tree: https://github.com/cminyard/linux-ipmi ipmi-wdt-rework head: a22010ce71ef67492980e4c55ad7864679826b53 commit: d8aebbc6501b431180c705c6e8a4fc4e129325ec [5/10] watchdog: Export an interface to start the watchdog config: s390-allyesconfig (attached as .config) compiler: s390-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross git checkout d8aebbc6501b431180c705c6e8a4fc4e129325ec # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): drivers/hwmon/sch56xx-common.c:245:12: error: static declaration of 'watchdog_set_timeout' follows non-static declaration 245 | static int watchdog_set_timeout(struct watchdog_device *wddev, | ^~~~~~~~~~~~~~~~~~~~ In file included from drivers/hwmon/sch56xx-common.c:17: include/linux/watchdog.h:205:5: note: previous declaration of 'watchdog_set_timeout' was here 205 | int watchdog_set_timeout(struct watchdog_device *wdd, unsigned int timeout); | ^~~~~~~~~~~~~~~~~~~~ 289 | static int watchdog_start(struct watchdog_device *wddev) | ^~~~~~~~~~~~~~ In file included from drivers/hwmon/sch56xx-common.c:17: include/linux/watchdog.h:209:5: note: previous declaration of 'watchdog_start' was here 209 | int watchdog_start(struct watchdog_device *wdd); | ^~~~~~~~~~~~~~ vim +/watchdog_start +289 drivers/hwmon/sch56xx-common.c 312869ec935ab3b Hans de Goede 2012-03-18 288 fb551405c0f8e15 Hans de Goede 2012-05-22 @289 static int watchdog_start(struct watchdog_device *wddev) 312869ec935ab3b Hans de Goede 2012-03-18 290 { fb551405c0f8e15 Hans de Goede 2012-05-22 291 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); 312869ec935ab3b Hans de Goede 2012-03-18 292 int ret; 312869ec935ab3b Hans de Goede 2012-03-18 293 u8 val; 312869ec935ab3b Hans de Goede 2012-03-18 294 312869ec935ab3b Hans de Goede 2012-03-18 295 /* 312869ec935ab3b Hans de Goede 2012-03-18 296 * The sch56xx's watchdog cannot really be started / stopped 312869ec935ab3b Hans de Goede 2012-03-18 297 * it is always running, but we can avoid the timer expiring 312869ec935ab3b Hans de Goede 2012-03-18 298 * from causing a system reset by clearing the output enable bit. 312869ec935ab3b Hans de Goede 2012-03-18 299 * 312869ec935ab3b Hans de Goede 2012-03-18 300 * The sch56xx's watchdog will set the watchdog event bit, bit 0 312869ec935ab3b Hans de Goede 2012-03-18 301 * of the second interrupt source register (at base-address + 9), 312869ec935ab3b Hans de Goede 2012-03-18 302 * when the timer expires. 312869ec935ab3b Hans de Goede 2012-03-18 303 * 312869ec935ab3b Hans de Goede 2012-03-18 304 * This will only cause a system reset if the 0-1 flank happens when 312869ec935ab3b Hans de Goede 2012-03-18 305 * output enable is true. Setting output enable after the flank will 312869ec935ab3b Hans de Goede 2012-03-18 306 * not cause a reset, nor will the timer expiring a second time. 312869ec935ab3b Hans de Goede 2012-03-18 307 * This means we must clear the watchdog event bit in case it is set. 312869ec935ab3b Hans de Goede 2012-03-18 308 * 312869ec935ab3b Hans de Goede 2012-03-18 309 * The timer may still be running (after a recent watchdog_stop) and 312869ec935ab3b Hans de Goede 2012-03-18 310 * mere milliseconds away from expiring, so the timer must be reset 312869ec935ab3b Hans de Goede 2012-03-18 311 * first! 312869ec935ab3b Hans de Goede 2012-03-18 312 */ 312869ec935ab3b Hans de Goede 2012-03-18 313 312869ec935ab3b Hans de Goede 2012-03-18 314 mutex_lock(data->io_lock); 312869ec935ab3b Hans de Goede 2012-03-18 315 312869ec935ab3b Hans de Goede 2012-03-18 316 /* 1. Reset the watchdog countdown counter */ 312869ec935ab3b Hans de Goede 2012-03-18 317 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET, 312869ec935ab3b Hans de Goede 2012-03-18 318 data->watchdog_preset); 312869ec935ab3b Hans de Goede 2012-03-18 319 if (ret) 312869ec935ab3b Hans de Goede 2012-03-18 320 goto leave; 312869ec935ab3b Hans de Goede 2012-03-18 321 85a2e40cb505357 Hans de Goede 2012-05-22 322 /* 2. Enable output */ 85a2e40cb505357 Hans de Goede 2012-05-22 323 val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE; 312869ec935ab3b Hans de Goede 2012-03-18 324 ret = sch56xx_write_virtual_reg(data->addr, 85a2e40cb505357 Hans de Goede 2012-05-22 325 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val); 312869ec935ab3b Hans de Goede 2012-03-18 326 if (ret) 312869ec935ab3b Hans de Goede 2012-03-18 327 goto leave; 312869ec935ab3b Hans de Goede 2012-03-18 328 312869ec935ab3b Hans de Goede 2012-03-18 329 data->watchdog_output_enable = val; 312869ec935ab3b Hans de Goede 2012-03-18 330 312869ec935ab3b Hans de Goede 2012-03-18 331 /* 3. Clear the watchdog event bit if set */ 312869ec935ab3b Hans de Goede 2012-03-18 332 val = inb(data->addr + 9); 312869ec935ab3b Hans de Goede 2012-03-18 333 if (val & 0x01) 312869ec935ab3b Hans de Goede 2012-03-18 334 outb(0x01, data->addr + 9); 312869ec935ab3b Hans de Goede 2012-03-18 335 312869ec935ab3b Hans de Goede 2012-03-18 336 leave: 312869ec935ab3b Hans de Goede 2012-03-18 337 mutex_unlock(data->io_lock); 312869ec935ab3b Hans de Goede 2012-03-18 338 return ret; 312869ec935ab3b Hans de Goede 2012-03-18 339 } 312869ec935ab3b Hans de Goede 2012-03-18 340 :::::: The code at line 289 was first introduced by commit :::::: fb551405c0f8e15d6fc7ae6e16a5e15382f8b8ac watchdog: sch56xx: Use watchdog core :::::: TO: Hans de Goede <hdegoede(a)redhat.com&gt; :::::: CC: Wim Van Sebroeck <wim(a)iguana.be&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org