cow lab initialized

This commit is contained in:
2025-06-28 09:57:36 +08:00
parent 7c42fbed17
commit c6fa25504f
25 changed files with 351 additions and 617 deletions

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@@ -1,193 +0,0 @@
//
// test program for the alarm lab.
// you can modify this file for testing,
// but please make sure your kernel
// modifications pass the original
// versions of these tests.
//
#include "kernel/param.h"
#include "kernel/types.h"
#include "kernel/stat.h"
#include "kernel/riscv.h"
#include "user/user.h"
void test0();
void test1();
void test2();
void test3();
void periodic();
void slow_handler();
void dummy_handler();
int
main(int argc, char *argv[])
{
test0();
test1();
test2();
test3();
exit(0);
}
volatile static int count;
void
periodic()
{
count = count + 1;
printf("alarm!\n");
sigreturn();
}
// tests whether the kernel calls
// the alarm handler even a single time.
void
test0()
{
int i;
printf("test0 start\n");
count = 0;
sigalarm(2, periodic);
for(i = 0; i < 1000*500000; i++){
if((i % 1000000) == 0)
write(2, ".", 1);
if(count > 0)
break;
}
sigalarm(0, 0);
if(count > 0){
printf("test0 passed\n");
} else {
printf("\ntest0 failed: the kernel never called the alarm handler\n");
}
}
void __attribute__ ((noinline)) foo(int i, int *j) {
if((i % 2500000) == 0) {
write(2, ".", 1);
}
*j += 1;
}
//
// tests that the kernel calls the handler multiple times.
//
// tests that, when the handler returns, it returns to
// the point in the program where the timer interrupt
// occurred, with all registers holding the same values they
// held when the interrupt occurred.
//
void
test1()
{
int i;
int j;
printf("test1 start\n");
count = 0;
j = 0;
sigalarm(2, periodic);
for(i = 0; i < 500000000; i++){
if(count >= 10)
break;
foo(i, &j);
}
if(count < 10){
printf("\ntest1 failed: too few calls to the handler\n");
} else if(i != j){
// the loop should have called foo() i times, and foo() should
// have incremented j once per call, so j should equal i.
// once possible source of errors is that the handler may
// return somewhere other than where the timer interrupt
// occurred; another is that that registers may not be
// restored correctly, causing i or j or the address ofj
// to get an incorrect value.
printf("\ntest1 failed: foo() executed fewer times than it was called\n");
} else {
printf("test1 passed\n");
}
}
//
// tests that kernel does not allow reentrant alarm calls.
void
test2()
{
int i;
int pid;
int status;
printf("test2 start\n");
if ((pid = fork()) < 0) {
printf("test2: fork failed\n");
}
if (pid == 0) {
count = 0;
sigalarm(2, slow_handler);
for(i = 0; i < 1000*500000; i++){
if((i % 1000000) == 0)
write(2, ".", 1);
if(count > 0)
break;
}
if (count == 0) {
printf("\ntest2 failed: alarm not called\n");
exit(1);
}
exit(0);
}
wait(&status);
if (status == 0) {
printf("test2 passed\n");
}
}
void
slow_handler()
{
count++;
printf("alarm!\n");
if (count > 1) {
printf("test2 failed: alarm handler called more than once\n");
exit(1);
}
for (int i = 0; i < 1000*500000; i++) {
asm volatile("nop"); // avoid compiler optimizing away loop
}
sigalarm(0, 0);
sigreturn();
}
//
// dummy alarm handler; after running immediately uninstall
// itself and finish signal handling
void
dummy_handler()
{
sigalarm(0, 0);
sigreturn();
}
//
// tests that the return from sys_sigreturn() does not
// modify the a0 register
void
test3()
{
uint64 a0;
sigalarm(1, dummy_handler);
printf("test3 start\n");
asm volatile("lui a5, 0");
asm volatile("addi a0, a5, 0xac" : : : "a0");
for(int i = 0; i < 500000000; i++)
;
asm volatile("mv %0, a0" : "=r" (a0) );
if(a0 != 0xac)
printf("test3 failed: register a0 changed\n");
else
printf("test3 passed\n");
}

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@@ -1,10 +0,0 @@
#include "kernel/types.h"
#include "kernel/stat.h"
#include "user/user.h"
int
main(int argc, char *argv[])
{
sleep(1);
exit(0);
}

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@@ -1,17 +0,0 @@
#include "kernel/param.h"
#include "kernel/types.h"
#include "kernel/stat.h"
#include "user/user.h"
int g(int x) {
return x+3;
}
int f(int x) {
return g(x);
}
void main(void) {
printf("%d %d\n", f(8)+1, 13);
exit(0);
}

240
user/cowtest.c Normal file
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@@ -0,0 +1,240 @@
//
// tests for copy-on-write fork() assignment.
//
#include "kernel/types.h"
#include "kernel/memlayout.h"
#include "user/user.h"
// allocate more than half of physical memory,
// then fork. this will fail in the default
// kernel, which does not support copy-on-write.
void
simpletest()
{
uint64 phys_size = PHYSTOP - KERNBASE;
int sz = (phys_size / 3) * 2;
printf("simple: ");
char *p = sbrk(sz);
if(p == (char*)0xffffffffffffffffL){
printf("sbrk(%d) failed\n", sz);
exit(-1);
}
for(char *q = p; q < p + sz; q += 4096){
*(int*)q = getpid();
}
int pid = fork();
if(pid < 0){
printf("fork() failed\n");
exit(-1);
}
if(pid == 0)
exit(0);
wait(0);
if(sbrk(-sz) == (char*)0xffffffffffffffffL){
printf("sbrk(-%d) failed\n", sz);
exit(-1);
}
printf("ok\n");
}
// three processes all write COW memory.
// this causes more than half of physical memory
// to be allocated, so it also checks whether
// copied pages are freed.
void
threetest()
{
uint64 phys_size = PHYSTOP - KERNBASE;
int sz = phys_size / 4;
int pid1, pid2;
printf("three: ");
char *p = sbrk(sz);
if(p == (char*)0xffffffffffffffffL){
printf("sbrk(%d) failed\n", sz);
exit(-1);
}
pid1 = fork();
if(pid1 < 0){
printf("fork failed\n");
exit(-1);
}
if(pid1 == 0){
pid2 = fork();
if(pid2 < 0){
printf("fork failed");
exit(-1);
}
if(pid2 == 0){
for(char *q = p; q < p + (sz/5)*4; q += 4096){
*(int*)q = getpid();
}
for(char *q = p; q < p + (sz/5)*4; q += 4096){
if(*(int*)q != getpid()){
printf("wrong content\n");
exit(-1);
}
}
exit(-1);
}
for(char *q = p; q < p + (sz/2); q += 4096){
*(int*)q = 9999;
}
exit(0);
}
for(char *q = p; q < p + sz; q += 4096){
*(int*)q = getpid();
}
wait(0);
sleep(1);
for(char *q = p; q < p + sz; q += 4096){
if(*(int*)q != getpid()){
printf("wrong content\n");
exit(-1);
}
}
if(sbrk(-sz) == (char*)0xffffffffffffffffL){
printf("sbrk(-%d) failed\n", sz);
exit(-1);
}
printf("ok\n");
}
char junk1[4096];
int fds[2];
char junk2[4096];
char buf[4096];
char junk3[4096];
// test whether copyout() simulates COW faults.
void
filetest()
{
printf("file: ");
buf[0] = 99;
for(int i = 0; i < 4; i++){
if(pipe(fds) != 0){
printf("pipe() failed\n");
exit(-1);
}
int pid = fork();
if(pid < 0){
printf("fork failed\n");
exit(-1);
}
if(pid == 0){
sleep(1);
if(read(fds[0], buf, sizeof(i)) != sizeof(i)){
printf("error: read failed\n");
exit(1);
}
sleep(1);
int j = *(int*)buf;
if(j != i){
printf("error: read the wrong value\n");
exit(1);
}
exit(0);
}
if(write(fds[1], &i, sizeof(i)) != sizeof(i)){
printf("error: write failed\n");
exit(-1);
}
}
int xstatus = 0;
for(int i = 0; i < 4; i++) {
wait(&xstatus);
if(xstatus != 0) {
exit(1);
}
}
if(buf[0] != 99){
printf("error: child overwrote parent\n");
exit(1);
}
printf("ok\n");
}
//
// try to expose races in page reference counting.
//
void
forkforktest()
{
printf("forkfork: ");
int sz = 256 * 4096;
char *p = sbrk(sz);
memset(p, 27, sz);
int children = 3;
for(int iter = 0; iter < 100; iter++){
for(int nc = 0; nc < children; nc++){
if(fork() == 0){
sleep(2);
fork();
fork();
exit(0);
}
}
for(int nc = 0; nc < children; nc++){
int st;
wait(&st);
}
}
sleep(5);
for(int i = 0; i < sz; i += 4096){
if(p[i] != 27){
printf("error: parent's memory was modified!\n");
exit(1);
}
}
printf("ok\n");
}
int
main(int argc, char *argv[])
{
simpletest();
// check that the first simpletest() freed the physical memory.
simpletest();
threetest();
threetest();
threetest();
filetest();
forkforktest();
printf("ALL COW TESTS PASSED\n");
exit(0);
}

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@@ -22,8 +22,6 @@ int getpid(void);
char* sbrk(int);
int sleep(int);
int uptime(void);
int sigalarm(int, void(*)());
int sigreturn(void);
// ulib.c
int stat(const char*, struct stat*);

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@@ -244,7 +244,7 @@ copyinstr3(char *s)
// See if the kernel refuses to read/write user memory that the
// application doesn't have anymore, because it returned it.
void
rwsbrk(char* argv)
rwsbrk()
{
int fd, n;

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@@ -36,5 +36,3 @@ entry("getpid");
entry("sbrk");
entry("sleep");
entry("uptime");
entry("sigalarm");
entry("sigreturn");