process.c

8 files changed, 106 insertions, 9 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index 741e158..5e6cb9d 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -41,6 +41,7 @@ OBJS = \
 	src/scheduler/ap_init.o \
 	src/scheduler/ap_startup.o \
 	src/scheduler/atomic.o \
+	src/scheduler/process.o \
 	src/scheduler/scheduler.o \
 	src/scheduler/switch.o \
 	src/sys/syscall_asm.o \
diff --git a/kernel/include/process.h b/kernel/include/process.h
new file mode 100644
index 0000000..ff82924
--- /dev/null
+++ b/kernel/include/process.h
@@ -0,0 +1,21 @@
+#ifndef PROCESS_H
+#define PROCESS_H
+
+#include <types.h>
+#include <libk/list.h>
+
+void save_context_to_rsp(uint64_t irq_rsp, uint64_t task_rsp);
+__attribute__((noreturn)) void restore_context_from_rsp(uint64_t task_rsp);
+
+struct process_t {
+	uint64_t rsp;
+	list_t list;
+};
+typedef struct process_t process_t;
+
+extern process_t process_queue;
+extern process_t *curr_process;
+
+__attribute__((noreturn)) void context_switch(uint64_t irq_rsp);
+
+#endif
diff --git a/kernel/include/scheduler.h b/kernel/include/scheduler.h
index 2f751f0..73a9d2b 100644
--- a/kernel/include/scheduler.h
+++ b/kernel/include/scheduler.h
@@ -1,6 +1,8 @@
 #ifndef SCHEDULER_H
 #define SCHEDULER_H
 
-void scheduler(void);
+#include <process.h>
+
+process_t *scheduler(void);
 
 #endif
diff --git a/kernel/include/timer.h b/kernel/include/timer.h
index 899f09f..a86bfe7 100644
--- a/kernel/include/timer.h
+++ b/kernel/include/timer.h
@@ -4,6 +4,7 @@
 #include <types.h>
 
 #define TICKS_PER_SECOND 1000
+#define CONTEXT_SWITCHES_PER_SECOND 20
 
 void timer_handler(uint64_t rsp);
 void wait(uint64_t ms);
diff --git a/kernel/src/devices/timer.c b/kernel/src/devices/timer.c
index 0f6fc20..7971b20 100644
--- a/kernel/src/devices/timer.c
+++ b/kernel/src/devices/timer.c
@@ -4,8 +4,10 @@
 #include <libk/list.h>
 #include <io.h>
 #include <idt.h>
+#include <process.h>
 
-uint32_t tick = 0;
+uint32_t scheduler_ticks = 0;
+uint32_t seconds_tick = 0;
 uint32_t seconds = 0;
 
 struct wait_queue {
@@ -23,12 +25,16 @@ void timer_handler(uint64_t rsp)
 		pos->ticks--;
 	}
 
-	tick++;
-
-	if (tick >= TICKS_PER_SECOND) {
-		tick = 0;
+	seconds_tick++;
+	if (seconds_tick >= TICKS_PER_SECOND) {
+		seconds_tick = 0;
 		seconds++;
 	}
+	scheduler_ticks++;
+	if (scheduler_ticks >= TICKS_PER_SECOND / CONTEXT_SWITCHES_PER_SECOND) {
+		scheduler_ticks = 0;
+/*		context_switch(rsp); */
+	}
 }
 
 void wait(uint64_t ms)
diff --git a/kernel/src/scheduler/process.c b/kernel/src/scheduler/process.c
index e69de29..e85cc11 100644
--- a/kernel/src/scheduler/process.c
+++ b/kernel/src/scheduler/process.c
@@ -0,0 +1,60 @@
+#include <types.h>
+#include <regs.h>
+#include <heap.h>
+#include <scheduler.h>
+#include <libk/list.h>
+#include <process.h>
+
+process_t process_queue;
+process_t *curr_process;
+
+void init_process(uint64_t priv_lvl, uint64_t rip, uint64_t rdi, uint64_t rsi,
+		  uint64_t rdx)
+{
+	uint32_t stack_size = 32 * 1024;
+	uint64_t rsp = (uint64_t)kalloc(stack_size) + stack_size;
+	regs_t *regs = (regs_t *)(rsp + sizeof(regs_t));
+
+	regs->rax = 0;
+	regs->rbx = 0;
+	regs->rcx = 0;
+	regs->rdx = rdx;
+	regs->rdi = rdi;
+	regs->rsi = rsi;
+	regs->rsp = rsp;
+	regs->rbp = 0;
+	regs->r8 = 0;
+	regs->r9 = 0;
+	regs->r10 = 0;
+	regs->r11 = 0;
+	regs->r12 = 0;
+	regs->r13 = 0;
+	regs->r14 = 0;
+	regs->r15 = 0;
+	regs->rip = rip;
+	regs->rflags = 0;
+	regs->error = 0;
+
+	if (priv_lvl == 0) {
+		regs->cs = 0x8;
+		regs->ss = 0x10;
+		regs->seg = 0x0010001000100010;
+	} else {
+		regs->cs = 0x23;
+		regs->ss = 0x1b;
+		regs->seg = 0x001b001b001b001b;
+	}
+
+	process_t *new_process = (process_t *)kalloc(sizeof(process_t));
+	add_to_list(&new_process->list, &process_queue.list,
+		    process_queue.list.next);
+}
+
+__attribute__((noreturn)) void context_switch(uint64_t irq_rsp)
+{
+	save_context_to_rsp(irq_rsp, curr_process->rsp);
+
+	process_t *next_process = scheduler();
+
+	restore_context_from_rsp(next_process->rsp);
+}
diff --git a/kernel/src/scheduler/scheduler.c b/kernel/src/scheduler/scheduler.c
index b8f3dab..263c11a 100644
--- a/kernel/src/scheduler/scheduler.c
+++ b/kernel/src/scheduler/scheduler.c
@@ -1,6 +1,12 @@
 #include <types.h>
 #include <scheduler.h>
+#include <libk/list.h>
+#include <process.h>
 
-void schedule(void)
+process_t *scheduler(void)
 {
+	process_t *pos = curr_process;
+	process_t *next_process = list_next_entry(pos, list);
+
+	return next_process;
 }
diff --git a/kernel/src/scheduler/switch.S b/kernel/src/scheduler/switch.S
index 4e216e0..4d5dfb6 100644
--- a/kernel/src/scheduler/switch.S
+++ b/kernel/src/scheduler/switch.S
@@ -2,7 +2,7 @@
 
 /* %rdi - irq's rsp */
 /* %rsi - task's rsp */
-.global save_to_rsp
+.global save_context_to_rsp
 save_context_to_rsp:
 	mov %rsi, %rsp
 	push SS_OFF(%rdi)
@@ -29,7 +29,7 @@ save_context_to_rsp:
 	push R15_OFF(%rdi)
 
 /* %rdi - task's rsp */
-.global restore_from_rsp
+.global restore_context_from_rsp
 restore_context_from_rsp:
 	mov %rdi, %rsp
 	pop_callee_saved