Changeset 38dc82d in mainline for kernel/arch/sparc64/src/mm/sun4u/tlb.c

Timestamp:

2016-08-31T14:16:45Z (9 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

346b12a2

Parents:

dc05a9a

Message:

Make page_mapping_find() return a copy rather than the actual PTE

This makes page_mapping_find() more suitable for use with lock-free data
structures such as CHT that guarantee existence of the data only for
some limited time while a condition holds (e.g. inside of a RCU-protected
critical section that must be around all CHT lookups).

File:

• kernel/arch/sparc64/src/mm/sun4u/tlb.c (modified) (6 diffs)

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

@@ -197 +197 @@
 {
         size_t index = (istate->tpc >> MMU_PAGE_WIDTH) % MMU_PAGES_PER_PAGE;
-        pte_t *t;
-
-        t = page_mapping_find(AS, istate->tpc, true);
-        if (t && PTE_EXECUTABLE(t)) {
+        pte_t t;
+
+        bool found = page_mapping_find(AS, istate->tpc, true, &t);
+        if (found && PTE_EXECUTABLE(&t)) {
                 /*
                  * The mapping was found in the software page hash table.
                  * Insert it into ITLB.
                  */
-                t->a = true;
-                itlb_pte_copy(t, index);
+                t.a = true;
+                itlb_pte_copy(&t, index);
 #ifdef CONFIG_TSB
-                itsb_pte_copy(t, index);
+                itsb_pte_copy(&t, index);
 #endif
         } else {
@@ -233 +233 @@
         uintptr_t page_16k;
         size_t index;
-        pte_t *t;
+        pte_t t;
         as_t *as = AS;
 
@@ -253 +253 @@
         }
 
-        t = page_mapping_find(as, page_16k, true);
-        if (t) {
+        bool found = page_mapping_find(as, page_16k, true, &t);
+        if (found) {
                 /*
                  * The mapping was found in the software page hash table.
                  * Insert it into DTLB.
                  */
-                t->a = true;
-                dtlb_pte_copy(t, index, true);
+                t.a = true;
+                dtlb_pte_copy(&t, index, true);
 #ifdef CONFIG_TSB
-                dtsb_pte_copy(t, index, true);
+                dtsb_pte_copy(&t, index, true);
 #endif
         } else {
@@ -283 +283 @@
         uintptr_t page_16k;
         size_t index;
-        pte_t *t;
+        pte_t t;
         as_t *as = AS;
 
@@ -293 +293 @@
                 as = AS_KERNEL;
 
-        t = page_mapping_find(as, page_16k, true);
-        if (t && PTE_WRITABLE(t)) {
+        bool found = page_mapping_find(as, page_16k, true, &t);
+        if (found && PTE_WRITABLE(&t)) {
                 /*
                  * The mapping was found in the software page hash table and is
@@ -300 +300 @@
                  * into DTLB.
                  */
-                t->a = true;
-                t->d = true;
+                t.a = true;
+                t.d = true;
                 dtlb_demap(TLB_DEMAP_PAGE, TLB_DEMAP_SECONDARY,
                     page_16k + index * MMU_PAGE_SIZE);
-                dtlb_pte_copy(t, index, false);
+                dtlb_pte_copy(&t, index, false);
 #ifdef CONFIG_TSB
-                dtsb_pte_copy(t, index, false);
+                dtsb_pte_copy(&t, index, false);
 #endif
         } else {