Changeset c520034 in mainline for kernel/arch/sparc64/src/mm/sun4u/tlb.c

Timestamp:

2011-12-31T18:19:35Z (12 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

295f658, 77c2b02, 96cd5b4

Parents:

852052d (diff), 22f0561 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Support for kernel non-identity mappings, phase I.

• identity/non-identity kernel memory split on all architectures
• low/high physical memory split on all architectures
• frame allocator understands low/high memory
• high physical memory currently unused (Phase II)
• more compact frame_t
• zone conf frames, pte_t, kernel stacks allocated from low memory
• lockless TLB-miss handlers everywhere (newly sparc64, ia64)
• preallocate PTL1 page tables for non-identity and prevent their deallocation
• hw_map() unification
• new resource allocator used for allocating kernel virtual addresses

Breakage:

• sparc64/sun4v creates too large kernel identity; not fixed because of lack of testing hw
• ppc32's tlb_refill() seems wrong as it creates too large kernel identity, but appears unused and the architecture works normally

Not implemented yet (phase II):

• allow high memory to be used for common kernel allocations

File:

• kernel/arch/sparc64/src/mm/sun4u/tlb.c (modified) (9 diffs)

kernel/arch/sparc64/src/mm/sun4u/tlb.c

@@ -206 +206 @@
         pte_t *t;
 
-        page_table_lock(AS, true);
         t = page_mapping_find(AS, page_16k, true);
         if (t && PTE_EXECUTABLE(t)) {
@@ -218 +217 @@
                 itsb_pte_copy(t, index);
 #endif
-                page_table_unlock(AS, true);
         } else {
                 /*
@@ -224 +222 @@
                  * handler.
                  */
-                page_table_unlock(AS, true);
                 if (as_page_fault(page_16k, PF_ACCESS_EXEC, istate) ==
                     AS_PF_FAULT) {
@@ -250 +247 @@
         size_t index;
         pte_t *t;
+        as_t *as = AS;
 
         page_8k = (uint64_t) tag.vpn << MMU_PAGE_WIDTH;
@@ -261 +259 @@
                             "Dereferencing NULL pointer.");
                 } else if (page_8k >= end_of_identity) {
-                        /*
-                         * The kernel is accessing the I/O space.
-                         * We still do identity mapping for I/O,
-                         * but without caching.
-                         */
-                        dtlb_insert_mapping(page_8k, KA2PA(page_8k),
-                            PAGESIZE_8K, false, false);
-                        return;
+                        /* Kernel non-identity. */
+                        as = AS_KERNEL;
+                } else {
+                        do_fast_data_access_mmu_miss_fault(istate, tag,
+                    "Unexpected kernel page fault.");
                 }
-                do_fast_data_access_mmu_miss_fault(istate, tag, "Unexpected "
-                    "kernel page fault.");
-        }
-
-        page_table_lock(AS, true);
-        t = page_mapping_find(AS, page_16k, true);
+        }
+
+        t = page_mapping_find(as, page_16k, true);
         if (t) {
                 /*
@@ -286 +278 @@
                 dtsb_pte_copy(t, index, true);
 #endif
-                page_table_unlock(AS, true);
         } else {
                 /*
                  * Forward the page fault to the address space page fault
                  * handler.
-                 */             
-                page_table_unlock(AS, true);
+                 */
                 if (as_page_fault(page_16k, PF_ACCESS_READ, istate) ==
                     AS_PF_FAULT) {
@@ -314 +304 @@
         size_t index;
         pte_t *t;
+        as_t *as = AS;
 
         page_16k = ALIGN_DOWN((uint64_t) tag.vpn << MMU_PAGE_WIDTH, PAGE_SIZE);
         index = tag.vpn % MMU_PAGES_PER_PAGE;   /* 16K-page emulation */
 
-        page_table_lock(AS, true);
-        t = page_mapping_find(AS, page_16k, true);
+        if (tag.context == ASID_KERNEL)
+                as = AS_KERNEL;
+
+        t = page_mapping_find(as, page_16k, true);
         if (t && PTE_WRITABLE(t)) {
                 /*
@@ -334 +327 @@
                 dtsb_pte_copy(t, index, false);
 #endif
-                page_table_unlock(AS, true);
         } else {
                 /*
@@ -340 +332 @@
                  * handler.
                  */             
-                page_table_unlock(AS, true);
                 if (as_page_fault(page_16k, PF_ACCESS_WRITE, istate) ==
                     AS_PF_FAULT) {