[PATCH] i386/x86-64: Remove un/set_nmi_callback and reserve/release_lapic_nmi functions

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.

Also includes compile fixes by Andrew Morton.

Signed-off-by:  Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>

3 files changed, 31 insertions, 97 deletions

diff --git a/arch/i386/kernel/crash.c b/arch/i386/kernel/crash.c
index 5b96f038367..736c76d6b31 100644
--- a/arch/i386/kernel/crash.c
+++ b/arch/i386/kernel/crash.c
@@ -22,6 +22,8 @@
 #include <asm/nmi.h>
 #include <asm/hw_irq.h>
 #include <asm/apic.h>
+#include <asm/kdebug.h>
+
 #include <mach_ipi.h>
 
 
@@ -93,9 +95,18 @@ static void crash_save_self(struct pt_regs *regs)
 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
 static atomic_t waiting_for_crash_ipi;
 
-static int crash_nmi_callback(struct pt_regs *regs, int cpu)
+static int crash_nmi_callback(struct notifier_block *self,
+                        unsigned long val, void *data)
 {
+        struct pt_regs *regs;
         struct pt_regs fixed_regs;
+        int cpu;
+
+        if (val != DIE_NMI)
+                return NOTIFY_OK;
+
+        regs = ((struct die_args *)data)->regs;
+        cpu = raw_smp_processor_id();
 
         /* Don't do anything if this handler is invoked on crashing cpu.
          * Otherwise, system will completely hang. Crashing cpu can get
@@ -125,13 +136,18 @@ static void smp_send_nmi_allbutself(void)
         send_IPI_allbutself(NMI_VECTOR);
 }
 
+static struct notifier_block crash_nmi_nb = {
+        .notifier_call = crash_nmi_callback,
+};
+
 static void nmi_shootdown_cpus(void)
 {
         unsigned long msecs;
 
         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
         /* Would it be better to replace the trap vector here? */
-        set_nmi_callback(crash_nmi_callback);
+        if (register_die_notifier(&crash_nmi_nb))
+                return;         /* return what? */
         /* Ensure the new callback function is set before sending
          * out the NMI
          */
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index bd96ea4f294..acd3fdea2a2 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -42,20 +42,6 @@ static DEFINE_PER_CPU(unsigned long, evntsel_nmi_owner[3]);
  */
 #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(void)
         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);
@@ -866,6 +825,15 @@ 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)
@@ -873,37 +841,8 @@ static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
         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;
 }
 
@@ -917,7 +856,5 @@ 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);
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 282f0bd40df..7db664d0b25 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -706,13 +706,6 @@ void die_nmi (struct pt_regs *regs, const char *msg)
         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;
@@ -732,9 +725,10 @@ static void default_do_nmi(struct pt_regs * regs)
                  */
                 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)
@@ -765,19 +759,6 @@ fastcall void do_nmi(struct pt_regs * regs, long error_code)
         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)
 {