Merge tag 'tags/restart-handler-for-v3.18' into v3.18-next/cpuclk
Immutable branch with restart handler patches for v3.18
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 81ef686..250b6f6 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -114,18 +114,13 @@
BUG();
}
-static void null_restart(enum reboot_mode reboot_mode, const char *cmd)
-{
-}
-
/*
* Function pointers to optional machine specific functions
*/
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);
-void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd) = null_restart;
-EXPORT_SYMBOL_GPL(arm_pm_restart);
+void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
/*
* This is our default idle handler.
@@ -230,7 +225,10 @@
local_irq_disable();
smp_send_stop();
- arm_pm_restart(reboot_mode, cmd);
+ if (arm_pm_restart)
+ arm_pm_restart(reboot_mode, cmd);
+ else
+ do_kernel_restart(cmd);
/* Give a grace period for failure to restart of 1s */
mdelay(1000);
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 1309d64..398ab05 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -98,7 +98,6 @@
EXPORT_SYMBOL_GPL(pm_power_off);
void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
-EXPORT_SYMBOL_GPL(arm_pm_restart);
/*
* This is our default idle handler.
@@ -180,6 +179,8 @@
/* Now call the architecture specific reboot code. */
if (arm_pm_restart)
arm_pm_restart(reboot_mode, cmd);
+ else
+ do_kernel_restart(cmd);
/*
* Whoops - the architecture was unable to reboot.
diff --git a/drivers/power/reset/restart-poweroff.c b/drivers/power/reset/restart-poweroff.c
index 3e51f8d..edd707e 100644
--- a/drivers/power/reset/restart-poweroff.c
+++ b/drivers/power/reset/restart-poweroff.c
@@ -20,7 +20,8 @@
static void restart_poweroff_do_poweroff(void)
{
- arm_pm_restart(REBOOT_HARD, NULL);
+ reboot_mode = REBOOT_HARD;
+ machine_restart(NULL);
}
static int restart_poweroff_probe(struct platform_device *pdev)
diff --git a/drivers/watchdog/alim7101_wdt.c b/drivers/watchdog/alim7101_wdt.c
index 996b2f7..665e0e7 100644
--- a/drivers/watchdog/alim7101_wdt.c
+++ b/drivers/watchdog/alim7101_wdt.c
@@ -301,6 +301,28 @@
.fops = &wdt_fops,
};
+static int wdt_restart_handle(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ /*
+ * Cobalt devices have no way of rebooting themselves other
+ * than getting the watchdog to pull reset, so we restart the
+ * watchdog on reboot with no heartbeat.
+ */
+ wdt_change(WDT_ENABLE);
+
+ /* loop until the watchdog fires */
+ while (true)
+ ;
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block wdt_restart_handler = {
+ .notifier_call = wdt_restart_handle,
+ .priority = 128,
+};
+
/*
* Notifier for system down
*/
@@ -311,15 +333,6 @@
if (code == SYS_DOWN || code == SYS_HALT)
wdt_turnoff();
- if (code == SYS_RESTART) {
- /*
- * Cobalt devices have no way of rebooting themselves other
- * than getting the watchdog to pull reset, so we restart the
- * watchdog on reboot with no heartbeat
- */
- wdt_change(WDT_ENABLE);
- pr_info("Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second\n");
- }
return NOTIFY_DONE;
}
@@ -338,6 +351,7 @@
/* Deregister */
misc_deregister(&wdt_miscdev);
unregister_reboot_notifier(&wdt_notifier);
+ unregister_restart_handler(&wdt_restart_handler);
pci_dev_put(alim7101_pmu);
}
@@ -390,11 +404,17 @@
goto err_out;
}
+ rc = register_restart_handler(&wdt_restart_handler);
+ if (rc) {
+ pr_err("cannot register restart handler (err=%d)\n", rc);
+ goto err_out_reboot;
+ }
+
rc = misc_register(&wdt_miscdev);
if (rc) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
wdt_miscdev.minor, rc);
- goto err_out_reboot;
+ goto err_out_restart;
}
if (nowayout)
@@ -404,6 +424,8 @@
timeout, nowayout);
return 0;
+err_out_restart:
+ unregister_restart_handler(&wdt_restart_handler);
err_out_reboot:
unregister_reboot_notifier(&wdt_notifier);
err_out:
diff --git a/drivers/watchdog/moxart_wdt.c b/drivers/watchdog/moxart_wdt.c
index 4aa3a8a..a64405b 100644
--- a/drivers/watchdog/moxart_wdt.c
+++ b/drivers/watchdog/moxart_wdt.c
@@ -15,12 +15,12 @@
#include <linux/module.h>
#include <linux/err.h>
#include <linux/kernel.h>
+#include <linux/notifier.h>
#include <linux/platform_device.h>
+#include <linux/reboot.h>
#include <linux/watchdog.h>
#include <linux/moduleparam.h>
-#include <asm/system_misc.h>
-
#define REG_COUNT 0x4
#define REG_MODE 0x8
#define REG_ENABLE 0xC
@@ -29,17 +29,22 @@
struct watchdog_device dev;
void __iomem *base;
unsigned int clock_frequency;
+ struct notifier_block restart_handler;
};
-static struct moxart_wdt_dev *moxart_restart_ctx;
-
static int heartbeat;
-static void moxart_wdt_restart(enum reboot_mode reboot_mode, const char *cmd)
+static int moxart_restart_handle(struct notifier_block *this,
+ unsigned long mode, void *cmd)
{
- writel(1, moxart_restart_ctx->base + REG_COUNT);
- writel(0x5ab9, moxart_restart_ctx->base + REG_MODE);
- writel(0x03, moxart_restart_ctx->base + REG_ENABLE);
+ struct moxart_wdt_dev *moxart_wdt = container_of(this,
+ struct moxart_wdt_dev,
+ restart_handler);
+ writel(1, moxart_wdt->base + REG_COUNT);
+ writel(0x5ab9, moxart_wdt->base + REG_MODE);
+ writel(0x03, moxart_wdt->base + REG_ENABLE);
+
+ return NOTIFY_DONE;
}
static int moxart_wdt_stop(struct watchdog_device *wdt_dev)
@@ -136,8 +141,12 @@
if (err)
return err;
- moxart_restart_ctx = moxart_wdt;
- arm_pm_restart = moxart_wdt_restart;
+ moxart_wdt->restart_handler.notifier_call = moxart_restart_handle;
+ moxart_wdt->restart_handler.priority = 128;
+ err = register_restart_handler(&moxart_wdt->restart_handler);
+ if (err)
+ dev_err(dev, "cannot register restart notifier (err=%d)\n",
+ err);
dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
moxart_wdt->dev.timeout, nowayout);
@@ -149,9 +158,8 @@
{
struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev);
- arm_pm_restart = NULL;
+ unregister_restart_handler(&moxart_wdt->restart_handler);
moxart_wdt_stop(&moxart_wdt->dev);
- watchdog_unregister_device(&moxart_wdt->dev);
return 0;
}
diff --git a/drivers/watchdog/sunxi_wdt.c b/drivers/watchdog/sunxi_wdt.c
index 60deb9d..480bb55 100644
--- a/drivers/watchdog/sunxi_wdt.c
+++ b/drivers/watchdog/sunxi_wdt.c
@@ -21,14 +21,13 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
+#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/watchdog.h>
-#include <asm/system_misc.h>
-
#define WDT_MAX_TIMEOUT 16
#define WDT_MIN_TIMEOUT 1
#define WDT_MODE_TIMEOUT(n) ((n) << 3)
@@ -50,6 +49,7 @@
struct sunxi_wdt_dev {
struct watchdog_device wdt_dev;
void __iomem *wdt_base;
+ struct notifier_block restart_handler;
};
/*
@@ -74,24 +74,29 @@
[16] = 0xB, /* 16s */
};
-static void __iomem *reboot_wdt_base;
-static void sun4i_wdt_restart(enum reboot_mode mode, const char *cmd)
+static int sunxi_restart_handle(struct notifier_block *this, unsigned long mode,
+ void *cmd)
{
+ struct sunxi_wdt_dev *sunxi_wdt = container_of(this,
+ struct sunxi_wdt_dev,
+ restart_handler);
+ void __iomem *wdt_base = sunxi_wdt->wdt_base;
+
/* Enable timer and set reset bit in the watchdog */
- writel(WDT_MODE_EN | WDT_MODE_RST_EN, reboot_wdt_base + WDT_MODE);
+ writel(WDT_MODE_EN | WDT_MODE_RST_EN, wdt_base + WDT_MODE);
/*
* Restart the watchdog. The default (and lowest) interval
* value for the watchdog is 0.5s.
*/
- writel(WDT_CTRL_RELOAD, reboot_wdt_base + WDT_CTRL);
+ writel(WDT_CTRL_RELOAD, wdt_base + WDT_CTRL);
while (1) {
mdelay(5);
- writel(WDT_MODE_EN | WDT_MODE_RST_EN,
- reboot_wdt_base + WDT_MODE);
+ writel(WDT_MODE_EN | WDT_MODE_RST_EN, wdt_base + WDT_MODE);
}
+ return NOTIFY_DONE;
}
static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
@@ -205,8 +210,12 @@
if (unlikely(err))
return err;
- reboot_wdt_base = sunxi_wdt->wdt_base;
- arm_pm_restart = sun4i_wdt_restart;
+ sunxi_wdt->restart_handler.notifier_call = sunxi_restart_handle;
+ sunxi_wdt->restart_handler.priority = 128;
+ err = register_restart_handler(&sunxi_wdt->restart_handler);
+ if (err)
+ dev_err(&pdev->dev,
+ "cannot register restart handler (err=%d)\n", err);
dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
sunxi_wdt->wdt_dev.timeout, nowayout);
@@ -218,7 +227,7 @@
{
struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
- arm_pm_restart = NULL;
+ unregister_restart_handler(&sunxi_wdt->restart_handler);
watchdog_unregister_device(&sunxi_wdt->wdt_dev);
watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index 48bf152..67fc8fc 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -38,6 +38,9 @@
extern int register_reboot_notifier(struct notifier_block *);
extern int unregister_reboot_notifier(struct notifier_block *);
+extern int register_restart_handler(struct notifier_block *);
+extern int unregister_restart_handler(struct notifier_block *);
+extern void do_kernel_restart(char *cmd);
/*
* Architecture-specific implementations of sys_reboot commands.
diff --git a/kernel/reboot.c b/kernel/reboot.c
index a3a9e24..5925f5a 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -104,6 +104,87 @@
}
EXPORT_SYMBOL(unregister_reboot_notifier);
+/*
+ * Notifier list for kernel code which wants to be called
+ * to restart the system.
+ */
+static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
+
+/**
+ * register_restart_handler - Register function to be called to reset
+ * the system
+ * @nb: Info about handler function to be called
+ * @nb->priority: Handler priority. Handlers should follow the
+ * following guidelines for setting priorities.
+ * 0: Restart handler of last resort,
+ * with limited restart capabilities
+ * 128: Default restart handler; use if no other
+ * restart handler is expected to be available,
+ * and/or if restart functionality is
+ * sufficient to restart the entire system
+ * 255: Highest priority restart handler, will
+ * preempt all other restart handlers
+ *
+ * Registers a function with code to be called to restart the
+ * system.
+ *
+ * Registered functions will be called from machine_restart as last
+ * step of the restart sequence (if the architecture specific
+ * machine_restart function calls do_kernel_restart - see below
+ * for details).
+ * Registered functions are expected to restart the system immediately.
+ * If more than one function is registered, the restart handler priority
+ * selects which function will be called first.
+ *
+ * Restart handlers are expected to be registered from non-architecture
+ * code, typically from drivers. A typical use case would be a system
+ * where restart functionality is provided through a watchdog. Multiple
+ * restart handlers may exist; for example, one restart handler might
+ * restart the entire system, while another only restarts the CPU.
+ * In such cases, the restart handler which only restarts part of the
+ * hardware is expected to register with low priority to ensure that
+ * it only runs if no other means to restart the system is available.
+ *
+ * Currently always returns zero, as atomic_notifier_chain_register()
+ * always returns zero.
+ */
+int register_restart_handler(struct notifier_block *nb)
+{
+ return atomic_notifier_chain_register(&restart_handler_list, nb);
+}
+EXPORT_SYMBOL(register_restart_handler);
+
+/**
+ * unregister_restart_handler - Unregister previously registered
+ * restart handler
+ * @nb: Hook to be unregistered
+ *
+ * Unregisters a previously registered restart handler function.
+ *
+ * Returns zero on success, or %-ENOENT on failure.
+ */
+int unregister_restart_handler(struct notifier_block *nb)
+{
+ return atomic_notifier_chain_unregister(&restart_handler_list, nb);
+}
+EXPORT_SYMBOL(unregister_restart_handler);
+
+/**
+ * do_kernel_restart - Execute kernel restart handler call chain
+ *
+ * Calls functions registered with register_restart_handler.
+ *
+ * Expected to be called from machine_restart as last step of the restart
+ * sequence.
+ *
+ * Restarts the system immediately if a restart handler function has been
+ * registered. Otherwise does nothing.
+ */
+void do_kernel_restart(char *cmd)
+{
+ atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd);
+}
+
void migrate_to_reboot_cpu(void)
{
/* The boot cpu is always logical cpu 0 */