8d1cf34e7a
This patch tweaks the way some PTE bit combinations are defined, in such a way that the 32 and 64-bit variant become almost identical and that will make it easier to bring in a new common pte-* file for the new variant of the Book3-E support. The combination of bits defining access to kernel pages are now clearly separated from the combination used by userspace and the core VM. The resulting generated code should remain identical unless I made a mistake. Note: While at it, I removed a non-sensical statement related to CONFIG_KGDB in ppc_mmu_32.c which could cause kernel mappings to be user accessible when that option is enabled. Probably something that bitrot. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
49 lines
2.0 KiB
C
49 lines
2.0 KiB
C
#ifndef _ASM_POWERPC_PTE_HASH32_H
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#define _ASM_POWERPC_PTE_HASH32_H
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#ifdef __KERNEL__
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/*
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* The "classic" 32-bit implementation of the PowerPC MMU uses a hash
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* table containing PTEs, together with a set of 16 segment registers,
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* to define the virtual to physical address mapping.
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*
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* We use the hash table as an extended TLB, i.e. a cache of currently
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* active mappings. We maintain a two-level page table tree, much
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* like that used by the i386, for the sake of the Linux memory
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* management code. Low-level assembler code in hash_low_32.S
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* (procedure hash_page) is responsible for extracting ptes from the
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* tree and putting them into the hash table when necessary, and
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* updating the accessed and modified bits in the page table tree.
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*/
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#define _PAGE_PRESENT 0x001 /* software: pte contains a translation */
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#define _PAGE_HASHPTE 0x002 /* hash_page has made an HPTE for this pte */
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#define _PAGE_FILE 0x004 /* when !present: nonlinear file mapping */
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#define _PAGE_USER 0x004 /* usermode access allowed */
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#define _PAGE_GUARDED 0x008 /* G: prohibit speculative access */
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#define _PAGE_COHERENT 0x010 /* M: enforce memory coherence (SMP systems) */
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#define _PAGE_NO_CACHE 0x020 /* I: cache inhibit */
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#define _PAGE_WRITETHRU 0x040 /* W: cache write-through */
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#define _PAGE_DIRTY 0x080 /* C: page changed */
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#define _PAGE_ACCESSED 0x100 /* R: page referenced */
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#define _PAGE_EXEC 0x200 /* software: i-cache coherency required */
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#define _PAGE_RW 0x400 /* software: user write access allowed */
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#define _PAGE_SPECIAL 0x800 /* software: Special page */
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#ifdef CONFIG_PTE_64BIT
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/* We never clear the high word of the pte */
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#define _PTE_NONE_MASK (0xffffffff00000000ULL | _PAGE_HASHPTE)
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#else
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#define _PTE_NONE_MASK _PAGE_HASHPTE
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#endif
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#define _PMD_PRESENT 0
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#define _PMD_PRESENT_MASK (PAGE_MASK)
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#define _PMD_BAD (~PAGE_MASK)
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/* Hash table based platforms need atomic updates of the linux PTE */
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#define PTE_ATOMIC_UPDATES 1
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_PTE_HASH32_H */
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