syscall: Raise page fault if invalid address is passed to uprint

1 files changed, 7 insertions, 2 deletions

diff --git a/src/lib/syscall.zig b/src/lib/syscall.zig
index 62176db..d15810b 100644
--- a/src/lib/syscall.zig
+++ b/src/lib/syscall.zig
@@ -61,9 +61,14 @@ fn errorName(trap_frame: *const trap.Frame) !usize {
 
 // uprint(str_addr: usize, len: usize) void
 fn uprint(trap_frame: *const trap.Frame) void {
-    const procmem: *paging.Table = @ptrFromInt(instructions.satp.read().ppn << 12);
+    const vaddr = trap_frame.general_purpose_registers[10];
 
-    const paddr = procmem.translate(trap_frame.general_purpose_registers[10]).?;
+    const procmem: *paging.Table = @ptrFromInt(instructions.satp.read().ppn << 12);
+    const paddr = procmem.translate(vaddr) orelse {
+        const faulter: *volatile u8 = @ptrFromInt(vaddr);
+        _ = faulter.*;
+        unreachable;
+    };
 
     const str_ptr: [*]const u8 = @ptrFromInt(paddr);
     const str = str_ptr[0..trap_frame.general_purpose_registers[11]];