init commit of lab2_challenge2

LICENSE.txt

@@ -4,8 +4,9 @@ Copyright License
 The PKE software is:
 
 Copyright (c) 2021, Zhiyuan Shao (zyshao@hust.edu.cn), 
-                    Yi Gui (gy163email@163.com), 
+                    Yixin Song (474309045@qq.com),
-                    Yan Jiao (773709579@qq.com),
+                    Ziming Yuan (1223962053@qq.com),
+                    Boyang Li (liboyang_hust@163.com),
                    Huazhong University of Science and Technology
 
 Permission is hereby granted, free of charge, to any person obtaining

Makefile

@@ -70,7 +70,7 @@ USER_OBJS  		:= $(addprefix $(OBJ_DIR)/, $(patsubst %.c,%.o,$(USER_CPPS)))
 
 
 
-USER_TARGET 	:= $(OBJ_DIR)/app_sum_sequence
+USER_TARGET 	:= $(OBJ_DIR)/app_singlepageheap
 #------------------------targets------------------------
 $(OBJ_DIR):
 	@-mkdir -p $(OBJ_DIR)	

user/app_singlepageheap.c

@@ -0,0 +1,24 @@
+/*
+ * Below is the given application for lab2_challenge2_singlepageheap.
+ * This app performs malloc memory.
+ */
+
+#include "user_lib.h"
+#include "util/types.h"
+#include "util/string.h"
+int main(void) {
+  
+  char str[20] = "hello world.";
+  char *m = (char *)better_malloc(100);
+  char *p = (char *)better_malloc(50);
+  if((uint64)p - (uint64)m > 512 ){
+    printu("you need to manage the vm space precisely!");
+    exit(-1);
+  }
+  better_free((void *)m);
+
+  strcpy(p,str);
+  printu("%s\n",p);
+  exit(0);
+  return 0;
+}

user/app_sum_sequence.c

@@ -1,28 +0,0 @@
-/*
- * The application of lab2_3.
- */
-
-#include "user_lib.h"
-#include "util/types.h"
-
-//
-// compute the summation of an arithmetic sequence. for a given "n", compute
-// result = n + (n-1) + (n-2) + ... + 0
-// sum_sequence() calls itself recursively till 0. The recursive call, however,
-// may consume more memory (from stack) than a physical 4KB page, leading to a page fault.
-// PKE kernel needs to improved to handle such page fault by expanding the stack.
-//
-uint64 sum_sequence(uint64 n) {
-  if (n == 0)
-    return 0;
-  else
-    return sum_sequence( n-1 ) + n;
-}
-
-int main(void) {
-  // we need a large enough "n" to trigger pagefaults in the user stack
-  uint64 n = 1000;
-
-  printu("Summation of an arithmetic sequence from 0 to %ld is: %ld \n", n, sum_sequence(1000) );
-  exit(0);
-}

user/user_lib.c

@@ -51,15 +51,15 @@ int exit(int code) {
 }
 
 //
-// lib call to naive_malloc
+// lib call to better_malloc
 //
-void* naive_malloc() {
+void* better_malloc(int n) {
-  return (void*)do_user_call(SYS_user_allocate_page, 0, 0, 0, 0, 0, 0, 0);
+  return (void*)do_user_call(SYS_user_allocate_page, n, 0, 0, 0, 0, 0, 0);
 }
 
 //
-// lib call to naive_free
+// lib call to better_free
 //
-void naive_free(void* va) {
+void better_free(void* va) {
   do_user_call(SYS_user_free_page, (uint64)va, 0, 0, 0, 0, 0, 0);
 }

user/user_lib.h

@@ -4,5 +4,5 @@
 
 int printu(const char *s, ...);
 int exit(int code);
-void* naive_malloc();
+void* better_malloc(int n);
-void naive_free(void* va);
+void better_free(void* va);