6 files changed, 106 insertions, 96 deletions

diff --git a/kernel/include/x86_64_regs.S b/kernel/include/x86_64_regs.S
new file mode 100644
index 0000000..7b72d76
--- /dev/null
+++ b/kernel/include/x86_64_regs.S
@@ -0,0 +1,78 @@
+/* isr stack */
+/* ss:rsp (original rsp) -> rflags -> cs -> rip */
+
+/* callee saved registers: rbx, rbp, rsp, r12, r13, r14, r15 */
+/* isr saved registers: rsp, rip, rflags, cs, ss */
+
+/* if the code will stay on same thread of execution use push/pop_caller_saved
+ * else use push/pop_callee_saved with push/pop_caller_saved
+ */
+
+/* push 0x30 bytes to stack */
+.macro push_callee_saved
+	push %rbx
+	push %rbp
+	push %r12
+	push %r13
+	push %r14
+	push %r15
+.endm
+
+/* pop 0x30 bytes from stack */
+.macro pop_callee_saved
+	push %rbx
+	push %rbp
+	push %r12
+	push %r13
+	push %r14
+	push %r15
+.endm
+
+/* push 0x50 bytes to stack */
+.macro push_caller_saved
+	push %rax
+	push %rcx
+	push %rdx
+	push %rsi
+	push %rdi
+	push %r8
+	push %r9
+	push %r10
+	push %r11
+	mov %ds, %ax
+	shl $16, %rax
+	mov %es, %ax
+	shl $16, %rax
+	mov %fs, %ax
+	shl $16, %rax
+	mov %gs, %ax
+	push %rax
+	mov $0x10, %ax
+	mov %ax, %ds
+	mov %ax, %ss
+	mov %ax, %es
+	mov %ax, %fs
+	mov %ax, %gs
+	mov 0x48(%rsp), %rax
+.endm
+
+/* pop 0x50 bytes from stack */
+.macro pop_caller_saved
+	pop %rax
+	mov %ax, %gs
+	shr $16, %rax
+	mov %ax, %fs
+	shr $16, %rax
+	mov %ax, %es
+	shr $16, %rax
+	mov %ax, %ds
+	pop %r11
+	pop %r10
+	pop %r9
+	pop %r8
+	pop %rdi
+	pop %rsi
+	pop %rdx
+	pop %rcx
+	pop %rax
+.endm
diff --git a/kernel/src/cpu/irq_stub.S b/kernel/src/cpu/irq_stub.S
index 3ba4360..33d87e1 100644
--- a/kernel/src/cpu/irq_stub.S
+++ b/kernel/src/cpu/irq_stub.S
@@ -1,61 +1,15 @@
 .extern panic_rsp
 
-.macro pushall
-	push %rax
-	push %rbx
-	push %rcx
-	push %rdx
-	push %rsi
-	push %rdi
-	push %r8
-	push %r9
-	push %r10
-	push %r11
-	push %r12
-	push %r13
-	push %r14
-	push %r15
-	mov %ds, %ax
-	push %rax
-	mov %es, %ax
-	push %rax
-	mov %ss, %ax
-	push %rax
-	mov $0x10, %ax
-	mov %ax, %ds
-	mov %ax, %es
-	mov 0x80(%rsp), %rax
-.endm
-
-.macro popall
-	pop %rax
-	pop %rax
-	mov %ax, %es
-	pop %rax
-	mov %ax, %ds
-	pop %r15
-	pop %r14
-	pop %r13
-	pop %r12
-	pop %r11
-	pop %r10
-	pop %r9
-	pop %r8
-	pop %rdi
-	pop %rsi
-	pop %rdx
-	pop %rcx
-	pop %rbx
-	pop %rax
-.endm
+#include "x86_64_regs.S"
 
 .macro isrstub
-	pushall
-	mov 0x88(%rsp), %rsi
+	push_caller_saved
+	/* get error code from stack */
+	mov 0x50(%rsp), %rsi
 	mov %rsp, panic_rsp
 	cld
 	call isr_def_handler
-	popall
+	pop_caller_saved
 	add $8, %rsp
 	iretq
 .endm
@@ -78,12 +32,12 @@ isr\number:
 .macro irq number
 .global irq\number
 irq\number:
-	pushall
+	push_caller_saved
 	mov $\number, %rdi
 	mov %rsp, panic_rsp
 	cld
 	call irq_def_handler
-	popall
+	pop_caller_saved
 	iretq
 .endm
 
diff --git a/kernel/src/mem/pmm.c b/kernel/src/mem/pmm.c
index e8245f2..f0b4884 100644
--- a/kernel/src/mem/pmm.c
+++ b/kernel/src/mem/pmm.c
@@ -1,5 +1,4 @@
 #include <paging.h>
-#include <heap.h>
 #include <libk/list.h>
 #include <libk/stdio.h>
 #include <libk/serial_stdio.h>
@@ -33,12 +32,6 @@ void init_pmm()
 		}
 	}
 	all_mem_cnt = free_mem_cnt;
-
-	// print addr of every free block of memory
-	//list_t* pok;
-	//list_for_each(pok, (&pmm_list)) {
-	//	serial_printf("0x%x\n", pok);
-	//}
 }
 
 void memory_usage()
diff --git a/kernel/src/scheduler/ap_init.S b/kernel/src/scheduler/ap_init.S
index 47efc6f..ac758c8 100644
--- a/kernel/src/scheduler/ap_init.S
+++ b/kernel/src/scheduler/ap_init.S
@@ -1,6 +1,5 @@
 .section .apinit, "a"
 
-
 .SET stack_top, 0x3008000
 .SET stack_off, 0x8000
 
diff --git a/kernel/src/scheduler/switch.S b/kernel/src/scheduler/switch.S
new file mode 100644
index 0000000..f4d0e79
--- /dev/null
+++ b/kernel/src/scheduler/switch.S
@@ -0,0 +1,18 @@
+#include "x86_64_regs.S"
+
+.global context_switch
+context_switch:
+	/* switch rsp to old task's %rsp */
+
+	/* save all old task's registers */
+	push_caller_saved
+	push_callee_saved
+
+	/* save old task's rsp & rip */
+	call schedule
+	/* get new task's rsp & rip */
+
+	/* restore all new task's registers */
+	pop_callee_saved
+	pop_caller_saved
+	iretq
diff --git a/kernel/src/sys/syscall_asm.S b/kernel/src/sys/syscall_asm.S
index 2e3c0bb..8287e95 100644
--- a/kernel/src/sys/syscall_asm.S
+++ b/kernel/src/sys/syscall_asm.S
@@ -1,47 +1,15 @@
 .extern syscall_handler
 
-.macro pushall
-	push %rax
-	push %rbx
-	push %rcx
-	push %rdx
-	push %rsi
-	push %rdi
-	push %r8
-	push %r9
-	push %r10
-	push %r11
-	push %r12
-	push %r13
-	push %r14
-	push %r15
-.endm
-
-.macro popall
-	pop %r15
-	pop %r14
-	pop %r13
-	pop %r12
-	pop %r11
-	pop %r10
-	pop %r9
-	pop %r8
-	pop %rdi
-	pop %rsi
-	pop %rdx
-	pop %rcx
-	pop %rbx
-	pop %rax
-.endm
+#include "x86_64_regs.S"
 
 .global __syscall
 __syscall:
 	pushq %rcx
 	pushq %r11
 
-	pushall
+	push_caller_saved
 	call syscall_handler
-	popall
+	pop_caller_saved
 
 	popfq
 	popq %rcx