4 files changed, 90 insertions, 9 deletions

diff --git a/src/kernel/include/pager.h b/src/kernel/include/pager.h
new file mode 100644
index 0000000..5491d10
--- /dev/null
+++ b/src/kernel/include/pager.h
@@ -0,0 +1,73 @@
+#pragma once
+
+#include <hashtbl.h>
+#include <mutex.h>
+
+#include <paging.h>
+
+#define PAGE_PINNED		0x01
+#define PAGE_ACCESSED	0x02
+#define PAGE_DIRTY		0x04
+
+typedef struct pager pager_t;
+typedef struct user_region user_region_t;
+typedef struct fs_node fs_node_t;
+
+typedef struct {
+	size_t (*read)(fs_node_t* data, size_t offset, size_t len, char* ptr);
+	size_t (*write)(fs_node_t* data, size_t offset, size_t len, const char* ptr);
+	bool (*resize)(fs_node_t* data, size_t new_size);
+} vfs_pager_ops_t;
+
+typedef struct {
+	void (*page_in)(pager_t *p, size_t offset, size_t len);			// allocates the pages
+	void (*page_commit)(pager_t *p, size_t offset, size_t len);		// writes pages back to storage (if applicable)
+	void (*page_out)(pager_t *p, size_t offset, size_t len);		// frees the pages (no need to write back)
+	void (*page_release)(pager_t *p, size_t offset, size_t len);	// called on delete/resize
+} pager_ops_t;
+
+typedef struct pager {
+	pager_ops_t *ops;
+
+	union {
+		struct {
+			fs_node_t* vfs_data;
+			vfs_pager_ops_t *vfs_ops;
+		} vfs_pager;
+		struct {
+			size_t phys_offset;
+		} device_pager;
+	};
+
+	size_t size;
+
+	hashtbl_t *pages;
+	mutex_t lock;
+
+	user_region_t *maps;
+} pager_t;
+
+pager_t* new_swap_pager(size_t size);
+pager_t* new_vfs_pager(size_t size, fs_node_t* vfs_node, vfs_pager_ops_t *vfs_ops);
+pager_t* new_dev_pager(size_t size, size_t phys_offset);
+
+void delete_pager(pager_t *p);
+
+bool pager_resize(pager_t *p, size_t newsize);
+
+// void pager_pin_region(pager_t *pager, size_t offset, size_t len);	// implement later
+// void pager_unpin_region(pager_t *pager, size_t offset, size_t len);
+
+void pager_access(pager_t *p, size_t offset, size_t len, bool accessed, bool dirty);
+void pager_commit_dirty(pager_t *p);
+
+int pager_get_frame(pager_t *p, size_t offset);
+
+size_t pager_read(pager_t *p, size_t offset, size_t len, char* buf);
+size_t pager_write(pager_t *p, size_t offset, size_t len, const char* buf);
+
+void pager_add_map(pager_t *p, user_region_t *reg);
+void pager_rm_map(pager_t *p, user_region_t *reg);
+
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/process.h b/src/kernel/include/process.h
index 8dfa274..8cdfe85 100644
--- a/src/kernel/include/process.h
+++ b/src/kernel/include/process.h
@@ -15,9 +15,9 @@
 
 #include <thread.h>
 #include <vfs.h>
+#include <pager.h>
 
-#include <mmap.h>
-
+#include <mmap.h>	// common header for mmaps
 #include <proc.h> 	// common header defining process statuses
 
 #define USERSTACK_ADDR	0xB8000000
@@ -31,12 +31,15 @@ typedef struct user_region {
 	void* addr;
 	size_t size;
 
-	int mode;
+	fs_handle_t *file;
+	pager_t *pager;
+	size_t offset;
+	bool own_pager;
 
-	fs_handle_t *file;		// null if not mmaped-file
-	size_t file_offset;
+	int16_t mode;
 
-	struct user_region *next;
+	struct user_region *next_in_proc;
+	struct user_region *next_for_pager;
 } user_region_t;
 
 typedef struct process {
diff --git a/src/kernel/include/sys.h b/src/kernel/include/sys.h
index 944df96..61bfc59 100644
--- a/src/kernel/include/sys.h
+++ b/src/kernel/include/sys.h
@@ -75,9 +75,10 @@ static inline void invlpg(void* addr) {
 
 #define PAGE_SIZE		0x1000
 #define PAGE_MASK		0xFFFFF000
-#define PAGE_ALIGN_DOWN(x)	(((size_t)x) & PAGE_MASK) 
-#define PAGE_ALIGN_UP(x)  	((((size_t)x)&(~PAGE_MASK)) == 0 ? ((size_t)x) : (((size_t)x) & PAGE_MASK) + PAGE_SIZE)
-#define PAGE_ID(x)			(((size_t)x) / PAGE_SIZE)
+#define PAGE_ALIGNED(x)     ((((size_t)(x)) & (~PAGE_MASK)) == 0)
+#define PAGE_ALIGN_DOWN(x)	(((size_t)(x)) & PAGE_MASK) 
+#define PAGE_ALIGN_UP(x)  	((((size_t)(x))&(~PAGE_MASK)) == 0 ? ((size_t)x) : (((size_t)x) & PAGE_MASK) + PAGE_SIZE)
+#define PAGE_ID(x)			(((size_t)(x)) / PAGE_SIZE)
 #define PAGE_SHIFT		12
 #define PT_SHIFT		10
 // PAGE_SHIFT + PT_SHIFT + PT_SHIFT = 32
diff --git a/src/kernel/include/vfs.h b/src/kernel/include/vfs.h
index cc6d11c..cdd9e8d 100644
--- a/src/kernel/include/vfs.h
+++ b/src/kernel/include/vfs.h
@@ -8,6 +8,8 @@
 
 #include <fs.h> 		// common header
 
+#include <pager.h>
+
 // How to use :
 // - When using a filesystem : never call the operations in fs_*_ops_t directly, use
 // 		the functions defined bellow in section "public functions";
@@ -108,6 +110,8 @@ typedef struct fs_node {
 	// These fields are filled by the FS's specific walk() code
 	fs_node_ops_t *ops;
 	fs_node_ptr data;
+
+	pager_t *pager;
 } fs_node_t;
 
 // -------------------------------------------