kernel: initial alloc and free implementation

kernel-src/arch/x86-64/main.c

@@ -8,6 +8,7 @@
 #include <arch/mmu.h>
 #include <kernel/vmm.h>
 #include <kernel/slab.h>
+#include <kernel/alloc.h>
 
 static cpu_t bsp_cpu;
 
@@ -22,5 +23,6 @@ void kernel_entry() {
 	logging_sethook(term_putchar);
 	arch_mmu_init();
 	vmm_init();
+	alloc_init();
 	__assert(!"kernel entry end");
 }

kernel-src/include/kernel/alloc.h

@@ -0,0 +1,10 @@
+#ifndef _ALLOC_H
+#define _ALLOC_H
+
+#include <stddef.h>
+
+void alloc_init();
+void *alloc(size_t s);
+void free(void *addr);
+
+#endif

kernel-src/mm/alloc.c

@@ -0,0 +1,54 @@
+#include <kernel/alloc.h>
+#include <kernel/slab.h>
+#include <logging.h>
+#include <string.h>
+
+#define CACHE_COUNT 12
+
+static size_t allocsizes[CACHE_COUNT] = {32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536};
+static scache_t *caches[CACHE_COUNT];
+
+static void initarea(scache_t *cache, void *obj) {
+	printf("slab ctor called\n");
+	size_t *ptr = obj;
+	*ptr = cache->size - sizeof(size_t);
+	memset(ptr + 1, 0, *ptr);
+}
+
+static scache_t *getcachefromsize(size_t size) {
+	// XXX find a faster way to check this
+	scache_t *cache = NULL;
+	for (int i = 0; i < CACHE_COUNT; ++i) {
+		if (size <= allocsizes[i]) {
+			cache = caches[i];
+			break;
+		}
+	}
+	__assert(cache);
+	return cache;
+}
+
+void *alloc(size_t size) {
+	scache_t *cache = getcachefromsize(size);
+	size_t *ret = slab_allocate(cache);
+	if (ret == NULL)
+		return NULL;
+	return ret + 1;
+}
+
+void free(void *ptr) {
+	size_t *start = ptr;
+	size_t size = *start;
+	start += 1;
+	scache_t *cache = getcachefromsize(size);
+	slab_free(cache, ptr);
+}
+
+
+
+void alloc_init() {
+	for (int i = 0; i < CACHE_COUNT; ++i) {
+		caches[i] = slab_newcache(allocsizes[i] + sizeof(size_t), 0, initarea, initarea);
+		__assert(caches[i]);
+	}
+}