Kernel: Move kmalloc() into a Kernel/Heap/ directory

Kernel/Heap/kmalloc.cpp

@@ -0,0 +1,217 @@
+/*
+ * Really really *really* Q&D malloc() and free() implementations
+ * just to get going. Don't ever let anyone see this shit. :^)
+ */
+
+#include <AK/Assertions.h>
+#include <AK/Types.h>
+#include <Kernel/Arch/i386/CPU.h>
+#include <Kernel/KSyms.h>
+#include <Kernel/Process.h>
+#include <Kernel/Scheduler.h>
+#include <Kernel/StdLib.h>
+#include <Kernel/Heap/kmalloc.h>
+
+#define SANITIZE_KMALLOC
+
+struct [[gnu::packed]] allocation_t
+{
+    size_t start;
+    size_t nchunk;
+};
+
+#define CHUNK_SIZE 8
+#define POOL_SIZE (1024 * 1024)
+
+#define ETERNAL_BASE_PHYSICAL (1 * MB)
+#define ETERNAL_RANGE_SIZE (2 * MB)
+
+#define BASE_PHYSICAL (3 * MB)
+#define RANGE_SIZE (1 * MB)
+
+static u8 alloc_map[POOL_SIZE / CHUNK_SIZE / 8];
+
+volatile size_t sum_alloc = 0;
+volatile size_t sum_free = POOL_SIZE;
+volatile size_t kmalloc_sum_eternal = 0;
+
+u32 g_kmalloc_call_count;
+u32 g_kfree_call_count;
+bool g_dump_kmalloc_stacks;
+
+static u8* s_next_eternal_ptr;
+static u8* s_end_of_eternal_range;
+
+bool is_kmalloc_address(const void* ptr)
+{
+    if (ptr >= (u8*)ETERNAL_BASE_PHYSICAL && ptr < s_next_eternal_ptr)
+        return true;
+    return (size_t)ptr >= BASE_PHYSICAL && (size_t)ptr <= (BASE_PHYSICAL + POOL_SIZE);
+}
+
+void kmalloc_init()
+{
+    memset(&alloc_map, 0, sizeof(alloc_map));
+    memset((void*)BASE_PHYSICAL, 0, POOL_SIZE);
+
+    kmalloc_sum_eternal = 0;
+    sum_alloc = 0;
+    sum_free = POOL_SIZE;
+
+    s_next_eternal_ptr = (u8*)ETERNAL_BASE_PHYSICAL;
+    s_end_of_eternal_range = s_next_eternal_ptr + ETERNAL_RANGE_SIZE;
+}
+
+void* kmalloc_eternal(size_t size)
+{
+    void* ptr = s_next_eternal_ptr;
+    s_next_eternal_ptr += size;
+    ASSERT(s_next_eternal_ptr < s_end_of_eternal_range);
+    kmalloc_sum_eternal += size;
+    return ptr;
+}
+
+void* kmalloc_aligned(size_t size, size_t alignment)
+{
+    void* ptr = kmalloc(size + alignment + sizeof(void*));
+    size_t max_addr = (size_t)ptr + alignment;
+    void* aligned_ptr = (void*)(max_addr - (max_addr % alignment));
+    ((void**)aligned_ptr)[-1] = ptr;
+    return aligned_ptr;
+}
+
+void kfree_aligned(void* ptr)
+{
+    kfree(((void**)ptr)[-1]);
+}
+
+void* kmalloc_page_aligned(size_t size)
+{
+    void* ptr = kmalloc_aligned(size, PAGE_SIZE);
+    size_t d = (size_t)ptr;
+    ASSERT((d & PAGE_MASK) == d);
+    return ptr;
+}
+
+void* kmalloc_impl(size_t size)
+{
+    InterruptDisabler disabler;
+    ++g_kmalloc_call_count;
+
+    if (g_dump_kmalloc_stacks && ksyms_ready) {
+        dbgprintf("kmalloc(%u)\n", size);
+        dump_backtrace();
+    }
+
+    // We need space for the allocation_t structure at the head of the block.
+    size_t real_size = size + sizeof(allocation_t);
+
+    if (sum_free < real_size) {
+        dump_backtrace();
+        kprintf("%s(%u) kmalloc(): PANIC! Out of memory (sucks, dude)\nsum_free=%u, real_size=%u\n", current->process().name().characters(), current->pid(), sum_free, real_size);
+        hang();
+    }
+
+    size_t chunks_needed = real_size / CHUNK_SIZE;
+    if (real_size % CHUNK_SIZE)
+        ++chunks_needed;
+
+    size_t chunks_here = 0;
+    size_t first_chunk = 0;
+
+    for (size_t i = 0; i < (POOL_SIZE / CHUNK_SIZE / 8); ++i) {
+        if (alloc_map[i] == 0xff) {
+            // Skip over completely full bucket.
+            chunks_here = 0;
+            continue;
+        }
+        // FIXME: This scan can be optimized further with LZCNT.
+        for (size_t j = 0; j < 8; ++j) {
+            if (!(alloc_map[i] & (1 << j))) {
+                if (chunks_here == 0) {
+                    // Mark where potential allocation starts.
+                    first_chunk = i * 8 + j;
+                }
+
+                ++chunks_here;
+
+                if (chunks_here == chunks_needed) {
+                    auto* a = (allocation_t*)(BASE_PHYSICAL + (first_chunk * CHUNK_SIZE));
+                    u8* ptr = (u8*)a;
+                    ptr += sizeof(allocation_t);
+                    a->nchunk = chunks_needed;
+                    a->start = first_chunk;
+
+                    for (size_t k = first_chunk; k < (first_chunk + chunks_needed); ++k) {
+                        alloc_map[k / 8] |= 1 << (k % 8);
+                    }
+
+                    sum_alloc += a->nchunk * CHUNK_SIZE;
+                    sum_free -= a->nchunk * CHUNK_SIZE;
+#ifdef SANITIZE_KMALLOC
+                    memset(ptr, 0xbb, (a->nchunk * CHUNK_SIZE) - sizeof(allocation_t));
+#endif
+                    return ptr;
+                }
+            } else {
+                // This is in use, so restart chunks_here counter.
+                chunks_here = 0;
+            }
+        }
+    }
+
+    kprintf("%s(%u) kmalloc(): PANIC! Out of memory (no suitable block for size %u)\n", current->process().name().characters(), current->pid(), size);
+    dump_backtrace();
+    hang();
+}
+
+void kfree(void* ptr)
+{
+    if (!ptr)
+        return;
+
+    InterruptDisabler disabler;
+    ++g_kfree_call_count;
+
+    auto* a = (allocation_t*)((((u8*)ptr) - sizeof(allocation_t)));
+
+    for (size_t k = a->start; k < (a->start + a->nchunk); ++k)
+        alloc_map[k / 8] &= ~(1 << (k % 8));
+
+    sum_alloc -= a->nchunk * CHUNK_SIZE;
+    sum_free += a->nchunk * CHUNK_SIZE;
+
+#ifdef SANITIZE_KMALLOC
+    memset(a, 0xaa, a->nchunk * CHUNK_SIZE);
+#endif
+}
+
+void* operator new(size_t size)
+{
+    return kmalloc(size);
+}
+
+void* operator new[](size_t size)
+{
+    return kmalloc(size);
+}
+
+void operator delete(void* ptr)
+{
+    return kfree(ptr);
+}
+
+void operator delete[](void* ptr)
+{
+    return kfree(ptr);
+}
+
+void operator delete(void* ptr, size_t)
+{
+    return kfree(ptr);
+}
+
+void operator delete[](void* ptr, size_t)
+{
+    return kfree(ptr);
+}