RISC-V: Don't add NULL bootargs to device-tree

Signed-off-by: NMichael Clark <mjc@sifive.com>
Reviewed-by: NAlistair Francis <alistair.francis@wdc.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: NPalmer Dabbelt <palmer@sifive.com>
Signed-off-by: NAlistair Francis <alistair.francis@wdc.com>
Signed-off-by: NPalmer Dabbelt <palmer@sifive.com>

hw/riscv/sifive_u.c

@@ -230,7 +230,9 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
 
     qemu_fdt_add_subnode(fdt, "/chosen");
     qemu_fdt_setprop_string(fdt, "/chosen", "stdout-path", nodename);
-    qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
+    if (cmdline) {
+        qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
+    }
     g_free(nodename);
 }
 

hw/riscv/spike.c

@@ -156,8 +156,10 @@ static void create_fdt(SpikeState *s, const struct MemmapEntry *memmap,
     g_free(cells);
     g_free(nodename);
 
-    qemu_fdt_add_subnode(fdt, "/chosen");
-    qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
+    if (cmdline) {
+        qemu_fdt_add_subnode(fdt, "/chosen");
+        qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
+    }
  }
 
 static void spike_v1_10_0_board_init(MachineState *machine)

hw/riscv/virt.c

@@ -254,7 +254,9 @@ static void *create_fdt(RISCVVirtState *s, const struct MemmapEntry *memmap,
 
     qemu_fdt_add_subnode(fdt, "/chosen");
     qemu_fdt_setprop_string(fdt, "/chosen", "stdout-path", nodename);
-    qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
+    if (cmdline) {
+        qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
+    }
     g_free(nodename);
 
     return fdt;