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5289f46b9d
flush_tlb_mm's "optimized" uniprocessor case of allocating a new context for userspace is exposing a race where we can suddely return to a syscall with the protection id and space id out of sync, trapping on the next userspace access. Debugged-by: James Bottomley <James.Bottomley@HansenPartnership.com> Tested-by: Helge Deller <deller@gmx.de> Signed-off-by: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
#ifndef _PARISC_TLBFLUSH_H
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#define _PARISC_TLBFLUSH_H
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/* TLB flushing routines.... */
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <asm/mmu_context.h>
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/* This is for the serialisation of PxTLB broadcasts. At least on the
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* N class systems, only one PxTLB inter processor broadcast can be
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* active at any one time on the Merced bus. This tlb purge
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* synchronisation is fairly lightweight and harmless so we activate
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* it on all SMP systems not just the N class. We also need to have
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* preemption disabled on uniprocessor machines, and spin_lock does that
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* nicely.
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*/
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extern spinlock_t pa_tlb_lock;
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#define purge_tlb_start(x) spin_lock(&pa_tlb_lock)
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#define purge_tlb_end(x) spin_unlock(&pa_tlb_lock)
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extern void flush_tlb_all(void);
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extern void flush_tlb_all_local(void *);
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/*
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* flush_tlb_mm()
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*
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* XXX This code is NOT valid for HP-UX compatibility processes,
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* (although it will probably work 99% of the time). HP-UX
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* processes are free to play with the space id's and save them
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* over long periods of time, etc. so we have to preserve the
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* space and just flush the entire tlb. We need to check the
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* personality in order to do that, but the personality is not
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* currently being set correctly.
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*
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* Of course, Linux processes could do the same thing, but
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* we don't support that (and the compilers, dynamic linker,
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* etc. do not do that).
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*/
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static inline void flush_tlb_mm(struct mm_struct *mm)
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{
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BUG_ON(mm == &init_mm); /* Should never happen */
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#if 1 || defined(CONFIG_SMP)
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flush_tlb_all();
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#else
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/* FIXME: currently broken, causing space id and protection ids
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* to go out of sync, resulting in faults on userspace accesses.
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*/
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if (mm) {
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if (mm->context != 0)
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free_sid(mm->context);
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mm->context = alloc_sid();
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if (mm == current->active_mm)
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load_context(mm->context);
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}
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#endif
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}
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static inline void flush_tlb_page(struct vm_area_struct *vma,
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unsigned long addr)
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{
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/* For one page, it's not worth testing the split_tlb variable */
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mb();
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mtsp(vma->vm_mm->context,1);
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purge_tlb_start();
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pdtlb(addr);
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pitlb(addr);
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purge_tlb_end();
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}
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void __flush_tlb_range(unsigned long sid,
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unsigned long start, unsigned long end);
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#define flush_tlb_range(vma,start,end) __flush_tlb_range((vma)->vm_mm->context,start,end)
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#define flush_tlb_kernel_range(start, end) __flush_tlb_range(0,start,end)
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#endif
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