Merge branch 'main' of https://github.com/kenshineto/kern into fat32

Merging main into here

17 files changed, 381 insertions, 138 deletions

diff --git a/kernel/include/comus/asm.h b/kernel/include/comus/asm.h
index c7597e7..4f376b1 100644
--- a/kernel/include/comus/asm.h
+++ b/kernel/include/comus/asm.h
@@ -36,8 +36,10 @@ static inline uint16_t inw(uint16_t port)
 
 static inline void rep_inw(uint16_t port, uint16_t *buffer, size_t count)
 {
-	while (count--)
-		*(buffer++) = inw(port);
+	__asm__ volatile("rep insw"
+					 : "+D"(buffer), "+c"(count)
+					 : "d"(port)
+					 : "memory");
 }
 
 static inline void outw(uint16_t port, uint16_t val)
diff --git a/kernel/include/comus/cpu.h b/kernel/include/comus/cpu.h
index ffc1782..df8f44e 100644
--- a/kernel/include/comus/cpu.h
+++ b/kernel/include/comus/cpu.h
@@ -31,6 +31,13 @@ struct cpu_feat {
 };
 
 struct cpu_regs {
+	// pgdir
+	uint64_t cr3;
+	// segments
+	uint16_t gs;
+	uint16_t fs;
+	uint16_t es;
+	uint16_t ds;
 	// registers
 	uint64_t r15;
 	uint64_t r14;
@@ -89,4 +96,9 @@ void cpu_feats(struct cpu_feat *feats);
  */
 void cpu_print_regs(struct cpu_regs *regs);
 
+/**
+ * Return from a syscall handler back into userspace
+ */
+__attribute__((noreturn)) void syscall_return(void);
+
 #endif /* cpu.h */
diff --git a/kernel/include/comus/drivers/ata.h b/kernel/include/comus/drivers/ata.h
index 2f35e03..c404d84 100644
--- a/kernel/include/comus/drivers/ata.h
+++ b/kernel/include/comus/drivers/ata.h
@@ -44,7 +44,7 @@ enum ide_error ata_init(void);
  *
  * @returns IDE_ERROR_OK (0) on success or an error code on failure
  */
-enum ide_error ide_device_read_sectors(ide_device_t, uint8_t numsects,
+enum ide_error ide_device_read_sectors(ide_device_t, uint16_t numsects,
 									   uint32_t lba,
 									   uint16_t buf[numsects * 256]);
 
@@ -53,7 +53,7 @@ enum ide_error ide_device_read_sectors(ide_device_t, uint8_t numsects,
  *
  * @returns 0 on success or an error code on failure
  */
-enum ide_error ide_device_write_sectors(ide_device_t, uint8_t numsects,
+enum ide_error ide_device_write_sectors(ide_device_t, uint16_t numsects,
 										uint32_t lba,
 										uint16_t buf[numsects * 256]);
 
diff --git a/kernel/include/comus/drivers/gpu.h b/kernel/include/comus/drivers/gpu.h
index 39c633f..0a8f4fa 100644
--- a/kernel/include/comus/drivers/gpu.h
+++ b/kernel/include/comus/drivers/gpu.h
@@ -11,7 +11,7 @@
 
 #include <stdint.h>
 
-struct gpu {
+struct gpu_dev {
 	const char *name;
 	uint16_t width;
 	uint16_t height;
@@ -31,7 +31,7 @@ struct psf2_font {
 	uint8_t data[];
 };
 
-extern struct gpu *gpu_dev;
+extern struct gpu_dev *gpu_dev;
 extern struct psf2_font en_font;
 
 /**
diff --git a/kernel/include/comus/drivers/gpu/bochs.h b/kernel/include/comus/drivers/gpu/bochs.h
index 7d26b60..ec70060 100644
--- a/kernel/include/comus/drivers/gpu/bochs.h
+++ b/kernel/include/comus/drivers/gpu/bochs.h
@@ -15,6 +15,6 @@
  * Loads the bochs graphics driver
  * @returns 0 on success, NULL on error
  */
-int bochs_init(struct gpu **gpu_dev);
+int bochs_init(struct gpu_dev **gpu_dev);
 
 #endif /* bochs.h */
diff --git a/kernel/include/comus/drivers/gpu/gop.h b/kernel/include/comus/drivers/gpu/gop.h
index 6475f05..d3af921 100644
--- a/kernel/include/comus/drivers/gpu/gop.h
+++ b/kernel/include/comus/drivers/gpu/gop.h
@@ -15,6 +15,6 @@
  * Loads the uefi gop graphics driver
  * @returns 0 on success, NULL on error
  */
-int gop_init(struct gpu **gpu_dev);
+int gop_init(struct gpu_dev **gpu_dev);
 
 #endif /* gop.h */
diff --git a/kernel/include/comus/drivers/ps2.h b/kernel/include/comus/drivers/ps2.h
new file mode 100644
index 0000000..7634e5f
--- /dev/null
+++ b/kernel/include/comus/drivers/ps2.h
@@ -0,0 +1,27 @@
+/**
+ * @file ps2.h
+ *
+ * @author Freya Murphy <freya@freyacat.org>
+ *
+ * PS/2 Mouse & Keyboard
+ */
+
+#ifndef PS2_H_
+#define PS2_H_
+
+/**
+ * Initalize the ps2 controller
+ */
+int ps2_init(void);
+
+/**
+ * Recieve input from ps2 keyboard during interrupt
+ */
+void ps2kb_recv(void);
+
+/**
+ * Recieve input from ps2 mouse during interrupt
+ */
+void ps2mouse_recv(void);
+
+#endif /* ps2.h */
diff --git a/kernel/include/comus/fs.h b/kernel/include/comus/fs.h
index e67b6fe..c48e3e1 100644
--- a/kernel/include/comus/fs.h
+++ b/kernel/include/comus/fs.h
@@ -9,7 +9,6 @@
 #ifndef FS_H_
 #define FS_H_
 
-#include <stdint.h>
 #include <stddef.h>
 #include <comus/limits.h>
 #include <comus/drivers/ata.h>
@@ -45,7 +44,7 @@ struct disk {
  * @param offset - the offset into the disk to read
  * @param len - the length of the data to read into `buffer`
  * @param buffer - the buffer to save data into
- * @returns bytes read on success, negative fs error code in failure
+ * @returns number of bytes read on success, negative fs error code in failure
  */
 int disk_read(struct disk *disk, size_t offset, size_t len, void *buffer);
 
@@ -56,7 +55,7 @@ int disk_read(struct disk *disk, size_t offset, size_t len, void *buffer);
  * @param offset - the offset into the disk to write
  * @param len - the length of the data to write into `buffer`
  * @param buffer - the buffer to read from
- * @returns bytes written on success, negative fs error code in failure
+ * @returns number of bytes written on success, negative fs error code in failure
  */
 int disk_write(struct disk *disk, size_t offset, size_t len, void *buffer);
 
@@ -65,104 +64,55 @@ enum file_type {
 	F_REG = 0,
 	// directory
 	F_DIR = 1,
-	// symbolic link
-	F_SYM = 2,
 };
 
-/// TODO: file name queue or storage area???
-/// hash map?!? (performance !!! :) )
+struct dirent {
+	int d_id;
+	unsigned long d_offset;
+	unsigned short d_namelen;
+	char d_name[N_FILE_NAME];
+};
+
+struct stat {
+	/// file id
+	int s_id;
+	/// file type
+	enum file_type s_type;
+	/// file length
+	unsigned long s_length;
+};
 
 struct file {
-	/// name of the file
-	char name[N_FILE_NAME];
-	/// parent directory of the file
-	struct file_s *parent;
-	/// type of the file
-	enum file_type type;
-	/// the filesystem of this file
-	struct file_system *fsys;
+	/// file id
+	int f_id;
+	/// read from the file
+	int (*read)(struct file *, char *, size_t);
+	/// write into the file
+	int (*write)(struct file *, char *, size_t);
+	/// seeks the file
+	int (*seek)(struct file *, long);
+	/// get directory entry at index
+	int (*ents)(struct file *, struct dirent *, size_t);
 };
 
-/// vtable for filesystem functions
-/// NOTE: feel free to change this as needed
-/// its just stuff that i thought may be good
 struct file_system {
 	/// set to 1 in fs array to state that fs is defined
 	/// system use only
-	int present;
+	int fs_present;
 	/// index into the loaded filesystems array
 	/// system use only
-	int id;
+	int fs_id;
+	/// mount point of this filesystem
+	/// system use only
+	char fs_mount[N_FILE_NAME];
 	/// the disk this filesystem is hooked up to
 	struct disk disk;
-	/// get root file in file file_system
-	/// @param fs - the file system
-	/// @returns the root file or NULL on failure
-	struct file *(*fs_get_root_file)(struct file_system *fs);
-	/// rename a file
-	/// @param fs - the file system
-	/// @param file - the file to rename
-	/// @param name - the new file name
-	/// @returns 0 on success, or an negative fs error code on failure
-	int (*fs_rename_file)(struct file_system *fs, struct file *file,
-						  char *name);
-	/// get length of file
-	/// @param fs - the file system
-	/// @param file - the file to get the length of
-	/// @param length - the pointer to save the length to
-	/// @return 0 on success, or an negative fs error code on failure
-	int (*fs_get_file_length)(struct file_system *fs, struct file *file,
-							  uint64_t *length);
-	/// get created date of file
-	/// @param fs - the file system
-	/// @param file - the file to get the date created
-	/// @param created - the pointer to save the created date to
-	/// @param modified - the pointer to save the modified date to
-	/// @param accessed - the pointer to save the accessed date to
-	/// @return 0 on success, or an negative fs error code on failure
-	int (*fs_get_file_dates)(struct file_system *fs, struct file *file,
-							 uint64_t *created, uint64_t *modified,
-							 uint64_t *accessed);
-	/// delete a file in the file system
-	/// @param fs - the file system
-	/// @param file - the file to delete
-	/// @returns 0 on success, or an negative fs error code on failure
-	int (*fs_delete_file)(struct file_system *fs, struct file *file);
-	/// create a file with a given name and type
-	/// @param fs - the file system
-	/// @param res - the new file structure to save the new file into
-	/// @param parent - the parent (directory) of the file to create
-	/// @param type - the type of file to create
-	/// @returns 0 on success, or an negative fs error code on failure
-	int (*fs_new_file)(struct file_system *fs, struct file *res,
-					   struct file *parent, enum file_type type);
-	/// get files in a directory
-	/// @param fs - the file system
-	/// @param dir - the directory to search into
-	/// @param start - the directory entry to start at
-	/// @param len - the max number of entrys to save starting at `start`
-	/// @param res - the list of structures to save into
-	/// @returns number of entries read, or an negative fs error code on failure
-	int (*fs_get_dir_ents)(struct file_system *fs, struct file *dir,
-						   size_t start, size_t len, struct file res[]);
-	/// read from a file
-	/// @param fs - the file system
-	/// @param file - the file to read from
-	/// @param offset - the offset of the file to read into
-	/// @param length - the length of the file to read starting at `offset`
-	/// @param buffer - the buffer to save the data into
-	/// @returns number of bytes read, or an negative fs error code on failure
-	int (*fs_read_file)(struct file_system *fs, struct file *file,
-						size_t offset, size_t length, uint8_t *buffer);
-	/// write into a file
-	/// @param fs - the file system
-	/// @param file - the file to write to
-	/// @param offset - the offset of the file to write into
-	/// @param length - the length of the data to write
-	/// @param buffer - the buffer the data to write is stored in
-	/// @returns number of bytes written, or an negative fs error code on failure
-	int (*fs_write_file)(struct file_system *fs, struct file *file,
-						 size_t offset, size_t length, uint8_t *buffer);
+	/// opens a file
+	int (*open)(const char *, struct file **);
+	/// closes a file
+	void (*close)(struct file *);
+	/// stats a file
+	int (*stat)(const char *, struct stat *);
 };
 
 // list of all disks on the system
@@ -190,29 +140,4 @@ struct disk *fs_get_root_disk(void);
  */
 struct file_system *fs_get_root_file_system(void);
 
-/**
- * Find a file in the given file system, traversing the path
- * Always use this function to find files globally
- *
- * @param fs - the file system to search
- * @param name - the absolute path of the file to look for
- * @param res - where to store the file structure
- * @returns 0 on success, or an negative fs error code on failure
- */
-int fs_find_file_abs(struct file_system *fs, char *abs_path, struct file *res);
-
-/**
- * Find a file in the given file system, traversing the path, relative to
- * another file.
- * Always use this function to find files globally
- *
- * @param rel - the relative file to search from
- * @param name - the absolute path of the file to look for
- * @param res - where to store the file structure
- * @returns 0 on success, or an negative fs error code on failure
- */
-int fs_find_file_rel(struct file *rel, char *rel_path, struct file *res);
-
-// NOTE: fell free to add more functions if needed :)
-
 #endif /* fs.h */
diff --git a/kernel/include/comus/input.h b/kernel/include/comus/input.h
new file mode 100644
index 0000000..b2b3053
--- /dev/null
+++ b/kernel/include/comus/input.h
@@ -0,0 +1,36 @@
+/**
+ * @file input.h
+ */
+
+#ifndef INPUT_H_
+#define INPUT_H_
+
+#include <comus/keycodes.h>
+#include <comus/limits.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+struct keycode {
+	char key;
+	char flags;
+};
+
+struct mouse_event {
+	bool updated;
+	bool lmb;
+	bool rmb;
+	bool mmb;
+	int relx;
+	int rely;
+};
+
+void keycode_push(struct keycode *ev);
+int keycode_pop(struct keycode *ev);
+size_t keycode_len(void);
+char keycode_to_char(struct keycode *ev);
+
+void mouse_event_push(struct mouse_event *ev);
+int mouse_event_pop(struct mouse_event *ev);
+size_t mouse_event_len(void);
+
+#endif /* input.h */
diff --git a/kernel/include/comus/keycodes.h b/kernel/include/comus/keycodes.h
new file mode 100644
index 0000000..ebf296a
--- /dev/null
+++ b/kernel/include/comus/keycodes.h
@@ -0,0 +1,138 @@
+/**
+ * @file keycodes.h
+ *
+ * @author Tristan Miller <trimill@trimill.xyz>
+ *
+ * Kernel keycodes
+ */
+
+#ifndef KEYCODES_H_
+#define KEYCODES_H_
+
+#define KC_FLAG_KEY_DOWN 0x01
+#define KC_FLAG_KEY_UP 0x02
+#define KC_FLAG_ERROR 0x04
+
+#define KEY_NONE 0x00
+#define KEY_UNKNOWN 0x01
+
+#define KEY_ESCAPE 0x10
+#define KEY_1 0x11
+#define KEY_2 0x12
+#define KEY_3 0x13
+#define KEY_4 0x14
+#define KEY_5 0x15
+#define KEY_6 0x16
+#define KEY_7 0x17
+#define KEY_8 0x18
+#define KEY_9 0x19
+#define KEY_0 0x1A
+#define KEY_MINUS 0x1B
+#define KEY_EQUAL 0x1C
+#define KEY_BACKSPACE 0x1D
+#define KEY_L_SHIFT 0x1E
+#define KEY_R_SHIFT 0x1F
+
+#define KEY_TAB 0x20
+#define KEY_Q 0x21
+#define KEY_W 0x22
+#define KEY_E 0x23
+#define KEY_R 0x24
+#define KEY_T 0x25
+#define KEY_Y 0x26
+#define KEY_U 0x27
+#define KEY_I 0x28
+#define KEY_O 0x29
+#define KEY_P 0x2A
+#define KEY_L_BRACE 0x2B
+#define KEY_R_BRACE 0x2C
+#define KEY_BACKSLASH 0x2D
+#define KEY_L_CTRL 0x2E
+#define KEY_R_CTRL 0x2F
+
+#define KEY_CAPS_LOCK 0x30
+#define KEY_A 0x31
+#define KEY_S 0x32
+#define KEY_D 0x33
+#define KEY_F 0x34
+#define KEY_G 0x35
+#define KEY_H 0x36
+#define KEY_J 0x37
+#define KEY_K 0x38
+#define KEY_L 0x39
+#define KEY_SEMICOLON 0x3A
+#define KEY_QUOTE 0x3B
+#define KEY_ENTER 0x3C
+#define KEY_MENU 0x3D
+#define KEY_L_ALT 0x3E
+#define KEY_R_ALT 0x3F
+
+#define KEY_SPACE 0x40
+#define KEY_Z 0x41
+#define KEY_X 0x42
+#define KEY_C 0x43
+#define KEY_V 0x44
+#define KEY_B 0x45
+#define KEY_N 0x46
+#define KEY_M 0x47
+#define KEY_COMMA 0x48
+#define KEY_PERIOD 0x49
+#define KEY_SLASH 0x4A
+#define KEY_BACKTICK 0x4B
+#define KEY_NUM_LOCK 0x4C
+#define KEY_SCROLL_LOCK 0x4D
+#define KEY_L_META 0x4E
+#define KEY_R_META 0x4F
+
+#define KEY_NP_SLASH 0x50
+#define KEY_NP_7 0x51
+#define KEY_NP_8 0x52
+#define KEY_NP_9 0x53
+#define KEY_NP_ASTERISK 0x54
+#define KEY_NP_4 0x55
+#define KEY_NP_5 0x56
+#define KEY_NP_6 0x57
+#define KEY_NP_MINUS 0x58
+#define KEY_NP_1 0x59
+#define KEY_NP_2 0x5A
+#define KEY_NP_3 0x5B
+#define KEY_NP_PLUS 0x5C
+#define KEY_NP_0 0x5D
+#define KEY_NP_PERIOD 0x5E
+#define KEY_NP_ENTER 0x5F
+
+#define KEY_PRINT_SCREEN 0x60
+#define KEY_PAUSE 0x61
+#define KEY_INSERT 0x62
+#define KEY_HOME 0x63
+#define KEY_PAGE_UP 0x64
+#define KEY_DELETE 0x65
+#define KEY_END 0x66
+#define KEY_PAGE_DOWN 0x67
+#define KEY_UP 0x68
+#define KEY_DOWN 0x69
+#define KEY_LEFT 0x6A
+#define KEY_RIGHT 0x6B
+// #define _ 0x6C
+// #define _ 0x6D
+// #define _ 0x6E
+// #define _ 0x6F
+
+#define KEY_F1 0x70
+#define KEY_F2 0x71
+#define KEY_F3 0x72
+#define KEY_F4 0x73
+#define KEY_F5 0x74
+#define KEY_F6 0x75
+#define KEY_F7 0x76
+#define KEY_F8 0x77
+#define KEY_F9 0x78
+#define KEY_F10 0x79
+#define KEY_F11 0x7A
+#define KEY_F12 0x7B
+// #define _ 0x7C
+// #define _ 0x7D
+// #define _ 0x7E
+// #define _ 0x7F
+
+#endif /* keycodes */
diff --git a/kernel/include/comus/limits.h b/kernel/include/comus/limits.h
index 675df47..4cb348d 100644
--- a/kernel/include/comus/limits.h
+++ b/kernel/include/comus/limits.h
@@ -20,8 +20,16 @@
 
 /// max fs limits
 #define N_FILE_NAME 256
+#define N_DIR_ENTS 256
 #define N_DISKS 8
 
+/// elf limits
+#define N_ELF_SEGMENTS 16
+
+/// input buffer
+#define N_KEYCODE 64
+#define N_MOUSEEV 64
+
 /// length of terminal buffer
 #define TERM_MAX_WIDTH 1920
 #define TERM_MAX_HEIGHT 1080
diff --git a/kernel/include/comus/memory.h b/kernel/include/comus/memory.h
index 942e7a8..47ea103 100644
--- a/kernel/include/comus/memory.h
+++ b/kernel/include/comus/memory.h
@@ -87,7 +87,7 @@ mem_ctx_t mem_ctx_alloc(void);
  *
  * @returns pointer context or NULL on failure
  */
-mem_ctx_t mem_ctx_clone(mem_ctx_t ctx, bool cow);
+mem_ctx_t mem_ctx_clone(const mem_ctx_t ctx, bool cow);
 
 /**
  * Free a memory context into a new one
@@ -104,6 +104,11 @@ void mem_ctx_free(mem_ctx_t ctx);
 void mem_ctx_switch(mem_ctx_t ctx);
 
 /**
+ * @returns the pgdir pointer in the memory ctx
+ */
+volatile void *mem_ctx_pgdir(mem_ctx_t ctx);
+
+/**
  * Allocates at least len bytes of memory starting at
  * physical address addr. Returned address can be
  * any virtural address.
@@ -121,7 +126,14 @@ void *mem_mapaddr(mem_ctx_t ctx, void *phys, void *virt, size_t len,
  * Unmaps mapped address from the kmapaddr function
  * @param virt - the vitural address returned from kmapaddr
  */
-void mem_unmapaddr(mem_ctx_t ctx, void *virt);
+void mem_unmapaddr(mem_ctx_t ctx, const void *virt);
+
+/**
+ * Gets the physical address for a given vitural address
+ * @param ctx - the memory context
+ * @param virt - the vitural address
+ */
+void *mem_get_phys(mem_ctx_t ctx, const void *virt);
 
 /**
  * Allocate a single page of memory with the given paging structure
@@ -169,7 +181,7 @@ void *mem_alloc_pages_at(mem_ctx_t ctx, size_t count, void *virt,
  *
  * @param ptr - the pointer provided by alloc_page or alloc_pages
  */
-void mem_free_pages(mem_ctx_t ctx, void *ptr);
+void mem_free_pages(mem_ctx_t ctx, const void *ptr);
 
 /**
  * Allocates at least len bytes of memory starting at
@@ -185,10 +197,26 @@ void mem_free_pages(mem_ctx_t ctx, void *ptr);
 void *kmapaddr(void *phys, void *virt, size_t len, unsigned int flags);
 
 /**
+ * Map a vitural address in a userspace context to kernel space
+ *
+ * @param ctx - the userspace memory context to map from
+ * @param virt - the vitural address given by userspace
+ * @param len - the length of the buffer to map
+ * @returns vitural address mapped in kernel context
+ */
+void *kmapuseraddr(mem_ctx_t ctx, const void *virt, size_t len);
+
+/**
+ * Gets the physical address for a given vitural address
+ * @param virt - the vitural address
+ */
+void *kget_phys(const void *virt);
+
+/**
  * Unmaps mapped address from the kmapaddr function
  * @param virt - the vitural address returned from kmapaddr
  */
-void kunmapaddr(void *virt);
+void kunmapaddr(const void *virt);
 
 /**
  * Allocate a single page of memory
@@ -210,6 +238,6 @@ void *kalloc_pages(size_t count);
  *
  * @param ptr - the pointer provided by alloc_page or alloc_pages
  */
-void kfree_pages(void *ptr);
+void kfree_pages(const void *ptr);
 
 #endif /* memory.h */
diff --git a/kernel/include/comus/procs.h b/kernel/include/comus/procs.h
index d92bc5d..7b1a70a 100644
--- a/kernel/include/comus/procs.h
+++ b/kernel/include/comus/procs.h
@@ -12,10 +12,12 @@
 #include <comus/cpu.h>
 #include <comus/limits.h>
 #include <comus/memory.h>
+#include <comus/syscalls.h>
 #include <lib.h>
+#include <elf.h>
 
-#define PCB_REG(pcb, x) ((pcb)->regs->x)
-#define PCB_RET(pcb) ((pcb)->regs->rax)
+#define PCB_REG(pcb, x) ((pcb)->regs.x)
+#define PCB_RET(pcb) ((pcb)->regs.rax)
 #define PCB_ARG1(pcb) PCB_REG((pcb), rdi)
 #define PCB_ARG2(pcb) PCB_REG((pcb), rsi)
 #define PCB_ARG3(pcb) PCB_REG((pcb), rdx)
@@ -33,11 +35,8 @@ enum proc_state {
 	PROC_STATE_READY,
 	PROC_STATE_RUNNING,
 	// runnable, but waiting for some event
-	PROC_STATE_SLEEPING,
 	PROC_STATE_BLOCKED,
-	PROC_STATE_WAITING,
 	// no longer runnalbe
-	PROC_STATE_KILLED,
 	PROC_STATE_ZOMBIE,
 	// sentinel
 	N_PROC_STATES,
@@ -46,8 +45,8 @@ enum proc_state {
 /// process control block
 struct pcb {
 	// context
-	struct cpu_regs *regs;
 	mem_ctx_t memctx;
+	struct cpu_regs regs;
 
 	// metadata
 	pid_t pid;
@@ -56,10 +55,20 @@ struct pcb {
 	size_t priority;
 	size_t ticks;
 
+	// heap
+	char *heap_start;
+	size_t heap_len;
+
+	// elf metadata
+	Elf64_Ehdr elf_header;
+	Elf64_Phdr elf_segments[N_ELF_SEGMENTS];
+	Elf64_Half n_elf_segments;
+
 	// queue linkage
 	struct pcb *next; // next PDB in queue
 
 	// process state information
+	uint64_t syscall;
 	uint64_t wakeup;
 	uint8_t exit_status;
 };
@@ -79,10 +88,9 @@ typedef struct pcb_queue_s *pcb_queue_t;
 
 /// public facing pcb queues
 extern pcb_queue_t pcb_freelist;
-extern pcb_queue_t ready;
-extern pcb_queue_t waiting;
-extern pcb_queue_t sleeping;
-extern pcb_queue_t zombie;
+extern pcb_queue_t ready_queue;
+extern pcb_queue_t zombie_queue;
+extern pcb_queue_t syscall_queue[N_SYSCALLS];
 
 /// pointer to the currently-running process
 extern struct pcb *current_pcb;
@@ -216,6 +224,11 @@ void schedule(struct pcb *pcb);
 /**
  * Select the next process to receive the CPU
  */
-void dispatch(void);
+__attribute__((noreturn)) void dispatch(void);
+
+/**
+ * Scheduler function called on every system tick
+ */
+void pcb_on_tick(void);
 
 #endif /* procs.h */
diff --git a/kernel/include/comus/syscalls.h b/kernel/include/comus/syscalls.h
index 3dc128d..f714184 100644
--- a/kernel/include/comus/syscalls.h
+++ b/kernel/include/comus/syscalls.h
@@ -27,9 +27,12 @@
 #define SYS_sleep 14
 #define SYS_brk 15
 #define SYS_sbrk 16
+#define SYS_poweroff 17
+#define SYS_drm 18
+#define SYS_ticks 19
 
 // UPDATE THIS DEFINITION IF MORE SYSCALLS ARE ADDED!
-#define N_SYSCALLS 13
+#define N_SYSCALLS 20
 
 // interrupt vector entry for system calls
 #define VEC_SYSCALL 0x80
diff --git a/kernel/include/comus/user.h b/kernel/include/comus/user.h
new file mode 100644
index 0000000..f51ada5
--- /dev/null
+++ b/kernel/include/comus/user.h
@@ -0,0 +1,30 @@
+/**
+ * @file user.h
+ *
+ * @author Freya Murphy <freya@freyacat.org>
+ *
+ * Userland functions
+ */
+
+#ifndef USER_H_
+#define USER_H_
+
+#include <comus/procs.h>
+#include <comus/fs.h>
+
+/**
+ * Load a user elf program from a file into a pcb
+ */
+int user_load(struct pcb *pcb, struct disk *disk);
+
+/**
+ * Clone a user process. Used for fork().
+ */
+struct pcb *user_clone(struct pcb *pcb);
+
+/**
+ * Clean up all loaded userland data from a pcb
+ */
+void user_cleanup(struct pcb *pcb);
+
+#endif /* user.h */
diff --git a/kernel/include/lib.h b/kernel/include/lib.h
index be4e739..edfbeb4 100644
--- a/kernel/include/lib.h
+++ b/kernel/include/lib.h
@@ -15,6 +15,7 @@
 #include <lib/kctype.h>
 #include <lib/kio.h>
 #include <lib/klib.h>
+#include <lib/kmath.h>
 #include <lib/kstring.h>
 
 #endif /* lib.h */
diff --git a/kernel/include/lib/kmath.h b/kernel/include/lib/kmath.h
new file mode 100644
index 0000000..3be953d
--- /dev/null
+++ b/kernel/include/lib/kmath.h
@@ -0,0 +1,20 @@
+/**
+ * @file kmath.h
+ *
+ * @author Ian McFarlane <i.mcfarlane2002@gmail.com>
+ *
+ * Kernel math functions
+ */
+
+#ifndef _KMATH_H
+#define _KMATH_H
+
+#include <stddef.h>
+
+// min and max both prefer a over b
+#define MAX(a, b) ((a) >= (b) ? (a) : (b))
+#define MIN(a, b) ((a) <= (b) ? (a) : (b))
+
+#define CLAMP(val, min, max) (MAX((min), MIN((val), (max))))
+
+#endif