Fix bug in terminal.cpp where it would use incorrect pointers in scroll_up, removed old debug code from kmain.cpp, kernel.cpp no longer appends itself to the process list, update process.cpp to take a filename when constructing a new process. Update idt.cpp to plug context_switch in to int 0x20 (IRQ0)

2021-11-27 13:11:44 +00:00 · 2021-11-27 13:11:44 +00:00 · d6c1cc1869
commit d6c1cc1869
parent bfa648d96b
8 changed files with 39 additions and 94 deletions
--- a/16
+++ b/16
@ -2,13 +2,16 @@ CFLAGS = -g -std=gnu11 -m32 -mgeneral-regs-only -nostdlib -fno-builtin -fno-exce
 CXXFLAGS = -g -m32 -fno-use-cxa-atexit -mgeneral-regs-only -nostdlib -fno-builtin -fno-rtti -fno-exceptions -fno-leading-underscore -fpermissive -fno-pie -fno-stack-protector -I.
 LDFLAGS = 

-DISK_IMG_FILES = build/kernel/kernel.bin build/program/program.bin hello.txt alpha.txt
+DISK_IMG_FILES = build/kernel/kernel.bin build/program/program.bin build/program/hello.bin \
+								 build/program/world.bin hello.txt alpha.txt
 KERNEL_OBJS = build/kernel/entry.o build/kernel/screenstuff.o build/kernel/io.o build/kernel/idt.o build/kernel/keyboard.o \
 							build/kernel/strings.o build/kernel/atapio.o build/kernel/kmain.o build/kernel/paging.o build/kernel/allocate.o \
 							build/kernel/gdt.o build/kernel/memory.o build/kernel/process.o build/kernel/datatypes/hash.o \
 							build/kernel/terminal.o build/kernel/global.o build/kernel/kernel.o
 STAGE2_OBJS = build/c_code_entry.o build/boot_stage2/io.o build/boot_stage2/atapio.o build/boot_stage2/strings.o build/boot_stage2/screenstuff.o build/boot_stage2/stage2.o build/boot_stage2/paging.o
-PROGRAM_OBJS = build/program_code_entry.o build/program/program.o
+PROGRAM_OBJS = build/program_code_entry.o build/program/program.o build/common/common.o
+HELLO_OBJS = build/program_code_entry.o build/program/hello.o build/common/common.o
+WORLD_OBJS = build/program_code_entry.o build/program/world.o build/common/common.o

 run: disk.img
 	qemu-system-x86_64 disk.img
@ -32,6 +35,7 @@ prepare:
 	mkdir -p build/kernel
 	mkdir -p build/kernel/datatypes
 	mkdir -p build/program
+	mkdir -p build/common
 	mountpoint img.d | grep not || umount img.d

 clean:
@ -69,4 +73,10 @@ build/%.o: src/%.asm
 # Program

 build/program/program.bin: src/program/program.ld $(PROGRAM_OBJS)
-	ld $(LDFLAGS) -T $< $(PROGRAM_OBJS)
+	ld $(LDFLAGS) -T $< $(PROGRAM_OBJS)
+
+build/program/hello.bin: src/program/hello.ld $(HELLO_OBJS)
+	ld $(LDFLAGS) -T $< $(HELLO_OBJS)
+
+build/program/world.bin: src/program/world.ld $(WORLD_OBJS)
+	ld $(LDFLAGS) -T $< $(WORLD_OBJS)
--- a/src/kernel/idt.cpp
+++ b/src/kernel/idt.cpp
@ -84,6 +84,8 @@ __attribute__((interrupt)) void context_switch(interrupt_frame* frame) {
    asm volatile ("mov %%esp, %0" : "=a" (cESP) :);
    currentProc->esp = cESP; // Store the current ESP of the current process process.

+    outb(0x20, 0x20);
+
    // Select the next processes page directory
    asm volatile ("mov %0, %%cr3" : : "r" (nextProc->PD->phys_addr)); 
    // Restore ESP of the new process.
@ -92,14 +94,11 @@ __attribute__((interrupt)) void context_switch(interrupt_frame* frame) {
    asm ("popa"); 
    
    // Clear the garbage that was on the stack from previous switch_context call.
-    asm ("add $44, %esp");
+    asm ("add $84, %esp");

    // Pop EBP
    asm ("pop %ebp");

-    // Re-enable interrupts.
-    asm ("sti");
-
    // Manually perform iret.
    asm ("iret");
  }
@ -152,10 +151,7 @@ __attribute__((interrupt)) void syscall(interrupt_frame* frame) {
      rval = file_size(esi);
      break;
    case 7: {
-      uint32_t size = file_size(esi);
-      uint8_t* filebuffer = new uint8_t[size];
-      load_file(esi, filebuffer);
-      Global::kernel->createProcess();
+      Global::kernel->createProcess(esi);
      break;
    }
    default:
@ -174,7 +170,7 @@ void init_idt() {
  for (int i=0; i<256; i++)
    set_entry(i, 0x08, &ignore_interrupt, 0x8E);
  
-  set_entry(0x20, 0x08, &interrupt_20, 0x8E);
+  set_entry(0x20, 0x08, &context_switch, 0x8E);
  set_entry(0xD, 0x08, &gpf, 0x8E);
  set_entry(0xE, 0x08, &page_fault, 0x8E);
  set_entry(0x80, 0x08, &context_switch, 0x8E);
--- a/src/kernel/kernel.cpp
+++ b/src/kernel/kernel.cpp
@ -9,15 +9,15 @@ Kernel::Kernel(PageDirectory* page_directory, PageMap* phys, PageMap* virt, uint

  Global::currentProc = 0;

-  this->processes.append(this);
+  //this->processes.append(this);
 }

 void Kernel::init_kernel() {
  this->pid_map = new xnoe::hashtable<uint32_t, Process*>();
 }

-Process* Kernel::createProcess() {
-  Process* p = new Process(currentPID, this->PD, 0xc0000000);
+Process* Kernel::createProcess(char* filename) {
+  Process* p = new Process(currentPID, this->PD, 0xc0000000, filename);
  this->pid_map->set(currentPID, p);
  currentPID++;

--- a/src/kernel/kernel.h
+++ b/src/kernel/kernel.h
@ -19,7 +19,7 @@ public:

  void init_kernel();

-  Process* createProcess();
+  Process* createProcess(char* filename);
 };

 #endif
--- a/src/kernel/kmain.cpp
+++ b/src/kernel/kmain.cpp
@ -44,79 +44,14 @@ int main() {
  
  term->printf("KERNEL OK!\n");

-  Process* p = kernel.createProcess();
-
-  //term->deactivate();
-  //term2->activate();
-
  Global::currentProc = &kernel;
-  asm ("int $0x80");

-  term->printf("\n\nIf you are reading this, the XnoeOS kernel successfully switched contexts to another process, and then switched contexts back to the kernel. Therefore we can conclude that context switching works.");
-
-  while (1);
+  Process* p1 = kernel.createProcess("WORLD   BIN");
+  Process* p2 = kernel.createProcess("HELLO   BIN");

  init_keyboard();
  
  enable_idt();

-  uint8_t* filebuffer = new uint8_t[0x3000];
-
-  char* buffer = 0;
-
-  while (1) {
-    if (buffer)
-      delete[] buffer;
-    buffer = new char[128];
-    printf(">>> ");
-    for (int i=0; i<128; i++)
-      buffer[i] = 0;
-    readline(128, buffer);
-
-    char* rest = split_on_first(' ', buffer);
-
-    if (strcmp(buffer, "help", 4)) {
-      printf(
-        "XnoeOS 32 Bit Mode Help.\n"
-        "------------------------\n"
-        " - help\n"
-        " : Shows this message\n"
-        " - clear\n"
-        " : Clears the screen\n"
-        " - echo\n"
-        " : Repeats the text written afterwards\n"
-        " - type\n"
-        " : Prints the contents of a file\n"
-      );
-    } else if (strcmp(buffer, "clear", 5)) {
-      clear_screen();
-      set_curpos(0, 0);
-    } else if (strcmp(buffer, "echo", 4)) {
-      printf("%s\n", rest);
-    } else if (strcmp(buffer, "type", 4)) {
-      char filenamebuffer[12];
-
-      decode_filename(rest, filenamebuffer);
-      if (!file_exists(filenamebuffer)) {
-        printf("File %s not found!\n", filenamebuffer);
-        continue;
-      }
-
-      for (int i=0; i<4096; i++)
-        filebuffer[i] = 0;
-      
-      load_file(filenamebuffer, filebuffer);
-      printf(filebuffer);
-    } else if (strcmp(buffer, "pagefault", 9)) {
-      uint32_t* bad_addr = 0xdeadbeef;
-      uint32_t a = *bad_addr;
-    } else {
-      char filenamebuffer[12];
-      decode_filename(buffer, filenamebuffer);
-      if (!file_exists(filenamebuffer)) {
-        printf("Bad Command or filename!\n");
-        continue;
-      }
-    }
-  }
+  while (1) asm ("hlt");
 }
--- a/src/kernel/process.cpp
+++ b/src/kernel/process.cpp
@ -30,7 +30,7 @@ Process::Process(uint32_t PID)
  this->stack = this->allocate(0x8000);
 }

-Process::Process(uint32_t PID, PageDirectory* inherit, uint32_t inheritBase)
+Process::Process(uint32_t PID, PageDirectory* inherit, uint32_t inheritBase, char* filename)
 : Allocator(new PageDirectory, new PageMap, 0) {
  this->PID = PID;
  this->page_remaining = 0;
@ -45,12 +45,12 @@ Process::Process(uint32_t PID, PageDirectory* inherit, uint32_t inheritBase)
  asm ("mov %%cr3, %0" : "=a" (pCR3) :);
  this->PD->select();

-  uint8_t* program_data = this->allocate(file_size("PROGRAM BIN") + 12) + 12;
+  uint8_t* program_data = this->allocate(file_size(filename) + 12) + 12;

  // We also need to initialise ESP and the stack
  uint32_t* stack32 = ((uint32_t)this->stack + 0x8000);
  stack32--;
-  *stack32 = 0x0; // EFLAGS
+  *stack32 = 0x200; // EFLAGS
  stack32--;
  *stack32 = 8; // CS 0x08
  stack32--;
@ -59,7 +59,7 @@ Process::Process(uint32_t PID, PageDirectory* inherit, uint32_t inheritBase)
  stack32--;
  *stack32 = ((uint32_t)this->stack + 0x8000); // EBP

-  stack32 -= 11;
+  stack32 -= 21;

  stack32--;
  *stack32 = 0; // EAX
@ -80,7 +80,7 @@ Process::Process(uint32_t PID, PageDirectory* inherit, uint32_t inheritBase)

  this->esp = stack32;

-  load_file("PROGRAM BIN", program_data);
+  load_file(filename, program_data);

  asm ("mov %0, %%cr3" : : "r" (pCR3));
 }
--- a/src/kernel/process.h
+++ b/src/kernel/process.h
@ -37,7 +37,7 @@ public:

  Process(uint32_t PID, void* stack, PageDirectory* page_directory, PageMap* phys, PageMap* virt, uint32_t virt_alloc_base);
  Process(uint32_t PID);
-  Process(uint32_t PID, PageDirectory* inherit, uint32_t inheritBase);
+  Process(uint32_t PID, PageDirectory* inherit, uint32_t inheritBase, char* filename);

  void* allocate(uint32_t size) override;
  void deallocate(uint32_t virt_addr) override;
--- a/src/kernel/terminal.cpp
+++ b/src/kernel/terminal.cpp
@ -3,18 +3,20 @@
 void Terminal::scroll_up() {
  // Scroll the entire buffer up.
  for (int y = 0; y < (height * pages); y++) {
-    uint16_t* cline = y * width;
-    uint16_t* nline = (y+1) * width;
+    uint16_t* cline = buffer + y * width;
+    uint16_t* nline = buffer + (y+1) * width;
    for (int x = 0; x < width; x++) {
      cline[x] = nline[x];
    }
  }
  // Clear the last line
-  uint16_t* last_line = (height * pages - 1) * width;
+  uint16_t* last_line = buffer + (height * pages - 1) * width;
  for (int x = 0; x < width; x++) {
    last_line[x] = 0x0720;
  }
  this->cur_y--;
+
+  this->update();
 }

 void Terminal::putchar(uint32_t ptr, uint8_t c, uint8_t edata) {
@ -61,8 +63,10 @@ void Terminal::printf(const char* string, ...) {
      this->cur_y++;
    }

-    if (this->cur_y == this->height)
+    if (this->cur_y == this->height) {
      this->scroll_up();
+      printf("This gets called...");
+    }

    if (current == '%') {
      int type = string[index++];