From d1874a0c2805fcfa9162c972d6b7541e57adb542 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 23 Apr 2019 10:51:12 +0200 Subject: s390/mm: make the pxd_offset functions more robust Change the way how pgd_offset, p4d_offset, pud_offset and pmd_offset walk the page tables. pgd_offset now always calculates the index for the top-level page table and adds it to the pgd, this is either a segment table offset for a 2-level setup, a region-3 offset for 3-levels, region-2 offset for 4-levels, or a region-1 offset for a 5-level setup. The other three functions p4d_offset, pud_offset and pmd_offset will only add the respective offset if they dereference the passed pointer. With the new way of walking the page tables a sequence like this from mm/gup.c now works: pgdp = pgd_offset(current->mm, addr); pgd = READ_ONCE(*pgdp); p4dp = p4d_offset(&pgd, addr); p4d = READ_ONCE(*p4dp); pudp = pud_offset(&p4d, addr); pud = READ_ONCE(*pudp); pmdp = pmd_offset(&pud, addr); pmd = READ_ONCE(*pmdp); Signed-off-by: Martin Schwidefsky --- arch/s390/mm/gup.c | 33 ++++++++++++--------------------- 1 file changed, 12 insertions(+), 21 deletions(-) (limited to 'arch/s390/mm') diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c index 2809d11c7a28..a5ffcb132191 100644 --- a/arch/s390/mm/gup.c +++ b/arch/s390/mm/gup.c @@ -18,7 +18,7 @@ * inlines everything into a single function which results in too much * register pressure. */ -static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr, +static inline int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { struct page *head, *page; @@ -27,7 +27,7 @@ static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr, mask = (write ? _PAGE_PROTECT : 0) | _PAGE_INVALID | _PAGE_SPECIAL; - ptep = ((pte_t *) pmd_deref(pmd)) + pte_index(addr); + ptep = pte_offset_map(&pmd, addr); do { pte = *ptep; barrier(); @@ -93,16 +93,13 @@ static inline int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr, } -static inline int gup_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr, +static inline int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { unsigned long next; pmd_t *pmdp, pmd; - pmdp = (pmd_t *) pudp; - if ((pud_val(pud) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) - pmdp = (pmd_t *) pud_deref(pud); - pmdp += pmd_index(addr); + pmdp = pmd_offset(&pud, addr); do { pmd = *pmdp; barrier(); @@ -120,7 +117,7 @@ static inline int gup_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr, if (!gup_huge_pmd(pmdp, pmd, addr, next, write, pages, nr)) return 0; - } else if (!gup_pte_range(pmdp, pmd, addr, next, + } else if (!gup_pte_range(pmd, addr, next, write, pages, nr)) return 0; } while (pmdp++, addr = next, addr != end); @@ -166,16 +163,13 @@ static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr, return 1; } -static inline int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, +static inline int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { unsigned long next; pud_t *pudp, pud; - pudp = (pud_t *) p4dp; - if ((p4d_val(p4d) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2) - pudp = (pud_t *) p4d_deref(p4d); - pudp += pud_index(addr); + pudp = pud_offset(&p4d, addr); do { pud = *pudp; barrier(); @@ -186,7 +180,7 @@ static inline int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, if (!gup_huge_pud(pudp, pud, addr, next, write, pages, nr)) return 0; - } else if (!gup_pmd_range(pudp, pud, addr, next, write, pages, + } else if (!gup_pmd_range(pud, addr, next, write, pages, nr)) return 0; } while (pudp++, addr = next, addr != end); @@ -194,23 +188,20 @@ static inline int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, return 1; } -static inline int gup_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, +static inline int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { unsigned long next; p4d_t *p4dp, p4d; - p4dp = (p4d_t *) pgdp; - if ((pgd_val(pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R1) - p4dp = (p4d_t *) pgd_deref(pgd); - p4dp += p4d_index(addr); + p4dp = p4d_offset(&pgd, addr); do { p4d = *p4dp; barrier(); next = p4d_addr_end(addr, end); if (p4d_none(p4d)) return 0; - if (!gup_pud_range(p4dp, p4d, addr, next, write, pages, nr)) + if (!gup_pud_range(p4d, addr, next, write, pages, nr)) return 0; } while (p4dp++, addr = next, addr != end); @@ -253,7 +244,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, next = pgd_addr_end(addr, end); if (pgd_none(pgd)) break; - if (!gup_p4d_range(pgdp, pgd, addr, next, write, pages, &nr)) + if (!gup_p4d_range(pgd, addr, next, write, pages, &nr)) break; } while (pgdp++, addr = next, addr != end); local_irq_restore(flags); -- cgit v1.2.3