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As discussed earlier, we attempt to enforce protection keys in software. However, the code checks all faults to ensure that they are not violating protection key permissions. It was assumed that all faults are either write faults where we check PKRU[key].WD (write disable) or read faults where we check the AD (access disable) bit. But, there is a third category of faults for protection keys: instruction faults. Instruction faults never run afoul of protection keys because they do not affect instruction fetches. So, plumb the PF_INSTR bit down in to the arch_vma_access_permitted() function where we do the protection key checks. We also add a new FAULT_FLAG_INSTRUCTION. This is because handle_mm_fault() is not passed the architecture-specific error_code where we keep PF_INSTR, so we need to encode the instruction fetch information in to the arch-generic fault flags. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210224.96928009@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
41 lines
960 B
C
41 lines
960 B
C
/*
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* Define generic no-op hooks for arch_dup_mmap, arch_exit_mmap
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* and arch_unmap to be included in asm-FOO/mmu_context.h for any
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* arch FOO which doesn't need to hook these.
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*/
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#ifndef _ASM_GENERIC_MM_HOOKS_H
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#define _ASM_GENERIC_MM_HOOKS_H
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static inline void arch_dup_mmap(struct mm_struct *oldmm,
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struct mm_struct *mm)
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{
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}
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static inline void arch_exit_mmap(struct mm_struct *mm)
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{
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}
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static inline void arch_unmap(struct mm_struct *mm,
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struct vm_area_struct *vma,
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unsigned long start, unsigned long end)
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{
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}
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static inline void arch_bprm_mm_init(struct mm_struct *mm,
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struct vm_area_struct *vma)
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{
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}
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static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
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bool write, bool execute, bool foreign)
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{
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/* by default, allow everything */
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return true;
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}
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static inline bool arch_pte_access_permitted(pte_t pte, bool write)
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{
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/* by default, allow everything */
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return true;
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}
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#endif /* _ASM_GENERIC_MM_HOOKS_H */
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