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Commit 5ec29e31 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull core locking updates from Ingo Molnar:
 "This update:

   - extends and simplifies x86 NMI callback handling code to enhance
     and fix the HP hw-watchdog driver

   - simplifies the x86 NMI callback handling code to fix a kmemcheck
     bug.

   - enhances the hung-task debugger"

* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/nmi: Fix the type of the nmiaction.flags field
  x86/nmi: Fix page faults by nmiaction if kmemcheck is enabled
  x86/nmi: Add new NMI queues to deal with IO_CHK and SERR
  watchdog, hpwdt: Remove priority option for NMI callback
  hung task debugging: Inject NMI when hung and going to panic
parents abd209b7 6ff968cc

arch/x86/include/asm/nmi.h

+20 −2
Original line number Diff line number Diff line
@@ -27,6 +27,8 @@ void arch_trigger_all_cpu_backtrace(void); 
enum {

	NMI_LOCAL=0,

	NMI_UNKNOWN,

	NMI_SERR,

	NMI_IO_CHECK,

	NMI_MAX

};
@@ -35,8 +37,24 @@ enum { 


typedef int (*nmi_handler_t)(unsigned int, struct pt_regs *);



int register_nmi_handler(unsigned int, nmi_handler_t, unsigned long,

			 const char *);

struct nmiaction {

	struct list_head	list;

	nmi_handler_t		handler;

	unsigned long		flags;

	const char		*name;

};



#define register_nmi_handler(t, fn, fg, n)		\

({							\

	static struct nmiaction fn##_na = {		\

		.handler = (fn),			\

		.name = (n),				\

		.flags = (fg),				\

	};						\

	__register_nmi_handler((t), &fn##_na);	\

})



int __register_nmi_handler(unsigned int, struct nmiaction *);



void unregister_nmi_handler(unsigned int, const char *);

arch/x86/kernel/nmi.c

+24 −59
Original line number Diff line number Diff line
@@ -31,14 +31,6 @@ 
#include <asm/nmi.h>

#include <asm/x86_init.h>



#define NMI_MAX_NAMELEN	16

struct nmiaction {

	struct list_head list;

	nmi_handler_t handler;

	unsigned int flags;

	char *name;

};



struct nmi_desc {

	spinlock_t lock;

	struct list_head head;
@@ -54,6 +46,14 @@ static struct nmi_desc nmi_desc[NMI_MAX] = 
		.lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock),

		.head = LIST_HEAD_INIT(nmi_desc[1].head),

	},

	{

		.lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[2].lock),

		.head = LIST_HEAD_INIT(nmi_desc[2].head),

	},

	{

		.lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[3].lock),

		.head = LIST_HEAD_INIT(nmi_desc[3].head),

	},



};
@@ -107,11 +107,14 @@ static int notrace __kprobes nmi_handle(unsigned int type, struct pt_regs *regs, 
	return handled;

}



static int __setup_nmi(unsigned int type, struct nmiaction *action)

int __register_nmi_handler(unsigned int type, struct nmiaction *action)

{

	struct nmi_desc *desc = nmi_to_desc(type);

	unsigned long flags;



	if (!action->handler)

		return -EINVAL;



	spin_lock_irqsave(&desc->lock, flags);



	/*
@@ -120,6 +123,8 @@ static int __setup_nmi(unsigned int type, struct nmiaction *action) 
	 * to manage expectations

	 */

	WARN_ON_ONCE(type == NMI_UNKNOWN && !list_empty(&desc->head));

	WARN_ON_ONCE(type == NMI_SERR && !list_empty(&desc->head));

	WARN_ON_ONCE(type == NMI_IO_CHECK && !list_empty(&desc->head));



	/*

	 * some handlers need to be executed first otherwise a fake
@@ -133,8 +138,9 @@ static int __setup_nmi(unsigned int type, struct nmiaction *action) 
	spin_unlock_irqrestore(&desc->lock, flags);

	return 0;

}

EXPORT_SYMBOL(__register_nmi_handler);



static struct nmiaction *__free_nmi(unsigned int type, const char *name)

void unregister_nmi_handler(unsigned int type, const char *name)

{

	struct nmi_desc *desc = nmi_to_desc(type);

	struct nmiaction *n;
@@ -157,61 +163,16 @@ static struct nmiaction *__free_nmi(unsigned int type, const char *name) 


	spin_unlock_irqrestore(&desc->lock, flags);

	synchronize_rcu();

	return (n);

}



int register_nmi_handler(unsigned int type, nmi_handler_t handler,

			unsigned long nmiflags, const char *devname)

{

	struct nmiaction *action;

	int retval = -ENOMEM;



	if (!handler)

		return -EINVAL;



	action = kzalloc(sizeof(struct nmiaction), GFP_KERNEL);

	if (!action)

		goto fail_action;



	action->handler = handler;

	action->flags = nmiflags;

	action->name = kstrndup(devname, NMI_MAX_NAMELEN, GFP_KERNEL);

	if (!action->name)

		goto fail_action_name;



	retval = __setup_nmi(type, action);



	if (retval)

		goto fail_setup_nmi;



	return retval;



fail_setup_nmi:

	kfree(action->name);

fail_action_name:

	kfree(action);

fail_action:	



	return retval;

}

EXPORT_SYMBOL_GPL(register_nmi_handler);



void unregister_nmi_handler(unsigned int type, const char *name)

{

	struct nmiaction *a;



	a = __free_nmi(type, name);

	if (a) {

		kfree(a->name);

		kfree(a);

	}

}



EXPORT_SYMBOL_GPL(unregister_nmi_handler);



static notrace __kprobes void

pci_serr_error(unsigned char reason, struct pt_regs *regs)

{

	/* check to see if anyone registered against these types of errors */

	if (nmi_handle(NMI_SERR, regs, false))

		return;



	pr_emerg("NMI: PCI system error (SERR) for reason %02x on CPU %d.\n",

		 reason, smp_processor_id());
@@ -241,6 +202,10 @@ io_check_error(unsigned char reason, struct pt_regs *regs) 
{

	unsigned long i;



	/* check to see if anyone registered against these types of errors */

	if (nmi_handle(NMI_IO_CHECK, regs, false))

		return;



	pr_emerg(

	"NMI: IOCK error (debug interrupt?) for reason %02x on CPU %d.\n",

		 reason, smp_processor_id());

drivers/watchdog/hpwdt.c

+24 −22
Original line number Diff line number Diff line
@@ -147,7 +147,6 @@ struct cmn_registers { 


static unsigned int hpwdt_nmi_decoding;

static unsigned int allow_kdump;

static unsigned int priority;		/* hpwdt at end of die_notify list */

static unsigned int is_icru;

static DEFINE_SPINLOCK(rom_lock);

static void *cru_rom_addr;
@@ -723,28 +722,35 @@ static int __devinit hpwdt_init_nmi_decoding(struct pci_dev *dev) 
	}



	/*

	 * If the priority is set to 1, then we will be put first on the

	 * die notify list to handle a critical NMI. The default is to

	 * be last so other users of the NMI signal can function.

	 * Only one function can register for NMI_UNKNOWN

	 */

	retval = register_nmi_handler(NMI_UNKNOWN, hpwdt_pretimeout,

					(priority) ? NMI_FLAG_FIRST : 0,

					"hpwdt");

	if (retval != 0) {

	retval = register_nmi_handler(NMI_UNKNOWN, hpwdt_pretimeout, 0, "hpwdt");

	if (retval)

		goto error;

	retval = register_nmi_handler(NMI_SERR, hpwdt_pretimeout, 0, "hpwdt");

	if (retval)

		goto error1;

	retval = register_nmi_handler(NMI_IO_CHECK, hpwdt_pretimeout, 0, "hpwdt");

	if (retval)

		goto error2;



	dev_info(&dev->dev,

			"HP Watchdog Timer Driver: NMI decoding initialized"

			", allow kernel dump: %s (default = 0/OFF)\n",

			(allow_kdump == 0) ? "OFF" : "ON");

	return 0;



error2:

	unregister_nmi_handler(NMI_SERR, "hpwdt");

error1:

	unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");

error:

	dev_warn(&dev->dev,

		"Unable to register a die notifier (err=%d).\n",

		retval);

	if (cru_rom_addr)

		iounmap(cru_rom_addr);

	}



	dev_info(&dev->dev,

			"HP Watchdog Timer Driver: NMI decoding initialized"

			", allow kernel dump: %s (default = 0/OFF)"

			", priority: %s (default = 0/LAST).\n",

			(allow_kdump == 0) ? "OFF" : "ON",

			(priority == 0) ? "LAST" : "FIRST");

	return 0;

	return retval;

}



static void hpwdt_exit_nmi_decoding(void)
@@ -881,10 +887,6 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 
#ifdef CONFIG_HPWDT_NMI_DECODING

module_param(allow_kdump, int, 0);

MODULE_PARM_DESC(allow_kdump, "Start a kernel dump after NMI occurs");



module_param(priority, int, 0);

MODULE_PARM_DESC(priority, "The hpwdt driver handles NMIs first or last"

		" (default = 0/Last)\n");

#endif /* !CONFIG_HPWDT_NMI_DECODING */



module_init(hpwdt_init);

kernel/hung_task.c

+3 −1
Original line number Diff line number Diff line
@@ -108,9 +108,11 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) 


	touch_nmi_watchdog();



	if (sysctl_hung_task_panic)

	if (sysctl_hung_task_panic) {

		trigger_all_cpu_backtrace();

		panic("hung_task: blocked tasks");

	}

}



/*

 * To avoid extending the RCU grace period for an unbounded amount of time,