From cfcb02e713f9b0bbfa268fdcc34ba0aae820e12b Mon Sep 17 00:00:00 2001
From: hinus <hinus@163.com>
Date: Mon, 14 Jun 2021 23:21:29 +0800
Subject: [PATCH] Title: Setup Interruption Descrition Table Issue:
 https://gitee.com/hinus/linux_kernel_011/issues/I3V4FC Description: macro
 'set_intr_gate' to setup IDT.

---
 include/asm/system.h  | 15 +++++++++++++++
 include/linux/head.h  | 11 +++++++++++
 include/linux/sched.h |  3 +++
 kernel/Makefile       |  5 ++++-
 kernel/main.c         |  5 ++++-
 kernel/sched.c        | 10 ++++++++++
 kernel/sys_call.S     | 30 ++++++++++++++++++++++++++++++
 7 files changed, 77 insertions(+), 2 deletions(-)
 create mode 100644 include/linux/head.h
 create mode 100644 kernel/sys_call.S

diff --git a/include/asm/system.h b/include/asm/system.h
index 5090d22..001b687 100644
--- a/include/asm/system.h
+++ b/include/asm/system.h
@@ -6,4 +6,19 @@
 #define nop()   __asm__("nop"::)
 #define iret()  __asm__("iret"::)
 
+#define _set_gate(gate_addr, type, dpl, addr) \
+__asm__("movw %%dx, %%ax\n\t"   \
+        "movw %0, %%dx\n\t"     \
+        "movl %%eax, %1\n\t"    \
+        "movl %%edx, %2"        \
+        :                       \
+        :"i"((short)(0x8000 + (dpl << 13) + (type << 8))),  \
+        "o"(*((char*)(gate_addr))),                         \
+        "o"(*(4 + (char*)(gate_addr))),                     \
+        "d"((char*)(addr)), "a" (0x00080000))
+
+
+#define set_intr_gate(n, addr) \
+    _set_gate(&idt[n], 14, 0, addr)
+
 #endif
diff --git a/include/linux/head.h b/include/linux/head.h
new file mode 100644
index 0000000..7bf5f67
--- /dev/null
+++ b/include/linux/head.h
@@ -0,0 +1,11 @@
+#ifndef _HEAD_H
+#define _HEAD_H
+
+typedef struct desc_struct {
+    unsigned long a, b;
+} desc_table[256];
+
+extern unsigned long pg_dir[1024];
+extern desc_table idt,gdt;
+
+#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 79cbdbd..e7f1a39 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1,6 +1,9 @@
 #ifndef _SCHED_H
 #define _SCHED_H
 
+#include <linux/head.h>
 #include <linux/mm.h>
 
+void sched_init();
+
 #endif
diff --git a/kernel/Makefile b/kernel/Makefile
index caaa841..f8f04ec 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -2,7 +2,7 @@ GCC := gcc
 CCFLAG := -I../include -nostdinc -Wall -fomit-frame-pointer -fno-stack-protector -c -m32
 LDFLAG := -Ttext 0x0 -s --oformat binary -m elf_i386
 INCDIR := ../include
-OBJS   := head.o main.o sched.o printk.o vsprintf.o chr_drv/chr_drv.a mm/mm.o
+OBJS   := head.o main.o sys_call.o sched.o printk.o vsprintf.o chr_drv/chr_drv.a mm/mm.o
 
 system: $(OBJS)
 	$(LD) $(LDFLAG) -e startup_32 -o $@ $^
@@ -10,6 +10,9 @@ system: $(OBJS)
 head.o : head.S
 	$(GCC) -m32 -traditional -c -o $@ $<
 
+sys_call.o : sys_call.S
+	$(GCC) -m32 -traditional -c -o $@ $<
+
 main.o : main.c
 	$(GCC) $(CCFLAG) -o $@ $<
 
diff --git a/kernel/main.c b/kernel/main.c
index 22038da..c563dcc 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -2,6 +2,7 @@
 
 #include <linux/tty.h>
 #include <linux/kernel.h>
+#include <linux/sched.h>
 
 extern void mem_init(long start, long end);
 
@@ -36,11 +37,13 @@ void main(void)
 
     main_memory_start = buffer_memory_end;
     mem_init(main_memory_start, memory_end);
+    sched_init();
 
     tty_init();
-    printk("memory start: %d, end: %d", main_memory_start, memory_end);
+    printk("memory start: %d, end: %d\n\r" , main_memory_start, memory_end);
 
     __asm__ __volatile__(
+            "int $0x80\n\r"
             "loop:\n\r"
             "jmp loop"
             ::);
diff --git a/kernel/sched.c b/kernel/sched.c
index 97a9e99..7be08e4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1,5 +1,11 @@
+#include <linux/sched.h>
+
+#include <asm/system.h>
+
 #define PAGE_SIZE 4096
 
+extern int system_call();
+
 long user_stack[PAGE_SIZE >> 2];
 
 struct
@@ -8,3 +14,7 @@ struct
     short b;
 } stack_start = {&user_stack[PAGE_SIZE >> 2], 0x10};
 
+void sched_init() {
+    set_intr_gate(0x80, &system_call);
+}
+
diff --git a/kernel/sys_call.S b/kernel/sys_call.S
new file mode 100644
index 0000000..a71dab3
--- /dev/null
+++ b/kernel/sys_call.S
@@ -0,0 +1,30 @@
+.code32
+.text
+.globl system_call
+int_msg:
+    .asciz  "In kernel interrupt"
+
+system_call:
+    /* we do not have function _printk now, so trick it */
+    pushl %eax
+    pushl %ecx
+    pushl %edx
+    pushw %ds
+    pushw %es
+    pushw %fs
+    movl  $0x10, %eax
+    movw  %ax, %ds
+    movw  %ax, %es
+    movw  %ax, %fs
+    /* call  _printk */
+    pushl $int_msg
+    call  printk
+    popl  %eax
+    popw  %fs
+    popw  %es
+    popw  %ds
+    popl  %edx
+    popl  %ecx
+    popl  %eax
+    iret
+
-- 
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