low-level keyboard input (not hooked up to /dev yet)

fix acquire() to cli() *before* incrementing nlock
make T_SYSCALL a trap gate, not an interrupt gate
sadly, various crashes if you hold down a keyboard key...

Notes

@@ -241,3 +241,41 @@ maybe a race; acquire does
   cpu = cpu()
 what if another acquire calls holding w/ locked = 1 but
   before cpu is set?
+
+if I type a lot (kbd), i get a panic
+cpu1 in scheduler: panic "holding locks in scheduler"
+cpu0 also in the same panic!
+recursive interrupt?
+  FL_IF is probably set during interrupt... is that correct?
+again:
+  olding locks in scheduler
+  trap v 33 eip 100ED3 c (that is, interrupt while holding a lock)
+  100ed3 is in lapic_write
+again:
+  trap v 33 eip 102A3C cpu 1 nlock 1 (in acquire)
+  panic: interrupt while holding a lock
+again:
+  trap v 33 eip 102A3C cpu 1 nlock 1
+  panic: interrupt while holding a lock
+OR is it the cprintf("kbd overflow")?
+  no, get panic even w/o that cprintf
+OR a release() at interrupt time turns interrupts back on?
+  of course i don't think they were off...
+OK, fixing trap.c to make interrupts turn off FL_IF
+  that makes it take longer, but still panics
+  (maybe b/c release sets FL_IF)
+
+shouldn't something (PIC?) prevent recursive interrupts of same IRQ?
+  or should FL_IF be clear during all interrupts?
+
+maybe acquire should remember old FL_IF value, release should restore
+  if acquire did cli()
+
+DUH the increment of nlock in acquire() happens before the cli!
+  so the panic is probably not a real problem
+  test nlock, cli(), then increment?
+
+BUT now userfs doesn't do the final cat README
+
+AND w/ cprintf("kbd overflow"), panic holding locks in scheduler
+  maybe also simulataneous panic("interrupt while holding a lock")

console.c

@@ -174,8 +174,186 @@ console_write (int minor, void *buf, int n)
   return n;
 }
 
+
+/* This is i8042reg.h + kbdreg.h from NetBSD. */
+#define	KBSTATP		0x64	/* kbd controller status port(I) */
+#define	 KBS_DIB	0x01	/* kbd data in buffer */
+#define	KBDATAP		0x60	/* kbd data port(I) */
+
+#define NO		0
+
+#define SHIFT		(1<<0)
+#define CTL		(1<<1)
+#define ALT		(1<<2)
+
+#define CAPSLOCK	(1<<3)
+#define NUMLOCK		(1<<4)
+#define SCROLLLOCK	(1<<5)
+
+#define E0ESC		(1<<6)
+
+// Special keycodes
+#define KEY_HOME	0xE0
+#define KEY_END		0xE1
+#define KEY_UP		0xE2
+#define KEY_DN		0xE3
+#define KEY_LF		0xE4
+#define KEY_RT		0xE5
+#define KEY_PGUP	0xE6
+#define KEY_PGDN	0xE7
+#define KEY_INS		0xE8
+#define KEY_DEL		0xE9
+
+static uchar shiftcode[256] = 
+{
+	[0x1D] CTL,
+	[0x2A] SHIFT,
+	[0x36] SHIFT,
+	[0x38] ALT,
+	[0x9D] CTL,
+	[0xB8] ALT
+};
+
+static uchar togglecode[256] = 
+{
+	[0x3A] CAPSLOCK,
+	[0x45] NUMLOCK,
+	[0x46] SCROLLLOCK
+};
+
+static uchar normalmap[256] =
+{
+	NO,   0x1B, '1',  '2',  '3',  '4',  '5',  '6',	// 0x00
+	'7',  '8',  '9',  '0',  '-',  '=',  '\b', '\t',
+	'q',  'w',  'e',  'r',  't',  'y',  'u',  'i',	// 0x10
+	'o',  'p',  '[',  ']',  '\n', NO,   'a',  's',
+	'd',  'f',  'g',  'h',  'j',  'k',  'l',  ';',	// 0x20
+	'\'', '`',  NO,   '\\', 'z',  'x',  'c',  'v',
+	'b',  'n',  'm',  ',',  '.',  '/',  NO,   '*',	// 0x30
+	NO,   ' ',  NO,   NO,   NO,   NO,   NO,   NO,
+	NO,   NO,   NO,   NO,   NO,   NO,   NO,   '7',	// 0x40
+	'8',  '9',  '-',  '4',  '5',  '6',  '+',  '1',
+	'2',  '3',  '0',  '.',  NO,   NO,   NO,   NO,	// 0x50
+	[0x97] KEY_HOME,	[0x9C] '\n' /*KP_Enter*/,
+	[0xB5] '/' /*KP_Div*/,	[0xC8] KEY_UP,
+	[0xC9] KEY_PGUP,	[0xCB] KEY_LF,
+	[0xCD] KEY_RT,		[0xCF] KEY_END,
+	[0xD0] KEY_DN,		[0xD1] KEY_PGDN,
+	[0xD2] KEY_INS,		[0xD3] KEY_DEL
+};
+
+static uchar shiftmap[256] = 
+{
+	NO,   033,  '!',  '@',  '#',  '$',  '%',  '^',	// 0x00
+	'&',  '*',  '(',  ')',  '_',  '+',  '\b', '\t',
+	'Q',  'W',  'E',  'R',  'T',  'Y',  'U',  'I',	// 0x10
+	'O',  'P',  '{',  '}',  '\n', NO,   'A',  'S',
+	'D',  'F',  'G',  'H',  'J',  'K',  'L',  ':',	// 0x20
+	'"',  '~',  NO,   '|',  'Z',  'X',  'C',  'V',
+	'B',  'N',  'M',  '<',  '>',  '?',  NO,   '*',	// 0x30
+	NO,   ' ',  NO,   NO,   NO,   NO,   NO,   NO,
+	NO,   NO,   NO,   NO,   NO,   NO,   NO,   '7',	// 0x40
+	'8',  '9',  '-',  '4',  '5',  '6',  '+',  '1',
+	'2',  '3',  '0',  '.',  NO,   NO,   NO,   NO,	// 0x50
+	[0x97] KEY_HOME,	[0x9C] '\n' /*KP_Enter*/,
+	[0xB5] '/' /*KP_Div*/,	[0xC8] KEY_UP,
+	[0xC9] KEY_PGUP,	[0xCB] KEY_LF,
+	[0xCD] KEY_RT,		[0xCF] KEY_END,
+	[0xD0] KEY_DN,		[0xD1] KEY_PGDN,
+	[0xD2] KEY_INS,		[0xD3] KEY_DEL
+};
+
+#define C(x) (x - '@')
+
+static uchar ctlmap[256] = 
+{
+	NO,      NO,      NO,      NO,      NO,      NO,      NO,      NO, 
+	NO,      NO,      NO,      NO,      NO,      NO,      NO,      NO, 
+	C('Q'),  C('W'),  C('E'),  C('R'),  C('T'),  C('Y'),  C('U'),  C('I'),
+	C('O'),  C('P'),  NO,      NO,      '\r',    NO,      C('A'),  C('S'),
+	C('D'),  C('F'),  C('G'),  C('H'),  C('J'),  C('K'),  C('L'),  NO, 
+	NO,      NO,      NO,      C('\\'), C('Z'),  C('X'),  C('C'),  C('V'),
+	C('B'),  C('N'),  C('M'),  NO,      NO,      C('/'),  NO,      NO,
+	[0x97] KEY_HOME,
+	[0xB5] C('/'),		[0xC8] KEY_UP,
+	[0xC9] KEY_PGUP,	[0xCB] KEY_LF,
+	[0xCD] KEY_RT,		[0xCF] KEY_END,
+	[0xD0] KEY_DN,		[0xD1] KEY_PGDN,
+	[0xD2] KEY_INS,		[0xD3] KEY_DEL
+};
+
+static uchar *charcode[4] = {
+	normalmap,
+	shiftmap,
+	ctlmap,
+	ctlmap
+};
+
+#define KBD_BUF 64
+char kbd_buf[KBD_BUF];
+int kbd_r;
+int kbd_w;
+struct spinlock kbd_lock = { "kbd_lock" };
+
+void
+kbd_intr()
+{
+  uint st, data, c;
+  static uint shift;
+
+  st = inb(KBSTATP);
+  if ((st & KBS_DIB) == 0){
+    lapic_eoi();
+    return;
+  }
+  data = inb(KBDATAP);
+
+  if (data == 0xE0) {
+    shift |= E0ESC;
+    lapic_eoi();
+    return;
+  } else if (data & 0x80) {
+    // Key released
+    data = (shift & E0ESC ? data : data & 0x7F);
+    shift &= ~(shiftcode[data] | E0ESC);
+    lapic_eoi();
+    return;
+  } else if (shift & E0ESC) {
+    // Last character was an E0 escape; or with 0x80
+    data |= 0x80;
+    shift &= ~E0ESC;
+  }
+  
+  shift |= shiftcode[data];
+  shift ^= togglecode[data];
+  
+  c = charcode[shift & (CTL | SHIFT)][data];
+  if (shift & CAPSLOCK) {
+    if ('a' <= c && c <= 'z')
+      c += 'A' - 'a';
+    else if ('A' <= c && c <= 'Z')
+      c += 'a' - 'A';
+  }
+  
+  acquire(&kbd_lock);
+
+  if(((kbd_w + 1) % KBD_BUF) != kbd_r){
+    kbd_buf[kbd_w++] = c;
+    if(kbd_w >= KBD_BUF)
+      kbd_w = 0;
+  } else {
+    cprintf("kbd overflow\n");
+  }
+
+  release(&kbd_lock);
+
+  lapic_eoi();
+}
+
 void
 console_init()
 {
   devsw[CONSOLE].d_write = console_write;
+
+  ioapic_enable (IRQ_KBD, 1);
 }

defs.h

@@ -4,8 +4,10 @@ void kfree(char *cp, int len);
 void kinit(void);
 
 // console.c
+void console_init(void);
 void cprintf(char *fmt, ...);
 void panic(char *s);
+void kbd_intr(void);
 
 // proc.c
 struct proc;

fcntl.h

@@ -0,0 +1,4 @@
+#define O_CREATE  0x200
+#define O_RDONLY  0x000
+#define O_WRONLY  0x001
+#define O_RDWR    0x002

fs.c

@@ -329,6 +329,7 @@ writei(struct inode *ip, void *addr, uint off, uint n)
     return r;
   } else {
     panic ("writei: unknown type\n");
+    return 0;
   }
 }
 

fs.h

@@ -36,8 +36,3 @@ struct dirent {
   ushort inum;
   char name[DIRSIZ];
 };
-
-#define O_CREATE  0x200
-#define O_RDONLY  0x000
-#define O_WRONLY  0x001
-#define O_RDWR    0x002

ide.c

@@ -49,7 +49,7 @@ ide_init(void)
   if (ncpu < 2) {
     panic ("ide_init: disk interrupt is going to the second  cpu\n");
   }
-  ioapic_enable (14, 1); // 14 is IRQ # for IDE
+  ioapic_enable (IRQ_IDE, 1);
   ide_wait_ready(0);
   cprintf ("cpu%d: ide_init:done\n", cpu());
 }

main.c

@@ -71,7 +71,7 @@ main0(void)
   p->tf->eflags = FL_IF;
   setupsegs(p);
 
-  // init disk device
+  // initialize I/O devices, let them enable interrupts
   console_init();
   ide_init(); 
 

mkfs.c

@@ -75,7 +75,7 @@ main(int argc, char *argv[])
   sb.nblocks = xint(nblocks); // so whole disk is size sectors
   sb.ninodes = xint(ninodes);
 
-  bitblocks = sb.size/(512*8) + 1; 
+  bitblocks = size/(512*8) + 1; 
   usedblocks = ninodes / IPB + 3 + bitblocks;
   freeblock = usedblocks;
 

spinlock.c

@@ -30,8 +30,10 @@ acquire(struct spinlock * lock)
   if(holding(lock))
     panic("acquire");
 
-	if(cpus[cpu()].nlock++ == 0)
+  if(cpus[cpu()].nlock == 0)
     cli();
+  cpus[cpu()].nlock++;
+                
 	while(cmpxchg(0, 1, &lock->locked) == 1)
 		;
 	cpuid(0, 0, 0, 0, 0);	// memory barrier
@@ -53,6 +55,8 @@ release(struct spinlock * lock)
 	lock->locked = 0;
 	if(--cpus[cpu()].nlock == 0)
 		sti();
+        // xxx we may have just turned interrupts on during
+        // an interrupt, is that ok?
 }
 
 int

syscall.c

@@ -12,6 +12,7 @@
 #include "fsvar.h"
 #include "elf.h"
 #include "fd.h"
+#include "fcntl.h"
 
 /*
  * User code makes a system call with INT T_SYSCALL.

trap.c

@@ -21,7 +21,7 @@ tvinit(void)
   for(i = 0; i < 256; i++){
     SETGATE(idt[i], 1, SEG_KCODE << 3, vectors[i], 0);
   }
-  SETGATE(idt[T_SYSCALL], T_SYSCALL, SEG_KCODE << 3, vectors[48], 3);
+  SETGATE(idt[T_SYSCALL], 1, SEG_KCODE << 3, vectors[48], 3);
 }
 
 void
@@ -40,12 +40,12 @@ trap(struct trapframe *tf)
             v, tf->eip, cpu(), cpus[cpu()].nlock);
     panic("interrupt while holding a lock");
   }
-  if((read_eflags() & FL_IF) == 0)
-    panic("interrupt but interrupts now disabled");
 
   if(v == T_SYSCALL){
     struct proc *cp = curproc[cpu()];
     int num = cp->tf->eax;
+    if((read_eflags() & FL_IF) == 0)
+      panic("syscall but interrupts now disabled");
     if(cp == 0)
       panic("syscall with no proc");
     if(cp->killed)
@@ -73,6 +73,9 @@ trap(struct trapframe *tf)
     return;
   }
 
+  //if(read_eflags() & FL_IF)
+  //panic("interrupt but interrupts enabled");
+
   if(v == (IRQ_OFFSET + IRQ_TIMER)){
     struct proc *cp = curproc[cpu()];
     lapic_timerintr();
@@ -97,5 +100,12 @@ trap(struct trapframe *tf)
     return;
   }
 
+  if(v == (IRQ_OFFSET + IRQ_KBD)){
+    kbd_intr();
+    return;
+  }
+
+  cprintf("trap %d\n", v);
+
   return;
 }

userfs.c

@@ -1,6 +1,7 @@
 #include "user.h"
 #include "types.h"
 #include "fs.h"
+#include "fcntl.h"
 
 // file system tests
 

x86.h

@@ -362,6 +362,7 @@ struct trapframe {
 
 #define IRQ_OFFSET      32	// IRQ 0 corresponds to int IRQ_OFFSET
 
+#define IRQ_KBD         1
 #define IRQ_IDE         14
 #define IRQ_ERROR       19
 #define IRQ_SPURIOUS    31