[kbuild-all] drivers/tty/serial/mvebu-uart.c:605 mvebu_uart_putc() warn: this loop depends on readl() succeeding

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 449dc8c97089a6e09fb2dac4d92b1b7ac0eb7c1e commit: 05933aac7b11911955de307a329dc2a7a14b7bd0 ia64: remove now unused machvec indirections date: 12 months ago config: ia64-randconfig-m031-20200808 (attached as .config) compiler: ia64-linux-gcc (GCC) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; New smatch warnings: drivers/tty/serial/mvebu-uart.c:605 mvebu_uart_putc() warn: this loop depends on readl() succeeding Old smatch warnings: drivers/tty/serial/mvebu-uart.c:293 mvebu_uart_rx_chars() warn: this loop depends on readl() succeeding vim +605 drivers/tty/serial/mvebu-uart.c 30530791a7a032 Wilson Ding 2016-02-16 595 30530791a7a032 Wilson Ding 2016-02-16 596 #ifdef CONFIG_SERIAL_MVEBU_CONSOLE 30530791a7a032 Wilson Ding 2016-02-16 597 /* Early Console */ 30530791a7a032 Wilson Ding 2016-02-16 598 static void mvebu_uart_putc(struct uart_port *port, int c) 30530791a7a032 Wilson Ding 2016-02-16 599 { 30530791a7a032 Wilson Ding 2016-02-16 600 unsigned int st; 30530791a7a032 Wilson Ding 2016-02-16 601 30530791a7a032 Wilson Ding 2016-02-16 602 for (;;) { 30530791a7a032 Wilson Ding 2016-02-16 603 st = readl(port->membase + UART_STAT); 30530791a7a032 Wilson Ding 2016-02-16 604 if (!(st & STAT_TX_FIFO_FUL)) 30530791a7a032 Wilson Ding 2016-02-16 @605 break; 30530791a7a032 Wilson Ding 2016-02-16 606 } 30530791a7a032 Wilson Ding 2016-02-16 607 5218d76958644a Miquel Raynal 2017-10-13 608 /* At early stage, DT is not parsed yet, only use UART0 */ 5218d76958644a Miquel Raynal 2017-10-13 609 writel(c, port->membase + UART_STD_TSH); 30530791a7a032 Wilson Ding 2016-02-16 610 30530791a7a032 Wilson Ding 2016-02-16 611 for (;;) { 30530791a7a032 Wilson Ding 2016-02-16 612 st = readl(port->membase + UART_STAT); 30530791a7a032 Wilson Ding 2016-02-16 613 if (st & STAT_TX_FIFO_EMP) 30530791a7a032 Wilson Ding 2016-02-16 614 break; 30530791a7a032 Wilson Ding 2016-02-16 615 } 30530791a7a032 Wilson Ding 2016-02-16 616 } 30530791a7a032 Wilson Ding 2016-02-16 617 :::::: The code at line 605 was first introduced by commit :::::: 30530791a7a032dc27dbbab56b8afabd5138074c serial: mvebu-uart: initial support for Armada-3700 serial port :::::: TO: Wilson Ding <dingwei(a)marvell.com&gt; :::::: CC: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org