From 3247689ab2dfdd410b39da105eca42dbb435f148 Mon Sep 17 00:00:00 2001
From: Imbus <>
Date: Mon, 31 Mar 2025 19:48:14 +0200
Subject: [PATCH] Reset kernel code + userspace program

---
 Makefile         |  1 +
 kernel/syscall.c |  3 ++-
 kernel/syscall.h |  1 +
 kernel/sysproc.c | 11 ++++++++++-
 user/reset.c     | 10 ++++++++++
 user/user.h      |  3 +++
 user/usys.py     |  1 +
 7 files changed, 28 insertions(+), 2 deletions(-)
 create mode 100644 user/reset.c

diff --git a/Makefile b/Makefile
index ed77f93..c060b88 100644
--- a/Makefile
+++ b/Makefile
@@ -136,6 +136,7 @@ UPROGS=\
 	$U/_zombie\
 	$U/_clear\
 	$U/_halt\
+	$U/_reset\
 
 fs.img: mkfs/mkfs README.md $(UPROGS)
 	mkfs/mkfs fs.img README.md $(UPROGS)
diff --git a/kernel/syscall.c b/kernel/syscall.c
index a027276..da3ef63 100644
--- a/kernel/syscall.c
+++ b/kernel/syscall.c
@@ -103,6 +103,7 @@ extern u64 sys_mkdir(void);
 extern u64 sys_close(void);
 extern u64 sys_trace(void);
 extern u64 sys_halt(void);
+extern u64 sys_reset(void);
 
 // An array mapping syscall numbers from syscall.h
 // to the function that handles the system call.
@@ -112,7 +113,7 @@ static u64 (*syscalls[])(void) = {
   [SYS_chdir] = sys_chdir, [SYS_dup] = sys_dup,       [SYS_getpid] = sys_getpid, [SYS_sbrk] = sys_sbrk,
   [SYS_sleep] = sys_sleep, [SYS_uptime] = sys_uptime, [SYS_open] = sys_open,     [SYS_write] = sys_write,
   [SYS_mknod] = sys_mknod, [SYS_unlink] = sys_unlink, [SYS_link] = sys_link,     [SYS_mkdir] = sys_mkdir,
-  [SYS_close] = sys_close, [SYS_trace] = sys_trace,   [SYS_halt] = sys_halt,
+  [SYS_close] = sys_close, [SYS_trace] = sys_trace,   [SYS_halt] = sys_halt,     [SYS_reset] = sys_reset,
 };
 
 void
diff --git a/kernel/syscall.h b/kernel/syscall.h
index 0162584..e6bd0e4 100644
--- a/kernel/syscall.h
+++ b/kernel/syscall.h
@@ -24,3 +24,4 @@
 #define SYS_close  21
 #define SYS_trace  22
 #define SYS_halt   23
+#define SYS_reset  24
diff --git a/kernel/sysproc.c b/kernel/sysproc.c
index 8c1f1d5..954f48f 100644
--- a/kernel/sysproc.c
+++ b/kernel/sysproc.c
@@ -101,5 +101,14 @@ void
 sys_halt(void)
 {
   (*(volatile u32 *)QEMU_POWER) = 0x5555;
-  panic("sys_poweroff");
+  panic("sys_halt");
+}
+
+void
+sys_reset(void)
+{
+  // TODO: Revisit and review
+  // asm volatile("j _entry");
+  (*(volatile u32 *)QEMU_POWER) = 0x3333;
+  panic("sys_reset");
 }
diff --git a/user/reset.c b/user/reset.c
new file mode 100644
index 0000000..d6962e7
--- /dev/null
+++ b/user/reset.c
@@ -0,0 +1,10 @@
+#include "user.h"
+
+/** Reset the machine */
+int
+main(int argc, char *argv[])
+{
+  printf("System resetting...\n");
+  reset();
+  return 0;
+}
diff --git a/user/user.h b/user/user.h
index d889278..17b053f 100644
--- a/user/user.h
+++ b/user/user.h
@@ -80,6 +80,9 @@ int trace(int);
 /** halt */
 void halt(void);
 
+/** halt */
+void reset(void);
+
 /**
  * Library functions (ulib.c)
  */
diff --git a/user/usys.py b/user/usys.py
index f17f05d..01c25cd 100755
--- a/user/usys.py
+++ b/user/usys.py
@@ -40,6 +40,7 @@ syscalls = [
     "uptime",
     "trace",
     "halt",
+    "reset",
 ]
 
 assembly = "\n\n".join(map(genstub, syscalls))