WebSVN – HelenOS – Diff – /trunk/kernel/generic/src/mm/backend_elf.c

 int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)
+{
     elf_header_t *elf = area->backend_data.elf;
     elf_segment_header_t *entry = area->backend_data.segment;
     btree_node_t *leaf;
-    uintptr_t base, frame;
+    uintptr_t base, frame, page, start_anon;
     index_t i;
     bool dirty = false;
     if (!as_area_check_access(area, access))
         return AS_PF_FAULT;
-    ASSERT((addr >= entry->p_vaddr) &&
+    ASSERT((addr >= ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE)) &&
         (addr < entry->p_vaddr + entry->p_memsz));
-    i = (addr - entry->p_vaddr) >> PAGE_WIDTH;
+    i = (addr - ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE)) >> PAGE_WIDTH;
+    base = (uintptr_t)
-    base = (uintptr_t) (((void *) elf) + entry->p_offset);
+        (((void *) elf) + ALIGN_DOWN(entry->p_offset, PAGE_SIZE));
+    /* Virtual address of faulting page*/
-    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
+    page = ALIGN_DOWN(addr, PAGE_SIZE);
+    /* Virtual address of the end of initialized part of segment */
+    start_anon = entry->p_vaddr + entry->p_filesz;
     if (area->sh_info) {
         bool found = false;
         /*
          * The address space area is shared.
          */
         mutex_lock(&area->sh_info->lock);
         frame = (uintptr_t) btree_search(&area->sh_info->pagemap,
-            ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
+            page - area->base, &leaf);
         if (!frame) {
             unsigned int i;
             /*
              * Workaround for valid NULL address.
              */
             for (i = 0; i < leaf->keys; i++) {
-                if (leaf->key[i] ==
+                if (leaf->key[i] == page) {
-                    ALIGN_DOWN(addr, PAGE_SIZE)) {
                     found = true;
                     break;
+                }
+            }
+        }
         if (frame || found) {
             frame_reference_add(ADDR2PFN(frame));
             page_mapping_insert(AS, addr, frame,
                 as_area_get_flags(area));
-            if (!used_space_insert(area,
+            if (!used_space_insert(area, page, 1))
-                ALIGN_DOWN(addr, PAGE_SIZE), 1))
                 panic("Could not insert used space.\n");
             mutex_unlock(&area->sh_info->lock);
             return AS_PF_OK;
+        }
+    }
     /*
      * The area is either not shared or the pagemap does not contain the
      * mapping.
      */
-    if (ALIGN_DOWN(addr, PAGE_SIZE) + PAGE_SIZE <
-        entry->p_vaddr + entry->p_filesz) {
+    if (page >= entry->p_vaddr && page + PAGE_SIZE <= start_anon) {
         /*
          * Initialized portion of the segment. The memory is backed
          * directly by the content of the ELF image. Pages are
          * only copied if the segment is writable so that there
          * can be more instantions of the same memory ELF image
         if (entry->p_flags & PF_W) {
             frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
             memcpy((void *) PA2KA(frame),
                 (void *) (base + i * FRAME_SIZE), FRAME_SIZE);
             dirty = true;
-            if (area->sh_info) {
-                frame_reference_add(ADDR2PFN(frame));
-                btree_insert(&area->sh_info->pagemap,
-                    ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
-                    (void *) frame, leaf);
-            }
         } else {
-            frame = KA2PA(base + i*FRAME_SIZE);
+            frame = KA2PA(base + i * FRAME_SIZE);
+        }
-    } else if (ALIGN_DOWN(addr, PAGE_SIZE) >=
+    } else if (page >= start_anon) {
-        ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
         /*
          * This is the uninitialized portion of the segment.
          * It is not physically present in the ELF image.
          * To resolve the situation, a frame must be allocated
          * and cleared.
          */
         frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
         memsetb(PA2KA(frame), FRAME_SIZE, 0);
         dirty = true;
-        if (area->sh_info) {
-            frame_reference_add(ADDR2PFN(frame));
-            btree_insert(&area->sh_info->pagemap,
-                ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
-                (void *) frame, leaf);
-        }
     } else {
-        size_t size;
+        size_t pad_lo, pad_hi;
         /*
          * The mixed case.
+         *
-         * The lower part is backed by the ELF image and
+         * The middle part is backed by the ELF image and
-         * the upper part is anonymous memory.
+         * the lower and upper parts are anonymous memory.
+         * (The segment can be and often is shorter than 1 page).
          */
+        if (page < entry->p_vaddr)
-        size = entry->p_filesz - (i<<PAGE_WIDTH);
+            pad_lo = entry->p_vaddr - page;
+        else
+            pad_lo = 0;
+        if (start_anon < page + PAGE_SIZE)
+            pad_hi = page + PAGE_SIZE - start_anon;
+        else
+            pad_hi = 0;
         frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
-        memsetb(PA2KA(frame) + size, FRAME_SIZE - size, 0);
+        memcpy((void *) (PA2KA(frame) + pad_lo),
-        memcpy((void *) PA2KA(frame), (void *) (base + i * FRAME_SIZE),
+            (void *) (base + i * FRAME_SIZE + pad_lo),
-            size);
+            FRAME_SIZE - pad_lo - pad_hi);
+        memsetb(PA2KA(frame), pad_lo, 0);
+        memsetb(PA2KA(frame) + FRAME_SIZE - pad_hi, pad_hi, 0);
         dirty = true;
+    }
-        if (area->sh_info) {
+    if (dirty && area->sh_info) {
-            frame_reference_add(ADDR2PFN(frame));
+        frame_reference_add(ADDR2PFN(frame));
-            btree_insert(&area->sh_info->pagemap,
+        btree_insert(&area->sh_info->pagemap, page - area->base,
-                ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
-                (void *) frame, leaf);
+            (void *) frame, leaf);
-        }
+    }
     if (area->sh_info)
         mutex_unlock(&area->sh_info->lock);
     page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
-    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
+    if (!used_space_insert(area, page, 1))
         panic("Could not insert used space.\n");
     return AS_PF_OK;
+}
  */
 void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)
+{
     elf_header_t *elf = area->backend_data.elf;
     elf_segment_header_t *entry = area->backend_data.segment;
-    uintptr_t base;
+    uintptr_t base, start_anon;
     index_t i;
-    ASSERT((page >= entry->p_vaddr) &&
+    ASSERT((page >= ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE)) &&
         (page < entry->p_vaddr + entry->p_memsz));
-    i = (page - entry->p_vaddr) >> PAGE_WIDTH;
+    i = (page - ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE)) >> PAGE_WIDTH;
-    base = (uintptr_t) (((void *) elf) + entry->p_offset);
+    base = (uintptr_t) (((void *) elf) +
-    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
+        ALIGN_DOWN(entry->p_offset, FRAME_SIZE));
+    start_anon = entry->p_vaddr + entry->p_filesz;
-    if (page + PAGE_SIZE <
-        ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
+    if (page >= entry->p_vaddr && page + PAGE_SIZE <= start_anon) {
         if (entry->p_flags & PF_W) {
             /*
              * Free the frame with the copy of writable segment
              * data.
              */
             /*
              * Skip read-only areas of used space that are backed
              * by the ELF image.
              */
             if (!(area->flags & AS_AREA_WRITE))
+                if (base >= entry->p_vaddr &&
-                if (base + count * PAGE_SIZE <= start_anon)
+                    base + count * PAGE_SIZE <= start_anon)
                     continue;
             for (j = 0; j < count; j++) {
                 pte_t *pte;
                 /*
                  * Skip read-only pages that are backed by the
                  * ELF image.
                  */
                 if (!(area->flags & AS_AREA_WRITE))
+                    if (base >= entry->p_vaddr &&
-                    if (base + (j + 1) * PAGE_SIZE <=
+                        base + (j + 1) * PAGE_SIZE <=
                         start_anon)
                         continue;
                 page_table_lock(area->as, false);
                 pte = page_mapping_find(area->as,

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(root)/trunk/kernel/generic/src/mm/backend_elf.c – Rev 2745 → 3007