arm64: mm: detect bad __create_mapping uses

[deliverable/linux.git] / arch / arm64 / mm / mmu.c

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index abb66f84d4ac896c0978b3c2584470d5db15a8ba..6e4b4351ce9e69919d3b653c72eb8b0b87501a01 100644 (file)
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -64,8 +64,12 @@ EXPORT_SYMBOL(phys_mem_access_prot);
 
 static void __init *early_alloc(unsigned long sz)
 {
-       void *ptr = __va(memblock_alloc(sz, sz));
-       BUG_ON(!ptr);
+       phys_addr_t phys;
+       void *ptr;
+
+       phys = memblock_alloc(sz, sz);
+       BUG_ON(!phys);
+       ptr = __va(phys);
        memset(ptr, 0, sz);
        return ptr;
 }
@@ -81,55 +85,19 @@ static void split_pmd(pmd_t *pmd, pte_t *pte)
        do {
                /*
                 * Need to have the least restrictive permissions available
-                * permissions will be fixed up later. Default the new page
-                * range as contiguous ptes.
+                * permissions will be fixed up later
                 */
-               set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC_CONT));
+               set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
                pfn++;
        } while (pte++, i++, i < PTRS_PER_PTE);
 }
 
-/*
- * Given a PTE with the CONT bit set, determine where the CONT range
- * starts, and clear the entire range of PTE CONT bits.
- */
-static void clear_cont_pte_range(pte_t *pte, unsigned long addr)
-{
-       int i;
-
-       pte -= CONT_RANGE_OFFSET(addr);
-       for (i = 0; i < CONT_PTES; i++) {
-               set_pte(pte, pte_mknoncont(*pte));
-               pte++;
-       }
-       flush_tlb_all();
-}
-
-/*
- * Given a range of PTEs set the pfn and provided page protection flags
- */
-static void __populate_init_pte(pte_t *pte, unsigned long addr,
-                               unsigned long end, phys_addr_t phys,
-                               pgprot_t prot)
-{
-       unsigned long pfn = __phys_to_pfn(phys);
-
-       do {
-               /* clear all the bits except the pfn, then apply the prot */
-               set_pte(pte, pfn_pte(pfn, prot));
-               pte++;
-               pfn++;
-               addr += PAGE_SIZE;
-       } while (addr != end);
-}
-
 static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
-                                 unsigned long end, phys_addr_t phys,
+                                 unsigned long end, unsigned long pfn,
                                  pgprot_t prot,
                                  void *(*alloc)(unsigned long size))
 {
        pte_t *pte;
-       unsigned long next;
 
        if (pmd_none(*pmd) || pmd_sect(*pmd)) {
                pte = alloc(PTRS_PER_PTE * sizeof(pte_t));
@@ -142,27 +110,9 @@ static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
 
        pte = pte_offset_kernel(pmd, addr);
        do {
-               next = min(end, (addr + CONT_SIZE) & CONT_MASK);
-               if (((addr | next | phys) & ~CONT_MASK) == 0) {
-                       /* a block of CONT_PTES  */
-                       __populate_init_pte(pte, addr, next, phys,
-                                           __pgprot(pgprot_val(prot) | PTE_CONT));
-               } else {
-                       /*
-                        * If the range being split is already inside of a
-                        * contiguous range but this PTE isn't going to be
-                        * contiguous, then we want to unmark the adjacent
-                        * ranges, then update the portion of the range we
-                        * are interrested in.
-                        */
-                        clear_cont_pte_range(pte, addr);
-                        __populate_init_pte(pte, addr, next, phys, prot);
-               }
-
-               pte += (next - addr) >> PAGE_SHIFT;
-               phys += next - addr;
-               addr = next;
-       } while (addr != end);
+               set_pte(pte, pfn_pte(pfn, prot));
+               pfn++;
+       } while (pte++, addr += PAGE_SIZE, addr != end);
 }
 
 static void split_pud(pud_t *old_pud, pmd_t *pmd)
@@ -223,7 +173,8 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
                                }
                        }
                } else {
-                       alloc_init_pte(pmd, addr, next, phys, prot, alloc);
+                       alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
+                                      prot, alloc);
                }
                phys += next - addr;
        } while (pmd++, addr = next, addr != end);
@@ -300,6 +251,13 @@ static void  __create_mapping(struct mm_struct *mm, pgd_t *pgd,
 {
        unsigned long addr, length, end, next;
 
+       /*
+        * If the virtual and physical address don't have the same offset
+        * within a page, we cannot map the region as the caller expects.
+        */
+       if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
+               return;
+
        addr = virt & PAGE_MASK;
        length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));