Reboot when Ctrl+Alt+Del is pressed.

Suggested by Anthony Romano.
Implementation with assistance from and reviewed by Godmar Back.

diff --git a/src/devices/kbd.c b/src/devices/kbd.c
index 4d7dfdf1a315df6cd3b92564c2719bc815d694de..1aa71f5a3062c1888b3d3342d9a2d6675765b4e6 100644 (file)
--- a/src/devices/kbd.c
+++ b/src/devices/kbd.c
@@ -4,6 +4,7 @@
 #include <stdio.h>
 #include <string.h>
 #include "devices/input.h"
+#include "threads/init.h"
 #include "threads/interrupt.h"
 #include "threads/io.h"
 
@@ -53,7 +54,7 @@ struct keymap
    that we handle elsewhere.  */
 static const struct keymap invariant_keymap[] = 
   {
-    {0x01, "\033"},
+    {0x01, "\033"},             /* Escape. */
     {0x0e, "\b"},
     {0x0f, "\tQWERTYUIOP"},
     {0x1c, "\r"},
@@ -61,6 +62,7 @@ static const struct keymap invariant_keymap[] =
     {0x2c, "ZXCVBNM"},
     {0x37, "*"},
     {0x39, " "},
+    {0x53, "\177"},             /* Delete. */
     {0, NULL},
   };
 
@@ -131,6 +133,10 @@ keyboard_interrupt (struct intr_frame *args UNUSED)
       /* Ordinary character. */
       if (!release) 
         {
+          /* Reboot if Ctrl+Alt+Del pressed. */
+          if (c == 0177 && ctrl && alt)
+            reboot ();
+
           /* Handle Ctrl, Shift.
              Note that Ctrl overrides Shift. */
           if (ctrl && c >= 0x40 && c < 0x60) 

diff --git a/src/devices/timer.c b/src/devices/timer.c
index a4521de86e32b91b7a939f68e06d6f6c7a0b83b3..70234a808844e425d8309f6cd04c09ce11ad230e 100644 (file)
--- a/src/devices/timer.c
+++ b/src/devices/timer.c
@@ -28,6 +28,7 @@ static intr_handler_func timer_interrupt;
 static bool too_many_loops (unsigned loops);
 static void busy_wait (int64_t loops);
 static void real_time_sleep (int64_t num, int32_t denom);
+static void real_time_delay (int64_t num, int32_t denom);
 
 /* Sets up the 8254 Programmable Interval Timer (PIT) to
    interrupt PIT_FREQ times per second, and registers the
@@ -92,7 +93,8 @@ timer_elapsed (int64_t then)
   return timer_ticks () - then;
 }
 
-/* Suspends execution for approximately TICKS timer ticks. */
+/* Sleeps for approximately TICKS timer ticks.  Interrupts must
+   be turned on. */
 void
 timer_sleep (int64_t ticks) 
 {
@@ -103,27 +105,69 @@ timer_sleep (int64_t ticks)
     thread_yield ();
 }
 
-/* Suspends execution for approximately MS milliseconds. */
+/* Sleeps for approximately MS milliseconds.  Interrupts must be
+   turned on. */
 void
 timer_msleep (int64_t ms) 
 {
   real_time_sleep (ms, 1000);
 }
 
-/* Suspends execution for approximately US microseconds. */
+/* Sleeps for approximately US microseconds.  Interrupts must be
+   turned on. */
 void
 timer_usleep (int64_t us) 
 {
   real_time_sleep (us, 1000 * 1000);
 }
 
-/* Suspends execution for approximately NS nanoseconds. */
+/* Sleeps for approximately NS nanoseconds.  Interrupts must be
+   turned on. */
 void
 timer_nsleep (int64_t ns) 
 {
   real_time_sleep (ns, 1000 * 1000 * 1000);
 }
 
+/* Busy-waits for approximately MS milliseconds.  Interrupts need
+   not be turned on.
+
+   Busy waiting wastes CPU cycles, and busy waiting with
+   interrupts off for the interval between timer ticks or longer
+   will cause timer ticks to be lost.  Thus, use timer_msleep()
+   instead if interrupts are enabled. */
+void
+timer_mdelay (int64_t ms) 
+{
+  real_time_delay (ms, 1000);
+}
+
+/* Sleeps for approximately US microseconds.  Interrupts need not
+   be turned on.
+
+   Busy waiting wastes CPU cycles, and busy waiting with
+   interrupts off for the interval between timer ticks or longer
+   will cause timer ticks to be lost.  Thus, use timer_usleep()
+   instead if interrupts are enabled. */
+void
+timer_udelay (int64_t us) 
+{
+  real_time_delay (us, 1000 * 1000);
+}
+
+/* Sleeps execution for approximately NS nanoseconds.  Interrupts
+   need not be turned on.
+
+   Busy waiting wastes CPU cycles, and busy waiting with
+   interrupts off for the interval between timer ticks or longer
+   will cause timer ticks to be lost.  Thus, use timer_nsleep()
+   instead if interrupts are enabled.*/
+void
+timer_ndelay (int64_t ns) 
+{
+  real_time_delay (ns, 1000 * 1000 * 1000);
+}
+
 /* Prints timer statistics. */
 void
 timer_print_stats (void) 
@@ -195,10 +239,17 @@ real_time_sleep (int64_t num, int32_t denom)
   else 
     {
       /* Otherwise, use a busy-wait loop for more accurate
-         sub-tick timing.  We scale the numerator and denominator
-         down by 1000 to avoid the possibility of overflow. */
-      ASSERT (denom % 1000 == 0);
-      busy_wait (loops_per_tick * num / 1000 * TIMER_FREQ / (denom / 1000)); 
+         sub-tick timing. */
+      real_time_delay (num, denom); 
     }
 }
 
+/* Busy-wait for approximately NUM/DENOM seconds. */
+static void
+real_time_delay (int64_t num, int32_t denom)
+{
+  /* Scale the numerator and denominator down by 1000 to avoid
+     the possibility of overflow. */
+  ASSERT (denom % 1000 == 0);
+  busy_wait (loops_per_tick * num / 1000 * TIMER_FREQ / (denom / 1000)); 
+}

diff --git a/src/devices/timer.h b/src/devices/timer.h
index 45a3f72e1127cd02f97b79d995277bec67a0812f..cd3d6bbfeb8d94046224d2676326705247f4a710 100644 (file)
--- a/src/devices/timer.h
+++ b/src/devices/timer.h
@@ -13,11 +13,17 @@ void timer_calibrate (void);
 int64_t timer_ticks (void);
 int64_t timer_elapsed (int64_t);
 
+/* Sleep and yield the CPU to other threads. */
 void timer_sleep (int64_t ticks);
 void timer_msleep (int64_t milliseconds);
 void timer_usleep (int64_t microseconds);
 void timer_nsleep (int64_t nanoseconds);
 
+/* Busy waits. */
+void timer_mdelay (int64_t milliseconds);
+void timer_udelay (int64_t microseconds);
+void timer_ndelay (int64_t nanoseconds);
+
 void timer_print_stats (void);
 
 #endif /* devices/timer.h */

diff --git a/src/threads/init.c b/src/threads/init.c
index 9815a2030749dcece5d2c4e378a5b79120d1d9b7..ac9460307d3d2b3d5596713bedb8c040db65bf0c 100644 (file)
--- a/src/threads/init.c
+++ b/src/threads/init.c
@@ -396,15 +396,15 @@ reboot (void)
           {
             if ((inb (0x64) & 0x02) == 0)   
               break;
-            timer_usleep (2);
+            timer_udelay (2);
           }
 
-        timer_usleep (50);
+        timer_udelay (50);
 
         /* Pulse bit 0 of the output port P2 of the keyboard controller. 
          * This will reset the CPU. */
         outb (0x64, 0xfe);
-        timer_usleep (50);
+        timer_udelay (50);
     }
 }