Add /proc/mm and a /bin/mm utility that just dumps it.

This shows some info about the MM. Right now it's just the zone count
and the number of free physical pages. Lots more can be added.

Also added "exit" to sh so we can nest shells and exit from them.

I also noticed that we were leaking all the physical pages, so fixed that.

AK/Vector.h

@@ -116,6 +116,21 @@ public:
         m_impl->remove(index);
     }
 
+    void append(Vector<T>&& other)
+    {
+        Vector<T> tmp = move(other);
+        ensureCapacity(size() + tmp.size());
+        for (auto&& v : tmp) {
+            uncheckedAppend(move(v));
+        }
+    }
+
+    void uncheckedAppend(T&& value)
+    {
+        new (m_impl->slot(m_impl->m_size)) T(move(value));
+        ++m_impl->m_size;
+    }
+
     void append(T&& value)
     {
         ensureCapacity(size() + 1);

Kernel/MemoryManager.cpp

@@ -34,9 +34,7 @@ void MemoryManager::initializePaging()
     memset(m_pageTableOne, 0, 4096);
     memset(m_pageDirectory, 0, 4096);
 
-    kprintf("MM: Page directory @ %p\n", m_pageDirectory);
-    kprintf("MM: Page table zero @ %p\n", m_pageTableZero);
-    kprintf("MM: Page table one @ %p\n", m_pageTableOne);
+    kprintf("[MM] Page directory @ %p\n", m_pageDirectory);
 
     // Make null dereferences crash.
     protectMap(LinearAddress(0), 4 * KB);
@@ -72,7 +70,7 @@ auto MemoryManager::ensurePTE(LinearAddress linearAddress) -> PageTableEntry
 
     PageDirectoryEntry pde = PageDirectoryEntry(&m_pageDirectory[pageDirectoryIndex]);
     if (!pde.isPresent()) {
-        kprintf("PDE %u !present, allocating\n", pageDirectoryIndex);
+        kprintf("[MM] PDE %u not present, allocating\n", pageDirectoryIndex);
         if (pageDirectoryIndex == 0) {
             pde.setPageTableBase((dword)m_pageTableZero);
             pde.setUserAllowed(true);
@@ -85,7 +83,7 @@ auto MemoryManager::ensurePTE(LinearAddress linearAddress) -> PageTableEntry
             pde.setWritable(true);
         } else {
             auto* pageTable = allocatePageTable();
-            kprintf("allocated page table %u (for laddr=%p) at %p\n", pageDirectoryIndex, linearAddress.get(), pageTable);
+            kprintf("[MM] Allocated page table #%u (for laddr=%p) at %p\n", pageDirectoryIndex, linearAddress.get(), pageTable);
             memset(pageTable, 0, 4096);
             pde.setPageTableBase((dword)pageTable);
             pde.setUserAllowed(true);
@@ -134,7 +132,7 @@ void MemoryManager::initialize()
 PageFaultResponse MemoryManager::handlePageFault(const PageFault& fault)
 {
     ASSERT_INTERRUPTS_DISABLED();
-    kprintf("MM: handlePageFault(%w) at laddr=%p\n", fault.code(), fault.address().get());
+    kprintf("[MM] handlePageFault(%w) at laddr=%p\n", fault.code(), fault.address().get());
     if (fault.isNotPresent()) { 
         kprintf("  >> NP fault!\n");
     } else if (fault.isProtectionViolation()) {
@@ -143,11 +141,36 @@ PageFaultResponse MemoryManager::handlePageFault(const PageFault& fault)
     return PageFaultResponse::ShouldCrash;
 }
 
+void MemoryManager::registerZone(Zone& zone)
+{
+    ASSERT_INTERRUPTS_DISABLED();
+    m_zones.set(&zone);
+}
+
+void MemoryManager::unregisterZone(Zone& zone)
+{
+    ASSERT_INTERRUPTS_DISABLED();
+    m_zones.remove(&zone);
+    m_freePages.append(move(zone.m_pages));
+}
+
+Zone::Zone(Vector<PhysicalAddress>&& pages)
+    : m_pages(move(pages))
+{
+    MM.registerZone(*this);
+}
+
+Zone::~Zone()
+{
+    MM.unregisterZone(*this);
+}
+
 RetainPtr<Zone> MemoryManager::createZone(size_t size)
 {
+    InterruptDisabler disabler;
     auto pages = allocatePhysicalPages(ceilDiv(size, PAGE_SIZE));
     if (pages.isEmpty()) {
-        kprintf("MM: createZone: no physical pages for size %u", size);
+        kprintf("[MM] createZone: no physical pages for size %u", size);
         return nullptr;
     }
     return adopt(*new Zone(move(pages)));
@@ -170,7 +193,7 @@ byte* MemoryManager::quickMapOnePage(PhysicalAddress physicalAddress)
 {
     ASSERT_INTERRUPTS_DISABLED();
     auto pte = ensurePTE(LinearAddress(4 * MB));
-    kprintf("quickmap %x @ %x {pte @ %p}\n", physicalAddress.get(), 4*MB, pte.ptr());
+    kprintf("[MM] quickmap %x @ %x {pte @ %p}\n", physicalAddress.get(), 4*MB, pte.ptr());
     pte.setPhysicalPageBase(physicalAddress.pageBase());
     pte.setPresent(true);
     pte.setWritable(true);
@@ -297,7 +320,7 @@ bool MemoryManager::mapRegionsForTask(Task& task)
 bool copyToZone(Zone& zone, const void* data, size_t size)
 {
     if (zone.size() < size) {
-        kprintf("copyToZone: can't fit %u bytes into zone with size %u\n", size, zone.size());
+        kprintf("[MM] copyToZone: can't fit %u bytes into zone with size %u\n", size, zone.size());
         return false;
     }
 
@@ -314,4 +337,3 @@ bool copyToZone(Zone& zone, const void* data, size_t size)
 
     return true;
 }
-

Kernel/MemoryManager.h

@@ -5,7 +5,7 @@
 #include <AK/Retainable.h>
 #include <AK/RetainPtr.h>
 #include <AK/Vector.h>
-#include <AK/HashMap.h>
+#include <AK/HashTable.h>
 #include "Task.h"
 
 class Task;
@@ -17,7 +17,7 @@ enum class PageFaultResponse {
 
 struct Zone : public Retainable<Zone> {
 public:
-    ~Zone() { }
+    ~Zone();
     size_t size() const { return m_pages.size() * PAGE_SIZE; }
 
     const Vector<PhysicalAddress>& pages() const { return m_pages; }
@@ -25,10 +25,7 @@ public:
 private:
     friend class MemoryManager;
     friend bool copyToZone(Zone&, const void* data, size_t);
-    explicit Zone(Vector<PhysicalAddress>&& pages)
-        : m_pages(move(pages))
-    {
-    }
+    explicit Zone(Vector<PhysicalAddress>&&);
 
     Vector<PhysicalAddress> m_pages;
 };
@@ -38,6 +35,7 @@ bool copyToZone(Zone&, const void* data, size_t);
 #define MM MemoryManager::the()
 
 class MemoryManager {
+    friend ByteBuffer procfs$mm();
 public:
     static MemoryManager& the() PURE;
 
@@ -62,6 +60,9 @@ public:
     bool mapRegionsForTask(Task&);
     bool unmapRegionsForTask(Task&);
 
+    void registerZone(Zone&);
+    void unregisterZone(Zone&);
+
 private:
     MemoryManager();
     ~MemoryManager();
@@ -161,7 +162,7 @@ private:
     dword* m_pageTableZero;
     dword* m_pageTableOne;
 
-    HashMap<int, RetainPtr<Zone>> m_zones;
+    HashTable<Zone*> m_zones;
 
     Vector<PhysicalAddress> m_freePages;
 };

Kernel/ProcFileSystem.cpp

@@ -118,6 +118,18 @@ void ProcFileSystem::removeProcess(Task& task)
     m_pid2inode.remove(pid);
 }
 
+ByteBuffer procfs$mm()
+{
+    InterruptDisabler disabler;
+    auto buffer = ByteBuffer::createUninitialized(1024);
+    char* ptr = (char*)buffer.pointer();
+    ptr += ksprintf(ptr, "Zone count: %u\n", MM.m_zones.size());
+    ptr += ksprintf(ptr, "Free physical pages: %u\n", MM.m_freePages.size());
+    buffer.trim(ptr - (char*)buffer.pointer());
+    return buffer;
+}
+
+
 ByteBuffer procfs$mounts()
 {
     InterruptDisabler disabler;
@@ -171,6 +183,7 @@ ByteBuffer procfs$summary()
 bool ProcFileSystem::initialize()
 {
     SyntheticFileSystem::initialize();
+    addFile(createGeneratedFile("mm", procfs$mm));
     addFile(createGeneratedFile("mounts", procfs$mounts));
     addFile(createGeneratedFile("kmalloc", procfs$kmalloc));
     addFile(createGeneratedFile("summary", procfs$summary));

Kernel/sync-sh

@@ -15,6 +15,7 @@ cp ../Userland/cat mnt/bin/cat
 cp ../Userland/uname mnt/bin/uname
 cp ../Userland/clear mnt/bin/clear
 cp ../Userland/tst mnt/bin/tst
+cp ../Userland/mm mnt/bin/mm
 cp kernel.map mnt/
 umount mnt
 sync

Userland/.gitignore

@@ -13,3 +13,4 @@ cat
 uname
 clear
 tst
+mm

Userland/Makefile

@@ -12,7 +12,8 @@ OBJS = \
        cat.o \
        uname.o \
        clear.o \
-       tst.o
+       tst.o \
+       mm.o
 
 APPS = \
        id \
@@ -28,7 +29,8 @@ APPS = \
        cat \
        uname \
        clear \
-       tst
+       tst \
+       mm
 
 ARCH_FLAGS =
 STANDARD_FLAGS = -std=c++17 -nostdinc++ -nostdlib
@@ -90,6 +92,9 @@ clear: clear.o
 tst: tst.o
 	$(LD) -o $@ $(LDFLAGS) $< ../LibC/LibC.a
 
+mm: mm.o
+	$(LD) -o $@ $(LDFLAGS) $< ../LibC/LibC.a
+
 .cpp.o:
 	@echo "CXX $<"; $(CXX) $(CXXFLAGS) -o $@ -c $<
 

Userland/mm.cpp

@@ -0,0 +1,25 @@
+#include <LibC/stdio.h>
+#include <LibC/unistd.h>
+
+int main(int c, char** v)
+{
+    int fd = open("/proc/mm");
+    if (fd == -1) {
+        perror("failed to open /proc/mm");
+        return 1;
+    }
+    for (;;) {
+        char buf[128];
+        ssize_t nread = read(fd, buf, sizeof(buf));
+        if (nread == 0)
+            break;
+        if (nread < 0) {
+            perror("failed to read");
+            return 2;
+        }
+        for (ssize_t i = 0; i < nread; ++i) {
+            putchar(buf[i]);
+        }
+    }
+    return 0;
+}

Userland/ps.cpp

@@ -5,7 +5,7 @@ int main(int c, char** v)
 {
     int fd = open("/proc/summary");
     if (fd == -1) {
-        printf("failed to open /proc/summary :(\n");
+        perror("failed to open /proc/summary");
         return 1;
     }
     for (;;) {
@@ -14,7 +14,7 @@ int main(int c, char** v)
         if (nread == 0)
             break;
         if (nread < 0) {
-            printf("failed to read :(\n");
+            perror("failed to read");
             return 2;
         }
         for (ssize_t i = 0; i < nread; ++i) {

Userland/sh.cpp

@@ -26,6 +26,13 @@ static int sh_pwd(int, const char**)
     return 0;
 }
 
+static int sh_exit(int, const char**)
+{
+    printf("Good-bye!\n");
+    exit(0);
+    return 0;
+}
+
 static int sh_cd(int argc, const char** argv)
 {
     if (argc == 1) {
@@ -77,6 +84,10 @@ static bool handle_builtin(int argc, const char** argv, int& retval)
         retval = sh_pwd(argc, argv);
         return true;
     }
+    if (!strcmp(argv[0], "exit")) {
+        retval = sh_exit(argc, argv);
+        return true;
+    }
     return false;
 }