sanchayanmaity/xv6-cs450
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low-level keyboard input (not hooked up to /dev yet)

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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...
This commit is contained in:
rtm 2006-08-10 02:07:10 +00:00
parent 28d9ef04dd
commit 8a8be1b8c3
14 changed files with 249 additions and 14 deletions
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38
Notes
View file

@ -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")

178
console.c
View file

@ -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);
}

2
defs.h
View file

@ -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;

4
fcntl.h Normal file
View file

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

1
fs.c
View file

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

5
fs.h
View file

@ -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

2
ide.c
View file

@ -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());
}

2
main.c
View file

@ -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();

2
mkfs.c
View file

@ -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;

6
spinlock.c
View file

@ -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

1
syscall.c
View file

@ -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.

16
trap.c
View file

@ -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;
}

1
userfs.c
View file

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

1
x86.h
View file

@ -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