From: Christoph Hellwig <hch@xxxxxx> Subject: sparc64: use the generic get_user_pages_fast code The sparc64 code is mostly equivalent to the generic one, minus various bugfixes and two arch overrides that this patch adds to pgtable.h. Link: http://lkml.kernel.org/r/20190625143715.1689-10-hch@xxxxxx Signed-off-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx> Cc: David Miller <davem@xxxxxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: James Hogan <jhogan@xxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Nicholas Piggin <npiggin@xxxxxxxxx> Cc: Paul Burton <paul.burton@xxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Rich Felker <dalias@xxxxxxxx> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/sparc/Kconfig | 1 arch/sparc/include/asm/pgtable_64.h | 18 + arch/sparc/mm/Makefile | 2 arch/sparc/mm/gup.c | 340 -------------------------- 4 files changed, 20 insertions(+), 341 deletions(-) --- a/arch/sparc/include/asm/pgtable_64.h~sparc64-use-the-generic-get_user_pages_fast-code +++ a/arch/sparc/include/asm/pgtable_64.h @@ -1100,6 +1100,24 @@ static inline unsigned long untagged_add } #define untagged_addr untagged_addr +static inline bool pte_access_permitted(pte_t pte, bool write) +{ + u64 prot; + + if (tlb_type == hypervisor) { + prot = _PAGE_PRESENT_4V | _PAGE_P_4V; + if (write) + prot |= _PAGE_WRITE_4V; + } else { + prot = _PAGE_PRESENT_4U | _PAGE_P_4U; + if (write) + prot |= _PAGE_WRITE_4U; + } + + return (pte_val(pte) & (prot | _PAGE_SPECIAL)) == prot; +} +#define pte_access_permitted pte_access_permitted + #include <asm/tlbflush.h> #include <asm-generic/pgtable.h> --- a/arch/sparc/Kconfig~sparc64-use-the-generic-get_user_pages_fast-code +++ a/arch/sparc/Kconfig @@ -28,6 +28,7 @@ config SPARC select RTC_DRV_M48T59 select RTC_SYSTOHC select HAVE_ARCH_JUMP_LABEL if SPARC64 + select HAVE_GENERIC_GUP if SPARC64 select GENERIC_IRQ_SHOW select ARCH_WANT_IPC_PARSE_VERSION select GENERIC_PCI_IOMAP --- a/arch/sparc/mm/gup.c +++ /dev/null @@ -1,340 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Lockless get_user_pages_fast for sparc, cribbed from powerpc - * - * Copyright (C) 2008 Nick Piggin - * Copyright (C) 2008 Novell Inc. - */ - -#include <linux/sched.h> -#include <linux/mm.h> -#include <linux/vmstat.h> -#include <linux/pagemap.h> -#include <linux/rwsem.h> -#include <asm/pgtable.h> -#include <asm/adi.h> - -/* - * The performance critical leaf functions are made noinline otherwise gcc - * inlines everything into a single function which results in too much - * register pressure. - */ -static noinline int gup_pte_range(pmd_t pmd, unsigned long addr, - unsigned long end, int write, struct page **pages, int *nr) -{ - unsigned long mask, result; - pte_t *ptep; - - if (tlb_type == hypervisor) { - result = _PAGE_PRESENT_4V|_PAGE_P_4V; - if (write) - result |= _PAGE_WRITE_4V; - } else { - result = _PAGE_PRESENT_4U|_PAGE_P_4U; - if (write) - result |= _PAGE_WRITE_4U; - } - mask = result | _PAGE_SPECIAL; - - ptep = pte_offset_kernel(&pmd, addr); - do { - struct page *page, *head; - pte_t pte = *ptep; - - if ((pte_val(pte) & mask) != result) - return 0; - VM_BUG_ON(!pfn_valid(pte_pfn(pte))); - - /* The hugepage case is simplified on sparc64 because - * we encode the sub-page pfn offsets into the - * hugepage PTEs. We could optimize this in the future - * use page_cache_add_speculative() for the hugepage case. - */ - page = pte_page(pte); - head = compound_head(page); - if (!page_cache_get_speculative(head)) - return 0; - if (unlikely(pte_val(pte) != pte_val(*ptep))) { - put_page(head); - return 0; - } - - pages[*nr] = page; - (*nr)++; - } while (ptep++, addr += PAGE_SIZE, addr != end); - - return 1; -} - -static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr, - unsigned long end, int write, struct page **pages, - int *nr) -{ - struct page *head, *page; - int refs; - - if (!(pmd_val(pmd) & _PAGE_VALID)) - return 0; - - if (write && !pmd_write(pmd)) - return 0; - - refs = 0; - page = pmd_page(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); - head = compound_head(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(pmd_val(pmd) != pmd_val(*pmdp))) { - *nr -= refs; - while (refs--) - put_page(head); - return 0; - } - - return 1; -} - -static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr, - unsigned long end, int write, struct page **pages, - int *nr) -{ - struct page *head, *page; - int refs; - - if (!(pud_val(pud) & _PAGE_VALID)) - return 0; - - if (write && !pud_write(pud)) - return 0; - - refs = 0; - page = pud_page(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); - head = compound_head(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(pud_val(pud) != pud_val(*pudp))) { - *nr -= refs; - while (refs--) - put_page(head); - return 0; - } - - return 1; -} - -static 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; - - pmdp = pmd_offset(&pud, addr); - do { - pmd_t pmd = *pmdp; - - next = pmd_addr_end(addr, end); - if (pmd_none(pmd)) - return 0; - if (unlikely(pmd_large(pmd))) { - if (!gup_huge_pmd(pmdp, pmd, addr, next, - write, pages, nr)) - return 0; - } else if (!gup_pte_range(pmd, addr, next, write, - pages, nr)) - return 0; - } while (pmdp++, addr = next, addr != end); - - return 1; -} - -static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) -{ - unsigned long next; - pud_t *pudp; - - pudp = pud_offset(&pgd, addr); - do { - pud_t pud = *pudp; - - next = pud_addr_end(addr, end); - if (pud_none(pud)) - return 0; - if (unlikely(pud_large(pud))) { - if (!gup_huge_pud(pudp, pud, addr, next, - write, pages, nr)) - return 0; - } else if (!gup_pmd_range(pud, addr, next, write, pages, nr)) - return 0; - } while (pudp++, addr = next, addr != end); - - return 1; -} - -/* - * Note a difference with get_user_pages_fast: this always returns the - * number of pages pinned, 0 if no pages were pinned. - */ -int __get_user_pages_fast(unsigned long start, int nr_pages, int write, - struct page **pages) -{ - struct mm_struct *mm = current->mm; - unsigned long addr, len, end; - unsigned long next, flags; - pgd_t *pgdp; - int nr = 0; - -#ifdef CONFIG_SPARC64 - if (adi_capable()) { - long addr = start; - - /* If userspace has passed a versioned address, kernel - * will not find it in the VMAs since it does not store - * the version tags in the list of VMAs. Storing version - * tags in list of VMAs is impractical since they can be - * changed any time from userspace without dropping into - * kernel. Any address search in VMAs will be done with - * non-versioned addresses. Ensure the ADI version bits - * are dropped here by sign extending the last bit before - * ADI bits. IOMMU does not implement version tags. - */ - addr = (addr << (long)adi_nbits()) >> (long)adi_nbits(); - start = addr; - } -#endif - start &= PAGE_MASK; - addr = start; - len = (unsigned long) nr_pages << PAGE_SHIFT; - end = start + len; - - local_irq_save(flags); - pgdp = pgd_offset(mm, addr); - do { - pgd_t pgd = *pgdp; - - next = pgd_addr_end(addr, end); - if (pgd_none(pgd)) - break; - if (!gup_pud_range(pgd, addr, next, write, pages, &nr)) - break; - } while (pgdp++, addr = next, addr != end); - local_irq_restore(flags); - - return nr; -} - -int get_user_pages_fast(unsigned long start, int nr_pages, - unsigned int gup_flags, struct page **pages) -{ - struct mm_struct *mm = current->mm; - unsigned long addr, len, end; - unsigned long next; - pgd_t *pgdp; - int nr = 0; - -#ifdef CONFIG_SPARC64 - if (adi_capable()) { - long addr = start; - - /* If userspace has passed a versioned address, kernel - * will not find it in the VMAs since it does not store - * the version tags in the list of VMAs. Storing version - * tags in list of VMAs is impractical since they can be - * changed any time from userspace without dropping into - * kernel. Any address search in VMAs will be done with - * non-versioned addresses. Ensure the ADI version bits - * are dropped here by sign extending the last bit before - * ADI bits. IOMMU does not implements version tags, - */ - addr = (addr << (long)adi_nbits()) >> (long)adi_nbits(); - start = addr; - } -#endif - start &= PAGE_MASK; - addr = start; - len = (unsigned long) nr_pages << PAGE_SHIFT; - end = start + len; - - /* - * XXX: batch / limit 'nr', to avoid large irq off latency - * needs some instrumenting to determine the common sizes used by - * important workloads (eg. DB2), and whether limiting the batch size - * will decrease performance. - * - * It seems like we're in the clear for the moment. Direct-IO is - * the main guy that batches up lots of get_user_pages, and even - * they are limited to 64-at-a-time which is not so many. - */ - /* - * This doesn't prevent pagetable teardown, but does prevent - * the pagetables from being freed on sparc. - * - * So long as we atomically load page table pointers versus teardown, - * we can follow the address down to the the page and take a ref on it. - */ - local_irq_disable(); - - pgdp = pgd_offset(mm, addr); - do { - pgd_t pgd = *pgdp; - - next = pgd_addr_end(addr, end); - if (pgd_none(pgd)) - goto slow; - if (!gup_pud_range(pgd, addr, next, gup_flags & FOLL_WRITE, - pages, &nr)) - goto slow; - } while (pgdp++, addr = next, addr != end); - - local_irq_enable(); - - VM_BUG_ON(nr != (end - start) >> PAGE_SHIFT); - return nr; - - { - int ret; - -slow: - local_irq_enable(); - - /* Try to get the remaining pages with get_user_pages */ - start += nr << PAGE_SHIFT; - pages += nr; - - ret = get_user_pages_unlocked(start, - (end - start) >> PAGE_SHIFT, pages, - gup_flags); - - /* Have to be a bit careful with return values */ - if (nr > 0) { - if (ret < 0) - ret = nr; - else - ret += nr; - } - - return ret; - } -} --- a/arch/sparc/mm/Makefile~sparc64-use-the-generic-get_user_pages_fast-code +++ a/arch/sparc/mm/Makefile @@ -5,7 +5,7 @@ asflags-y := -ansi ccflags-y := -Werror -obj-$(CONFIG_SPARC64) += ultra.o tlb.o tsb.o gup.o +obj-$(CONFIG_SPARC64) += ultra.o tlb.o tsb.o obj-y += fault_$(BITS).o obj-y += init_$(BITS).o obj-$(CONFIG_SPARC32) += extable.o srmmu.o iommu.o io-unit.o _
