add paging support

1 files changed, 72 insertions, 2 deletions

diff --git a/api/syscall.h b/api/syscall.h
index bdd9972..8c35270 100644
--- a/api/syscall.h
+++ b/api/syscall.h
@@ -6,6 +6,14 @@
 
 #include "obj.h"
 
+/* General syscall behavior:
+ * If the message passed is not a JOVE_OBJ_MESSAGE type, the kernel will return EBADOBJ.
+ * If the message is too small to hold the target path, the kernel will return ETOOSMALL.
+ * If the target path does not target a real object, the kernel will return EBADPATH.
+ * If the target does not support the callid, the kernel will return EBADARG.
+ * Otherwise, behavior depends on the syscall specified in callid.
+ * */
+
 struct syscall_header
 {
     uint16_t callid;
@@ -13,28 +21,51 @@ struct syscall_header
     objpath_part_t path[];
 };
 
+/* If the message is too small for data, the kernel will return ETOOSMALL.
+ * */
 struct syscall_generic_write
 {
     size_t len;
     char data[];
 };
 
+/* If the message is too small for path, the kernel will return ETOOSMALL.
+ * If the path does not point to an object, the kernel will return EBADPATH.
+ * */
 struct syscall_generic_objpath
 {
     uint16_t pathlen;
     objpath_part_t path[];
 };
 
-#define SYSCALL_UNTYPED_SIZE 0
-#define SYSCALL_UNTYPED_ALIGN 1
+/* The kernel will return the physical memory address of this untyped object. */
+#define SYSCALL_UNTYPED_ADDRESS 0
+/* The kernel will return the size of this untyped object. */
+#define SYSCALL_UNTYPED_SIZE 1
 
+/* If newtype is not a valid JOVE object, the kernel will return EBADARG.
+ * If the untyped object is too small for this object, the kernel will return ETOOSMALL.
+ * If the untyped object is too big for this object, the kernel will return ETOOBIG.
+ * New objects will be initialized with default values.
+ * */
 #define SYSCALL_UNTYPED_RETYPE 2
 struct syscall_untyped_retype
 {
     uint16_t newtype;
 };
 
+/* Splits the tail of the untyped object into another untyped object with [bytes] length.
+ * If bytes is less than JOVE_UNTYPED_MINSIZE, the kernel will return ETOOSMALL.
+ * If the syscall message is too small for dest_path, the kernel will return ETOOSMALL.
+ * If dest_path does not target a JOVE_OBJ_NONE object, the kernel will return EBADOBJ.
+ * Destination path will be occupied by the untyped object created by the split.
+ * */
 #define SYSCALL_UNTYPED_SPLIT 3
+/* Follows rules declared above syscall_generic_objpath.
+ * If dest_path does not target a JOVE_OBJ_UNTYPED object, the kernel will return EBADPATH.
+ * If the dest untyped object is not adjacent to the target object, the kernel will return EBADOBJ.
+ * Destination path will be set to JOVE_OBJ_NONE and target untyped will grow to include the object.
+ * */
 #define SYSCALL_UNTYPED_MERGE 4
 struct syscall_untyped_split
 {
@@ -43,8 +74,47 @@ struct syscall_untyped_split
     objpath_part_t dest_path[];
 };
 
+/* Follows rules declared above syscall_generic_objpath.
+ * Returns the object type at path. 
+ * */
 #define SYSCALL_OBJDIR_OBJTYPE 0
 
+/*
+ * If virtual_address does not have a page table, the kernel will return ENOMAP.
+ * If virtual_address already has a mapping, the kernel will return EEXIST.
+ * Follows the rules defined above syscall_pagedir_map.
+ * Maps the untyped page frame to the page table at virtual_address with the passed flags bits.
+ * */
+#define SYSCALL_PAGEDIR_MAP_FRAME 0
+
+/* If virtual_address already has a page table, the kernel will return EHASMAP.
+ * Follows the rules defined above syscall_pagedir_map.
+ * Creates a page table using the untyped object for memory allocation at virtual_address.
+ * Flags bits are always set to writeable and executable.
+ * */
+#define SYSCALL_PAGEDIR_MAP_TABLE 1
+
+/* If virtual_address is above the JOVE_USER_MEMORY_LIMIT, the kernel will return EBADARG.
+ * If the message is too small for untyped_path, the kernel will return ETOOSMALL.
+ * If untyped_path does not point to a valid JOVE_OBJ_UNTYPED, the kernel will return EBADOBJ.
+ * If the untyped object is not aligned to 0x1000, the kernel will return EALIGN.
+ * If the untyped object is not sized to 0x1000, the kernel will return EBADSIZE.
+ *
+ * */
+struct syscall_pagedir_flags
+{
+    uint8_t writeable : 1;
+    uint8_t executable : 1;
+    uint8_t flg_unused : 6;
+};
+struct syscall_pagedir_map
+{
+    struct syscall_pagedir_flags flags;
+    uintptr_t virtual_address;
+    uint16_t untyped_pathlen;
+    objpath_part_t untyped_path[];
+};
+
 #define SYSCALL_VTT_WRITE 0
 
 #endif