Changeset 38dc82d in mainline for kernel/arch/sparc64/src/mm/sun4v/tlb.c

Timestamp:

2016-08-31T14:16:45Z (8 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/sun4v/tlb.c (modified) (6 diffs)

kernel/arch/sparc64/src/mm/sun4v/tlb.c

@@ -211 +211 @@
 {
         uintptr_t va = ALIGN_DOWN(istate->tpc, PAGE_SIZE);
-        pte_t *t;
-
-        t = page_mapping_find(AS, va, true);
-
-        if (t && PTE_EXECUTABLE(t)) {
+        pte_t t;
+
+        bool found = page_mapping_find(AS, va, 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);
+                t.a = true;
+                itlb_pte_copy(&t);
 #ifdef CONFIG_TSB
-                itsb_pte_copy(t);
+                itsb_pte_copy(&t);
 #endif
         } else {
@@ -244 +243 @@
 void fast_data_access_mmu_miss(unsigned int tt, istate_t *istate)
 {
-        pte_t *t;
+        pte_t t;
         uintptr_t va = DMISS_ADDRESS(istate->tlb_tag_access);
         uint16_t ctx = DMISS_CONTEXT(istate->tlb_tag_access);
@@ -261 +260 @@
         }
 
-        t = page_mapping_find(as, va, true);
-        if (t) {
+        bool found = page_mapping_find(as, va, 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, true);
+                t.a = true;
+                dtlb_pte_copy(&t, true);
 #ifdef CONFIG_TSB
-                dtsb_pte_copy(t, true);
+                dtsb_pte_copy(&t, true);
 #endif
         } else {
@@ -288 +287 @@
 void fast_data_access_protection(unsigned int tt, istate_t *istate)
 {
-        pte_t *t;
+        pte_t t;
         uintptr_t va = DMISS_ADDRESS(istate->tlb_tag_access);
         uint16_t ctx = DMISS_CONTEXT(istate->tlb_tag_access);
@@ -296 +295 @@
                 as = AS_KERNEL;
 
-        t = page_mapping_find(as, va, true);
-        if (t && PTE_WRITABLE(t)) {
+        bool found = page_mapping_find(as, va, true, &t);
+        if (found && PTE_WRITABLE(&t)) {
                 /*
                  * The mapping was found in the software page hash table and is
@@ -303 +302 @@
                  * into DTLB.
                  */
-                t->a = true;
-                t->d = true;
+                t.a = true;
+                t.d = true;
                 mmu_demap_page(va, ctx, MMU_FLAG_DTLB);
-                dtlb_pte_copy(t, false);
+                dtlb_pte_copy(&t, false);
 #ifdef CONFIG_TSB
-                dtsb_pte_copy(t, false);
+                dtsb_pte_copy(&t, false);
 #endif
         } else {