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![Alexander Egorenkov](/assets/img/avatar_default.png)
Change naming of the internal diag288 helper functions to improve overall readability and reduce confusion: * Rename __diag288() to diag288(). * Get rid of the misnamed helper __diag288_lpar() that was used not only on LPARs but also zVM and KVM systems. * Rename __diag288_vm() to diag288_str(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20230203073958.1585738-6-egorenar@linux.ibm.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
231 lines
5.5 KiB
C
231 lines
5.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Watchdog driver for z/VM and LPAR using the diag 288 interface.
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*
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* Under z/VM, expiration of the watchdog will send a "system restart" command
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* to CP.
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*
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* The command can be altered using the module parameter "cmd". This is
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* not recommended because it's only supported on z/VM but not whith LPAR.
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*
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* On LPAR, the watchdog will always trigger a system restart. the module
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* paramter cmd is meaningless here.
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*
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*
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* Copyright IBM Corp. 2004, 2013
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* Author(s): Arnd Bergmann (arndb@de.ibm.com)
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* Philipp Hachtmann (phacht@de.ibm.com)
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*
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*/
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#define KMSG_COMPONENT "diag288_wdt"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/slab.h>
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#include <linux/watchdog.h>
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#include <asm/ebcdic.h>
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#include <asm/diag.h>
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#include <linux/io.h>
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#define MAX_CMDLEN 240
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#define DEFAULT_CMD "SYSTEM RESTART"
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#define MIN_INTERVAL 15 /* Minimal time supported by diag88 */
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#define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */
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#define WDT_DEFAULT_TIMEOUT 30
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/* Function codes - init, change, cancel */
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#define WDT_FUNC_INIT 0
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#define WDT_FUNC_CHANGE 1
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#define WDT_FUNC_CANCEL 2
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#define WDT_FUNC_CONCEAL 0x80000000
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/* Action codes for LPAR watchdog */
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#define LPARWDT_RESTART 0
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static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD;
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static bool conceal_on;
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static bool nowayout_info = WATCHDOG_NOWAYOUT;
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
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MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>");
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MODULE_DESCRIPTION("System z diag288 Watchdog Timer");
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module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644);
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MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)");
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module_param_named(conceal, conceal_on, bool, 0644);
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MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)");
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module_param_named(nowayout, nowayout_info, bool, 0444);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)");
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MODULE_ALIAS("vmwatchdog");
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static char *cmd_buf;
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static int diag288(unsigned int func, unsigned int timeout,
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unsigned long action, unsigned int len)
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{
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union register_pair r1 = { .even = func, .odd = timeout, };
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union register_pair r3 = { .even = action, .odd = len, };
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int err;
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diag_stat_inc(DIAG_STAT_X288);
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err = -EINVAL;
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asm volatile(
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" diag %[r1],%[r3],0x288\n"
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"0: la %[err],0\n"
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"1:\n"
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EX_TABLE(0b, 1b)
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: [err] "+d" (err)
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: [r1] "d" (r1.pair), [r3] "d" (r3.pair)
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: "cc", "memory");
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return err;
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}
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static int diag288_str(unsigned int func, unsigned int timeout, char *cmd)
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{
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ssize_t len;
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len = strscpy(cmd_buf, cmd, MAX_CMDLEN);
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if (len < 0)
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return len;
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ASCEBC(cmd_buf, MAX_CMDLEN);
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EBC_TOUPPER(cmd_buf, MAX_CMDLEN);
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return diag288(func, timeout, virt_to_phys(cmd_buf), len);
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}
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static int wdt_start(struct watchdog_device *dev)
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{
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int ret;
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unsigned int func;
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if (MACHINE_IS_VM) {
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func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
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: WDT_FUNC_INIT;
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ret = diag288_str(func, dev->timeout, wdt_cmd);
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WARN_ON(ret != 0);
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} else {
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ret = diag288(WDT_FUNC_INIT, dev->timeout, LPARWDT_RESTART, 0);
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}
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if (ret) {
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pr_err("The watchdog cannot be activated\n");
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return ret;
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}
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return 0;
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}
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static int wdt_stop(struct watchdog_device *dev)
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{
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return diag288(WDT_FUNC_CANCEL, 0, 0, 0);
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}
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static int wdt_ping(struct watchdog_device *dev)
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{
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int ret;
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unsigned int func;
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if (MACHINE_IS_VM) {
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/*
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* It seems to be ok to z/VM to use the init function to
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* retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must
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* be used when the watchdog is running.
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*/
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func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
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: WDT_FUNC_INIT;
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ret = diag288_str(func, dev->timeout, wdt_cmd);
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WARN_ON(ret != 0);
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} else {
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ret = diag288(WDT_FUNC_CHANGE, dev->timeout, 0, 0);
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}
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if (ret)
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pr_err("The watchdog timer cannot be started or reset\n");
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return ret;
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}
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static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
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{
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dev->timeout = new_to;
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return wdt_ping(dev);
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}
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static const struct watchdog_ops wdt_ops = {
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.owner = THIS_MODULE,
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.start = wdt_start,
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.stop = wdt_stop,
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.ping = wdt_ping,
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.set_timeout = wdt_set_timeout,
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};
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static const struct watchdog_info wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
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.firmware_version = 0,
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.identity = "z Watchdog",
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};
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static struct watchdog_device wdt_dev = {
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.parent = NULL,
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.info = &wdt_info,
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.ops = &wdt_ops,
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.bootstatus = 0,
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.timeout = WDT_DEFAULT_TIMEOUT,
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.min_timeout = MIN_INTERVAL,
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.max_timeout = MAX_INTERVAL,
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};
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static int __init diag288_init(void)
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{
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int ret;
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watchdog_set_nowayout(&wdt_dev, nowayout_info);
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if (MACHINE_IS_VM) {
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cmd_buf = kmalloc(MAX_CMDLEN, GFP_KERNEL);
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if (!cmd_buf) {
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pr_err("The watchdog cannot be initialized\n");
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return -ENOMEM;
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}
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ret = diag288_str(WDT_FUNC_INIT, MIN_INTERVAL, "BEGIN");
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if (ret != 0) {
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pr_err("The watchdog cannot be initialized\n");
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kfree(cmd_buf);
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return -EINVAL;
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}
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} else {
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if (diag288(WDT_FUNC_INIT, WDT_DEFAULT_TIMEOUT,
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LPARWDT_RESTART, 0)) {
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pr_err("The watchdog cannot be initialized\n");
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return -EINVAL;
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}
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}
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if (diag288(WDT_FUNC_CANCEL, 0, 0, 0)) {
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pr_err("The watchdog cannot be deactivated\n");
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return -EINVAL;
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}
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return watchdog_register_device(&wdt_dev);
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}
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static void __exit diag288_exit(void)
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{
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watchdog_unregister_device(&wdt_dev);
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kfree(cmd_buf);
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}
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module_init(diag288_init);
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module_exit(diag288_exit);
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