diff options
Diffstat (limited to 'arch/powerpc/mm/hugetlbpage.c')
-rw-r--r-- | arch/powerpc/mm/hugetlbpage.c | 309 |
1 files changed, 182 insertions, 127 deletions
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 237c8e5f264..834ca8eb38f 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -21,6 +21,9 @@ #include <asm/pgalloc.h> #include <asm/tlb.h> #include <asm/setup.h> +#include <asm/hugetlb.h> + +#ifdef CONFIG_HUGETLB_PAGE #define PAGE_SHIFT_64K 16 #define PAGE_SHIFT_16M 24 @@ -100,68 +103,9 @@ int pgd_huge(pgd_t pgd) } #endif -/* - * We have 4 cases for pgds and pmds: - * (1) invalid (all zeroes) - * (2) pointer to next table, as normal; bottom 6 bits == 0 - * (3) leaf pte for huge page, bottom two bits != 00 - * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table - */ -pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift) -{ - pgd_t *pg; - pud_t *pu; - pmd_t *pm; - pte_t *ret_pte; - hugepd_t *hpdp = NULL; - unsigned pdshift = PGDIR_SHIFT; - - if (shift) - *shift = 0; - - pg = pgdir + pgd_index(ea); - - if (pgd_huge(*pg)) { - ret_pte = (pte_t *) pg; - goto out; - } else if (is_hugepd(pg)) - hpdp = (hugepd_t *)pg; - else if (!pgd_none(*pg)) { - pdshift = PUD_SHIFT; - pu = pud_offset(pg, ea); - - if (pud_huge(*pu)) { - ret_pte = (pte_t *) pu; - goto out; - } else if (is_hugepd(pu)) - hpdp = (hugepd_t *)pu; - else if (!pud_none(*pu)) { - pdshift = PMD_SHIFT; - pm = pmd_offset(pu, ea); - - if (pmd_huge(*pm)) { - ret_pte = (pte_t *) pm; - goto out; - } else if (is_hugepd(pm)) - hpdp = (hugepd_t *)pm; - else if (!pmd_none(*pm)) - return pte_offset_kernel(pm, ea); - } - } - if (!hpdp) - return NULL; - - ret_pte = hugepte_offset(hpdp, ea, pdshift); - pdshift = hugepd_shift(*hpdp); -out: - if (shift) - *shift = pdshift; - return ret_pte; -} -EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte); - pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) { + /* Only called for hugetlbfs pages, hence can ignore THP */ return find_linux_pte_or_hugepte(mm->pgd, addr, NULL); } @@ -357,7 +301,7 @@ void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages) int alloc_bootmem_huge_page(struct hstate *hstate) { struct huge_bootmem_page *m; - int idx = shift_to_mmu_psize(hstate->order + PAGE_SHIFT); + int idx = shift_to_mmu_psize(huge_page_shift(hstate)); int nr_gpages = gpage_freearray[idx].nr_gpages; if (nr_gpages == 0) @@ -592,8 +536,14 @@ static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud, do { pmd = pmd_offset(pud, addr); next = pmd_addr_end(addr, end); - if (pmd_none_or_clear_bad(pmd)) + if (!is_hugepd(pmd)) { + /* + * if it is not hugepd pointer, we should already find + * it cleared. + */ + WARN_ON(!pmd_none_or_clear_bad(pmd)); continue; + } #ifdef CONFIG_PPC_FSL_BOOK3E /* * Increment next by the size of the huge mapping since @@ -730,11 +680,14 @@ follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) struct page *page; unsigned shift; unsigned long mask; - + /* + * Transparent hugepages are handled by generic code. We can skip them + * here. + */ ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift); /* Verify it is a huge page else bail. */ - if (!ptep || !shift) + if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep)) return ERR_PTR(-EINVAL); mask = (1UL << shift) - 1; @@ -753,69 +706,6 @@ follow_huge_pmd(struct mm_struct *mm, unsigned long address, return NULL; } -int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, - unsigned long end, int write, struct page **pages, int *nr) -{ - unsigned long mask; - unsigned long pte_end; - struct page *head, *page, *tail; - pte_t pte; - int refs; - - pte_end = (addr + sz) & ~(sz-1); - if (pte_end < end) - end = pte_end; - - pte = *ptep; - mask = _PAGE_PRESENT | _PAGE_USER; - if (write) - mask |= _PAGE_RW; - - if ((pte_val(pte) & mask) != mask) - return 0; - - /* hugepages are never "special" */ - VM_BUG_ON(!pfn_valid(pte_pfn(pte))); - - refs = 0; - head = pte_page(pte); - - page = head + ((addr & (sz-1)) >> PAGE_SHIFT); - tail = page; - do { - VM_BUG_ON(compound_head(page) != head); - pages[*nr] = page; - (*nr)++; - page++; - refs++; - } while (addr += PAGE_SIZE, addr != end); - - if (!page_cache_add_speculative(head, refs)) { - *nr -= refs; - return 0; - } - - if (unlikely(pte_val(pte) != pte_val(*ptep))) { - /* Could be optimized better */ - *nr -= refs; - while (refs--) - put_page(head); - return 0; - } - - /* - * Any tail page need their mapcount reference taken before we - * return. - */ - while (refs--) { - if (PageTail(tail)) - get_huge_page_tail(tail); - tail++; - } - - return 1; -} - static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end, unsigned long sz) { @@ -1032,3 +922,168 @@ void flush_dcache_icache_hugepage(struct page *page) } } } + +#endif /* CONFIG_HUGETLB_PAGE */ + +/* + * We have 4 cases for pgds and pmds: + * (1) invalid (all zeroes) + * (2) pointer to next table, as normal; bottom 6 bits == 0 + * (3) leaf pte for huge page, bottom two bits != 00 + * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table + * + * So long as we atomically load page table pointers we are safe against teardown, + * we can follow the address down to the the page and take a ref on it. + */ + +pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift) +{ + pgd_t pgd, *pgdp; + pud_t pud, *pudp; + pmd_t pmd, *pmdp; + pte_t *ret_pte; + hugepd_t *hpdp = NULL; + unsigned pdshift = PGDIR_SHIFT; + + if (shift) + *shift = 0; + + pgdp = pgdir + pgd_index(ea); + pgd = ACCESS_ONCE(*pgdp); + /* + * Always operate on the local stack value. This make sure the + * value don't get updated by a parallel THP split/collapse, + * page fault or a page unmap. The return pte_t * is still not + * stable. So should be checked there for above conditions. + */ + if (pgd_none(pgd)) + return NULL; + else if (pgd_huge(pgd)) { + ret_pte = (pte_t *) pgdp; + goto out; + } else if (is_hugepd(&pgd)) + hpdp = (hugepd_t *)&pgd; + else { + /* + * Even if we end up with an unmap, the pgtable will not + * be freed, because we do an rcu free and here we are + * irq disabled + */ + pdshift = PUD_SHIFT; + pudp = pud_offset(&pgd, ea); + pud = ACCESS_ONCE(*pudp); + + if (pud_none(pud)) + return NULL; + else if (pud_huge(pud)) { + ret_pte = (pte_t *) pudp; + goto out; + } else if (is_hugepd(&pud)) + hpdp = (hugepd_t *)&pud; + else { + pdshift = PMD_SHIFT; + pmdp = pmd_offset(&pud, ea); + pmd = ACCESS_ONCE(*pmdp); + /* + * A hugepage collapse is captured by pmd_none, because + * it mark the pmd none and do a hpte invalidate. + * + * A hugepage split is captured by pmd_trans_splitting + * because we mark the pmd trans splitting and do a + * hpte invalidate + * + */ + if (pmd_none(pmd) || pmd_trans_splitting(pmd)) + return NULL; + + if (pmd_huge(pmd) || pmd_large(pmd)) { + ret_pte = (pte_t *) pmdp; + goto out; + } else if (is_hugepd(&pmd)) + hpdp = (hugepd_t *)&pmd; + else + return pte_offset_kernel(&pmd, ea); + } + } + if (!hpdp) + return NULL; + + ret_pte = hugepte_offset(hpdp, ea, pdshift); + pdshift = hugepd_shift(*hpdp); +out: + if (shift) + *shift = pdshift; + return ret_pte; +} +EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte); + +int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, + unsigned long end, int write, struct page **pages, int *nr) +{ + unsigned long mask; + unsigned long pte_end; + struct page *head, *page, *tail; + pte_t pte; + int refs; + + pte_end = (addr + sz) & ~(sz-1); + if (pte_end < end) + end = pte_end; + + pte = ACCESS_ONCE(*ptep); + mask = _PAGE_PRESENT | _PAGE_USER; + if (write) + mask |= _PAGE_RW; + + if ((pte_val(pte) & mask) != mask) + return 0; + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + /* + * check for splitting here + */ + if (pmd_trans_splitting(pte_pmd(pte))) + return 0; +#endif + + /* hugepages are never "special" */ + VM_BUG_ON(!pfn_valid(pte_pfn(pte))); + + refs = 0; + head = pte_page(pte); + + page = head + ((addr & (sz-1)) >> PAGE_SHIFT); + tail = page; + do { + VM_BUG_ON(compound_head(page) != head); + pages[*nr] = page; + (*nr)++; + page++; + refs++; + } while (addr += PAGE_SIZE, addr != end); + + if (!page_cache_add_speculative(head, refs)) { + *nr -= refs; + return 0; + } + + if (unlikely(pte_val(pte) != pte_val(*ptep))) { + /* Could be optimized better */ + *nr -= refs; + while (refs--) + put_page(head); + return 0; + } + + /* + * Any tail page need their mapcount reference taken before we + * return. + */ + while (refs--) { + if (PageTail(tail)) + get_huge_page_tail(tail); + tail++; + } + + return 1; +} |