From 0ae9ad7d929d93227c818334b135397ae25a34db Mon Sep 17 00:00:00 2001
From: Mathieu Maret <mathieu.maret@gmail.com>
Date: Thu, 20 Aug 2020 23:54:01 +0200
Subject: [PATCH] protect vga access from mutlithread

---
 drivers/vga.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/vga.c b/drivers/vga.c
index a391992..1558316 100644
--- a/drivers/vga.c
+++ b/drivers/vga.c
@@ -1,6 +1,7 @@
 #include "vga.h"
 #include "io.h"
 #include "klibc.h"
+#include "irq.h"
 
 static uint vgaBgColor;
 static uint vgaColor;
@@ -18,20 +19,28 @@ int VGASetup(uint bgColor, uint color)
 
 void clearScreen(uint bgColor)
 {
+    uint32_t flags;
     volatile short *vga = (short *)VGA_ADDR;
     long int colorAttr  = bgColor << 12;
+
+    disable_IRQs(flags);
     for (int i = 0; i < VGA_WIDTH * VGA_HEIGHT; i++) {
         vga[i] = colorAttr;
     }
+    restore_IRQs(flags);
 }
 
 void clearScreenLine(uint bgColor, uint line)
 {
+    uint32_t flags;
     volatile short *vga = (short *)VGA_ADDR;
     long int colorAttr  = bgColor << 12;
+
+    disable_IRQs(flags);
     for (uint i = VGA_WIDTH * line; i < VGA_WIDTH * (line + 1); i++) {
         vga[i] = colorAttr;
     }
+    restore_IRQs(flags);
 }
 
 void printIntDetails(int integer, uint color, uint bgColor, int startX, int startY)
@@ -67,6 +76,9 @@ void vgaScrollUp(void)
 {
     long int colorAttr  = vgaBgColor << 12;
     volatile short *vga = (short *)VGA_ADDR;
+    int flags;
+
+    disable_IRQs(flags);
     for (int i = 1; i < VGA_HEIGHT - 1; i++) { // last line is status line. Do not scroll it
         memcpy((void *)&vga[VGA_WIDTH * (i - 1)], (void *)&vga[VGA_WIDTH * i],
                VGA_WIDTH * sizeof(short));
@@ -74,10 +86,14 @@ void vgaScrollUp(void)
     for (int i = 0; i < VGA_WIDTH; i++) {
         vga[(VGA_HEIGHT - 2) * VGA_WIDTH + i] = colorAttr;
     }
+    restore_IRQs(flags);
 }
 
 void VGAputc(const char str)
 {
+    int flags;
+
+    disable_IRQs(flags);
     if (str == '\n') {
         line++;
         col = 0;
@@ -106,18 +122,23 @@ void VGAputc(const char str)
         }
     }
     cursorMove(col, line);
+    restore_IRQs(flags);
 }
 
 void printStringDetails(const char *str, uint color, uint bgColor, int startX, int startY)
 {
+    uint32_t flags;
     volatile short *vga = (short *)VGA_ADDR;
     int i               = 0;
     long int colorAttr  = (bgColor << 4 | (color & 0x0f)) << 8;
+
+    disable_IRQs(flags);
     while (*str) {
         vga[VGA_WIDTH * startY + startX + i] = colorAttr | *str;
         str++;
         i++;
     }
+    restore_IRQs(flags);
 }
 
 void cursorEnable(uint8_t cursor_start, uint8_t cursor_end)