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sparc64: Handle hugepage TSB being NULL.
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Accomodate the possibility that the TSB might be NULL at
the point that update_mmu_cache() is invoked.  This is
necessary because we will sometimes need to defer the TSB
allocation to the first fault that happens in the 'mm'.

Seperate out the hugepage PTE test into a seperate function
so that the logic is clearer.

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Feb 20, 2013
1 parent a55ee1f commit bcd896b
Showing 1 changed file with 22 additions and 16 deletions.
38 changes: 22 additions & 16 deletions arch/sparc/mm/init_64.c
Original file line number Diff line number Diff line change
Expand Up @@ -314,16 +314,31 @@ static void __update_mmu_tsb_insert(struct mm_struct *mm, unsigned long tsb_inde
struct tsb *tsb = mm->context.tsb_block[tsb_index].tsb;
unsigned long tag;

if (unlikely(!tsb))
return;

tsb += ((address >> tsb_hash_shift) &
(mm->context.tsb_block[tsb_index].tsb_nentries - 1UL));
tag = (address >> 22UL);
tsb_insert(tsb, tag, tte);
}

#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
static inline bool is_hugetlb_pte(pte_t pte)
{
if ((tlb_type == hypervisor &&
(pte_val(pte) & _PAGE_SZALL_4V) == _PAGE_SZHUGE_4V) ||
(tlb_type != hypervisor &&
(pte_val(pte) & _PAGE_SZALL_4U) == _PAGE_SZHUGE_4U))
return true;
return false;
}
#endif

void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep)
{
unsigned long tsb_index, tsb_hash_shift, flags;
struct mm_struct *mm;
unsigned long flags;
pte_t pte = *ptep;

if (tlb_type != hypervisor) {
Expand All @@ -335,25 +350,16 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *

mm = vma->vm_mm;

tsb_index = MM_TSB_BASE;
tsb_hash_shift = PAGE_SHIFT;

spin_lock_irqsave(&mm->context.lock, flags);

#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
if (mm->context.tsb_block[MM_TSB_HUGE].tsb != NULL) {
if ((tlb_type == hypervisor &&
(pte_val(pte) & _PAGE_SZALL_4V) == _PAGE_SZHUGE_4V) ||
(tlb_type != hypervisor &&
(pte_val(pte) & _PAGE_SZALL_4U) == _PAGE_SZHUGE_4U)) {
tsb_index = MM_TSB_HUGE;
tsb_hash_shift = HPAGE_SHIFT;
}
}
if (mm->context.huge_pte_count && is_hugetlb_pte(pte))
__update_mmu_tsb_insert(mm, MM_TSB_HUGE, HPAGE_SHIFT,
address, pte_val(pte));
else
#endif

__update_mmu_tsb_insert(mm, tsb_index, tsb_hash_shift,
address, pte_val(pte));
__update_mmu_tsb_insert(mm, MM_TSB_BASE, PAGE_SHIFT,
address, pte_val(pte));

spin_unlock_irqrestore(&mm->context.lock, flags);
}
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