Changes in kernel/arch/mips64/src/mm/tlb.c [1dbc43f:9d58539] in mainline

File:

• kernel/arch/mips64/src/mm/tlb.c (modified) (7 diffs)

kernel/arch/mips64/src/mm/tlb.c

@@ -79 +79 @@
  * @param access   Access mode that caused the fault.
  * @param istate   Pointer to interrupted state.
+ * @param pfrc     Pointer to variable where as_page_fault()
+ *                 return code will be stored.
  *
  * @return PTE on success, NULL otherwise.
@@ -84 +86 @@
  */
 static pte_t *find_mapping_and_check(uintptr_t badvaddr, int access,
-    istate_t *istate)
+    istate_t *istate, int *pfrc)
 {
         entry_hi_t hi;
         hi.value = cp0_entry_hi_read();
         
-        ASSERT(hi.asid == AS->asid);
+        /*
+         * Handler cannot succeed if the ASIDs don't match.
+         */
+        if (hi.asid != AS->asid) {
+                printf("EntryHi.asid=%d, AS->asid=%d\n", hi.asid, AS->asid);
+                return NULL;
+        }
         
         /*
@@ -101 +109 @@
                  */
                 return pte;
-        }
-
-        /*
-         * Mapping not found in page tables.
-         * Resort to higher-level page fault handler.
-         */
-        if (as_page_fault(badvaddr, access, istate) == AS_PF_OK) {
+        } else {
+                int rc;
+                
                 /*
-                 * The higher-level page fault handler succeeded,
-                 * The mapping ought to be in place.
+                 * Mapping not found in page tables.
+                 * Resort to higher-level page fault handler.
                  */
-                pte = page_mapping_find(AS, badvaddr, true);
-                ASSERT(pte);
-                ASSERT(pte->p);
-                ASSERT((pte->w) || (access != PF_ACCESS_WRITE));
-                return pte;
-        }
-
-        return NULL;
+                switch (rc = as_page_fault(badvaddr, access, istate)) {
+                case AS_PF_OK:
+                        /*
+                         * The higher-level page fault handler succeeded,
+                         * The mapping ought to be in place.
+                         */
+                        pte = page_mapping_find(AS, badvaddr, true);
+                        ASSERT(pte);
+                        ASSERT(pte->p);
+                        ASSERT((pte->w) || (access != PF_ACCESS_WRITE));
+                        return pte;
+                case AS_PF_DEFER:
+                        *pfrc = AS_PF_DEFER;
+                        return NULL;
+                case AS_PF_FAULT:
+                        *pfrc = AS_PF_FAULT;
+                        return NULL;
+                default:
+                        panic("Unexpected return code (%d).", rc);
+                }
+        }
 }
 
@@ -139 +156 @@
 }
 
+static void tlb_refill_fail(istate_t *istate)
+{
+        uintptr_t va = cp0_badvaddr_read();
+        
+        fault_if_from_uspace(istate, "TLB Refill Exception on %p.",
+            (void *) va);
+        panic_memtrap(istate, PF_ACCESS_UNKNOWN, va, "TLB Refill Exception.");
+}
+
+static void tlb_invalid_fail(istate_t *istate)
+{
+        uintptr_t va = cp0_badvaddr_read();
+        
+        fault_if_from_uspace(istate, "TLB Invalid Exception on %p.",
+            (void *) va);
+        panic_memtrap(istate, PF_ACCESS_UNKNOWN, va, "TLB Invalid Exception.");
+}
+
+static void tlb_modified_fail(istate_t *istate)
+{
+        uintptr_t va = cp0_badvaddr_read();
+        
+        fault_if_from_uspace(istate, "TLB Modified Exception on %p.",
+            (void *) va);
+        panic_memtrap(istate, PF_ACCESS_WRITE, va, "TLB Modified Exception.");
+}
+
 /** Process TLB Refill Exception.
  *
@@ -152 +196 @@
         mutex_unlock(&AS->lock);
         
-        pte_t *pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate);
-        if (pte) {
-                /*
-                 * Record access to PTE.
-                 */
-                pte->a = 1;
-        
-                entry_lo_t lo;
-                entry_hi_t hi;
-        
-                tlb_prepare_entry_hi(&hi, asid, badvaddr);
-                tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->c,
-                    pte->frame);
-        
-                /*
-                 * New entry is to be inserted into TLB
-                 */
-                cp0_entry_hi_write(hi.value);
-        
-                if ((badvaddr / PAGE_SIZE) % 2 == 0) {
-                        cp0_entry_lo0_write(lo.value);
-                        cp0_entry_lo1_write(0);
-                } else {
-                        cp0_entry_lo0_write(0);
-                        cp0_entry_lo1_write(lo.value);
+        int pfrc;
+        pte_t *pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ,
+            istate, &pfrc);
+        if (!pte) {
+                switch (pfrc) {
+                case AS_PF_FAULT:
+                        goto fail;
+                        break;
+                case AS_PF_DEFER:
+                        /*
+                         * The page fault came during copy_from_uspace()
+                         * or copy_to_uspace().
+                         */
+                        return;
+                default:
+                        panic("Unexpected pfrc (%d).", pfrc);
                 }
-        
-                cp0_pagemask_write(TLB_PAGE_MASK_16K);
-                tlbwr();
-        }
+        }
+        
+        /*
+         * Record access to PTE.
+         */
+        pte->a = 1;
+        
+        entry_lo_t lo;
+        entry_hi_t hi;
+        
+        tlb_prepare_entry_hi(&hi, asid, badvaddr);
+        tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->c,
+            pte->frame);
+        
+        /*
+         * New entry is to be inserted into TLB
+         */
+        cp0_entry_hi_write(hi.value);
+        
+        if ((badvaddr / PAGE_SIZE) % 2 == 0) {
+                cp0_entry_lo0_write(lo.value);
+                cp0_entry_lo1_write(0);
+        } else {
+                cp0_entry_lo0_write(0);
+                cp0_entry_lo1_write(lo.value);
+        }
+        
+        cp0_pagemask_write(TLB_PAGE_MASK_16K);
+        tlbwr();
+        
+        return;
+        
+fail:
+        tlb_refill_fail(istate);
 }
 
@@ -206 +271 @@
         index.value = cp0_index_read();
         
-        ASSERT(!index.p);
-        
-        pte_t *pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate);
-        if (pte) {
-                /*
-                 * Read the faulting TLB entry.
-                 */
-                tlbr();
-        
-                /*
-                 * Record access to PTE.
-                 */
-                pte->a = 1;
-
-                entry_lo_t lo;
-                tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->c,
-                    pte->frame);
-        
-                /*
-                 * The entry is to be updated in TLB.
-                 */
-                if ((badvaddr / PAGE_SIZE) % 2 == 0)
-                        cp0_entry_lo0_write(lo.value);
-                else
-                        cp0_entry_lo1_write(lo.value);
-        
-                cp0_pagemask_write(TLB_PAGE_MASK_16K);
-                tlbwi();
-        }
-        
+        /*
+         * Fail if the entry is not in TLB.
+         */
+        if (index.p) {
+                printf("TLB entry not found.\n");
+                goto fail;
+        }
+        
+        int pfrc;
+        pte_t *pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ,
+            istate, &pfrc);
+        if (!pte) {
+                switch (pfrc) {
+                case AS_PF_FAULT:
+                        goto fail;
+                        break;
+                case AS_PF_DEFER:
+                        /*
+                         * The page fault came during copy_from_uspace()
+                         * or copy_to_uspace().
+                         */
+                        return;
+                default:
+                        panic("Unexpected pfrc (%d).", pfrc);
+                }
+        }
+        
+        /*
+         * Read the faulting TLB entry.
+         */
+        tlbr();
+        
+        /*
+         * Record access to PTE.
+         */
+        pte->a = 1;
+        
+        entry_lo_t lo;
+        tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->c,
+            pte->frame);
+        
+        /*
+         * The entry is to be updated in TLB.
+         */
+        if ((badvaddr / PAGE_SIZE) % 2 == 0)
+                cp0_entry_lo0_write(lo.value);
+        else
+                cp0_entry_lo1_write(lo.value);
+        
+        cp0_pagemask_write(TLB_PAGE_MASK_16K);
+        tlbwi();
+        
+        return;
+        
+fail:
+        tlb_invalid_fail(istate);
 }
 
@@ -260 +351 @@
         index.value = cp0_index_read();
         
-        ASSERT(!index.p);
-        
-        pte_t *pte = find_mapping_and_check(badvaddr, PF_ACCESS_WRITE, istate);
-        if (pte) {
-                /*
-                 * Read the faulting TLB entry.
-                 */
-                tlbr();
-        
-                /*
-                 * Record access and write to PTE.
-                 */
-                pte->a = 1;
-                pte->d = 1;
-        
-                entry_lo_t lo;
-                tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->w, pte->c,
-                    pte->frame);
-        
-                /*
-                 * The entry is to be updated in TLB.
-                 */
-                if ((badvaddr / PAGE_SIZE) % 2 == 0)
-                        cp0_entry_lo0_write(lo.value);
-                else
-                        cp0_entry_lo1_write(lo.value);
-        
-                cp0_pagemask_write(TLB_PAGE_MASK_16K);
-                tlbwi();
-        }
+        /*
+         * Fail if the entry is not in TLB.
+         */
+        if (index.p) {
+                printf("TLB entry not found.\n");
+                goto fail;
+        }
+        
+        int pfrc;
+        pte_t *pte = find_mapping_and_check(badvaddr, PF_ACCESS_WRITE,
+            istate, &pfrc);
+        if (!pte) {
+                switch (pfrc) {
+                case AS_PF_FAULT:
+                        goto fail;
+                        break;
+                case AS_PF_DEFER:
+                        /*
+                         * The page fault came during copy_from_uspace()
+                         * or copy_to_uspace().
+                         */
+                        return;
+                default:
+                        panic("Unexpected pfrc (%d).", pfrc);
+                }
+        }
+        
+        /*
+         * Read the faulting TLB entry.
+         */
+        tlbr();
+        
+        /*
+         * Record access and write to PTE.
+         */
+        pte->a = 1;
+        pte->d = 1;
+        
+        entry_lo_t lo;
+        tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->w, pte->c,
+            pte->frame);
+        
+        /*
+         * The entry is to be updated in TLB.
+         */
+        if ((badvaddr / PAGE_SIZE) % 2 == 0)
+                cp0_entry_lo0_write(lo.value);
+        else
+                cp0_entry_lo1_write(lo.value);
+        
+        cp0_pagemask_write(TLB_PAGE_MASK_16K);
+        tlbwi();
+        
+        return;
+        
+fail:
+        tlb_modified_fail(istate);
 }