *pgtable_t;
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#define pte_val(x) ((x).pte)
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#define pgd_val(x) ((x).pgd)
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#define pgprot_val(x) ((x).pgprot)
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#define __pte(x) ((pte_t) { (x) } )
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#define __pgd(x) ((pgd_t) { (x) } )
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#define __pgprot(x) ((pgprot_t) { (x) } )
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extern unsigned long _rambase;
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extern unsigned long _ramstart;
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extern unsigned long _ramend;
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#endif /* !__ASSEMBLY__ */
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#ifdef CONFIG_MMU
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#include <asm/page_mm.h>
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#else
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#include <asm/page_no.h>
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#endif
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#define __phys_to_pfn(paddr) ((unsigned long)((paddr) >> PAGE_SHIFT))
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#define __pfn_to_phys(pfn) PFN_PHYS(pfn)
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#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#include <asm-generic/getorder.h>
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#endif /* _M68K_PAGE_H */
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