m68k: Process bootinfo records before saving them

The RNG seed boot record is memzeroed after processing, in order to
preserve forward secrecy. By saving the bootinfo for procfs prior to
that, forward secrecy is violated, since it becomes possible to recover
past states. So, save the bootinfo block only after first processing
them.

Fixes: a1ee38ab1a75 ("m68k: virt: Use RNG seed from bootinfo block")
Signed-off-by: Jason A. Donenfeld <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Geert Uytterhoeven <[e-mail]>

arch/m68k/kernel/setup_mm.c

···
 
 static void __init m68k_parse_bootinfo(const struct bi_record *record)
 {
+	const struct bi_record *first_record = record;
 	uint16_t tag;
-
-	save_bootinfo(record);
 
 	while ((tag = be16_to_cpu(record->tag)) != BI_LAST) {
 		int unknown = 0;
···
 				tag);
 		record = (struct bi_record *)((unsigned long)record + size);
 	}
+
+	save_bootinfo(first_record);
 
 	m68k_realnum_memory = m68k_num_memory;
 #ifdef CONFIG_SINGLE_MEMORY_CHUNK