diff options
| -rw-r--r-- | include/linux/mm.h | 1 | ||||
| -rw-r--r-- | mm/memory.c | 92 |
2 files changed, 93 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 6a75a7a78bf1..74f90d7eb5ef 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -163,6 +163,7 @@ extern unsigned int kobjsize(const void *objp); #define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */ #define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */ #define VM_MAPPED_COPY 0x01000000 /* T if mapped copy of data (nommu mmap) */ +#define VM_INCOMPLETE 0x02000000 /* Strange partial PFN mapping marker */ #ifndef VM_STACK_DEFAULT_FLAGS /* arch can override this */ #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS diff --git a/mm/memory.c b/mm/memory.c index 74839b3a3999..990e7dc666f8 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1147,6 +1147,95 @@ int zeromap_page_range(struct vm_area_struct *vma, } /* + * This is the old fallback for page remapping. + * + * For historical reasons, it only allows reserved pages. Only + * old drivers should use this, and they needed to mark their + * pages reserved for the old functions anyway. + */ +static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot) +{ + int retval; + pgd_t * pgd; + pud_t * pud; + pmd_t * pmd; + pte_t * pte; + spinlock_t *ptl; + + retval = -EINVAL; + if (PageAnon(page) || !PageReserved(page)) + goto out; + retval = -ENOMEM; + flush_dcache_page(page); + pgd = pgd_offset(mm, addr); + pud = pud_alloc(mm, pgd, addr); + if (!pud) + goto out; + pmd = pmd_alloc(mm, pud, addr); + if (!pmd) + goto out; + pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); + if (!pte) + goto out; + retval = -EBUSY; + if (!pte_none(*pte)) + goto out_unlock; + + /* Ok, finally just insert the thing.. */ + get_page(page); + inc_mm_counter(mm, file_rss); + page_add_file_rmap(page); + set_pte_at(mm, addr, pte, mk_pte(page, prot)); + + retval = 0; +out_unlock: + pte_unmap_unlock(pte, ptl); +out: + return retval; +} + +/* + * Somebody does a pfn remapping that doesn't actually work as a vma. + * + * Do it as individual pages instead, and warn about it. It's bad form, + * and very inefficient. + */ +static int incomplete_pfn_remap(struct vm_area_struct *vma, + unsigned long start, unsigned long end, + unsigned long pfn, pgprot_t prot) +{ + static int warn = 10; + struct page *page; + int retval; + + if (!(vma->vm_flags & VM_INCOMPLETE)) { + if (warn) { + warn--; + printk("%s does an incomplete pfn remapping", current->comm); + dump_stack(); + } + } + vma->vm_flags |= VM_INCOMPLETE | VM_IO | VM_RESERVED; + + if (start < vma->vm_start || end > vma->vm_end) + return -EINVAL; + + if (!pfn_valid(pfn)) + return -EINVAL; + + retval = 0; + page = pfn_to_page(pfn); + while (start < end) { + retval = insert_page(vma->vm_mm, start, page, prot); + if (retval < 0) + break; + start += PAGE_SIZE; + page++; + } + return retval; +} + +/* * maps a range of physical memory into the requested pages. the old * mappings are removed. any references to nonexistent pages results * in null mappings (currently treated as "copy-on-access") @@ -1220,6 +1309,9 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, struct mm_struct *mm = vma->vm_mm; int err; + if (addr != vma->vm_start || end != vma->vm_end) + return incomplete_pfn_remap(vma, addr, end, pfn, prot); + /* * Physically remapped pages are special. Tell the * rest of the world about it: |