#include <linux/migrate.h>
#include <linux/string.h>
#include <linux/dma-debug.h>
+#include <linux/debugfs.h>
#include <asm/io.h>
#include <asm/pgalloc.h>
* It is undesirable to test vma->vm_file as it
* should be non-null for valid hugetlb area.
* However, vm_file will be NULL in the error
- * cleanup path of do_mmap_pgoff. When
+ * cleanup path of mmap_region. When
* hugetlbfs ->mmap method fails,
- * do_mmap_pgoff() nullifies vma->vm_file
+ * mmap_region() nullifies vma->vm_file
* before calling this function to clean up.
* Since no pte has actually been setup, it is
* safe to do nothing in this case.
VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
- /*
- * Require read or write permissions.
- * If FOLL_FORCE is set, we only require the "MAY" flags.
- */
- vm_flags = (gup_flags & FOLL_WRITE) ?
- (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
- vm_flags &= (gup_flags & FOLL_FORCE) ?
- (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
-
/*
* If FOLL_FORCE and FOLL_NUMA are both set, handle_mm_fault
* would be called on PROT_NONE ranges. We must never invoke
/* user gate pages are read-only */
if (gup_flags & FOLL_WRITE)
- return i ? : -EFAULT;
+ goto efault;
if (pg > TASK_SIZE)
pgd = pgd_offset_k(pg);
else
BUG_ON(pud_none(*pud));
pmd = pmd_offset(pud, pg);
if (pmd_none(*pmd))
- return i ? : -EFAULT;
+ goto efault;
VM_BUG_ON(pmd_trans_huge(*pmd));
pte = pte_offset_map(pmd, pg);
if (pte_none(*pte)) {
pte_unmap(pte);
- return i ? : -EFAULT;
+ goto efault;
}
vma = get_gate_vma(mm);
if (pages) {
page = pte_page(*pte);
else {
pte_unmap(pte);
- return i ? : -EFAULT;
+ goto efault;
}
}
pages[i] = page;
goto next_page;
}
- if (!vma ||
- (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
- !(vm_flags & vma->vm_flags))
- return i ? : -EFAULT;
+ if (!vma)
+ goto efault;
+ vm_flags = vma->vm_flags;
+ if (vm_flags & (VM_IO | VM_PFNMAP))
+ goto efault;
+
+ if (gup_flags & FOLL_WRITE) {
+ if (!(vm_flags & VM_WRITE)) {
+ if (!(gup_flags & FOLL_FORCE))
+ goto efault;
+ /*
+ * We used to let the write,force case do COW
+ * in a VM_MAYWRITE VM_SHARED !VM_WRITE vma, so
+ * ptrace could set a breakpoint in a read-only
+ * mapping of an executable, without corrupting
+ * the file (yet only when that file had been
+ * opened for writing!). Anon pages in shared
+ * mappings are surprising: now just reject it.
+ */
+ if (!is_cow_mapping(vm_flags)) {
+ WARN_ON_ONCE(vm_flags & VM_MAYWRITE);
+ goto efault;
+ }
+ }
+ } else {
+ if (!(vm_flags & VM_READ)) {
+ if (!(gup_flags & FOLL_FORCE))
+ goto efault;
+ /*
+ * Is there actually any vma we can reach here
+ * which does not have VM_MAYREAD set?
+ */
+ if (!(vm_flags & VM_MAYREAD))
+ goto efault;
+ }
+ }
if (is_vm_hugetlb_page(vma)) {
i = follow_hugetlb_page(mm, vma, pages, vmas,
return -EFAULT;
}
if (ret & VM_FAULT_SIGBUS)
- return i ? i : -EFAULT;
+ goto efault;
BUG();
}
} while (nr_pages && start < vma->vm_end);
} while (nr_pages);
return i;
+efault:
+ return i ? : -EFAULT;
}
EXPORT_SYMBOL(__get_user_pages);
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @write: whether pages will be written to by the caller
- * @force: whether to force write access even if user mapping is
- * readonly. This will result in the page being COWed even
- * in MAP_SHARED mappings. You do not want this.
+ * @force: whether to force access even when user mapping is currently
+ * protected (but never forces write access to shared mapping).
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long. Or NULL, if caller
* only intends to ensure the pages are faulted in.
*/
if (!page_mkwrite) {
wait_on_page_locked(dirty_page);
- set_page_dirty_balance(dirty_page, page_mkwrite);
+ set_page_dirty_balance(dirty_page);
/* file_update_time outside page_lock */
if (vma->vm_file)
file_update_time(vma->vm_file);
}
__SetPageUptodate(new_page);
- if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
+ if (mem_cgroup_charge_anon(new_page, mm, GFP_KERNEL))
goto oom_free_new;
mmun_start = address & PAGE_MASK;
*/
__SetPageUptodate(page);
- if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
+ if (mem_cgroup_charge_anon(page, mm, GFP_KERNEL))
goto oom_free_page;
entry = mk_pte(page, vma->vm_page_prot);
return ret;
}
-static void do_set_pte(struct vm_area_struct *vma, unsigned long address,
+/**
+ * do_set_pte - setup new PTE entry for given page and add reverse page mapping.
+ *
+ * @vma: virtual memory area
+ * @address: user virtual address
+ * @page: page to map
+ * @pte: pointer to target page table entry
+ * @write: true, if new entry is writable
+ * @anon: true, if it's anonymous page
+ *
+ * Caller must hold page table lock relevant for @pte.
+ *
+ * Target users are page handler itself and implementations of
+ * vm_ops->map_pages.
+ */
+void do_set_pte(struct vm_area_struct *vma, unsigned long address,
struct page *page, pte_t *pte, bool write, bool anon)
{
pte_t entry;
update_mmu_cache(vma, address, pte);
}
+#define FAULT_AROUND_ORDER 4
+
+#ifdef CONFIG_DEBUG_FS
+static unsigned int fault_around_order = FAULT_AROUND_ORDER;
+
+static int fault_around_order_get(void *data, u64 *val)
+{
+ *val = fault_around_order;
+ return 0;
+}
+
+static int fault_around_order_set(void *data, u64 val)
+{
+ BUILD_BUG_ON((1UL << FAULT_AROUND_ORDER) > PTRS_PER_PTE);
+ if (1UL << val > PTRS_PER_PTE)
+ return -EINVAL;
+ fault_around_order = val;
+ return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fault_around_order_fops,
+ fault_around_order_get, fault_around_order_set, "%llu\n");
+
+static int __init fault_around_debugfs(void)
+{
+ void *ret;
+
+ ret = debugfs_create_file("fault_around_order", 0644, NULL, NULL,
+ &fault_around_order_fops);
+ if (!ret)
+ pr_warn("Failed to create fault_around_order in debugfs");
+ return 0;
+}
+late_initcall(fault_around_debugfs);
+
+static inline unsigned long fault_around_pages(void)
+{
+ return 1UL << fault_around_order;
+}
+
+static inline unsigned long fault_around_mask(void)
+{
+ return ~((1UL << (PAGE_SHIFT + fault_around_order)) - 1);
+}
+#else
+static inline unsigned long fault_around_pages(void)
+{
+ unsigned long nr_pages;
+
+ nr_pages = 1UL << FAULT_AROUND_ORDER;
+ BUILD_BUG_ON(nr_pages > PTRS_PER_PTE);
+ return nr_pages;
+}
+
+static inline unsigned long fault_around_mask(void)
+{
+ return ~((1UL << (PAGE_SHIFT + FAULT_AROUND_ORDER)) - 1);
+}
+#endif
+
+static void do_fault_around(struct vm_area_struct *vma, unsigned long address,
+ pte_t *pte, pgoff_t pgoff, unsigned int flags)
+{
+ unsigned long start_addr;
+ pgoff_t max_pgoff;
+ struct vm_fault vmf;
+ int off;
+
+ start_addr = max(address & fault_around_mask(), vma->vm_start);
+ off = ((address - start_addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
+ pte -= off;
+ pgoff -= off;
+
+ /*
+ * max_pgoff is either end of page table or end of vma
+ * or fault_around_pages() from pgoff, depending what is neast.
+ */
+ max_pgoff = pgoff - ((start_addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) +
+ PTRS_PER_PTE - 1;
+ max_pgoff = min3(max_pgoff, vma_pages(vma) + vma->vm_pgoff - 1,
+ pgoff + fault_around_pages() - 1);
+
+ /* Check if it makes any sense to call ->map_pages */
+ while (!pte_none(*pte)) {
+ if (++pgoff > max_pgoff)
+ return;
+ start_addr += PAGE_SIZE;
+ if (start_addr >= vma->vm_end)
+ return;
+ pte++;
+ }
+
+ vmf.virtual_address = (void __user *) start_addr;
+ vmf.pte = pte;
+ vmf.pgoff = pgoff;
+ vmf.max_pgoff = max_pgoff;
+ vmf.flags = flags;
+ vma->vm_ops->map_pages(vma, &vmf);
+}
+
static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pmd_t *pmd,
pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
struct page *fault_page;
spinlock_t *ptl;
pte_t *pte;
- int ret;
+ int ret = 0;
+
+ /*
+ * Let's call ->map_pages() first and use ->fault() as fallback
+ * if page by the offset is not ready to be mapped (cold cache or
+ * something).
+ */
+ if (vma->vm_ops->map_pages) {
+ pte = pte_offset_map_lock(mm, pmd, address, &ptl);
+ do_fault_around(vma, address, pte, pgoff, flags);
+ if (!pte_same(*pte, orig_pte))
+ goto unlock_out;
+ pte_unmap_unlock(pte, ptl);
+ }
ret = __do_fault(vma, address, pgoff, flags, &fault_page);
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
return ret;
}
do_set_pte(vma, address, fault_page, pte, false, false);
- pte_unmap_unlock(pte, ptl);
unlock_page(fault_page);
+unlock_out:
+ pte_unmap_unlock(pte, ptl);
return ret;
}
if (!new_page)
return VM_FAULT_OOM;
- if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL)) {
+ if (mem_cgroup_charge_anon(new_page, mm, GFP_KERNEL)) {
page_cache_release(new_page);
return VM_FAULT_OOM;
}
projects / deliverable / linux.git / blobdiff