s390/boot: Use strspcy() instead of strcpy()

Convert all strcpy() usages to strscpy(). strcpy() is deprecated since
it performs no bounds checking on the destination buffer.

Reviewed-by: Mikhail Zaslonko <[e-mail]>
Signed-off-by: Heiko Carstens <[e-mail]>

arch/s390/boot/ipl_parm.c

···
 	if (has_ebcdic_char(parmarea.command_line))
 		EBCASC(parmarea.command_line, COMMAND_LINE_SIZE);
 	/* copy arch command line */
-	strcpy(early_command_line, strim(parmarea.command_line));
+	strscpy(early_command_line, strim(parmarea.command_line));
 
 	/* append IPL PARM data to the boot command line */
 	if (!is_prot_virt_guest() && ipl_block_valid)
···
 	int rc;
 
 	__kaslr_enabled = IS_ENABLED(CONFIG_RANDOMIZE_BASE);
-	args = strcpy(command_line_buf, early_command_line);
+	strscpy(command_line_buf, early_command_line);
+	args = command_line_buf;
 	while (*args) {
 		args = next_arg(args, &param, &val);
 

arch/s390/boot/printk.c

···
 	/* store strings separated by '\0' */
 	if (len + 1 > avail)
 		boot_rb_off = 0;
-	strcpy(boot_rb + boot_rb_off, str);
+	avail = sizeof(boot_rb) - boot_rb_off - 1;
+	strscpy(boot_rb + boot_rb_off, str, avail);
 	boot_rb_off += len + 1;
 }
 
···
 		strscpy(buf, p, MAX_SYMLEN);
 		/* reserve 15 bytes for offset/len in symbol+0x1234/0x1234 */
 		p = buf + strnlen(buf, MAX_SYMLEN - 15);
-		strcpy(p, "+0x");
+		strscpy(p, "+0x", MAX_SYMLEN - (p - buf));
 		as_hex(p + 3, off, 0);
 		strcat(p, "/0x");
 		as_hex(p + strlen(p), len, 0);