mm.c/h -> frames.c/h: Naming indicating dealing with physical not virtual memory

kernel/frames.c

@@ -19,37 +19,43 @@
  */
 
 #include <list.h>
-#include <mm.h>
+#include <frames.h>
 #include <print.h>
 #include <types.h>
 
-struct dlist_node mm_free_page_list;
+struct dlist_node free_frames_list;
 
-void mm_init() {
-	init_list(&mm_free_page_list);
+void frames_init() {
+	init_list(&free_frames_list);
 }
 
-//presupposes mm_free_page_list is a properly initialized list
-void insert_page(struct page *p) {
-	if (list_empty(&mm_free_page_list) || p->address < container(mm_free_page_list.next, struct page, list)->address) {
-		insert_after(&mm_free_page_list, &p->list);
-	} else if (p->address > container(mm_free_page_list.prev, struct page, list)->address) {
-		insert_before(&mm_free_page_list, &p->list);
+/*
+ * Adds a page frame struct to the list of free page frames. Presupposes
+ * free_frames_list is a properly initialized list.
+ */
+static void insert_page_frame(struct frame *p) {
+	if (list_empty(&free_frames_list) || p->address < container(free_frames_list.next, struct frame, list)->address) {
+		insert_after(&free_frames_list, &p->list);
+	} else if (p->address > container(free_frames_list.prev, struct frame, list)->address) {
+		insert_before(&free_frames_list, &p->list);
 	} else {
-		struct page *it;
-		for_each_list(it, &mm_free_page_list, struct page, list) {
+		struct frame *it;
+		for_each_list(it, &free_frames_list, struct frame, list) {
 			if (p->address < it->address) {
 				insert_before(&it->list, &p->list);
 				return;
 			}
 		}
-		print("Error: failed to insert page\n");
+		print("Error: failed to insert page frame\n");
 	}
 }
 
-void mm_add_free_region(void *start, void *end) {
+/*
+ * Called to add a segment of memory to the frame allocation pool.
+ */
+static void add_physical_memory(void *start, void *end) {
 	unsigned int num_pages, usable_pages;
-	struct page *p;
+	struct frame *p;
 	void *page;
 
 	//If region starts at 0x0, make it start at next page to not screw up null pointer detection, etc.
@@ -73,40 +79,44 @@ void mm_add_free_region(void *start, void *end) {
 	//TODO we're potentially losing memory here because we're calculating
 	//the number of page structs we need even for those pages that will contain only page structs
 	num_pages = ((char *)end + 1 - (char *)start) / MM_PAGE_SIZE;
-	usable_pages = num_pages - num_pages * sizeof(struct page) / MM_PAGE_SIZE;
-	if (num_pages * sizeof(struct page) % MM_PAGE_SIZE)
+	usable_pages = num_pages - num_pages * sizeof(struct frame) / MM_PAGE_SIZE;
+	if (num_pages * sizeof(struct frame) % MM_PAGE_SIZE)
 		usable_pages--;
 
-	p = (struct page *)start;
+	p = (struct frame *)start;
 	for (page = ((char *)start) + (num_pages - usable_pages)*MM_PAGE_SIZE; page < end; page = (void *)(((char *)page) + MM_PAGE_SIZE)) {
 		p->address = page;
-		insert_page(p);
+		insert_page_frame(p);
 		p++;
 	}
 }
 
-struct page* mm_get_free_pages(unsigned int power) {
+/*
+ * Attempt to get 2^power contiguous page frames. Returns the frame struct of
+ * the first frame on success or a null pointer on failure.
+ */
+struct frame* get_free_frames(unsigned int power) {
 	unsigned int num_pages = 1<<power;
-	struct page *it;
+	struct frame *it;
 
-	if (list_empty(&mm_free_page_list)) {
+	if (list_empty(&free_frames_list)) {
 		print("Error: Out of memory\n");
-		return (struct page*)0;
+		return (struct frame*)0;
 	}
 
 	if (!num_pages) {
 		print("Error: mm_get_free_pages must be called with power from 0 to 31, inclusive (power=%d)\n", power);
-		return (struct page*)0;
+		return (struct frame*)0;
 	}
 
-	for_each_list(it, &mm_free_page_list, struct page, list) {
+	for_each_list(it, &free_frames_list, struct frame, list) {
 		unsigned int curr_pages = 1;
-		struct page *it2;
-		for (it2 = container(it->list.next, struct page, list);
-					it2->list.next != &mm_free_page_list && curr_pages < num_pages;
-					it2 = container(it2->list.next, struct page, list)) {
-			if ((char*)it2->address != (char*)container(it2->list.prev, struct page, list)->address + MM_PAGE_SIZE) {
-				it = it2; //fast-forward 'it' to start of next contiguous section of pages 
+		struct frame *it2;
+		for (it2 = container(it->list.next, struct frame, list);
+					it2->list.next != &free_frames_list && curr_pages < num_pages;
+					it2 = container(it2->list.next, struct frame, list)) {
+			if ((char*)it2->address != (char*)container(it2->list.prev, struct frame, list)->address + MM_PAGE_SIZE) {
+				it = it2; //fast-forward 'it' to start of next contiguous section of pages
 				break;
 			} else {
 				curr_pages++;
@@ -117,14 +127,17 @@ struct page* mm_get_free_pages(unsigned int power) {
 			return it;
 		}
 	}
-	return (struct page*)0;
+	return (struct frame*)0;
 }
 
-int mm_put_free_pages(struct page *p) {
-	struct page *it;
-	for_each_list(it, &mm_free_page_list, struct page, list) {
-		if (p->address < it->address) {
-			insert_splice_before(&it->list, &p->list, p->list.prev);
+/*
+ * Return pages allocated to the pool of unused pages.
+ */
+int put_free_frames(struct frame *f) {
+	struct frame *it;
+	for_each_list(it, &free_frames_list, struct frame, list) {
+		if (f->address < it->address) {
+			insert_splice_before(&it->list, &f->list, f->list.prev);
 			return 0;
 		}
 	}

kernel/init.c

@@ -20,9 +20,9 @@
 
 #include <console.h>
 #include <framebuffer.h>
+#include <frames.h>
 #include <kmalloc.h>
 #include <print.h>
-#include <mm.h>
 #include <mmu.h>
 #include <types.h>
 
@@ -109,7 +109,7 @@ int main(void) {
 	serial_console_init();
 
 	//setup memory subsystems
-	mm_init();
+	frames_init();
 	kmalloc_init();
 	if (detect_memory()) {
 		print("Error: Failed to detect memory.\n");

kernel/kernel.mk

@@ -6,11 +6,11 @@ include $(BASEDIR)/header.mk
 OBJS_$(d) := $(d)/console.o \
 	$(d)/font.o \
 	$(d)/framebuffer.o \
+	$(d)/frames.o \
 	$(d)/init.o \
 	$(d)/kmalloc.o \
 	$(d)/list.o \
 	$(d)/math.o \
-	$(d)/mm.o \
 	$(d)/print.o
 
 KOBJS += $(OBJS_$(d))

kernel/kmalloc.c

@@ -19,7 +19,7 @@
  */
 
 #include <kmalloc.h>
-#include <mm.h>
+#include <frames.h>
 #include <list.h>
 #include <print.h>
 
@@ -96,12 +96,12 @@ coalesce:
 void *_kmalloc(unsigned int bytes, unsigned int tries);
 
 void *grow_and_retry(unsigned int bytes, unsigned int tries) {
-	struct page *p;
+	struct frame *f;
 
-	if ((p = mm_get_free_pages(curr_page_power))) {
-		struct kmalloc_region *region = (struct kmalloc_region *)p->address;
-		//TODO don't throw away p, but keep it in a list (allocate a little at the beginning of this chunk for a list element), so we can free pages later if we want to
-		region->end = (char *)region + MM_PAGE_SIZE * (1 << curr_page_power) - 1;
+	if ((f = get_free_frames(curr_page_power))) {
+		struct kmalloc_region *region = (struct kmalloc_region *)f->address;
+		//TODO don't throw away f, but keep it in a list (allocate a little at the beginning of this chunk for a list element), so we can free pages later if we want to
+		region->end = (char *)region + CONFIG_PAGE_SIZE * (1 << curr_page_power) - 1;
 		add_region(region);
 		curr_page_power++;
 		return _kmalloc(bytes, tries);