[patch 7/8] Remove un/set_nmi_callback and reserve/release_lapic_nmi functions

From: dzickus
Date: Tue May 09 2006 - 16:57:29 EST

Next message: dzickus: "[patch 6/8] Cleanup NMI interrupt path"
Previous message: Roland Dreier: "Re: [RFC PATCH 34/35] Add the Xen virtual network device driver."
In reply to: dzickus: "[patch 0/8] [RFC PATCH] nmi watchdog: x86 32/64 cleanup"
Next in thread: dzickus: "[patch 6/8] Cleanup NMI interrupt path"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Removes the un/set_nmi_callback and reserve/release_lapic_nmi functions as
they are no longer needed. The various subsystems are modified to register
with the die_notifier instead.

Signed-off-by: Don Zickus <dzickus@xxxxxxxxxx>

Index: linux-don/arch/x86_64/kernel/nmi.c
===================================================================
--- linux-don.orig/arch/x86_64/kernel/nmi.c
+++ linux-don/arch/x86_64/kernel/nmi.c
@@ -42,20 +42,6 @@ static DEFINE_PER_CPU(unsigned, evntsel_
*/
#define NMI_MAX_COUNTER_BITS 66

-/*
- * lapic_nmi_owner tracks the ownership of the lapic NMI hardware:
- * - it may be reserved by some other driver, or not
- * - when not reserved by some other driver, it may be used for
- * the NMI watchdog, or not
- *
- * This is maintained separately from nmi_active because the NMI
- * watchdog may also be driven from the I/O APIC timer.
- */
-static DEFINE_SPINLOCK(lapic_nmi_owner_lock);
-static unsigned int lapic_nmi_owner;
-#define LAPIC_NMI_WATCHDOG (1<<0)
-#define LAPIC_NMI_RESERVED (1<<1)
-
/* nmi_active:
* >0: the lapic NMI watchdog is active, but can be disabled
* <0: the lapic NMI watchdog has not been set up, and cannot
@@ -322,33 +308,6 @@ static void enable_lapic_nmi_watchdog(vo
touch_nmi_watchdog();
}

-int reserve_lapic_nmi(void)
-{
- unsigned int old_owner;
-
- spin_lock(&lapic_nmi_owner_lock);
- old_owner = lapic_nmi_owner;
- lapic_nmi_owner |= LAPIC_NMI_RESERVED;
- spin_unlock(&lapic_nmi_owner_lock);
- if (old_owner & LAPIC_NMI_RESERVED)
- return -EBUSY;
- if (old_owner & LAPIC_NMI_WATCHDOG)
- disable_lapic_nmi_watchdog();
- return 0;
-}
-
-void release_lapic_nmi(void)
-{
- unsigned int new_owner;
-
- spin_lock(&lapic_nmi_owner_lock);
- new_owner = lapic_nmi_owner & ~LAPIC_NMI_RESERVED;
- lapic_nmi_owner = new_owner;
- spin_unlock(&lapic_nmi_owner_lock);
- if (new_owner & LAPIC_NMI_WATCHDOG)
- enable_lapic_nmi_watchdog();
-}
-
void disable_timer_nmi_watchdog(void)
{
BUG_ON(nmi_watchdog != NMI_IO_APIC);
@@ -763,13 +722,6 @@ done:
return rc;
}

-static __kprobes int dummy_nmi_callback(struct pt_regs * regs, int cpu)
-{
- return 0;
-}
-
-static nmi_callback_t nmi_callback = dummy_nmi_callback;
-
asmlinkage __kprobes void do_nmi(struct pt_regs * regs, long error_code)
{
nmi_enter();
@@ -780,18 +732,11 @@ asmlinkage __kprobes void do_nmi(struct

int do_nmi_callback(struct pt_regs * regs, int cpu)
{
- return rcu_dereference(nmi_callback)(regs, cpu);
-}
-
-void set_nmi_callback(nmi_callback_t callback)
-{
- vmalloc_sync_all();
- rcu_assign_pointer(nmi_callback, callback);
-}
-
-void unset_nmi_callback(void)
-{
- nmi_callback = dummy_nmi_callback;
+#ifdef CONFIG_SYSCTL
+ if (unknown_nmi_panic)
+ return unknown_nmi_panic_callback(regs, cpu);
+#endif
+ return 0;
}

#ifdef CONFIG_SYSCTL
@@ -801,37 +746,8 @@ static int unknown_nmi_panic_callback(st
unsigned char reason = get_nmi_reason();
char buf[64];

- if (!(reason & 0xc0)) {
- sprintf(buf, "NMI received for unknown reason %02x\n", reason);
- die_nmi(buf,regs);
- }
- return 0;
-}
-
-/*
- * proc handler for /proc/sys/kernel/unknown_nmi_panic
- */
-int proc_unknown_nmi_panic(struct ctl_table *table, int write, struct file *file,
- void __user *buffer, size_t *length, loff_t *ppos)
-{
- int old_state;
-
- old_state = unknown_nmi_panic;
- proc_dointvec(table, write, file, buffer, length, ppos);
- if (!!old_state == !!unknown_nmi_panic)
- return 0;
-
- if (unknown_nmi_panic) {
- if (reserve_lapic_nmi() < 0) {
- unknown_nmi_panic = 0;
- return -EBUSY;
- } else {
- set_nmi_callback(unknown_nmi_panic_callback);
- }
- } else {
- release_lapic_nmi();
- unset_nmi_callback();
- }
+ sprintf(buf, "NMI received for unknown reason %02x\n", reason);
+ die_nmi(buf,regs);
return 0;
}

@@ -845,8 +761,6 @@ EXPORT_SYMBOL(reserve_perfctr_nmi);
EXPORT_SYMBOL(release_perfctr_nmi);
EXPORT_SYMBOL(reserve_evntsel_nmi);
EXPORT_SYMBOL(release_evntsel_nmi);
-EXPORT_SYMBOL(reserve_lapic_nmi);
-EXPORT_SYMBOL(release_lapic_nmi);
EXPORT_SYMBOL(disable_timer_nmi_watchdog);
EXPORT_SYMBOL(enable_timer_nmi_watchdog);
EXPORT_SYMBOL(touch_nmi_watchdog);
Index: linux-don/arch/x86_64/kernel/x8664_ksyms.c
===================================================================
--- linux-don.orig/arch/x86_64/kernel/x8664_ksyms.c
+++ linux-don/arch/x86_64/kernel/x8664_ksyms.c
@@ -104,9 +104,6 @@ EXPORT_SYMBOL(screen_info);

EXPORT_SYMBOL(rtc_lock);

-EXPORT_SYMBOL_GPL(set_nmi_callback);
-EXPORT_SYMBOL_GPL(unset_nmi_callback);
-
/* Export string functions. We normally rely on gcc builtin for most of these,
but gcc sometimes decides not to inline them. */
#undef memcpy
Index: linux-don/include/asm-x86_64/nmi.h
===================================================================
--- linux-don.orig/include/asm-x86_64/nmi.h
+++ linux-don/include/asm-x86_64/nmi.h
@@ -7,25 +7,6 @@
#include <linux/pm.h>
#include <asm/io.h>

-struct pt_regs;
-
-typedef int (*nmi_callback_t)(struct pt_regs * regs, int cpu);
-
-/**
- * set_nmi_callback
- *
- * Set a handler for an NMI. Only one handler may be
- * set. Return 1 if the NMI was handled.
- */
-void set_nmi_callback(nmi_callback_t callback);
-
-/**
- * unset_nmi_callback
- *
- * Remove the handler previously set.
- */
-void unset_nmi_callback(void);
-
/**
* do_nmi_callback
*
@@ -72,8 +53,6 @@ extern int reserve_evntsel_nmi(unsigned
extern void release_evntsel_nmi(unsigned int);

extern void setup_apic_nmi_watchdog (void *);
-extern int reserve_lapic_nmi(void);
-extern void release_lapic_nmi(void);
extern void disable_timer_nmi_watchdog(void);
extern void enable_timer_nmi_watchdog(void);
extern int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);
Index: linux-don/arch/i386/oprofile/nmi_int.c
===================================================================
--- linux-don.orig/arch/i386/oprofile/nmi_int.c
+++ linux-don/arch/i386/oprofile/nmi_int.c
@@ -16,14 +16,15 @@
#include <asm/nmi.h>
#include <asm/msr.h>
#include <asm/apic.h>
+#include <asm/kdebug.h>

#include "op_counter.h"
#include "op_x86_model.h"
-
+
static struct op_x86_model_spec const * model;
static struct op_msrs cpu_msrs[NR_CPUS];
static unsigned long saved_lvtpc[NR_CPUS];
-
+
static int nmi_start(void);
static void nmi_stop(void);

@@ -81,13 +82,24 @@ static void exit_driverfs(void)
#define exit_driverfs() do { } while (0)
#endif /* CONFIG_PM */

-
-static int nmi_callback(struct pt_regs * regs, int cpu)
+int profile_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
{
- return model->check_ctrs(regs, &cpu_msrs[cpu]);
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+ int cpu = smp_processor_id();
+
+ switch(val) {
+ case DIE_NMI:
+ if (model->check_ctrs(args->regs, &cpu_msrs[cpu]))
+ ret = NOTIFY_STOP;
+ break;
+ default:
+ break;
+ }
+ return ret;
}
-
-
+
static void nmi_cpu_save_registers(struct op_msrs * msrs)
{
unsigned int const nr_ctrs = model->num_counters;
@@ -173,27 +185,29 @@ static void nmi_cpu_setup(void * dummy)
apic_write(APIC_LVTPC, APIC_DM_NMI);
}

+static struct notifier_block profile_exceptions_nb = {
+ .notifier_call = profile_exceptions_notify,
+ .next = NULL,
+ .priority = 0
+};

static int nmi_setup(void)
{
+ int err=0;
+
if (!allocate_msrs())
return -ENOMEM;

- /* We walk a thin line between law and rape here.
- * We need to be careful to install our NMI handler
- * without actually triggering any NMIs as this will
- * break the core code horrifically.
- */
- if (reserve_lapic_nmi() < 0) {
+ if ((err = register_die_notifier(&profile_exceptions_nb))){
free_msrs();
- return -EBUSY;
+ return err;
}
+
/* We need to serialize save and setup for HT because the subset
* of msrs are distinct for save and setup operations
*/
on_each_cpu(nmi_save_registers, NULL, 0, 1);
on_each_cpu(nmi_cpu_setup, NULL, 0, 1);
- set_nmi_callback(nmi_callback);
nmi_enabled = 1;
return 0;
}
@@ -249,8 +263,7 @@ static void nmi_shutdown(void)
{
nmi_enabled = 0;
on_each_cpu(nmi_cpu_shutdown, NULL, 0, 1);
- unset_nmi_callback();
- release_lapic_nmi();
+ unregister_die_notifier(&profile_exceptions_nb);
free_msrs();
}

Index: linux-don/arch/i386/oprofile/nmi_timer_int.c
===================================================================
--- linux-don.orig/arch/i386/oprofile/nmi_timer_int.c
+++ linux-don/arch/i386/oprofile/nmi_timer_int.c
@@ -17,32 +17,49 @@
#include <asm/nmi.h>
#include <asm/apic.h>
#include <asm/ptrace.h>
+#include <asm/kdebug.h>

-static int nmi_timer_callback(struct pt_regs * regs, int cpu)
+int profile_timer_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
{
- oprofile_add_sample(regs, 0);
- return 1;
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ switch(val) {
+ case DIE_NMI:
+ oprofile_add_sample(args->regs, 0);
+ ret = NOTIFY_STOP;
+ break;
+ default:
+ break;
+ }
+ return ret;
}

+static struct notifier_block profile_timer_exceptions_nb = {
+ .notifier_call = profile_timer_exceptions_notify,
+ .next = NULL,
+ .priority = 0
+};
+
static int timer_start(void)
{
- disable_timer_nmi_watchdog();
- set_nmi_callback(nmi_timer_callback);
+ if (register_die_notifier(&profile_timer_exceptions_nb))
+ return 1;
return 0;
}

static void timer_stop(void)
{
- enable_timer_nmi_watchdog();
- unset_nmi_callback();
+ unregister_die_notifier(&profile_timer_exceptions_nb);
synchronize_sched(); /* Allow already-started NMIs to complete. */
}

int __init op_nmi_timer_init(struct oprofile_operations * ops)
{
- if (atomic_read(&nmi_active) <= 0)
+ if ((nmi_watchdog != NMI_IO_APIC) || (atomic_read(&nmi_active) <= 0))
return -ENODEV;

ops->start = timer_start;
Index: linux-don/arch/i386/kernel/nmi.c
===================================================================
--- linux-don.orig/arch/i386/kernel/nmi.c
+++ linux-don/arch/i386/kernel/nmi.c
@@ -42,20 +42,6 @@ static DEFINE_PER_CPU(unsigned long, evn
*/
#define NMI_MAX_COUNTER_BITS 66

-/*
- * lapic_nmi_owner tracks the ownership of the lapic NMI hardware:
- * - it may be reserved by some other driver, or not
- * - when not reserved by some other driver, it may be used for
- * the NMI watchdog, or not
- *
- * This is maintained separately from nmi_active because the NMI
- * watchdog may also be driven from the I/O APIC timer.
- */
-static DEFINE_SPINLOCK(lapic_nmi_owner_lock);
-static unsigned int lapic_nmi_owner;
-#define LAPIC_NMI_WATCHDOG (1<<0)
-#define LAPIC_NMI_RESERVED (1<<1)
-
/* nmi_active:
* >0: the lapic NMI watchdog is active, but can be disabled
* <0: the lapic NMI watchdog has not been set up, and cannot
@@ -325,33 +311,6 @@ static void enable_lapic_nmi_watchdog(vo
touch_nmi_watchdog();
}

-int reserve_lapic_nmi(void)
-{
- unsigned int old_owner;
-
- spin_lock(&lapic_nmi_owner_lock);
- old_owner = lapic_nmi_owner;
- lapic_nmi_owner |= LAPIC_NMI_RESERVED;
- spin_unlock(&lapic_nmi_owner_lock);
- if (old_owner & LAPIC_NMI_RESERVED)
- return -EBUSY;
- if (old_owner & LAPIC_NMI_WATCHDOG)
- disable_lapic_nmi_watchdog();
- return 0;
-}
-
-void release_lapic_nmi(void)
-{
- unsigned int new_owner;
-
- spin_lock(&lapic_nmi_owner_lock);
- new_owner = lapic_nmi_owner & ~LAPIC_NMI_RESERVED;
- lapic_nmi_owner = new_owner;
- spin_unlock(&lapic_nmi_owner_lock);
- if (new_owner & LAPIC_NMI_WATCHDOG)
- enable_lapic_nmi_watchdog();
-}
-
void disable_timer_nmi_watchdog(void)
{
BUG_ON(nmi_watchdog != NMI_IO_APIC);
@@ -865,6 +824,15 @@ done:
return rc;
}

+int do_nmi_callback(struct pt_regs * regs, int cpu)
+{
+#ifdef CONFIG_SYSCTL
+ if (unknown_nmi_panic)
+ return unknown_nmi_panic_callback(regs, cpu);
+#endif
+ return 0;
+}
+
#ifdef CONFIG_SYSCTL

static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
@@ -872,37 +840,8 @@ static int unknown_nmi_panic_callback(st
unsigned char reason = get_nmi_reason();
char buf[64];

- if (!(reason & 0xc0)) {
- sprintf(buf, "NMI received for unknown reason %02x\n", reason);
- die_nmi(regs, buf);
- }
- return 0;
-}
-
-/*
- * proc handler for /proc/sys/kernel/unknown_nmi_panic
- */
-int proc_unknown_nmi_panic(ctl_table *table, int write, struct file *file,
- void __user *buffer, size_t *length, loff_t *ppos)
-{
- int old_state;
-
- old_state = unknown_nmi_panic;
- proc_dointvec(table, write, file, buffer, length, ppos);
- if (!!old_state == !!unknown_nmi_panic)
- return 0;
-
- if (unknown_nmi_panic) {
- if (reserve_lapic_nmi() < 0) {
- unknown_nmi_panic = 0;
- return -EBUSY;
- } else {
- set_nmi_callback(unknown_nmi_panic_callback);
- }
- } else {
- release_lapic_nmi();
- unset_nmi_callback();
- }
+ sprintf(buf, "NMI received for unknown reason %02x\n", reason);
+ die_nmi(regs, buf);
return 0;
}

@@ -916,7 +855,5 @@ EXPORT_SYMBOL(reserve_perfctr_nmi);
EXPORT_SYMBOL(release_perfctr_nmi);
EXPORT_SYMBOL(reserve_evntsel_nmi);
EXPORT_SYMBOL(release_evntsel_nmi);
-EXPORT_SYMBOL(reserve_lapic_nmi);
-EXPORT_SYMBOL(release_lapic_nmi);
EXPORT_SYMBOL(disable_timer_nmi_watchdog);
EXPORT_SYMBOL(enable_timer_nmi_watchdog);
Index: linux-don/arch/i386/kernel/traps.c
===================================================================
--- linux-don.orig/arch/i386/kernel/traps.c
+++ linux-don/arch/i386/kernel/traps.c
@@ -673,13 +673,6 @@ void die_nmi (struct pt_regs *regs, cons
do_exit(SIGSEGV);
}

-static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
-{
- return 0;
-}
-
-static nmi_callback_t nmi_callback = dummy_nmi_callback;
-
static void default_do_nmi(struct pt_regs * regs)
{
unsigned char reason = 0;
@@ -699,9 +692,10 @@ static void default_do_nmi(struct pt_reg
*/
if (nmi_watchdog_tick(regs, reason))
return;
+ if (!do_nmi_callback(regs, smp_processor_id()))
#endif
- if (!rcu_dereference(nmi_callback)(regs, smp_processor_id()))
unknown_nmi_error(reason, regs);
+
return;
}
if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
@@ -732,19 +726,6 @@ fastcall void do_nmi(struct pt_regs * re
nmi_exit();
}

-void set_nmi_callback(nmi_callback_t callback)
-{
- vmalloc_sync_all();
- rcu_assign_pointer(nmi_callback, callback);
-}
-EXPORT_SYMBOL_GPL(set_nmi_callback);
-
-void unset_nmi_callback(void)
-{
- nmi_callback = dummy_nmi_callback;
-}
-EXPORT_SYMBOL_GPL(unset_nmi_callback);
-
#ifdef CONFIG_KPROBES
fastcall void __kprobes do_int3(struct pt_regs *regs, long error_code)
{
Index: linux-don/include/asm-i386/nmi.h
===================================================================
--- linux-don.orig/include/asm-i386/nmi.h
+++ linux-don/include/asm-i386/nmi.h
@@ -6,24 +6,13 @@

#include <linux/pm.h>

-struct pt_regs;
-
-typedef int (*nmi_callback_t)(struct pt_regs * regs, int cpu);
-
-/**
- * set_nmi_callback
- *
- * Set a handler for an NMI. Only one handler may be
- * set. Return 1 if the NMI was handled.
- */
-void set_nmi_callback(nmi_callback_t callback);
-
/**
- * unset_nmi_callback
+ * do_nmi_callback
*
- * Remove the handler previously set.
+ * Check to see if a callback exists and execute it. Return 1
+ * if the handler exists and was handled successfully.
*/
-void unset_nmi_callback(void);
+int do_nmi_callback(struct pt_regs *regs, int cpu);

extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
extern int avail_to_resrv_perfctr_nmi(unsigned int);
@@ -33,8 +22,6 @@ extern int reserve_evntsel_nmi(unsigned
extern void release_evntsel_nmi(unsigned int);

extern void setup_apic_nmi_watchdog (void *);
-extern int reserve_lapic_nmi(void);
-extern void release_lapic_nmi(void);
extern void disable_timer_nmi_watchdog(void);
extern void enable_timer_nmi_watchdog(void);
extern int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);
Index: linux-don/kernel/sysctl.c
===================================================================
--- linux-don.orig/kernel/sysctl.c
+++ linux-don/kernel/sysctl.c
@@ -75,8 +75,6 @@ extern int percpu_pagelist_fraction;

#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
int unknown_nmi_panic;
-extern int proc_unknown_nmi_panic(ctl_table *, int, struct file *,
- void __user *, size_t *, loff_t *);
#endif

/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
@@ -630,7 +628,7 @@ static ctl_table kern_table[] = {
.data = &unknown_nmi_panic,
.maxlen = sizeof (int),
.mode = 0644,
- .proc_handler = &proc_unknown_nmi_panic,
+ .proc_handler = &proc_dointvec,
},
#endif
#if defined(CONFIG_X86)

--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: dzickus: "[patch 6/8] Cleanup NMI interrupt path"
Previous message: Roland Dreier: "Re: [RFC PATCH 34/35] Add the Xen virtual network device driver."
In reply to: dzickus: "[patch 0/8] [RFC PATCH] nmi watchdog: x86 32/64 cleanup"
Next in thread: dzickus: "[patch 6/8] Cleanup NMI interrupt path"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]