Add new project on memory protection and exception

P-Gu · 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)
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 Language files blank comment code
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-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
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-SUM: 50 545 619 2000 << exactly 2000!
+SUM: 50 558 636 2000 << exactly 2000!
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 ```
 

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 */