rx: re-randomize rng-seed on reboot

When the system reboots, the rng-seed that the FDT has should be
re-randomized, so that the new boot gets a new seed. Since the FDT is in
the ROM region at this point, we add a hook right after the ROM has been
added, so that we have a pointer to that copy of the FDT.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Message-id: 20221025004327.568476-12-Jason@zx2c4.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/rx/rx-gdbsim.c

@@ -25,6 +25,7 @@
 #include "hw/rx/rx62n.h"
 #include "sysemu/qtest.h"
 #include "sysemu/device_tree.h"
+#include "sysemu/reset.h"
 #include "hw/boards.h"
 #include "qom/object.h"
 
@@ -148,6 +149,8 @@ static void rx_gdbsim_init(MachineState *machine)
             dtb_offset = ROUND_DOWN(machine->ram_size - dtb_size, 16);
             rom_add_blob_fixed("dtb", dtb, dtb_size,
                                SDRAM_BASE + dtb_offset);
+            qemu_register_reset_nosnapshotload(qemu_fdt_randomize_seeds,
+                                rom_ptr(SDRAM_BASE + dtb_offset, dtb_size));
             /* Set dtb address to R1 */
             RX_CPU(first_cpu)->env.regs[1] = SDRAM_BASE + dtb_offset;
         }