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ea3cc330ac
This is an attempt at cleaning up a bit the way we handle execute permission on powerpc. _PAGE_HWEXEC is gone, _PAGE_EXEC is now only defined by CPUs that can do something with it, and the myriad of #ifdef's in the I$/D$ coherency code is reduced to 2 cases that hopefully should cover everything. The logic on BookE is a little bit different than what it was though not by much. Since now, _PAGE_EXEC will be set by the generic code for executable pages, we need to filter out if they are unclean and recover it. However, I don't expect the code to be more bloated than it already was in that area due to that change. I could boast that this brings proper enforcing of per-page execute permissions to all BookE and 40x but in fact, we've had that now for some time as a side effect of my previous rework in that area (and I didn't even know it :-) We would only enable execute permission if the page was cache clean and we would only cache clean it if we took and exec fault. Since we now enforce that the later only work if VM_EXEC is part of the VMA flags, we de-fact already enforce per-page execute permissions... Unless I missed something Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
48 lines
1.9 KiB
C
48 lines
1.9 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_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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