Add new project on memory protection and exception

yhzhang0128 · May 31, 2022 · 1664ae1 · 1664ae1
1 parent 4e3457c
commit 1664ae1
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Showing 4 changed files with 37 additions and 6 deletions.
diff --git a/README.md b/README.md
@@ -16,12 +16,12 @@ github.com/AlDanial/cloc v 1.92  T=0.03 s (1668.0 files/s, 105414.7 lines/s)
 -------------------------------------------------------------------------------
 Language                     files          blank        comment           code
 -------------------------------------------------------------------------------
-C                               35            454            490           1565
-C/C++ Header                    11             74            105            313
+C                               35            467            507           1563
+C/C++ Header                    11             74            105            315
 Assembly                         3              6             24             68
 make                             1             11              0             54
 -------------------------------------------------------------------------------
-SUM:                            50            545            619           2000 << exactly 2000!
+SUM:                            50            558            636           2000 << exactly 2000!
 -------------------------------------------------------------------------------
 ```
 

diff --git a/grass/process.c b/grass/process.c
@@ -14,8 +14,31 @@
 
 void intr_entry(int id);
 
+void excp_entry(int id) {
+    /* Student's code goes here: */
+
+    /* Kill the process if curr_pid is a user app instead of a grass server */
+
+    /* Student's code ends here. */
+
+    FATAL("excp_entry: kernel got exception %d", id);
+}
+
 void proc_init() {
     earth->intr_register(intr_entry);
+    earth->excp_register(excp_entry);
+
+    /* Student's code goes here: */
+
+    /* Setup PMP TOR region 0x00000000 - 0x08008000 as r/w/x */
+
+    /* Setup PMP NAPOT region 0x20400000 - 0x20800000 as r/-/x */
+
+    /* Setup PMP NAPOT region 0x20800000 - 0x20C00000 as r/-/- */
+
+    /* Setup PMP NAPOT region 0x80000000 - 0x80004000 as r/w/- */
+
+    /* Student's code ends here. */
 
     /* The first process is currently running */
     proc_set_running(proc_alloc());

diff --git a/grass/process.h b/grass/process.h
@@ -13,6 +13,8 @@ struct process{
 };
 extern int proc_curr_idx;
 extern struct process proc_set[MAX_NPROCESS];
+#define curr_pid      proc_set[proc_curr_idx].pid
+#define curr_status   proc_set[proc_curr_idx].status
 
 enum {
     PROC_UNUSED,

diff --git a/grass/scheduler.c b/grass/scheduler.c
@@ -21,9 +21,7 @@ static void proc_syscall();
 static void (*kernel_entry)();
 
 int proc_curr_idx;
-struct  process     proc_set[MAX_NPROCESS];
-#define curr_pid    proc_set[proc_curr_idx].pid
-#define curr_status proc_set[proc_curr_idx].status
+struct process proc_set[MAX_NPROCESS];
 
 void intr_entry(int id) {
     if (curr_pid < GPID_SHELL && id == INTR_ID_TMR) {
@@ -85,6 +83,14 @@ static void proc_yield() {
     earth->mmu_switch(curr_pid);
     timer_reset();
 
+    /* Student's code goes here: */
+
+    /* Modify mstatus.MPP to enter machine or user mode during mret
+     * depending on whether curr_pid is a grass server or a user app
+     */
+
+    /* Student's code ends here. */
+
     if (curr_status == PROC_READY) {
         proc_set_running(curr_pid);
         /* Prepare argc and argv */