sh: Tidy up vmalloc fault handling.
This rewrites the vmalloc fault handling as per x86, which subsequently allows for easy future tie-in for vmalloc_sync_all(). Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt
Родитель
c63c3105e4
Коммит
0f60bb25b4
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@ -2,7 +2,7 @@
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* Page fault handler for SH with an MMU.
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*
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* Copyright (C) 1999 Niibe Yutaka
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* Copyright (C) 2003 - 2008 Paul Mundt
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* Copyright (C) 2003 - 2009 Paul Mundt
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*
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* Based on linux/arch/i386/mm/fault.c:
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* Copyright (C) 1995 Linus Torvalds
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@ -35,6 +35,74 @@ static inline int notify_page_fault(struct pt_regs *regs, int trap)
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return ret;
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}
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static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
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{
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unsigned index = pgd_index(address);
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pgd_t *pgd_k;
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pud_t *pud, *pud_k;
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pmd_t *pmd, *pmd_k;
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pgd += index;
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pgd_k = init_mm.pgd + index;
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if (!pgd_present(*pgd_k))
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return NULL;
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pud = pud_offset(pgd, address);
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pud_k = pud_offset(pgd_k, address);
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if (!pud_present(*pud_k))
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return NULL;
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pmd = pmd_offset(pud, address);
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pmd_k = pmd_offset(pud_k, address);
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if (!pmd_present(*pmd_k))
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return NULL;
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if (!pmd_present(*pmd))
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set_pmd(pmd, *pmd_k);
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else
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BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
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return pmd_k;
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}
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/*
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* Handle a fault on the vmalloc or module mapping area
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*/
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static noinline int vmalloc_fault(unsigned long address)
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{
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pgd_t *pgd_k;
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pmd_t *pmd_k;
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pte_t *pte_k;
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/* Make sure we are in vmalloc area: */
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if (!(address >= VMALLOC_START && address < VMALLOC_END))
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return -1;
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/*
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* Synchronize this task's top level page-table
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* with the 'reference' page table.
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*
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* Do _not_ use "current" here. We might be inside
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* an interrupt in the middle of a task switch..
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*/
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pgd_k = get_TTB();
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pmd_k = vmalloc_sync_one(__va((unsigned long)pgd_k), address);
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if (!pmd_k)
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return -1;
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pte_k = pte_offset_kernel(pmd_k, address);
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if (!pte_present(*pte_k))
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return -1;
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return 0;
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}
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static int fault_in_kernel_space(unsigned long address)
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{
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return address >= TASK_SIZE;
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}
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/*
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* This routine handles page faults. It determines the address,
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* and the problem, and then passes it off to one of the appropriate
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@ -44,6 +112,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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unsigned long writeaccess,
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unsigned long address)
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{
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unsigned long vec;
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struct task_struct *tsk;
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struct mm_struct *mm;
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struct vm_area_struct * vma;
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@ -51,59 +120,30 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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int fault;
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siginfo_t info;
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/*
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* We don't bother with any notifier callbacks here, as they are
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* all handled through the __do_page_fault() fast-path.
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*/
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tsk = current;
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mm = tsk->mm;
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si_code = SEGV_MAPERR;
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vec = lookup_exception_vector();
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if (unlikely(address >= TASK_SIZE)) {
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/*
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* Synchronize this task's top level page-table
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* with the 'reference' page table.
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*
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* Do _not_ use "tsk" here. We might be inside
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* an interrupt in the middle of a task switch..
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*/
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int offset = pgd_index(address);
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pgd_t *pgd, *pgd_k;
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pud_t *pud, *pud_k;
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pmd_t *pmd, *pmd_k;
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pgd = get_TTB() + offset;
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pgd_k = swapper_pg_dir + offset;
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if (!pgd_present(*pgd)) {
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if (!pgd_present(*pgd_k))
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goto bad_area_nosemaphore;
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set_pgd(pgd, *pgd_k);
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/*
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* We fault-in kernel-space virtual memory on-demand. The
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* 'reference' page table is init_mm.pgd.
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*
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* NOTE! We MUST NOT take any locks for this case. We may
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* be in an interrupt or a critical region, and should
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* only copy the information from the master page table,
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* nothing more.
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*/
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if (unlikely(fault_in_kernel_space(address))) {
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if (vmalloc_fault(address) >= 0)
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return;
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}
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pud = pud_offset(pgd, address);
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pud_k = pud_offset(pgd_k, address);
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if (!pud_present(*pud)) {
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if (!pud_present(*pud_k))
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goto bad_area_nosemaphore;
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set_pud(pud, *pud_k);
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if (notify_page_fault(regs, vec))
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return;
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}
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pmd = pmd_offset(pud, address);
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pmd_k = pmd_offset(pud_k, address);
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if (pmd_present(*pmd) || !pmd_present(*pmd_k))
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goto bad_area_nosemaphore;
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set_pmd(pmd, *pmd_k);
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return;
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goto bad_area_nosemaphore;
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}
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mm = tsk->mm;
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if (unlikely(notify_page_fault(regs, lookup_exception_vector())))
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if (unlikely(notify_page_fault(regs, vec)))
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return;
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/* Only enable interrupts if they were on before the fault */
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@ -113,8 +153,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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perf_swcounter_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);
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/*
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* If we're in an interrupt or have no user
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* context, we must not take the fault..
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* If we're in an interrupt, have no user context or are running
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* in an atomic region then we must not take the fault:
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*/
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if (in_atomic() || !mm)
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goto no_context;
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@ -130,10 +170,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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goto bad_area;
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if (expand_stack(vma, address))
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goto bad_area;
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/*
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* Ok, we have a good vm_area for this memory access, so
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* we can handle it..
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*/
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/*
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* Ok, we have a good vm_area for this memory access, so
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* we can handle it..
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*/
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good_area:
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si_code = SEGV_ACCERR;
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if (writeaccess) {
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@ -171,10 +212,10 @@ survive:
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up_read(&mm->mmap_sem);
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return;
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/*
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* Something tried to access memory that isn't in our memory map..
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* Fix it, but check if it's kernel or user first..
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*/
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/*
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* Something tried to access memory that isn't in our memory map..
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* Fix it, but check if it's kernel or user first..
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*/
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bad_area:
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up_read(&mm->mmap_sem);
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