From e94eecd9a19b7e34f0e784168d28f4929d6b1b30 Mon Sep 17 00:00:00 2001
From: Imbus <>
Date: Sat, 11 Jan 2025 14:49:38 +0100
Subject: [PATCH 1/2] Better hart startup indicators

---
 kernel/main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/main.c b/kernel/main.c
index 107a20c..a136beb 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -30,10 +30,11 @@ main()
   } else {
     while(started == 0) {}
     __sync_synchronize();
-    printf("hart %d starting\n", cpuid());
+    printf("Hart/Core [%d]: Starting\n", cpuid());
     kvminithart();  // turn on paging
     trapinithart(); // install kernel trap vector
     plicinithart(); // ask PLIC for device interrupts
+    printf("Hart/Core [%d]: Online\n", cpuid());
   }
 
   scheduler();

From 146e7f65ca5e0076fac2560c02062bfb805a3144 Mon Sep 17 00:00:00 2001
From: Imbus <>
Date: Sat, 11 Jan 2025 14:50:17 +0100
Subject: [PATCH 2/2] Halt syscall and userspace util. Mapped qemu power.

---
 kernel/memlayout.h | 2 ++
 kernel/sysproc.c   | 3 ++-
 kernel/vm.c        | 3 +++
 user/halt.c        | 1 +
 4 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/memlayout.h b/kernel/memlayout.h
index 57c3839..ff6d045 100644
--- a/kernel/memlayout.h
+++ b/kernel/memlayout.h
@@ -23,6 +23,8 @@
 #define UART0     0x10000000L
 #define UART0_IRQ 10
 
+#define QEMU_POWER 0x100000
+
 // virtio mmio interface
 #define VIRTIO0     0x10001000
 #define VIRTIO0_IRQ 1
diff --git a/kernel/sysproc.c b/kernel/sysproc.c
index ba0aeb9..8c1f1d5 100644
--- a/kernel/sysproc.c
+++ b/kernel/sysproc.c
@@ -100,5 +100,6 @@ sys_trace(void)
 void
 sys_halt(void)
 {
-  /* TODO: Implement sys_halt */
+  (*(volatile u32 *)QEMU_POWER) = 0x5555;
+  panic("sys_poweroff");
 }
diff --git a/kernel/vm.c b/kernel/vm.c
index c4541bd..af3ff45 100644
--- a/kernel/vm.c
+++ b/kernel/vm.c
@@ -21,6 +21,9 @@ kvmmake(void)
   kpgtbl = (pagetable_t)kalloc();
   memset(kpgtbl, 0, PGSIZE);
 
+  // Map qemu
+  kvmmap(kpgtbl, QEMU_POWER, QEMU_POWER, PGSIZE, PTE_R | PTE_W);
+
   // uart registers
   kvmmap(kpgtbl, UART0, UART0, PGSIZE, PTE_R | PTE_W);
 
diff --git a/user/halt.c b/user/halt.c
index ab73dd3..9f26b81 100644
--- a/user/halt.c
+++ b/user/halt.c
@@ -4,6 +4,7 @@
 int
 main(int argc, char *argv[])
 {
+  printf("System powering down...\n");
   halt();
   return 0;
 }