Merge pull request #73 from bassaer/develop

[ver 1.15.1] fix context switch
bassaer · Mar 11, 2020 · 4caeb9f · 4caeb9f
2 parents f9a7141 + b9c6278
commit 4caeb9f
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Showing 14 changed files with 186 additions and 14 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # CHANGELOG
 
+## ver 1.15.1
+- fix context switch
+
 ## ver 1.15.0
 - use linear list for timer
 

diff --git a/Makefile b/Makefile
@@ -7,6 +7,7 @@ KERN_OBJ = kernel/main.o \
            kernel/console.o \
            kernel/intr.o \
            kernel/keyboard.o \
+           kernel/sched.o \
            kernel/timer.o
 
 LIB_OBJ  = lib/queue.o \

diff --git a/bin/free.c b/bin/free.c
@@ -5,6 +5,8 @@
 #include <mm/memory.h>
 #include <lib/string.h>
 
+#define MB      (1024*1024)
+
 int free() {
   char *fmt =
     "total : %dMB\n"
@@ -16,7 +18,6 @@ int free() {
   };
   stats(&mem);
 
-  int mb = 1024*1024;
-  printf(fmt, mem.total_bytes/mb, mem.used_bytes/mb, mem.free_bytes/mb);
+  printf(fmt, mem.total_bytes/MB, mem.used_bytes/MB, mem.free_bytes/MB);
   return EXIT_SUCCESS;
 }
diff --git a/bin/sleep.c b/bin/sleep.c
@@ -3,9 +3,12 @@
 #include <console.h>
 #include <exit.h>
 #include <io.h>
+#include <sched.h>
+#include <tss.h>
 #include <timer.h>
 #include <lib/queue.h>
 #include <lib/string.h>
+#include <mm/memory.h>
 
 void usage_sleep() {
   printf("usage : sleep <timeout>\n");
@@ -33,13 +36,35 @@ int sleep(char *args[], int size) {
   int timeout = atoi(args[1]) * 100;
   set_timer(timer, timeout);
 
+  tss_t tss2;
+  tss2.ldtr = 0;
+  tss2.iomap = 0x40000000;
+  tss2.eip = (int) &task2_main;
+  tss2.eax = 0;
+  tss2.ecx = 0;
+  tss2.edx = 0;
+  tss2.ebx = 0;
+  tss2.esp = (int)alloc_single_block();
+  tss2.ebp = 0;
+  tss2.esi = 0;
+  tss2.edi = 0;
+  tss2.es =  1 * 8;
+  tss2.cs =  2 * 8;
+  tss2.ss =  1 * 8;
+  tss2.ds =  1 * 8;
+  tss2.fs =  1 * 8;
+  tss2.gs =  1 * 8;
+
+  debug("tss2 = %x", (int *)tss2.eip);
+
   while(1) {
     // 割り込み無効化
     io_cli();
     if (queue_status(&queue) != 0) {
       // 割り込み有効化 + HLT
       io_stihlt();
     } else {
+      context_switch(tss2.eip);
       // 割り込み有効化
       io_sti();
       break;

diff --git a/include/dsctbl.h b/include/dsctbl.h
@@ -7,8 +7,22 @@
  */
 #define AR_INTGATE32  0x008e
 
+/**
+ * システム専用セグメント属性
+ * R: OK
+ * W: OK
+ * X: NG
+ */
 #define AR_DATA32_RW  0x4092
+
+/**
+ * システム専用セグメント属性
+ * R: OK
+ * W: NG
+ * X: OK
+ */
 #define AR_CODE32_ER  0x409a
+#define AR_TSS32      0x0089
 
 #define KERN_ADDR     0x00000000
 #define KERN_LIMIT    0xffffffff

diff --git a/include/io.h b/include/io.h
@@ -26,13 +26,13 @@ void io_cli(void);
  * GDTR(global descriptor table register) : GDT設定用レジスタ
  * GDT : 大域セグメント記述子, セグメンテーションを割り当てたテーブル
  */
-void load_gdtr(int limit, int addr);
+void set_gdtr(int limit, int addr);
 
 /**
  * IDTR(interrupt descriptor table register) : IDT設定用レジスタ
  * IDT : 割り込みと割り込みハンドラの対応テーブル
  */
-void load_idtr(int limit, int addr);
+void set_idtr(int limit, int addr);
 
 /**
  * ポート指定でのレジスタ書き込み
@@ -71,4 +71,15 @@ int load_cr0(void);
  */
 void store_cr0(int cr0);
 
+/**
+ * TRは現在実行中のタスクを記憶するためのレジスタ
+ * ltrはTRを変更するための命令
+ */
+void set_tr(int tr);
+
+/**
+ * 指定のアドレスにロングjumpする
+ */
+void context_switch();
+
 #endif
diff --git a/include/sched.h b/include/sched.h
@@ -0,0 +1,12 @@
+#ifndef MYOS_SCHED_H
+#define MYOS_SCHED_H
+
+void init_sched();
+
+void set_tr(int tr);
+
+void context_switch(int addr);
+
+void task2_main();
+
+#endif
diff --git a/include/tss.h b/include/tss.h
@@ -0,0 +1,57 @@
+#ifndef MYOS_TSS_H
+#define MYOS_TSS_H
+
+/**
+ * 32bit TSS(Task Status Segment)
+ */
+typedef struct {
+  /**
+   * タスク設定の内容
+   */
+  int backlink;
+  int esp0;
+  int ss0;
+  int esp1;
+  int ss1;
+  int esp2;
+  int ss2;
+  int cr3;
+
+  /**
+   * 32bitレジスタ
+   */
+  int eip;
+  int eflags;
+  int eax;
+  int ecx;
+  int edx;
+  int ebx;
+  int esp;
+  int ebp;
+  int esi;
+  int edi;
+
+  /**
+   * 16bitレジスタ
+   */
+  int es;
+  int cs;
+  int ss;
+  int ds;
+  int fs;
+  int gs;
+
+  /**
+   * タスク設定の内容
+   *
+   * 不正な値が入るとコンテキストスイッチが動作しないので
+   * 以下の初期値を設定する
+   * idtr  = 0
+   * iomap = 0x400000000
+   */
+  int ldtr;
+  int iomap;
+} tss_t;
+
+#endif
+
diff --git a/kernel/dsctbl.c b/kernel/dsctbl.c
@@ -13,13 +13,14 @@ void init_gdtidt() {
   // メモリ全体
   set_segmdesc(gdt + 1, 0xffffffff, 0x00000000, AR_DATA32_RW);
   // カーネル
-  set_segmdesc(gdt + 2, KERN_LIMIT, KERN_ADDR, AR_CODE32_ER);
-  load_gdtr(GDT_LIMIT, GDT_ADDR);
+  set_segmdesc(gdt + 2, 0xffffffff, 0x00000000, AR_CODE32_ER);
+  // GDTのリミットと番地をGDTR(48bitレジスタ)に設定
+  set_gdtr(GDT_LIMIT, GDT_ADDR);
 
   for (i = 0; i <= IDT_LIMIT / 8; i++) {
     set_gatedesc(idt + i, 0, 0, 0);
   }
-  load_idtr(IDT_LIMIT, IDT_ADDR);
+  set_idtr(IDT_LIMIT, IDT_ADDR);
 
   // IDTの設定
   // 2*8 -> 2番目のセグメント

diff --git a/kernel/func.s b/kernel/func.s
@@ -1,8 +1,9 @@
 .code32
 .global io_cli, io_sti, io_stihlt, io_hlt
-.global load_gdtr, load_idtr, outb_p, io_in
+.global set_gdtr, set_idtr, outb_p, io_in
 .global asm_handle_intr20, asm_handle_intr21, asm_handle_intr27
 .global io_load_eflags, io_store_eflags, load_cr0, store_cr0
+.global set_tr, context_switch
 .extern handle_intr20, handle_intr21, handle_intr27
 .text
 
@@ -23,13 +24,13 @@ io_cli:
     cli
     ret
 
-load_gdtr:
+set_gdtr:
     movw    4(%esp),    %ax
     movw    %ax,        6(%esp)
     lgdt    6(%esp)
     ret
 
-load_idtr:
+set_idtr:
     movw    4(%esp),    %ax
     movw    %ax,        6(%esp)
     lidt    6(%esp)
@@ -113,3 +114,11 @@ asm_handle_intr27:
     pop     %ds
     pop     %es
     iret
+
+set_tr:
+    ltr     4(%esp)
+    ret
+
+context_switch:
+    ljmp    *4(%esp)
+    ret
diff --git a/kernel/main.c b/kernel/main.c
@@ -11,6 +11,7 @@
 #include <intr.h>
 #include <io.h>
 #include <keyboard.h>
+#include <sched.h>
 #include <timer.h>
 #include <mm/memory.h>
 #include <sh.h>
@@ -34,6 +35,7 @@ int main(void) {
   init_keyboard(&queue);
   init_mem_info();
   init_shell();
+  init_sched();
 
   while(1) {
     io_cli(); // 割り込み無効化

diff --git a/kernel/sched.c b/kernel/sched.c
@@ -0,0 +1,38 @@
+#include <sched.h>
+
+#include <console.h>
+#include <io.h>
+#include <tss.h>
+#include <dsctbl.h>
+#include <mm/memory.h>
+
+void init_sched() {
+  /*
+  tss_t tss1;
+  tss1.ldtr = 0;
+  tss1.iomap = 0x40000000;
+  */
+
+
+  //segment_descriptor_t *gdt = (segment_descriptor_t *) GDT_ADDR;
+
+  //set_segmdesc(gdt + 3, 103, (int) &tss1, AR_TSS32);
+  //set_segmdesc(gdt + 4, 103, (int) &tss2, AR_TSS32);
+
+  //set_segmdesc(gdt + 3, 0xffffffff, 0x00000000, AR_TSS32);
+  //set_segmdesc(gdt + 4, 0xffffffff, 0x00000000, AR_TSS32);
+
+  //set_gdtr(GDT_LIMIT, GDT_ADDR);
+
+  //set_tr(3 * 8);
+}
+
+void task2_main() {
+  debug("task2_main!!");
+  /*
+  while(1) {
+    io_hlt();
+  }
+  */
+}
+
diff --git a/mm/memory.c b/mm/memory.c
@@ -97,7 +97,6 @@ int init_pg_table() {
 int map_page(unsigned long paddr, unsigned long vaddr) {
   page_directory_entry *curr_pd = get_curr_pd();
   if (curr_pd == NULL) {
-    debug("error at 94");
     return MEM_ERROR;
   }
   page_directory_entry *pde = get_pde(curr_pd, vaddr);
@@ -107,7 +106,6 @@ int map_page(unsigned long paddr, unsigned long vaddr) {
   } else {
     pg_table = (page_table_entry *)alloc_single_block();
     if (pg_table == NULL) {
-      debug("error at 102");
       return MEM_ERROR;
     }
     //.ブロック初期化

diff --git a/mm/pgtable.c b/mm/pgtable.c
@@ -96,11 +96,11 @@ page_table_entry get_pde_ptaddr(page_directory_entry *pd) {
 }
 
 void set_pd(page_directory_entry *pde) {
-  __asm__("movl %%cr3, %0"::"r"(pde));
+  __asm__ volatile("movl %%cr3, %0"::"r"(pde));
 }
 
 void enable_paging() {
-  __asm__(
+  __asm__ volatile(
       "pushl %eax;"
       "movl %cr0, %eax;"
       "OR 0x80000000, %eax;"