Free pages in PMap_Destroy and add extra assertions to catch errors in PAlloc.

sys/amd64/include/amd64.h

@@ -12,6 +12,8 @@
  * Page Tables
  */
 
+#define PGNUMMASK	0xFFFFFFFFFFFFF000ULL
+
 #define PGIDXSHIFT	9
 #define PGIDXMASK       (512 - 1)
 

sys/amd64/pmap.c

@@ -76,7 +76,7 @@ PMap_NewAS()
     AS *as = PAlloc_AllocPage();
 
     if (!as)
-	return 0;
+	return NULL;
 
     as->root = PAlloc_AllocPage();
     as->tables = 1;
@@ -84,7 +84,7 @@ PMap_NewAS()
 
     if (!as->root) {
 	PAlloc_Release(as);
-	return 0;
+	return NULL;
     }
 
     for (i = 0; i < PAGETABLE_ENTRIES / 2; i++)
@@ -101,15 +101,46 @@ PMap_NewAS()
 void
 PMap_DestroyAS(AS *space)
 {
-    int i;
+    // Only free the userspace portion (bottom half)
-
+    for (int i = 0; i < PAGETABLE_ENTRIES / 2; i++)
-    for (i = 0; i < PAGETABLE_ENTRIES / 2; i++)
     {
-	if (space->root->entries[i] != 0) {
+	PageEntry pte = space->root->entries[i];
-	    // Remove subpages
+	if (pte & PTE_P) {
-	    PAlloc_Release((void *)DMPA2VA(space->root->entries[i]));
+	    // Remove sub-pages
+	    PageTable *tbl2 = (PageTable *)DMPA2VA(pte & PGNUMMASK);
+	    for (int j = 0; j < PAGETABLE_ENTRIES; j++) {
+		PageEntry pte2 = tbl2->entries[j];
+		if (pte2 & PTE_P) {
+		    PageTable *tbl3 = (PageTable *)DMPA2VA(pte2 & PGNUMMASK);
+		    for (int k = 0; k < PAGETABLE_ENTRIES; k++) {
+			PageEntry pte3 = tbl3->entries[k];
+			if (pte3 & PTE_P) {
+			    ASSERT((pte3 & PTE_PS) == 0); // XXX: Large pages not supported
+			    PageTable *tbl4 = (PageTable *)DMPA2VA(pte3 & PGNUMMASK);
+			    for (int l = 0; l < PAGETABLE_ENTRIES; l++) {
+				PageEntry pte4 = tbl4->entries[l];
+				if (pte4 & PTE_P) {
+				    // Free userspace page
+				    PAlloc_Release((void *)DMPA2VA(pte4 & PGNUMMASK));
+				}
+			    }
+
+			    // Free 3rd level page table page
+			    PAlloc_Release((void *)DMPA2VA(pte3 & PGNUMMASK));
+			}
+		    }
+
+		    // Free 2nd level page table page
+		    PAlloc_Release((void *)DMPA2VA(pte2 & PGNUMMASK));
+		}
+	    }
+
+	    // Free page table page
+	    PAlloc_Release((void *)DMPA2VA(pte & PGNUMMASK));
 	}
     }
+
+    PAlloc_Release(space);
 }
 
 AS *
@@ -159,7 +190,7 @@ PMap_Translate(AS *space, uintptr_t va)
 	ASSERT(pte);
 	return 0;
     }
-    table = (PageTable *)DMPA2VA(pte & 0xFFFFFFFFFFFFF000);
+    table = (PageTable *)DMPA2VA(pte & PGNUMMASK);
 
     pte = table->entries[j];
     // XXX: Support 1GB pages
@@ -167,7 +198,7 @@ PMap_Translate(AS *space, uintptr_t va)
 	ASSERT(pte);
 	return 0;
     }
-    table = (PageTable *)DMPA2VA(pte & 0xFFFFFFFFFFFFF000);
+    table = (PageTable *)DMPA2VA(pte & PGNUMMASK);
 
     pte = table->entries[k];
     if ((pte & PTE_PS) == PTE_PS) {
@@ -179,7 +210,7 @@ PMap_Translate(AS *space, uintptr_t va)
 	ASSERT(pte);
 	return 0;
     }
-    table = (PageTable *)DMPA2VA(pte & 0xFFFFFFFFFFFFF000);
+    table = (PageTable *)DMPA2VA(pte & PGNUMMASK);
 
     // Handle 4KB pages
     entry = &table->entries[l];
@@ -210,7 +241,7 @@ PMapLookupEntry(AS *space, uint64_t va, PageEntry **entry, int size)
 	pte = DMVA2PA((uint64_t)newtable) | PTE_P | PTE_W | PTE_U;
 	table->entries[i] = pte;
     }
-    table = (PageTable *)DMPA2VA(pte & 0xFFFFFFFFFFFFF000);
+    table = (PageTable *)DMPA2VA(pte & PGNUMMASK);
 
     pte = table->entries[j];
     if (size == HUGE_PGSIZE) {
@@ -226,7 +257,7 @@ PMapLookupEntry(AS *space, uint64_t va, PageEntry **entry, int size)
 	pte = DMVA2PA((uint64_t)newtable) | PTE_P | PTE_W | PTE_U;
 	table->entries[j] = pte;
     }
-    table = (PageTable *)DMPA2VA(pte & 0xFFFFFFFFFFFFF000);
+    table = (PageTable *)DMPA2VA(pte & PGNUMMASK);
 
     pte = table->entries[k];
     if (size == LARGE_PGSIZE) {
@@ -242,7 +273,7 @@ PMapLookupEntry(AS *space, uint64_t va, PageEntry **entry, int size)
 	pte = DMVA2PA((uint64_t)newtable) | PTE_P | PTE_W | PTE_U;
 	table->entries[k] = pte;
     }
-    table = (PageTable *)DMPA2VA(pte & 0xFFFFFFFFFFFFF000);
+    table = (PageTable *)DMPA2VA(pte & PGNUMMASK);
 
     // Handle 4KB pages
     ASSERT(size == PGSIZE);
@@ -284,6 +315,8 @@ PMap_Unmap(AS *as, uint64_t va, uint64_t pages)
 	    return false;
 	}
 
+	NOT_IMPLEMENTED();
+
 	*entry = 0;
     }
 
@@ -388,7 +421,7 @@ PMap_Dump(AS *space)
 
     for (i = 0; i < PAGETABLE_ENTRIES; i++) {
 	PageEntry pte = root->entries[i];
-	PageTable *l1 = (PageTable *)DMPA2VA(pte & 0xFFFFFFFFFFFFF000);
+	PageTable *l1 = (PageTable *)DMPA2VA(pte & PGNUMMASK);
 
 	if (!(pte & PTE_P))
 	    continue;
@@ -397,7 +430,7 @@ PMap_Dump(AS *space)
 
 	for (j = 0; j < PAGETABLE_ENTRIES; j++) {
 	    PageEntry pte2 = l1->entries[j];
-	    PageTable *l2 = (PageTable *)DMPA2VA(pte2 & 0xFFFFFFFFFFFFF000);
+	    PageTable *l2 = (PageTable *)DMPA2VA(pte2 & PGNUMMASK);
 
 	    if (!(pte2 & PTE_P))
 		continue;
@@ -406,7 +439,7 @@ PMap_Dump(AS *space)
 
 	    for (k = 0; k < PAGETABLE_ENTRIES; k++) {
 		PageEntry pte3 = l2->entries[k];
-		PageTable *l3 = (PageTable *)DMPA2VA(pte3 & 0xFFFFFFFFFFFFF000);
+		PageTable *l3 = (PageTable *)DMPA2VA(pte3 & PGNUMMASK);
 
 		if (!(pte3 & PTE_P))
 		    continue;
@@ -439,3 +472,64 @@ Debug_PMapDump(int argc, const char *argv[])
 
 REGISTER_DBGCMD(pmapdump, "Dump memory mappings", Debug_PMapDump);
 
+void
+PMap_DumpConcise(AS *space)
+{
+    int i = 0;
+    int j = 0;
+    int k = 0;
+    int l = 0;
+    PageTable *root = space->root;
+
+    for (i = 0; i < PAGETABLE_ENTRIES/2; i++) {
+	PageEntry pte = root->entries[i];
+	PageTable *l1 = (PageTable *)DMPA2VA(pte & PGNUMMASK);
+
+	if (!(pte & PTE_P))
+	    continue;
+
+	for (j = 0; j < PAGETABLE_ENTRIES; j++) {
+	    PageEntry pte2 = l1->entries[j];
+	    PageTable *l2 = (PageTable *)DMPA2VA(pte2 & PGNUMMASK);
+
+	    if (!(pte2 & PTE_P))
+		continue;
+
+	    for (k = 0; k < PAGETABLE_ENTRIES; k++) {
+		PageEntry pte3 = l2->entries[k];
+		PageTable *l3 = (PageTable *)DMPA2VA(pte3 & PGNUMMASK);
+
+		if (!(pte3 & PTE_P))
+		    continue;
+
+		if ((pte3 & PTE_PS) == 0) {
+		    for (l = 0; l < PAGETABLE_ENTRIES; l++) {
+			PageEntry pte4 = l3->entries[l];
+
+			if (pte4 & PTE_P)
+			    kprintf("%016llx: %016llx P%c%c%c%c%c\n",
+				    AddrFromIJKL(i, j, k, l),
+				    (uint64_t)pte4,
+				    (pte4 & PTE_W) ? 'W' : ' ',
+				    (pte4 & PTE_NX) ? ' ' : 'X',
+				    (pte4 & PTE_U) ? 'U' : ' ',
+				    (pte4 & PTE_A) ? 'A' : ' ',
+				    (pte4 & PTE_D) ? 'D' : ' ');
+		    }
+		}
+	    }
+	}
+    }
+
+    return;
+}
+
+static void
+Debug_PMapDumpConcise(int argc, const char *argv[])
+{
+    PMap_DumpConcise(currentAS[THISCPU()]);
+}
+
+REGISTER_DBGCMD(pmapdumpconcise, "Dump concise memory mappings", Debug_PMapDumpConcise);
+
+

sys/kern/palloc.c

@@ -186,6 +186,8 @@ PAlloc_AllocPage()
     freePages--;
     Spinlock_Unlock(&pallocLock);
 
+    memset(pg, 0, PGSIZE);
+
     return (void *)pg;
 }
 
@@ -194,6 +196,8 @@ PAllocFreePage(void *region)
 {
     FreePage *pg = (FreePage *)region;
 
+    ASSERT(((uintptr_t)region % PGSIZE) == 0);
+
     LIST_INSERT_HEAD(&freeList, pg, entries);
 
 #ifndef NDEBUG
@@ -204,6 +208,7 @@ PAllocFreePage(void *region)
     PageInfo *info = PAllocGetInfo(pg);
     ASSERT(info->refCount == 0);
 #endif
+
     pg->magic = FREEPAGE_MAGIC_FREE;
     freePages++;
 }
@@ -225,6 +230,7 @@ PAlloc_Release(void *pg)
     PageInfo *info = PAllocGetInfo(pg);
 
     Spinlock_Lock(&pallocLock);
+    ASSERT(info->refCount != 0);
     info->refCount--;
     if (info->refCount == 0)
 	PAllocFreePage(pg);