Changeset 38dc82d in mainline for kernel/arch/ia64/src/mm/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/ia64/src/mm/tlb.c (modified) (13 diffs)

kernel/arch/ia64/src/mm/tlb.c

@@ -484 +484 @@
 {
         uintptr_t va;
-        pte_t *t;
+        pte_t t;
         
         va = istate->cr_ifa; /* faulting address */
@@ -490 +490 @@
         ASSERT(!is_kernel_fault(va));
 
-        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 software page hash table.
                  * Insert it into data translation cache.
                  */
-                itc_pte_copy(t);
+                itc_pte_copy(&t);
         } else {
                 /*
@@ -600 +600 @@
         
         
-        pte_t *entry = page_mapping_find(as, va, true);
-        if (entry) {
+        pte_t 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 data translation cache.
                  */
-                dtc_pte_copy(entry);
+                dtc_pte_copy(&t);
         } else {
                 if (try_memmap_io_insertion(va, istate))
@@ -641 +642 @@
 {
         uintptr_t va;
-        pte_t *t;
+        pte_t t;
         as_t *as = AS;
         
@@ -649 +650 @@
                 as = AS_KERNEL;
 
-        t = page_mapping_find(as, va, true);
-        ASSERT((t) && (t->p));
-        if ((t) && (t->p) && (t->w)) {
+        bool found = page_mapping_find(as, va, true, &t);
+
+        ASSERT(found);
+        ASSERT(t.p);
+
+        if (found && t.p && t.w) {
                 /*
                  * Update the Dirty bit in page tables and reinsert
                  * the mapping into DTC.
                  */
-                t->d = true;
-                dtc_pte_copy(t);
+                t.d = true;
+                dtc_pte_copy(&t);
         } else {
                 as_page_fault(va, PF_ACCESS_WRITE, istate);
@@ -672 +676 @@
 {
         uintptr_t va;
-        pte_t *t;
+        pte_t t;
         
         va = istate->cr_ifa;  /* faulting address */
@@ -678 +682 @@
         ASSERT(!is_kernel_fault(va));
         
-        t = page_mapping_find(AS, va, true);
-        ASSERT((t) && (t->p));
-        if ((t) && (t->p) && (t->x)) {
+        bool found = page_mapping_find(AS, va, true, &t);
+
+        ASSERT(found);
+        ASSERT(t.p);
+
+        if (found && t.p && t.x) {
                 /*
                  * Update the Accessed bit in page tables and reinsert
                  * the mapping into ITC.
                  */
-                t->a = true;
-                itc_pte_copy(t);
+                t.a = true;
+                itc_pte_copy(&t);
         } else {
                 as_page_fault(va, PF_ACCESS_EXEC, istate);
@@ -701 +708 @@
 {
         uintptr_t va;
-        pte_t *t;
+        pte_t t;
         as_t *as = AS;
         
@@ -709 +716 @@
                 as = AS_KERNEL;
 
-        t = page_mapping_find(as, va, true);
-        ASSERT((t) && (t->p));
-        if ((t) && (t->p)) {
+        bool found = page_mapping_find(as, va, true, &t);
+
+        ASSERT(found);
+        ASSERT(t.p);
+
+        if (found && t.p) {
                 /*
                  * Update the Accessed bit in page tables and reinsert
                  * the mapping into DTC.
                  */
-                t->a = true;
-                dtc_pte_copy(t);
+                t.a = true;
+                dtc_pte_copy(&t);
         } else {
                 if (as_page_fault(va, PF_ACCESS_READ, istate) == AS_PF_FAULT) {
@@ -736 +746 @@
 {
         uintptr_t va;
-        pte_t *t;
+        pte_t t;
         
         va = istate->cr_ifa;  /* faulting address */
@@ -745 +755 @@
          * Assume a write to a read-only page.
          */
-        t = page_mapping_find(AS, va, true);
-        ASSERT((t) && (t->p));
-        ASSERT(!t->w);
+        bool found = page_mapping_find(AS, va, true, &t);
+
+        ASSERT(found);
+        ASSERT(t.p);
+        ASSERT(!t.w);
+
         as_page_fault(va, PF_ACCESS_WRITE, istate);
 }
@@ -760 +773 @@
 {
         uintptr_t va;
-        pte_t *t;
+        pte_t t;
         
         va = istate->cr_ifa;  /* faulting address */
@@ -766 +779 @@
         ASSERT(!is_kernel_fault(va));
 
-        t = page_mapping_find(AS, va, true);
-        ASSERT(t);
-        
-        if (t->p) {
+        bool found = page_mapping_find(AS, va, true, &t);
+
+        ASSERT(found);
+        
+        if (t.p) {
                 /*
                  * If the Present bit is set in page hash table, just copy it
                  * and update ITC/DTC.
                  */
-                if (t->x)
-                        itc_pte_copy(t);
+                if (t.x)
+                        itc_pte_copy(&t);
                 else
-                        dtc_pte_copy(t);
+                        dtc_pte_copy(&t);
         } else {
                 as_page_fault(va, PF_ACCESS_READ, istate);