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chyyuu
2012-08-22 12:32:13 +08:00
parent e325fad98f
commit 15f7ebf37b
743 changed files with 94930 additions and 0 deletions
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27
code/lab1/kern/debug/assert.h Normal file
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#ifndef __KERN_DEBUG_ASSERT_H__
#define __KERN_DEBUG_ASSERT_H__
#include <defs.h>
void __warn(const char *file, int line, const char *fmt, ...);
void __noreturn __panic(const char *file, int line, const char *fmt, ...);
#define warn(...) \
__warn(__FILE__, __LINE__, __VA_ARGS__)
#define panic(...) \
__panic(__FILE__, __LINE__, __VA_ARGS__)
#define assert(x) \
do { \
if (!(x)) { \
panic("assertion failed: %s", #x); \
} \
} while (0)
// static_assert(x) will generate a compile-time error if 'x' is false.
#define static_assert(x) \
switch (x) { case 0: case (x): ; }
#endif /* !__KERN_DEBUG_ASSERT_H__ */

306
code/lab1/kern/debug/kdebug.c Normal file
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#include <defs.h>
#include <x86.h>
#include <stab.h>
#include <stdio.h>
#include <string.h>
#include <kdebug.h>
#define STACKFRAME_DEPTH 20
extern const struct stab __STAB_BEGIN__[]; // beginning of stabs table
extern const struct stab __STAB_END__[]; // end of stabs table
extern const char __STABSTR_BEGIN__[]; // beginning of string table
extern const char __STABSTR_END__[]; // end of string table
/* debug information about a particular instruction pointer */
struct eipdebuginfo {
const char *eip_file; // source code filename for eip
int eip_line; // source code line number for eip
const char *eip_fn_name; // name of function containing eip
int eip_fn_namelen; // length of function's name
uintptr_t eip_fn_addr; // start address of function
int eip_fn_narg; // number of function arguments
};
/* *
* stab_binsearch - according to the input, the initial value of
* range [*@region_left, *@region_right], find a single stab entry
* that includes the address @addr and matches the type @type,
* and then save its boundary to the locations that pointed
* by @region_left and @region_right.
*
* Some stab types are arranged in increasing order by instruction address.
* For example, N_FUN stabs (stab entries with n_type == N_FUN), which
* mark functions, and N_SO stabs, which mark source files.
*
* Given an instruction address, this function finds the single stab entry
* of type @type that contains that address.
*
* The search takes place within the range [*@region_left, *@region_right].
* Thus, to search an entire set of N stabs, you might do:
*
* left = 0;
* right = N - 1; (rightmost stab)
* stab_binsearch(stabs, &left, &right, type, addr);
*
* The search modifies *region_left and *region_right to bracket the @addr.
* *@region_left points to the matching stab that contains @addr,
* and *@region_right points just before the next stab.
* If *@region_left > *region_right, then @addr is not contained in any
* matching stab.
*
* For example, given these N_SO stabs:
* Index Type Address
* 0 SO f0100000
* 13 SO f0100040
* 117 SO f0100176
* 118 SO f0100178
* 555 SO f0100652
* 556 SO f0100654
* 657 SO f0100849
* this code:
* left = 0, right = 657;
* stab_binsearch(stabs, &left, &right, N_SO, 0xf0100184);
* will exit setting left = 118, right = 554.
* */
static void
stab_binsearch(const struct stab *stabs, int *region_left, int *region_right,
int type, uintptr_t addr) {
int l = *region_left, r = *region_right, any_matches = 0;
while (l <= r) {
int true_m = (l + r) / 2, m = true_m;
// search for earliest stab with right type
while (m >= l && stabs[m].n_type != type) {
m --;
}
if (m < l) { // no match in [l, m]
l = true_m + 1;
continue;
}
// actual binary search
any_matches = 1;
if (stabs[m].n_value < addr) {
*region_left = m;
l = true_m + 1;
} else if (stabs[m].n_value > addr) {
*region_right = m - 1;
r = m - 1;
} else {
// exact match for 'addr', but continue loop to find
// *region_right
*region_left = m;
l = m;
addr ++;
}
}
if (!any_matches) {
*region_right = *region_left - 1;
}
else {
// find rightmost region containing 'addr'
l = *region_right;
for (; l > *region_left && stabs[l].n_type != type; l --)
/* do nothing */;
*region_left = l;
}
}
/* *
* debuginfo_eip - Fill in the @info structure with information about
* the specified instruction address, @addr. Returns 0 if information
* was found, and negative if not. But even if it returns negative it
* has stored some information into '*info'.
* */
int
debuginfo_eip(uintptr_t addr, struct eipdebuginfo *info) {
const struct stab *stabs, *stab_end;
const char *stabstr, *stabstr_end;
info->eip_file = "<unknown>";
info->eip_line = 0;
info->eip_fn_name = "<unknown>";
info->eip_fn_namelen = 9;
info->eip_fn_addr = addr;
info->eip_fn_narg = 0;
stabs = __STAB_BEGIN__;
stab_end = __STAB_END__;
stabstr = __STABSTR_BEGIN__;
stabstr_end = __STABSTR_END__;
// String table validity checks
if (stabstr_end <= stabstr || stabstr_end[-1] != 0) {
return -1;
}
// Now we find the right stabs that define the function containing
// 'eip'. First, we find the basic source file containing 'eip'.
// Then, we look in that source file for the function. Then we look
// for the line number.
// Search the entire set of stabs for the source file (type N_SO).
int lfile = 0, rfile = (stab_end - stabs) - 1;
stab_binsearch(stabs, &lfile, &rfile, N_SO, addr);
if (lfile == 0)
return -1;
// Search within that file's stabs for the function definition
// (N_FUN).
int lfun = lfile, rfun = rfile;
int lline, rline;
stab_binsearch(stabs, &lfun, &rfun, N_FUN, addr);
if (lfun <= rfun) {
// stabs[lfun] points to the function name
// in the string table, but check bounds just in case.
if (stabs[lfun].n_strx < stabstr_end - stabstr) {
info->eip_fn_name = stabstr + stabs[lfun].n_strx;
}
info->eip_fn_addr = stabs[lfun].n_value;
addr -= info->eip_fn_addr;
// Search within the function definition for the line number.
lline = lfun;
rline = rfun;
} else {
// Couldn't find function stab! Maybe we're in an assembly
// file. Search the whole file for the line number.
info->eip_fn_addr = addr;
lline = lfile;
rline = rfile;
}
info->eip_fn_namelen = strfind(info->eip_fn_name, ':') - info->eip_fn_name;
// Search within [lline, rline] for the line number stab.
// If found, set info->eip_line to the right line number.
// If not found, return -1.
stab_binsearch(stabs, &lline, &rline, N_SLINE, addr);
if (lline <= rline) {
info->eip_line = stabs[rline].n_desc;
} else {
return -1;
}
// Search backwards from the line number for the relevant filename stab.
// We can't just use the "lfile" stab because inlined functions
// can interpolate code from a different file!
// Such included source files use the N_SOL stab type.
while (lline >= lfile
&& stabs[lline].n_type != N_SOL
&& (stabs[lline].n_type != N_SO || !stabs[lline].n_value)) {
lline --;
}
if (lline >= lfile && stabs[lline].n_strx < stabstr_end - stabstr) {
info->eip_file = stabstr + stabs[lline].n_strx;
}
// Set eip_fn_narg to the number of arguments taken by the function,
// or 0 if there was no containing function.
if (lfun < rfun) {
for (lline = lfun + 1;
lline < rfun && stabs[lline].n_type == N_PSYM;
lline ++) {
info->eip_fn_narg ++;
}
}
return 0;
}
/* *
* print_kerninfo - print the information about kernel, including the location
* of kernel entry, the start addresses of data and text segements, the start
* address of free memory and how many memory that kernel has used.
* */
void
print_kerninfo(void) {
extern char etext[], edata[], end[], kern_init[];
cprintf("Special kernel symbols:\n");
cprintf(" entry 0x%08x (phys)\n", kern_init);
cprintf(" etext 0x%08x (phys)\n", etext);
cprintf(" edata 0x%08x (phys)\n", edata);
cprintf(" end 0x%08x (phys)\n", end);
cprintf("Kernel executable memory footprint: %dKB\n", (end - kern_init + 1023)/1024);
}
/* *
* print_debuginfo - read and print the stat information for the address @eip,
* and info.eip_fn_addr should be the first address of the related function.
* */
void
print_debuginfo(uintptr_t eip) {
struct eipdebuginfo info;
if (debuginfo_eip(eip, &info) != 0) {
cprintf(" <unknow>: -- 0x%08x --\n", eip);
}
else {
char fnname[256];
int j;
for (j = 0; j < info.eip_fn_namelen; j ++) {
fnname[j] = info.eip_fn_name[j];
}
fnname[j] = '\0';
cprintf(" %s:%d: %s+%d\n", info.eip_file, info.eip_line,
fnname, eip - info.eip_fn_addr);
}
}
static __noinline uint32_t
read_eip(void) {
uint32_t eip;
asm volatile("movl 4(%%ebp), %0" : "=r" (eip));
return eip;
}
/* *
* print_stackframe - print a list of the saved eip values from the nested 'call'
* instructions that led to the current point of execution
*
* The x86 stack pointer, namely esp, points to the lowest location on the stack
* that is currently in use. Everything below that location in stack is free. Pushing
* a value onto the stack will invole decreasing the stack pointer and then writing
* the value to the place that stack pointer pointes to. And popping a value do the
* opposite.
*
* The ebp (base pointer) register, in contrast, is associated with the stack
* primarily by software convention. On entry to a C function, the function's
* prologue code normally saves the previous function's base pointer by pushing
* it onto the stack, and then copies the current esp value into ebp for the duration
* of the function. If all the functions in a program obey this convention,
* then at any given point during the program's execution, it is possible to trace
* back through the stack by following the chain of saved ebp pointers and determining
* exactly what nested sequence of function calls caused this particular point in the
* program to be reached. This capability can be particularly useful, for example,
* when a particular function causes an assert failure or panic because bad arguments
* were passed to it, but you aren't sure who passed the bad arguments. A stack
* backtrace lets you find the offending function.
*
* The inline function read_ebp() can tell us the value of current ebp. And the
* non-inline function read_eip() is useful, it can read the value of current eip,
* since while calling this function, read_eip() can read the caller's eip from
* stack easily.
*
* In print_debuginfo(), the function debuginfo_eip() can get enough information about
* calling-chain. Finally print_stackframe() will trace and print them for debugging.
*
* Note that, the length of ebp-chain is limited. In boot/bootasm.S, before jumping
* to the kernel entry, the value of ebp has been set to zero, that's the boundary.
* */
void
print_stackframe(void) {
/* LAB1 YOUR CODE : STEP 1 */
/* (1) call read_ebp() to get the value of ebp. the type is (uint32_t);
* (2) call read_eip() to get the value of eip. the type is (uint32_t);
* (3) from 0 .. STACKFRAME_DEPTH
* (3.1) printf value of ebp, eip
* (3.2) (uint32_t)calling arguments [0..4] = the contents in address (unit32_t)ebp +2 [0..4]
* (3.3) cprintf("\n");
* (3.4) call print_debuginfo(eip-1) to print the C calling function name and line number, etc.
* (3.5) popup a calling stackframe
* NOTICE: the calling funciton's return addr eip = ss:[ebp+4]
* the calling funciton's ebp = ss:[ebp]
*/
}

11
code/lab1/kern/debug/kdebug.h Normal file
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#ifndef __KERN_DEBUG_KDEBUG_H__
#define __KERN_DEBUG_KDEBUG_H__
#include <defs.h>
void print_kerninfo(void);
void print_stackframe(void);
void print_debuginfo(uintptr_t eip);
#endif /* !__KERN_DEBUG_KDEBUG_H__ */

128
code/lab1/kern/debug/monitor.c Normal file
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#include <stdio.h>
#include <string.h>
#include <trap.h>
#include <monitor.h>
#include <kdebug.h>
/* *
* Simple command-line kernel monitor useful for controlling the
* kernel and exploring the system interactively.
* */
struct command {
const char *name;
const char *desc;
// return -1 to force monitor to exit
int(*func)(int argc, char **argv, struct trapframe *tf);
};
static struct command commands[] = {
{"help", "Display this list of commands.", mon_help},
{"kerninfo", "Display information about the kernel.", mon_kerninfo},
{"backtrace", "Print backtrace of stack frame.", mon_backtrace},
};
#define NCOMMANDS (sizeof(commands)/sizeof(struct command))
/***** Kernel monitor command interpreter *****/
#define MAXARGS 16
#define WHITESPACE " \t\n\r"
/* parse - parse the command buffer into whitespace-separated arguments */
static int
parse(char *buf, char **argv) {
int argc = 0;
while (1) {
// find global whitespace
while (*buf != '\0' && strchr(WHITESPACE, *buf) != NULL) {
*buf ++ = '\0';
}
if (*buf == '\0') {
break;
}
// save and scan past next arg
if (argc == MAXARGS - 1) {
cprintf("Too many arguments (max %d).\n", MAXARGS);
}
argv[argc ++] = buf;
while (*buf != '\0' && strchr(WHITESPACE, *buf) == NULL) {
buf ++;
}
}
return argc;
}
/* *
* runcmd - parse the input string, split it into separated arguments
* and then lookup and invoke some related commands/
* */
static int
runcmd(char *buf, struct trapframe *tf) {
char *argv[MAXARGS];
int argc = parse(buf, argv);
if (argc == 0) {
return 0;
}
int i;
for (i = 0; i < NCOMMANDS; i ++) {
if (strcmp(commands[i].name, argv[0]) == 0) {
return commands[i].func(argc - 1, argv + 1, tf);
}
}
cprintf("Unknown command '%s'\n", argv[0]);
return 0;
}
/***** Implementations of basic kernel monitor commands *****/
void
monitor(struct trapframe *tf) {
cprintf("Welcome to the kernel debug monitor!!\n");
cprintf("Type 'help' for a list of commands.\n");
if (tf != NULL) {
print_trapframe(tf);
}
char *buf;
while (1) {
if ((buf = readline("K> ")) != NULL) {
if (runcmd(buf, tf) < 0) {
break;
}
}
}
}
/* mon_help - print the information about mon_* functions */
int
mon_help(int argc, char **argv, struct trapframe *tf) {
int i;
for (i = 0; i < NCOMMANDS; i ++) {
cprintf("%s - %s\n", commands[i].name, commands[i].desc);
}
return 0;
}
/* *
* mon_kerninfo - call print_kerninfo in kern/debug/kdebug.c to
* print the memory occupancy in kernel.
* */
int
mon_kerninfo(int argc, char **argv, struct trapframe *tf) {
print_kerninfo();
return 0;
}
/* *
* mon_backtrace - call print_stackframe in kern/debug/kdebug.c to
* print a backtrace of the stack.
* */
int
mon_backtrace(int argc, char **argv, struct trapframe *tf) {
print_stackframe();
return 0;
}

13
code/lab1/kern/debug/monitor.h Normal file
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#ifndef __KERN_DEBUG_MONITOR_H__
#define __KERN_DEBUG_MONITOR_H__
#include <trap.h>
void monitor(struct trapframe *tf);
int mon_help(int argc, char **argv, struct trapframe *tf);
int mon_kerninfo(int argc, char **argv, struct trapframe *tf);
int mon_backtrace(int argc, char **argv, struct trapframe *tf);
#endif /* !__KERN_DEBUG_MONITOR_H__ */

49
code/lab1/kern/debug/panic.c Normal file
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#include <defs.h>
#include <stdio.h>
#include <intr.h>
#include <monitor.h>
static bool is_panic = 0;
/* *
* __panic - __panic is called on unresolvable fatal errors. it prints
* "panic: 'message'", and then enters the kernel monitor.
* */
void
__panic(const char *file, int line, const char *fmt, ...) {
if (is_panic) {
goto panic_dead;
}
is_panic = 1;
// print the 'message'
va_list ap;
va_start(ap, fmt);
cprintf("kernel panic at %s:%d:\n ", file, line);
vcprintf(fmt, ap);
cprintf("\n");
va_end(ap);
panic_dead:
intr_disable();
while (1) {
monitor(NULL);
}
}
/* __warn - like panic, but don't */
void
__warn(const char *file, int line, const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
cprintf("kernel warning at %s:%d:\n ", file, line);
vcprintf(fmt, ap);
cprintf("\n");
va_end(ap);
}
bool
is_kernel_panic(void) {
return is_panic;
}

54
code/lab1/kern/debug/stab.h Normal file
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#ifndef __KERN_DEBUG_STAB_H__
#define __KERN_DEBUG_STAB_H__
#include <defs.h>
/* *
* STABS debugging info
*
* The kernel debugger can understand some debugging information in
* the STABS format. For more information on this format, see
* http://sources.redhat.com/gdb/onlinedocs/stabs_toc.html
*
* The constants below define some symbol types used by various debuggers
* and compilers. Kernel uses the N_SO, N_SOL, N_FUN, and N_SLINE types.
* */
#define N_GSYM 0x20 // global symbol
#define N_FNAME 0x22 // F77 function name
#define N_FUN 0x24 // procedure name
#define N_STSYM 0x26 // data segment variable
#define N_LCSYM 0x28 // bss segment variable
#define N_MAIN 0x2a // main function name
#define N_PC 0x30 // global Pascal symbol
#define N_RSYM 0x40 // register variable
#define N_SLINE 0x44 // text segment line number
#define N_DSLINE 0x46 // data segment line number
#define N_BSLINE 0x48 // bss segment line number
#define N_SSYM 0x60 // structure/union element
#define N_SO 0x64 // main source file name
#define N_LSYM 0x80 // stack variable
#define N_BINCL 0x82 // include file beginning
#define N_SOL 0x84 // included source file name
#define N_PSYM 0xa0 // parameter variable
#define N_EINCL 0xa2 // include file end
#define N_ENTRY 0xa4 // alternate entry point
#define N_LBRAC 0xc0 // left bracket
#define N_EXCL 0xc2 // deleted include file
#define N_RBRAC 0xe0 // right bracket
#define N_BCOMM 0xe2 // begin common
#define N_ECOMM 0xe4 // end common
#define N_ECOML 0xe8 // end common (local name)
#define N_LENG 0xfe // length of preceding entry
/* Entries in the STABS table are formatted as follows. */
struct stab {
uint32_t n_strx; // index into string table of name
uint8_t n_type; // type of symbol
uint8_t n_other; // misc info (usually empty)
uint16_t n_desc; // description field
uintptr_t n_value; // value of symbol
};
#endif /* !__KERN_DEBUG_STAB_H__ */

45
code/lab1/kern/driver/clock.c Normal file
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#include <x86.h>
#include <trap.h>
#include <stdio.h>
#include <picirq.h>
/* *
* Support for time-related hardware gadgets - the 8253 timer,
* which generates interruptes on IRQ-0.
* */
#define IO_TIMER1 0x040 // 8253 Timer #1
/* *
* Frequency of all three count-down timers; (TIMER_FREQ/freq)
* is the appropriate count to generate a frequency of freq Hz.
* */
#define TIMER_FREQ 1193182
#define TIMER_DIV(x) ((TIMER_FREQ + (x) / 2) / (x))
#define TIMER_MODE (IO_TIMER1 + 3) // timer mode port
#define TIMER_SEL0 0x00 // select counter 0
#define TIMER_RATEGEN 0x04 // mode 2, rate generator
#define TIMER_16BIT 0x30 // r/w counter 16 bits, LSB first
volatile size_t ticks;
/* *
* clock_init - initialize 8253 clock to interrupt 100 times per second,
* and then enable IRQ_TIMER.
* */
void
clock_init(void) {
// set 8253 timer-chip
outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
outb(IO_TIMER1, TIMER_DIV(100) % 256);
outb(IO_TIMER1, TIMER_DIV(100) / 256);
// initialize time counter 'ticks' to zero
ticks = 0;
cprintf("++ setup timer interrupts\n");
pic_enable(IRQ_TIMER);
}

11
code/lab1/kern/driver/clock.h Normal file
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#ifndef __KERN_DRIVER_CLOCK_H__
#define __KERN_DRIVER_CLOCK_H__
#include <defs.h>
extern volatile size_t ticks;
void clock_init(void);
#endif /* !__KERN_DRIVER_CLOCK_H__ */

455
code/lab1/kern/driver/console.c Normal file
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#include <defs.h>
#include <x86.h>
#include <stdio.h>
#include <string.h>
#include <kbdreg.h>
#include <picirq.h>
#include <trap.h>
/* stupid I/O delay routine necessitated by historical PC design flaws */
static void
delay(void) {
inb(0x84);
inb(0x84);
inb(0x84);
inb(0x84);
}
/***** Serial I/O code *****/
#define COM1 0x3F8
#define COM_RX 0 // In: Receive buffer (DLAB=0)
#define COM_TX 0 // Out: Transmit buffer (DLAB=0)
#define COM_DLL 0 // Out: Divisor Latch Low (DLAB=1)
#define COM_DLM 1 // Out: Divisor Latch High (DLAB=1)
#define COM_IER 1 // Out: Interrupt Enable Register
#define COM_IER_RDI 0x01 // Enable receiver data interrupt
#define COM_IIR 2 // In: Interrupt ID Register
#define COM_FCR 2 // Out: FIFO Control Register
#define COM_LCR 3 // Out: Line Control Register
#define COM_LCR_DLAB 0x80 // Divisor latch access bit
#define COM_LCR_WLEN8 0x03 // Wordlength: 8 bits
#define COM_MCR 4 // Out: Modem Control Register
#define COM_MCR_RTS 0x02 // RTS complement
#define COM_MCR_DTR 0x01 // DTR complement
#define COM_MCR_OUT2 0x08 // Out2 complement
#define COM_LSR 5 // In: Line Status Register
#define COM_LSR_DATA 0x01 // Data available
#define COM_LSR_TXRDY 0x20 // Transmit buffer avail
#define COM_LSR_TSRE 0x40 // Transmitter off
#define MONO_BASE 0x3B4
#define MONO_BUF 0xB0000
#define CGA_BASE 0x3D4
#define CGA_BUF 0xB8000
#define CRT_ROWS 25
#define CRT_COLS 80
#define CRT_SIZE (CRT_ROWS * CRT_COLS)
#define LPTPORT 0x378
static uint16_t *crt_buf;
static uint16_t crt_pos;
static uint16_t addr_6845;
/* TEXT-mode CGA/VGA display output */
static void
cga_init(void) {
volatile uint16_t *cp = (uint16_t *)CGA_BUF;
uint16_t was = *cp;
*cp = (uint16_t) 0xA55A;
if (*cp != 0xA55A) {
cp = (uint16_t*)MONO_BUF;
addr_6845 = MONO_BASE;
} else {
*cp = was;
addr_6845 = CGA_BASE;
}
// Extract cursor location
uint32_t pos;
outb(addr_6845, 14);
pos = inb(addr_6845 + 1) << 8;
outb(addr_6845, 15);
pos |= inb(addr_6845 + 1);
crt_buf = (uint16_t*) cp;
crt_pos = pos;
}
static bool serial_exists = 0;
static void
serial_init(void) {
// Turn off the FIFO
outb(COM1 + COM_FCR, 0);
// Set speed; requires DLAB latch
outb(COM1 + COM_LCR, COM_LCR_DLAB);
outb(COM1 + COM_DLL, (uint8_t) (115200 / 9600));
outb(COM1 + COM_DLM, 0);
// 8 data bits, 1 stop bit, parity off; turn off DLAB latch
outb(COM1 + COM_LCR, COM_LCR_WLEN8 & ~COM_LCR_DLAB);
// No modem controls
outb(COM1 + COM_MCR, 0);
// Enable rcv interrupts
outb(COM1 + COM_IER, COM_IER_RDI);
// Clear any preexisting overrun indications and interrupts
// Serial port doesn't exist if COM_LSR returns 0xFF
serial_exists = (inb(COM1 + COM_LSR) != 0xFF);
(void) inb(COM1+COM_IIR);
(void) inb(COM1+COM_RX);
if (serial_exists) {
pic_enable(IRQ_COM1);
}
}
static void
lpt_putc_sub(int c) {
int i;
for (i = 0; !(inb(LPTPORT + 1) & 0x80) && i < 12800; i ++) {
delay();
}
outb(LPTPORT + 0, c);
outb(LPTPORT + 2, 0x08 | 0x04 | 0x01);
outb(LPTPORT + 2, 0x08);
}
/* lpt_putc - copy console output to parallel port */
static void
lpt_putc(int c) {
if (c != '\b') {
lpt_putc_sub(c);
}
else {
lpt_putc_sub('\b');
lpt_putc_sub(' ');
lpt_putc_sub('\b');
}
}
/* cga_putc - print character to console */
static void
cga_putc(int c) {
// set black on white
if (!(c & ~0xFF)) {
c |= 0x0700;
}
switch (c & 0xff) {
case '\b':
if (crt_pos > 0) {
crt_pos --;
crt_buf[crt_pos] = (c & ~0xff) | ' ';
}
break;
case '\n':
crt_pos += CRT_COLS;
case '\r':
crt_pos -= (crt_pos % CRT_COLS);
break;
default:
crt_buf[crt_pos ++] = c; // write the character
break;
}
// What is the purpose of this?
if (crt_pos >= CRT_SIZE) {
int i;
memmove(crt_buf, crt_buf + CRT_COLS, (CRT_SIZE - CRT_COLS) * sizeof(uint16_t));
for (i = CRT_SIZE - CRT_COLS; i < CRT_SIZE; i ++) {
crt_buf[i] = 0x0700 | ' ';
}
crt_pos -= CRT_COLS;
}
// move that little blinky thing
outb(addr_6845, 14);
outb(addr_6845 + 1, crt_pos >> 8);
outb(addr_6845, 15);
outb(addr_6845 + 1, crt_pos);
}
static void
serial_putc_sub(int c) {
int i;
for (i = 0; !(inb(COM1 + COM_LSR) & COM_LSR_TXRDY) && i < 12800; i ++) {
delay();
}
outb(COM1 + COM_TX, c);
}
/* serial_putc - print character to serial port */
static void
serial_putc(int c) {
if (c != '\b') {
serial_putc_sub(c);
}
else {
serial_putc_sub('\b');
serial_putc_sub(' ');
serial_putc_sub('\b');
}
}
/* *
* Here we manage the console input buffer, where we stash characters
* received from the keyboard or serial port whenever the corresponding
* interrupt occurs.
* */
#define CONSBUFSIZE 512
static struct {
uint8_t buf[CONSBUFSIZE];
uint32_t rpos;
uint32_t wpos;
} cons;
/* *
* cons_intr - called by device interrupt routines to feed input
* characters into the circular console input buffer.
* */
static void
cons_intr(int (*proc)(void)) {
int c;
while ((c = (*proc)()) != -1) {
if (c != 0) {
cons.buf[cons.wpos ++] = c;
if (cons.wpos == CONSBUFSIZE) {
cons.wpos = 0;
}
}
}
}
/* serial_proc_data - get data from serial port */
static int
serial_proc_data(void) {
if (!(inb(COM1 + COM_LSR) & COM_LSR_DATA)) {
return -1;
}
int c = inb(COM1 + COM_RX);
if (c == 127) {
c = '\b';
}
return c;
}
/* serial_intr - try to feed input characters from serial port */
void
serial_intr(void) {
if (serial_exists) {
cons_intr(serial_proc_data);
}
}
/***** Keyboard input code *****/
#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)
static uint8_t shiftcode[256] = {
[0x1D] CTL,
[0x2A] SHIFT,
[0x36] SHIFT,
[0x38] ALT,
[0x9D] CTL,
[0xB8] ALT
};
static uint8_t togglecode[256] = {
[0x3A] CAPSLOCK,
[0x45] NUMLOCK,
[0x46] SCROLLLOCK
};
static uint8_t 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
[0xC7] 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 uint8_t 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
[0xC7] 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 uint8_t 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 uint8_t *charcode[4] = {
normalmap,
shiftmap,
ctlmap,
ctlmap
};
/* *
* kbd_proc_data - get data from keyboard
*
* The kbd_proc_data() function gets data from the keyboard.
* If we finish a character, return it, else 0. And return -1 if no data.
* */
static int
kbd_proc_data(void) {
int c;
uint8_t data;
static uint32_t shift;
if ((inb(KBSTATP) & KBS_DIB) == 0) {
return -1;
}
data = inb(KBDATAP);
if (data == 0xE0) {
// E0 escape character
shift |= E0ESC;
return 0;
} else if (data & 0x80) {
// Key released
data = (shift & E0ESC ? data : data & 0x7F);
shift &= ~(shiftcode[data] | E0ESC);
return 0;
} 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';
}
// Process special keys
// Ctrl-Alt-Del: reboot
if (!(~shift & (CTL | ALT)) && c == KEY_DEL) {
cprintf("Rebooting!\n");
outb(0x92, 0x3); // courtesy of Chris Frost
}
return c;
}
/* kbd_intr - try to feed input characters from keyboard */
static void
kbd_intr(void) {
cons_intr(kbd_proc_data);
}
static void
kbd_init(void) {
// drain the kbd buffer
kbd_intr();
pic_enable(IRQ_KBD);
}
/* cons_init - initializes the console devices */
void
cons_init(void) {
cga_init();
serial_init();
kbd_init();
if (!serial_exists) {
cprintf("serial port does not exist!!\n");
}
}
/* cons_putc - print a single character @c to console devices */
void
cons_putc(int c) {
lpt_putc(c);
cga_putc(c);
serial_putc(c);
}
/* *
* cons_getc - return the next input character from console,
* or 0 if none waiting.
* */
int
cons_getc(void) {
int c;
// poll for any pending input characters,
// so that this function works even when interrupts are disabled
// (e.g., when called from the kernel monitor).
serial_intr();
kbd_intr();
// grab the next character from the input buffer.
if (cons.rpos != cons.wpos) {
c = cons.buf[cons.rpos ++];
if (cons.rpos == CONSBUFSIZE) {
cons.rpos = 0;
}
return c;
}
return 0;
}

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#ifndef __KERN_DRIVER_CONSOLE_H__
#define __KERN_DRIVER_CONSOLE_H__
void cons_init(void);
void cons_putc(int c);
int cons_getc(void);
void serial_intr(void);
void kbd_intr(void);
#endif /* !__KERN_DRIVER_CONSOLE_H__ */

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code/lab1/kern/driver/intr.c Normal file
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#include <x86.h>
#include <intr.h>
/* intr_enable - enable irq interrupt */
void
intr_enable(void) {
sti();
}
/* intr_disable - disable irq interrupt */
void
intr_disable(void) {
cli();
}

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#ifndef __KERN_DRIVER_INTR_H__
#define __KERN_DRIVER_INTR_H__
void intr_enable(void);
void intr_disable(void);
#endif /* !__KERN_DRIVER_INTR_H__ */

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#ifndef __KERN_DRIVER_KBDREG_H__
#define __KERN_DRIVER_KBDREG_H__
// 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
/* 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 KBS_IBF 0x02 // kbd input buffer low
#define KBS_WARM 0x04 // kbd input buffer low
#define BS_OCMD 0x08 // kbd output buffer has command
#define KBS_NOSEC 0x10 // kbd security lock not engaged
#define KBS_TERR 0x20 // kbd transmission error
#define KBS_RERR 0x40 // kbd receive error
#define KBS_PERR 0x80 // kbd parity error
#define KBCMDP 0x64 // kbd controller port(O)
#define KBC_RAMREAD 0x20 // read from RAM
#define KBC_RAMWRITE 0x60 // write to RAM
#define KBC_AUXDISABLE 0xa7 // disable auxiliary port
#define KBC_AUXENABLE 0xa8 // enable auxiliary port
#define KBC_AUXTEST 0xa9 // test auxiliary port
#define KBC_KBDECHO 0xd2 // echo to keyboard port
#define KBC_AUXECHO 0xd3 // echo to auxiliary port
#define KBC_AUXWRITE 0xd4 // write to auxiliary port
#define KBC_SELFTEST 0xaa // start self-test
#define KBC_KBDTEST 0xab // test keyboard port
#define KBC_KBDDISABLE 0xad // disable keyboard port
#define KBC_KBDENABLE 0xae // enable keyboard port
#define KBC_PULSE0 0xfe // pulse output bit 0
#define KBC_PULSE1 0xfd // pulse output bit 1
#define KBC_PULSE2 0xfb // pulse output bit 2
#define KBC_PULSE3 0xf7 // pulse output bit 3
#define KBDATAP 0x60 // kbd data port(I)
#define KBOUTP 0x60 // kbd data port(O)
#define K_RDCMDBYTE 0x20
#define K_LDCMDBYTE 0x60
#define KC8_TRANS 0x40 // convert to old scan codes
#define KC8_MDISABLE 0x20 // disable mouse
#define KC8_KDISABLE 0x10 // disable keyboard
#define KC8_IGNSEC 0x08 // ignore security lock
#define KC8_CPU 0x04 // exit from protected mode reset
#define KC8_MENABLE 0x02 // enable mouse interrupt
#define KC8_KENABLE 0x01 // enable keyboard interrupt
#define CMDBYTE (KC8_TRANS|KC8_CPU|KC8_MENABLE|KC8_KENABLE)
/* keyboard commands */
#define KBC_RESET 0xFF // reset the keyboard
#define KBC_RESEND 0xFE // request the keyboard resend the last byte
#define KBC_SETDEFAULT 0xF6 // resets keyboard to its power-on defaults
#define KBC_DISABLE 0xF5 // as per KBC_SETDEFAULT, but also disable key scanning
#define KBC_ENABLE 0xF4 // enable key scanning
#define KBC_TYPEMATIC 0xF3 // set typematic rate and delay
#define KBC_SETTABLE 0xF0 // set scancode translation table
#define KBC_MODEIND 0xED // set mode indicators(i.e. LEDs)
#define KBC_ECHO 0xEE // request an echo from the keyboard
/* keyboard responses */
#define KBR_EXTENDED 0xE0 // extended key sequence
#define KBR_RESEND 0xFE // needs resend of command
#define KBR_ACK 0xFA // received a valid command
#define KBR_OVERRUN 0x00 // flooded
#define KBR_FAILURE 0xFD // diagnosic failure
#define KBR_BREAK 0xF0 // break code prefix - sent on key release
#define KBR_RSTDONE 0xAA // reset complete
#define KBR_ECHO 0xEE // echo response
#endif /* !__KERN_DRIVER_KBDREG_H__ */

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#include <defs.h>
#include <x86.h>
#include <picirq.h>
// I/O Addresses of the two programmable interrupt controllers
#define IO_PIC1 0x20 // Master (IRQs 0-7)
#define IO_PIC2 0xA0 // Slave (IRQs 8-15)
#define IRQ_SLAVE 2 // IRQ at which slave connects to master
// Current IRQ mask.
// Initial IRQ mask has interrupt 2 enabled (for slave 8259A).
static uint16_t irq_mask = 0xFFFF & ~(1 << IRQ_SLAVE);
static bool did_init = 0;
static void
pic_setmask(uint16_t mask) {
irq_mask = mask;
if (did_init) {
outb(IO_PIC1 + 1, mask);
outb(IO_PIC2 + 1, mask >> 8);
}
}
void
pic_enable(unsigned int irq) {
pic_setmask(irq_mask & ~(1 << irq));
}
/* pic_init - initialize the 8259A interrupt controllers */
void
pic_init(void) {
did_init = 1;
// mask all interrupts
outb(IO_PIC1 + 1, 0xFF);
outb(IO_PIC2 + 1, 0xFF);
// Set up master (8259A-1)
// ICW1: 0001g0hi
// g: 0 = edge triggering, 1 = level triggering
// h: 0 = cascaded PICs, 1 = master only
// i: 0 = no ICW4, 1 = ICW4 required
outb(IO_PIC1, 0x11);
// ICW2: Vector offset
outb(IO_PIC1 + 1, IRQ_OFFSET);
// ICW3: (master PIC) bit mask of IR lines connected to slaves
// (slave PIC) 3-bit # of slave's connection to master
outb(IO_PIC1 + 1, 1 << IRQ_SLAVE);
// ICW4: 000nbmap
// n: 1 = special fully nested mode
// b: 1 = buffered mode
// m: 0 = slave PIC, 1 = master PIC
// (ignored when b is 0, as the master/slave role
// can be hardwired).
// a: 1 = Automatic EOI mode
// p: 0 = MCS-80/85 mode, 1 = intel x86 mode
outb(IO_PIC1 + 1, 0x3);
// Set up slave (8259A-2)
outb(IO_PIC2, 0x11); // ICW1
outb(IO_PIC2 + 1, IRQ_OFFSET + 8); // ICW2
outb(IO_PIC2 + 1, IRQ_SLAVE); // ICW3
// NB Automatic EOI mode doesn't tend to work on the slave.
// Linux source code says it's "to be investigated".
outb(IO_PIC2 + 1, 0x3); // ICW4
// OCW3: 0ef01prs
// ef: 0x = NOP, 10 = clear specific mask, 11 = set specific mask
// p: 0 = no polling, 1 = polling mode
// rs: 0x = NOP, 10 = read IRR, 11 = read ISR
outb(IO_PIC1, 0x68); // clear specific mask
outb(IO_PIC1, 0x0a); // read IRR by default
outb(IO_PIC2, 0x68); // OCW3
outb(IO_PIC2, 0x0a); // OCW3
if (irq_mask != 0xFFFF) {
pic_setmask(irq_mask);
}
}

10
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#ifndef __KERN_DRIVER_PICIRQ_H__
#define __KERN_DRIVER_PICIRQ_H__
void pic_init(void);
void pic_enable(unsigned int irq);
#define IRQ_OFFSET 32
#endif /* !__KERN_DRIVER_PICIRQ_H__ */

104
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#include <defs.h>
#include <stdio.h>
#include <string.h>
#include <console.h>
#include <kdebug.h>
#include <picirq.h>
#include <trap.h>
#include <clock.h>
#include <intr.h>
#include <pmm.h>
int kern_init(void) __attribute__((noreturn));
static void lab1_switch_test(void);
int
kern_init(void) {
extern char edata[], end[];
memset(edata, 0, end - edata);
cons_init(); // init the console
const char *message = "(THU.CST) os is loading ...";
cprintf("%s\n\n", message);
print_kerninfo();
grade_backtrace();
pmm_init(); // init physical memory management
pic_init(); // init interrupt controller
idt_init(); // init interrupt descriptor table
clock_init(); // init clock interrupt
intr_enable(); // enable irq interrupt
//LAB1: CAHLLENGE 1 If you try to do it, uncomment lab1_switch_test()
// user/kernel mode switch test
//lab1_switch_test();
/* do nothing */
while (1);
}
void __attribute__((noinline))
grade_backtrace2(int arg0, int arg1, int arg2, int arg3) {
mon_backtrace(0, NULL, NULL);
}
void __attribute__((noinline))
grade_backtrace1(int arg0, int arg1) {
grade_backtrace2(arg0, (int)&arg0, arg1, (int)&arg1);
}
void __attribute__((noinline))
grade_backtrace0(int arg0, int arg1, int arg2) {
grade_backtrace1(arg0, arg2);
}
void
grade_backtrace(void) {
grade_backtrace0(0, (int)kern_init, 0xffff0000);
}
static void
lab1_print_cur_status(void) {
static int round = 0;
uint16_t reg1, reg2, reg3, reg4;
asm volatile (
"mov %%cs, %0;"
"mov %%ds, %1;"
"mov %%es, %2;"
"mov %%ss, %3;"
: "=m"(reg1), "=m"(reg2), "=m"(reg3), "=m"(reg4));
cprintf("%d: @ring %d\n", round, reg1 & 3);
cprintf("%d: cs = %x\n", round, reg1);
cprintf("%d: ds = %x\n", round, reg2);
cprintf("%d: es = %x\n", round, reg3);
cprintf("%d: ss = %x\n", round, reg4);
round ++;
}
static void
lab1_switch_to_user(void) {
//LAB1 CHALLENGE 1 : TODO
}
static void
lab1_switch_to_kernel(void) {
//LAB1 CHALLENGE 1 : TODO
}
static void
lab1_switch_test(void) {
lab1_print_cur_status();
cprintf("+++ switch to user mode +++\n");
lab1_switch_to_user();
lab1_print_cur_status();
cprintf("+++ switch to kernel mode +++\n");
lab1_switch_to_kernel();
lab1_print_cur_status();
}

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#include <stdio.h>
#define BUFSIZE 1024
static char buf[BUFSIZE];
/* *
* readline - get a line from stdin
* @prompt: the string to be written to stdout
*
* The readline() function will write the input string @prompt to
* stdout first. If the @prompt is NULL or the empty string,
* no prompt is issued.
*
* This function will keep on reading characters and saving them to buffer
* 'buf' until '\n' or '\r' is encountered.
*
* Note that, if the length of string that will be read is longer than
* buffer size, the end of string will be discarded.
*
* The readline() function returns the text of the line read. If some errors
* are happened, NULL is returned. The return value is a global variable,
* thus it should be copied before it is used.
* */
char *
readline(const char *prompt) {
if (prompt != NULL) {
cprintf("%s", prompt);
}
int i = 0, c;
while (1) {
c = getchar();
if (c < 0) {
return NULL;
}
else if (c >= ' ' && i < BUFSIZE - 1) {
cputchar(c);
buf[i ++] = c;
}
else if (c == '\b' && i > 0) {
cputchar(c);
i --;
}
else if (c == '\n' || c == '\r') {
cputchar(c);
buf[i] = '\0';
return buf;
}
}
}

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#include <defs.h>
#include <stdio.h>
#include <console.h>
/* HIGH level console I/O */
/* *
* cputch - writes a single character @c to stdout, and it will
* increace the value of counter pointed by @cnt.
* */
static void
cputch(int c, int *cnt) {
cons_putc(c);
(*cnt) ++;
}
/* *
* vcprintf - format a string and writes it to stdout
*
* The return value is the number of characters which would be
* written to stdout.
*
* Call this function if you are already dealing with a va_list.
* Or you probably want cprintf() instead.
* */
int
vcprintf(const char *fmt, va_list ap) {
int cnt = 0;
vprintfmt((void*)cputch, &cnt, fmt, ap);
return cnt;
}
/* *
* cprintf - formats a string and writes it to stdout
*
* The return value is the number of characters which would be
* written to stdout.
* */
int
cprintf(const char *fmt, ...) {
va_list ap;
int cnt;
va_start(ap, fmt);
cnt = vcprintf(fmt, ap);
va_end(ap);
return cnt;
}
/* cputchar - writes a single character to stdout */
void
cputchar(int c) {
cons_putc(c);
}
/* *
* cputs- writes the string pointed by @str to stdout and
* appends a newline character.
* */
int
cputs(const char *str) {
int cnt = 0;
char c;
while ((c = *str ++) != '\0') {
cputch(c, &cnt);
}
cputch('\n', &cnt);
return cnt;
}
/* getchar - reads a single non-zero character from stdin */
int
getchar(void) {
int c;
while ((c = cons_getc()) == 0)
/* do nothing */;
return c;
}

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#ifndef __KERN_MM_MEMLAYOUT_H__
#define __KERN_MM_MEMLAYOUT_H__
/* This file contains the definitions for memory management in our OS. */
/* global segment number */
#define SEG_KTEXT 1
#define SEG_KDATA 2
#define SEG_UTEXT 3
#define SEG_UDATA 4
#define SEG_TSS 5
/* global descrptor numbers */
#define GD_KTEXT ((SEG_KTEXT) << 3) // kernel text
#define GD_KDATA ((SEG_KDATA) << 3) // kernel data
#define GD_UTEXT ((SEG_UTEXT) << 3) // user text
#define GD_UDATA ((SEG_UDATA) << 3) // user data
#define GD_TSS ((SEG_TSS) << 3) // task segment selector
#define DPL_KERNEL (0)
#define DPL_USER (3)
#define KERNEL_CS ((GD_KTEXT) | DPL_KERNEL)
#define KERNEL_DS ((GD_KDATA) | DPL_KERNEL)
#define USER_CS ((GD_UTEXT) | DPL_USER)
#define USER_DS ((GD_UDATA) | DPL_USER)
#endif /* !__KERN_MM_MEMLAYOUT_H__ */

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#ifndef __KERN_MM_MMU_H__
#define __KERN_MM_MMU_H__
/* Eflags register */
#define FL_CF 0x00000001 // Carry Flag
#define FL_PF 0x00000004 // Parity Flag
#define FL_AF 0x00000010 // Auxiliary carry Flag
#define FL_ZF 0x00000040 // Zero Flag
#define FL_SF 0x00000080 // Sign Flag
#define FL_TF 0x00000100 // Trap Flag
#define FL_IF 0x00000200 // Interrupt Flag
#define FL_DF 0x00000400 // Direction Flag
#define FL_OF 0x00000800 // Overflow Flag
#define FL_IOPL_MASK 0x00003000 // I/O Privilege Level bitmask
#define FL_IOPL_0 0x00000000 // IOPL == 0
#define FL_IOPL_1 0x00001000 // IOPL == 1
#define FL_IOPL_2 0x00002000 // IOPL == 2
#define FL_IOPL_3 0x00003000 // IOPL == 3
#define FL_NT 0x00004000 // Nested Task
#define FL_RF 0x00010000 // Resume Flag
#define FL_VM 0x00020000 // Virtual 8086 mode
#define FL_AC 0x00040000 // Alignment Check
#define FL_VIF 0x00080000 // Virtual Interrupt Flag
#define FL_VIP 0x00100000 // Virtual Interrupt Pending
#define FL_ID 0x00200000 // ID flag
/* Application segment type bits */
#define STA_X 0x8 // Executable segment
#define STA_E 0x4 // Expand down (non-executable segments)
#define STA_C 0x4 // Conforming code segment (executable only)
#define STA_W 0x2 // Writeable (non-executable segments)
#define STA_R 0x2 // Readable (executable segments)
#define STA_A 0x1 // Accessed
/* System segment type bits */
#define STS_T16A 0x1 // Available 16-bit TSS
#define STS_LDT 0x2 // Local Descriptor Table
#define STS_T16B 0x3 // Busy 16-bit TSS
#define STS_CG16 0x4 // 16-bit Call Gate
#define STS_TG 0x5 // Task Gate / Coum Transmitions
#define STS_IG16 0x6 // 16-bit Interrupt Gate
#define STS_TG16 0x7 // 16-bit Trap Gate
#define STS_T32A 0x9 // Available 32-bit TSS
#define STS_T32B 0xB // Busy 32-bit TSS
#define STS_CG32 0xC // 32-bit Call Gate
#define STS_IG32 0xE // 32-bit Interrupt Gate
#define STS_TG32 0xF // 32-bit Trap Gate
/* Gate descriptors for interrupts and traps */
struct gatedesc {
unsigned gd_off_15_0 : 16; // low 16 bits of offset in segment
unsigned gd_ss : 16; // segment selector
unsigned gd_args : 5; // # args, 0 for interrupt/trap gates
unsigned gd_rsv1 : 3; // reserved(should be zero I guess)
unsigned gd_type : 4; // type(STS_{TG,IG32,TG32})
unsigned gd_s : 1; // must be 0 (system)
unsigned gd_dpl : 2; // descriptor(meaning new) privilege level
unsigned gd_p : 1; // Present
unsigned gd_off_31_16 : 16; // high bits of offset in segment
};
/* *
* Set up a normal interrupt/trap gate descriptor
* - istrap: 1 for a trap (= exception) gate, 0 for an interrupt gate
* - sel: Code segment selector for interrupt/trap handler
* - off: Offset in code segment for interrupt/trap handler
* - dpl: Descriptor Privilege Level - the privilege level required
* for software to invoke this interrupt/trap gate explicitly
* using an int instruction.
* */
#define SETGATE(gate, istrap, sel, off, dpl) { \
(gate).gd_off_15_0 = (uint32_t)(off) & 0xffff; \
(gate).gd_ss = (sel); \
(gate).gd_args = 0; \
(gate).gd_rsv1 = 0; \
(gate).gd_type = (istrap) ? STS_TG32 : STS_IG32; \
(gate).gd_s = 0; \
(gate).gd_dpl = (dpl); \
(gate).gd_p = 1; \
(gate).gd_off_31_16 = (uint32_t)(off) >> 16; \
}
/* Set up a call gate descriptor */
#define SETCALLGATE(gate, ss, off, dpl) { \
(gate).gd_off_15_0 = (uint32_t)(off) & 0xffff; \
(gate).gd_ss = (ss); \
(gate).gd_args = 0; \
(gate).gd_rsv1 = 0; \
(gate).gd_type = STS_CG32; \
(gate).gd_s = 0; \
(gate).gd_dpl = (dpl); \
(gate).gd_p = 1; \
(gate).gd_off_31_16 = (uint32_t)(off) >> 16; \
}
/* segment descriptors */
struct segdesc {
unsigned sd_lim_15_0 : 16; // low bits of segment limit
unsigned sd_base_15_0 : 16; // low bits of segment base address
unsigned sd_base_23_16 : 8; // middle bits of segment base address
unsigned sd_type : 4; // segment type (see STS_ constants)
unsigned sd_s : 1; // 0 = system, 1 = application
unsigned sd_dpl : 2; // descriptor Privilege Level
unsigned sd_p : 1; // present
unsigned sd_lim_19_16 : 4; // high bits of segment limit
unsigned sd_avl : 1; // unused (available for software use)
unsigned sd_rsv1 : 1; // reserved
unsigned sd_db : 1; // 0 = 16-bit segment, 1 = 32-bit segment
unsigned sd_g : 1; // granularity: limit scaled by 4K when set
unsigned sd_base_31_24 : 8; // high bits of segment base address
};
#define SEG_NULL \
(struct segdesc){0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
#define SEG(type, base, lim, dpl) \
(struct segdesc){ \
((lim) >> 12) & 0xffff, (base) & 0xffff, \
((base) >> 16) & 0xff, type, 1, dpl, 1, \
(unsigned)(lim) >> 28, 0, 0, 1, 1, \
(unsigned) (base) >> 24 \
}
#define SEG16(type, base, lim, dpl) \
(struct segdesc){ \
(lim) & 0xffff, (base) & 0xffff, \
((base) >> 16) & 0xff, type, 1, dpl, 1, \
(unsigned) (lim) >> 16, 0, 0, 1, 0, \
(unsigned) (base) >> 24 \
}
/* task state segment format (as described by the Pentium architecture book) */
struct taskstate {
uint32_t ts_link; // old ts selector
uintptr_t ts_esp0; // stack pointers and segment selectors
uint16_t ts_ss0; // after an increase in privilege level
uint16_t ts_padding1;
uintptr_t ts_esp1;
uint16_t ts_ss1;
uint16_t ts_padding2;
uintptr_t ts_esp2;
uint16_t ts_ss2;
uint16_t ts_padding3;
uintptr_t ts_cr3; // page directory base
uintptr_t ts_eip; // saved state from last task switch
uint32_t ts_eflags;
uint32_t ts_eax; // more saved state (registers)
uint32_t ts_ecx;
uint32_t ts_edx;
uint32_t ts_ebx;
uintptr_t ts_esp;
uintptr_t ts_ebp;
uint32_t ts_esi;
uint32_t ts_edi;
uint16_t ts_es; // even more saved state (segment selectors)
uint16_t ts_padding4;
uint16_t ts_cs;
uint16_t ts_padding5;
uint16_t ts_ss;
uint16_t ts_padding6;
uint16_t ts_ds;
uint16_t ts_padding7;
uint16_t ts_fs;
uint16_t ts_padding8;
uint16_t ts_gs;
uint16_t ts_padding9;
uint16_t ts_ldt;
uint16_t ts_padding10;
uint16_t ts_t; // trap on task switch
uint16_t ts_iomb; // i/o map base address
};
#endif /* !__KERN_MM_MMU_H__ */

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#include <defs.h>
#include <x86.h>
#include <mmu.h>
#include <memlayout.h>
#include <pmm.h>
/* *
* Task State Segment:
*
* The TSS may reside anywhere in memory. A special segment register called
* the Task Register (TR) holds a segment selector that points a valid TSS
* segment descriptor which resides in the GDT. Therefore, to use a TSS
* the following must be done in function gdt_init:
* - create a TSS descriptor entry in GDT
* - add enough information to the TSS in memory as needed
* - load the TR register with a segment selector for that segment
*
* There are several fileds in TSS for specifying the new stack pointer when a
* privilege level change happens. But only the fields SS0 and ESP0 are useful
* in our os kernel.
*
* The field SS0 contains the stack segment selector for CPL = 0, and the ESP0
* contains the new ESP value for CPL = 0. When an interrupt happens in protected
* mode, the x86 CPU will look in the TSS for SS0 and ESP0 and load their value
* into SS and ESP respectively.
* */
static struct taskstate ts = {0};
/* *
* Global Descriptor Table:
*
* The kernel and user segments are identical (except for the DPL). To load
* the %ss register, the CPL must equal the DPL. Thus, we must duplicate the
* segments for the user and the kernel. Defined as follows:
* - 0x0 : unused (always faults -- for trapping NULL far pointers)
* - 0x8 : kernel code segment
* - 0x10: kernel data segment
* - 0x18: user code segment
* - 0x20: user data segment
* - 0x28: defined for tss, initialized in gdt_init
* */
static struct segdesc gdt[] = {
SEG_NULL,
[SEG_KTEXT] = SEG(STA_X | STA_R, 0x0, 0xFFFFFFFF, DPL_KERNEL),
[SEG_KDATA] = SEG(STA_W, 0x0, 0xFFFFFFFF, DPL_KERNEL),
[SEG_UTEXT] = SEG(STA_X | STA_R, 0x0, 0xFFFFFFFF, DPL_USER),
[SEG_UDATA] = SEG(STA_W, 0x0, 0xFFFFFFFF, DPL_USER),
[SEG_TSS] = SEG_NULL,
};
static struct pseudodesc gdt_pd = {
sizeof(gdt) - 1, (uint32_t)gdt
};
/* *
* lgdt - load the global descriptor table register and reset the
* data/code segement registers for kernel.
* */
static inline void
lgdt(struct pseudodesc *pd) {
asm volatile ("lgdt (%0)" :: "r" (pd));
asm volatile ("movw %%ax, %%gs" :: "a" (USER_DS));
asm volatile ("movw %%ax, %%fs" :: "a" (USER_DS));
asm volatile ("movw %%ax, %%es" :: "a" (KERNEL_DS));
asm volatile ("movw %%ax, %%ds" :: "a" (KERNEL_DS));
asm volatile ("movw %%ax, %%ss" :: "a" (KERNEL_DS));
// reload cs
asm volatile ("ljmp %0, $1f\n 1:\n" :: "i" (KERNEL_CS));
}
/* temporary kernel stack */
uint8_t stack0[1024];
/* gdt_init - initialize the default GDT and TSS */
static void
gdt_init(void) {
// Setup a TSS so that we can get the right stack when we trap from
// user to the kernel. But not safe here, it's only a temporary value,
// it will be set to KSTACKTOP in lab2.
ts.ts_esp0 = (uint32_t)&stack0 + sizeof(stack0);
ts.ts_ss0 = KERNEL_DS;
// initialize the TSS filed of the gdt
gdt[SEG_TSS] = SEG16(STS_T32A, (uint32_t)&ts, sizeof(ts), DPL_KERNEL);
gdt[SEG_TSS].sd_s = 0;
// reload all segment registers
lgdt(&gdt_pd);
// load the TSS
ltr(GD_TSS);
}
/* pmm_init - initialize the physical memory management */
void
pmm_init(void) {
gdt_init();
}

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#ifndef __KERN_MM_PMM_H__
#define __KERN_MM_PMM_H__
void pmm_init(void);
#endif /* !__KERN_MM_PMM_H__ */

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#include <defs.h>
#include <mmu.h>
#include <memlayout.h>
#include <clock.h>
#include <trap.h>
#include <x86.h>
#include <stdio.h>
#include <assert.h>
#include <console.h>
#include <kdebug.h>
#define TICK_NUM 100
static void print_ticks() {
cprintf("%d ticks\n",TICK_NUM);
#ifdef DEBUG_GRADE
cprintf("End of Test.\n");
panic("EOT: kernel seems ok.");
#endif
}
/* *
* Interrupt descriptor table:
*
* Must be built at run time because shifted function addresses can't
* be represented in relocation records.
* */
static struct gatedesc idt[256] = {{0}};
static struct pseudodesc idt_pd = {
sizeof(idt) - 1, (uintptr_t)idt
};
/* idt_init - initialize IDT to each of the entry points in kern/trap/vectors.S */
void
idt_init(void) {
/* LAB1 YOUR CODE : STEP 2 */
/* (1) Where are the entry addrs of each Interrupt Service Routine (ISR)?
* All ISR's entry addrs are stored in __vectors. where is uintptr_t __vectors[] ?
* __vectors[] is in kern/trap/vector.S which is produced by tools/vector.c
* (try "make" command in lab1, then you will find vector.S in kern/trap DIR)
* You can use "extern uintptr_t __vectors[];" to define this extern variable which will be used later.
* (2) Now you should setup the entries of ISR in Interrupt Description Table (IDT).
* Can you see idt[256] in this file? Yes, it's IDT! you can use SETGATE macro to setup each item of IDT
* (3) After setup the contents of IDT, you will let CPU know where is the IDT by using 'lidt' instruction.
* You don't know the meaning of this instruction? just google it! and check the libs/x86.h to know more.
* Notice: the argument of lidt is idt_pd. try to find it!
*/
}
static const char *
trapname(int trapno) {
static const char * const excnames[] = {
"Divide error",
"Debug",
"Non-Maskable Interrupt",
"Breakpoint",
"Overflow",
"BOUND Range Exceeded",
"Invalid Opcode",
"Device Not Available",
"Double Fault",
"Coprocessor Segment Overrun",
"Invalid TSS",
"Segment Not Present",
"Stack Fault",
"General Protection",
"Page Fault",
"(unknown trap)",
"x87 FPU Floating-Point Error",
"Alignment Check",
"Machine-Check",
"SIMD Floating-Point Exception"
};
if (trapno < sizeof(excnames)/sizeof(const char * const)) {
return excnames[trapno];
}
if (trapno >= IRQ_OFFSET && trapno < IRQ_OFFSET + 16) {
return "Hardware Interrupt";
}
return "(unknown trap)";
}
/* trap_in_kernel - test if trap happened in kernel */
bool
trap_in_kernel(struct trapframe *tf) {
return (tf->tf_cs == (uint16_t)KERNEL_CS);
}
static const char *IA32flags[] = {
"CF", NULL, "PF", NULL, "AF", NULL, "ZF", "SF",
"TF", "IF", "DF", "OF", NULL, NULL, "NT", NULL,
"RF", "VM", "AC", "VIF", "VIP", "ID", NULL, NULL,
};
void
print_trapframe(struct trapframe *tf) {
cprintf("trapframe at %p\n", tf);
print_regs(&tf->tf_regs);
cprintf(" ds 0x----%04x\n", tf->tf_ds);
cprintf(" es 0x----%04x\n", tf->tf_es);
cprintf(" fs 0x----%04x\n", tf->tf_fs);
cprintf(" gs 0x----%04x\n", tf->tf_gs);
cprintf(" trap 0x%08x %s\n", tf->tf_trapno, trapname(tf->tf_trapno));
cprintf(" err 0x%08x\n", tf->tf_err);
cprintf(" eip 0x%08x\n", tf->tf_eip);
cprintf(" cs 0x----%04x\n", tf->tf_cs);
cprintf(" flag 0x%08x ", tf->tf_eflags);
int i, j;
for (i = 0, j = 1; i < sizeof(IA32flags) / sizeof(IA32flags[0]); i ++, j <<= 1) {
if ((tf->tf_eflags & j) && IA32flags[i] != NULL) {
cprintf("%s,", IA32flags[i]);
}
}
cprintf("IOPL=%d\n", (tf->tf_eflags & FL_IOPL_MASK) >> 12);
if (!trap_in_kernel(tf)) {
cprintf(" esp 0x%08x\n", tf->tf_esp);
cprintf(" ss 0x----%04x\n", tf->tf_ss);
}
}
void
print_regs(struct pushregs *regs) {
cprintf(" edi 0x%08x\n", regs->reg_edi);
cprintf(" esi 0x%08x\n", regs->reg_esi);
cprintf(" ebp 0x%08x\n", regs->reg_ebp);
cprintf(" oesp 0x%08x\n", regs->reg_oesp);
cprintf(" ebx 0x%08x\n", regs->reg_ebx);
cprintf(" edx 0x%08x\n", regs->reg_edx);
cprintf(" ecx 0x%08x\n", regs->reg_ecx);
cprintf(" eax 0x%08x\n", regs->reg_eax);
}
/* trap_dispatch - dispatch based on what type of trap occurred */
static void
trap_dispatch(struct trapframe *tf) {
char c;
switch (tf->tf_trapno) {
case IRQ_OFFSET + IRQ_TIMER:
/* LAB1 YOUR CODE : STEP 3 */
/* handle the timer interrupt */
/* (1) After a timer interrupt, you should record this event using a global variable (increase it), such as ticks in kern/driver/clock.c
* (2) Every TICK_NUM cycle, you can print some info using a funciton, such as print_ticks().
* (3) Too Simple? Yes, I think so!
*/
break;
case IRQ_OFFSET + IRQ_COM1:
c = cons_getc();
cprintf("serial [%03d] %c\n", c, c);
break;
case IRQ_OFFSET + IRQ_KBD:
c = cons_getc();
cprintf("kbd [%03d] %c\n", c, c);
break;
//LAB1 CHALLENGE 1 : YOUR CODE you should modify below codes.
case T_SWITCH_TOU:
case T_SWITCH_TOK:
panic("T_SWITCH_** ??\n");
break;
case IRQ_OFFSET + IRQ_IDE1:
case IRQ_OFFSET + IRQ_IDE2:
/* do nothing */
break;
default:
// in kernel, it must be a mistake
if ((tf->tf_cs & 3) == 0) {
print_trapframe(tf);
panic("unexpected trap in kernel.\n");
}
}
}
/* *
* trap - handles or dispatches an exception/interrupt. if and when trap() returns,
* the code in kern/trap/trapentry.S restores the old CPU state saved in the
* trapframe and then uses the iret instruction to return from the exception.
* */
void
trap(struct trapframe *tf) {
// dispatch based on what type of trap occurred
trap_dispatch(tf);
}

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#ifndef __KERN_TRAP_TRAP_H__
#define __KERN_TRAP_TRAP_H__
#include <defs.h>
/* Trap Numbers */
/* Processor-defined: */
#define T_DIVIDE 0 // divide error
#define T_DEBUG 1 // debug exception
#define T_NMI 2 // non-maskable interrupt
#define T_BRKPT 3 // breakpoint
#define T_OFLOW 4 // overflow
#define T_BOUND 5 // bounds check
#define T_ILLOP 6 // illegal opcode
#define T_DEVICE 7 // device not available
#define T_DBLFLT 8 // double fault
// #define T_COPROC 9 // reserved (not used since 486)
#define T_TSS 10 // invalid task switch segment
#define T_SEGNP 11 // segment not present
#define T_STACK 12 // stack exception
#define T_GPFLT 13 // general protection fault
#define T_PGFLT 14 // page fault
// #define T_RES 15 // reserved
#define T_FPERR 16 // floating point error
#define T_ALIGN 17 // aligment check
#define T_MCHK 18 // machine check
#define T_SIMDERR 19 // SIMD floating point error
#define T_SYSCALL 0x80 // SYSCALL, ONLY FOR THIS PROJ
/* Hardware IRQ numbers. We receive these as (IRQ_OFFSET + IRQ_xx) */
#define IRQ_OFFSET 32 // IRQ 0 corresponds to int IRQ_OFFSET
#define IRQ_TIMER 0
#define IRQ_KBD 1
#define IRQ_COM1 4
#define IRQ_IDE1 14
#define IRQ_IDE2 15
#define IRQ_ERROR 19
#define IRQ_SPURIOUS 31
/* *
* These are arbitrarily chosen, but with care not to overlap
* processor defined exceptions or interrupt vectors.
* */
#define T_SWITCH_TOU 120 // user/kernel switch
#define T_SWITCH_TOK 121 // user/kernel switch
/* registers as pushed by pushal */
struct pushregs {
uint32_t reg_edi;
uint32_t reg_esi;
uint32_t reg_ebp;
uint32_t reg_oesp; /* Useless */
uint32_t reg_ebx;
uint32_t reg_edx;
uint32_t reg_ecx;
uint32_t reg_eax;
};
struct trapframe {
struct pushregs tf_regs;
uint16_t tf_gs;
uint16_t tf_padding0;
uint16_t tf_fs;
uint16_t tf_padding1;
uint16_t tf_es;
uint16_t tf_padding2;
uint16_t tf_ds;
uint16_t tf_padding3;
uint32_t tf_trapno;
/* below here defined by x86 hardware */
uint32_t tf_err;
uintptr_t tf_eip;
uint16_t tf_cs;
uint16_t tf_padding4;
uint32_t tf_eflags;
/* below here only when crossing rings, such as from user to kernel */
uintptr_t tf_esp;
uint16_t tf_ss;
uint16_t tf_padding5;
} __attribute__((packed));
void idt_init(void);
void print_trapframe(struct trapframe *tf);
void print_regs(struct pushregs *regs);
bool trap_in_kernel(struct trapframe *tf);
#endif /* !__KERN_TRAP_TRAP_H__ */

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#include <memlayout.h>
# vectors.S sends all traps here.
.text
.globl __alltraps
__alltraps:
# push registers to build a trap frame
# therefore make the stack look like a struct trapframe
pushl %ds
pushl %es
pushl %fs
pushl %gs
pushal
# load GD_KDATA into %ds and %es to set up data segments for kernel
movl $GD_KDATA, %eax
movw %ax, %ds
movw %ax, %es
# push %esp to pass a pointer to the trapframe as an argument to trap()
pushl %esp
# call trap(tf), where tf=%esp
call trap
# pop the pushed stack pointer
popl %esp
# return falls through to trapret...
.globl __trapret
__trapret:
# restore registers from stack
popal
# restore %ds, %es, %fs and %gs
popl %gs
popl %fs
popl %es
popl %ds
# get rid of the trap number and error code
addl $0x8, %esp
iret

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