1 files changed, 137 insertions, 0 deletions
diff --git a/src/kernel/mem/mem.cpp b/src/kernel/mem/mem.cpp
new file mode 100644
index 0000000..5e04de3
--- /dev/null
+++ b/src/kernel/mem/mem.cpp
@@ -0,0 +1,137 @@
+#include "mem.h"
+#include <core/sys.h>
+#include <core/monitor.h>
+#include "paging.h"
+
+#include <config.h>
+
+#include "_dlmalloc.h"
+
+#include "mem.h"
+
+#define FREEPAGESTOKEEP 5
+
+#define KHEAP_IDXSIZE 0x4000		// only used with heap.std.h
+#define KHEAP_INITSIZE 0x00080000
+#define KHEAP_MAXSIZE 0x08000000
+
+size_t mem_placementAddr;
+bool _no_more_ksbrk = false;
+
+
+// ******************************
+// 									PAGE ALLOCATION
+// 															****************************
+static struct freepage {
+   size_t virt, phys;
+} freepages[FREEPAGESTOKEEP];
+uint32_t freepagecount = 0;
+
+/*	For internal use only. Populates the cache of pages that can be given to requesters. */
+static void get_free_pages() {
+	static uint32_t locked = 0;
+	uint32_t i;
+	if (locked) return;
+	locked = 1;
+	while (freepagecount < FREEPAGESTOKEEP) {
+		if (_no_more_ksbrk) {
+			for (i = 0xFFFFF000; i >= 0xF0000000; i -= 0x1000) {
+				if (pagedir_getPage(kernel_pagedir, i, 1)->frame == 0) break;
+			}
+			freepages[freepagecount].virt = i;
+			uint32_t frame = frame_alloc();
+			freepages[freepagecount].phys = frame * 0x1000;
+			page_map(pagedir_getPage(kernel_pagedir, i, 0), freepages[freepagecount].phys / 0x1000, 0, 0);
+			freepagecount++;
+		} else {
+			if (mem_placementAddr & 0xFFFFF000) {
+				mem_placementAddr &= 0xFFFFF000;
+				mem_placementAddr += 0x1000;
+			}
+			freepages[freepagecount].virt = (size_t)ksbrk(0x1000);
+			freepages[freepagecount].phys = freepages[freepagecount].virt - K_HIGHHALF_ADDR;
+			freepagecount++;
+		}
+	}
+	locked = 0;
+}
+
+/*	Gives one page from the cache to someone requesting it. */
+void* kmalloc_page(size_t *phys) {
+	cli();
+	get_free_pages();
+	freepagecount--;
+	*phys = freepages[freepagecount].phys;
+	size_t tmp = freepages[freepagecount].virt;
+	sti();
+	return (void*)tmp;
+}
+
+void kfree_page(void* ptr) {
+	size_t addr = (size_t)ptr;
+	if (_no_more_ksbrk) {
+		page_unmapFree(pagedir_getPage(kernel_pagedir, addr, 0));
+	}
+}
+
+//***********************************
+//										MEMORY ALLOCATION FOR DLMALLOC
+//																	*************************
+
+void* ksbrk(size_t size) {
+	if (!_no_more_ksbrk) {		// ksbrk is NOT being called by dlmalloc
+		if (size & 0x0FFF) {
+			size = (size & 0xFFFFF000) + 0x1000;
+		}
+	}
+
+	size_t tmp = mem_placementAddr;
+	size_t er_begin, er_end, i;
+
+	/* (DBG) monitor_write("<ksbrk ");
+	monitor_writeHex(size);
+	monitor_write(":");
+	monitor_writeHex(tmp);
+	monitor_write("> "); */
+
+	mem_placementAddr += size;
+
+	if (_no_more_ksbrk) {		//  paging enabled, we must allocate these pages
+		if (tmp < mem_placementAddr) {
+			er_begin = tmp;
+			if (er_begin & 0x0FFF) er_begin = (er_begin & 0xFFFFF000) + 0x1000;
+			er_end = mem_placementAddr;
+			if (er_end & 0x0FFF) er_end = (er_end & 0xFFFFF000) + 0x1000;
+			for (i = er_begin; i < er_end; i += 0x1000) {
+				page *p = pagedir_getPage(kernel_pagedir, i, 1);
+				size_t f = frame_alloc();
+				page_map(p, f, 0, 0);
+				/* (DBG) monitor_write("<map "); monitor_writeHex(i); monitor_write(" ");
+				monitor_writeHex(f); monitor_write("> "); */
+			}
+		} else if (tmp > mem_placementAddr) {
+			er_begin = (size_t)mem_placementAddr;
+			if (er_begin & 0x0FFF) er_begin = (er_begin & 0xFFFFF000) + 0x1000;
+			er_end = tmp;
+			if (er_end & 0x0FFF) er_end = (er_end & 0xFFFFF000) + 0x1000;
+			for (i = er_end - 0x1000; i >= er_begin; i -= 0x1000) {
+				// (DBG) monitor_write("<unmap:"); monitor_writeHex(i); monitor_write("> ");
+				page_unmapFree(pagedir_getPage(kernel_pagedir, i, 0));
+			}
+		}
+	}
+
+	return (void*)tmp;
+}
+
+void kbrk(void* ptr) {
+	monitor_write("<kbrk ");
+	monitor_writeHex((uint32_t)ptr);
+	monitor_write(">\n");
+
+	if ((size_t)ptr > (size_t)&end) {
+		ksbrk((size_t)ptr - (size_t)mem_placementAddr);
+	} else {
+		PANIC("INVALID KBRK.");
+	}
+}