Add slab allocator

core/alloc.c

@@ -0,0 +1,98 @@
+#define pr_fmt(fmt) "[alloc]: " fmt
+//#define DEBUG
+#include "alloc.h"
+#include "errno.h"
+#include "list.h"
+#include "math.h"
+#include "mem.h"
+#include "vga.h"
+
+// Slab will contains object from sizeof(void *) to PAGE_SIZE/2 by pow2
+#define SLUB_SIZE (PAGE_SHIFT - 1)
+struct slabDesc *slubArray[SLUB_SIZE];
+
+int initSlabDesc(struct slabDesc **desc, size_t size);
+int formatPage(struct slabDesc *desc, size_t size);
+
+int initSlab(void)
+{
+        uint start = log2(sizeof(void *));
+        for (uint i = start; i < SLUB_SIZE; i++) {
+                if (initSlabDesc(&slubArray[i - start], 1U << i))
+                        return ENOMEM;
+        }
+        return 0;
+}
+
+int initSlabDesc(struct slabDesc **desc, size_t size)
+{
+        if (size > PAGE_SIZE)
+                return ENOENT;
+        paddr_t alloc = allocPhyPage();
+        if (alloc == (paddr_t)NULL)
+                return ENOMEM;
+        if (pageMap((vaddr_t)alloc, alloc, PAGING_MEM_WRITE)) {
+                return ENOMEM;
+        }
+        *desc = (struct slabDesc *)alloc;
+        list_singleton(*desc, *desc);
+        (*desc)->page   = (vaddr_t)alloc;
+        (*desc)->full   = 0;
+        (*desc)->freeEl = (char *)(*desc) + sizeof(struct slabDesc);
+        (*desc)->size   = size;
+        pr_devel("got page %d for size %d first %d", alloc, size, (*desc)->freeEl);
+        return formatPage((*desc), size);
+}
+
+int formatPage(struct slabDesc *desc, size_t size)
+{
+        char *cur = (char *)desc + sizeof(struct slabDesc);
+        ulong i;
+        for (i = 0; i < ((PAGE_SIZE - sizeof(struct slabDesc)) / size - 1); i++) {
+                *((vaddr_t *)cur) = (vaddr_t)cur + size;
+                cur += size;
+        }
+        *((vaddr_t *)cur) = (vaddr_t)NULL;
+        pr_devel("last at %d allocated %d\n", cur, i + 1);
+        return 0;
+}
+
+static void *allocFromSlab(struct slabDesc *slab)
+{
+        vaddr_t *next = slab->freeEl;
+        if (*next == (vaddr_t)NULL) {
+                pr_devel("Slab %d full\n", slab);
+                slab->full = 1;
+        } else {
+                slab->freeEl = (void *)(*next);
+        }
+        return (void *)next;
+}
+
+void *malloc(size_t size)
+{
+        if (size > (1U << SLUB_SIZE)) {
+                printf("implement malloc for big size\n");
+                return NULL;
+        }
+        uint slubIdx = 0;
+        while (size > slubArray[slubIdx]->size) {
+                slubIdx++;
+        }
+        struct slabDesc *slab;
+        int slabIdx;
+        list_foreach(slubArray[slubIdx], slab, slabIdx)
+        {
+                if (!slab->full) {
+                        pr_devel("found place in slub %d at idx %d \n", slubIdx, slabIdx);
+                        return allocFromSlab(slab);
+                }
+        }
+        if (!list_foreach_early_break(slubArray[slubIdx], slab, slabIdx)) {
+                struct slabDesc *newSlab;
+                initSlabDesc(&newSlab, slab->size);
+                list_add_head(slubArray[slubIdx], newSlab);
+                return allocFromSlab(newSlab);
+        }
+        return NULL;
+}

core/alloc.h

@@ -0,0 +1,15 @@
+#pragma once
+#include "paging.h"
+#include "stdarg.h"
+
+struct slabDesc {
+        vaddr_t page;
+        size_t size;
+        void *freeEl;
+        char full;
+        struct slabDesc *next;
+        struct slabDesc *prev;
+};
+int initSlab(void);
+
+void *malloc(size_t size);

core/main.c

@@ -1,3 +1,4 @@
+#include "alloc.h"
 #include "exception.h"
 #include "gdt.h"
 #include "idt.h"
@@ -83,6 +84,7 @@ void kmain(unsigned long magic, unsigned long addr)
 #ifdef RUN_TEST
     run_test();
 #endif
+    initSlab();
 
     int count = 0;
     while (1) {

core/math.c

@@ -0,0 +1,11 @@
+#include "math.h"
+
+inline uint32_t log2(const uint32_t x) {
+  uint32_t y;
+  // Get the highest set bit
+  asm ( "\tbsr %1, %0\n"
+      : "=r"(y)
+      : "r" (x)
+  );
+  return y;
+}

core/math.h

@@ -0,0 +1,4 @@
+#pragma once
+#include "stdint.h"
+
+uint32_t log2(uint32_t x);

core/mem.h

@@ -3,8 +3,8 @@
 #include "stdarg.h"
 
 
-#define PAGE_SHIFT 12
-#define PAGE_SIZE (1 << PAGE_SHIFT)
+#define PAGE_SHIFT 12U
+#define PAGE_SIZE (1U << PAGE_SHIFT)
 
 // Defined in linker.ld script
 extern uint32_t __ld_kernel_begin;

core/paging.h

@@ -2,8 +2,8 @@
 #include "types.h"
 
 #define PAGING_MEM_USER 1
-#define PAGING_MEM_READ (1 << 1)
-#define PAGING_MEM_WRITE (1 << 2)
+#define PAGING_MEM_READ (1U << 1)
+#define PAGING_MEM_WRITE (1U << 2)
 
 int pagingSetup(paddr_t upperKernelAddr);
 

core/stdarg.h

@@ -41,9 +41,11 @@ typedef enum { FALSE=0, TRUE } bool_t;
 #if __x86_64__
 typedef unsigned long size_t;
 typedef long ssize_t;
+typedef unsigned long int  uintptr_t;
 #else
 typedef unsigned int size_t;
 typedef int ssize_t;
+typedef unsigned int    uintptr_t;
 #endif
 
 typedef void *va_list;