b1fba034a6
Introduce PAGE_EXECONLY_X macro which provides exec-only rights. The _X may be seen as redundant with the EXECONLY but it helps keep consistency, all macros having the EXEC right have _X. And put it next to PAGE_NONE as PAGE_EXECONLY_X is somehow PAGE_NONE + EXEC just like all other SOMETHING_X are just SOMETHING + EXEC. On book3s/64 PAGE_EXECONLY becomes PAGE_READONLY_X. On book3s/64, as PAGE_EXECONLY is only valid for Radix add VM_READ flag in vm_get_page_prot() for non-Radix. And update access_error() so that a non exec fault on a VM_EXEC only mapping is always invalid, even when the underlying layer don't always generate a fault for that. For 8xx, set PAGE_EXECONLY_X as _PAGE_NA | _PAGE_EXEC. For others, only set it as just _PAGE_EXEC With that change, 8xx, e500 and 44x fully honor execute-only protection. On 40x that is a partial implementation of execute-only. The implementation won't be complete because once a TLB has been loaded via the Instruction TLB miss handler, it will be possible to read the page. But at least it can't be read unless it is executed first. On 603 MMU, TLB missed are handled by SW and there are separate DTLB and ITLB. Execute-only is therefore now supported by not loading DTLB when read access is not permitted. On hash (604) MMU it is more tricky because hash table is common to load/store and execute. Nevertheless it is still possible to check whether _PAGE_READ is set before loading hash table for a load/store access. At least it can't be read unless it is executed first. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/4283ea9cbef9ff2fbee468904800e1962bc8fc18.1695659959.git.christophe.leroy@csgroup.eu
32 lines
1.1 KiB
C
32 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_PGTABLE_MASKS_H
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#define _ASM_POWERPC_PGTABLE_MASKS_H
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#ifndef _PAGE_NA
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#define _PAGE_NA 0
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#define _PAGE_NAX _PAGE_EXEC
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#define _PAGE_RO _PAGE_READ
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#define _PAGE_ROX (_PAGE_READ | _PAGE_EXEC)
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#define _PAGE_RW (_PAGE_READ | _PAGE_WRITE)
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#define _PAGE_RWX (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)
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#endif
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/* Permission flags for kernel mappings */
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#ifndef _PAGE_KERNEL_RO
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#define _PAGE_KERNEL_RO _PAGE_RO
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#define _PAGE_KERNEL_ROX _PAGE_ROX
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#define _PAGE_KERNEL_RW (_PAGE_RW | _PAGE_DIRTY)
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#define _PAGE_KERNEL_RWX (_PAGE_RWX | _PAGE_DIRTY)
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#endif
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/* Permission masks used to generate the __P and __S table */
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#define PAGE_NONE __pgprot(_PAGE_BASE | _PAGE_NA)
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#define PAGE_EXECONLY_X __pgprot(_PAGE_BASE | _PAGE_NAX)
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#define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_RW)
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#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_RWX)
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#define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_RO)
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#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_ROX)
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#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_RO)
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#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_ROX)
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#endif /* _ASM_POWERPC_PGTABLE_MASKS_H */
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