Merge git://oss.sgi.com:8090/xfs/xfs-2.6

[linux-drm-fsl-dcu.git] / arch / ia64 / kernel / traps.c

diff --git a/arch/ia64/kernel/traps.c b/arch/ia64/kernel/traps.c
index fffa9e0826bc3b8eab092da56ead23c7349d27b6..765cbe5ba6ae280474761231db44d890ff74cbde 100644 (file)
--- a/arch/ia64/kernel/traps.c
+++ b/arch/ia64/kernel/traps.c
@@ -24,8 +24,6 @@
 #include <asm/uaccess.h>
 #include <asm/kdebug.h>
 
-extern spinlock_t timerlist_lock;
-
 fpswa_interface_t *fpswa_interface;
 EXPORT_SYMBOL(fpswa_interface);
 
@@ -53,34 +51,6 @@ trap_init (void)
                fpswa_interface = __va(ia64_boot_param->fpswa);
 }
 
-/*
- * Unlock any spinlocks which will prevent us from getting the message out (timerlist_lock
- * is acquired through the console unblank code)
- */
-void
-bust_spinlocks (int yes)
-{
-       int loglevel_save = console_loglevel;
-
-       if (yes) {
-               oops_in_progress = 1;
-               return;
-       }
-
-#ifdef CONFIG_VT
-       unblank_screen();
-#endif
-       oops_in_progress = 0;
-       /*
-        * OK, the message is on the console.  Now we call printk() without
-        * oops_in_progress set so that printk will give klogd a poke.  Hold onto
-        * your hats...
-        */
-       console_loglevel = 15;          /* NMI oopser may have shut the console up */
-       printk(" ");
-       console_loglevel = loglevel_save;
-}
-
 void
 die (const char *str, struct pt_regs *regs, long err)
 {
@@ -307,6 +277,15 @@ fp_emulate (int fp_fault, void *bundle, long *ipsr, long *fpsr, long *isr, long
        return ret.status;
 }
 
+struct fpu_swa_msg {
+       unsigned long count;
+       unsigned long time;
+};
+static DEFINE_PER_CPU(struct fpu_swa_msg, cpulast);
+DECLARE_PER_CPU(struct fpu_swa_msg, cpulast);
+static struct fpu_swa_msg last __cacheline_aligned;
+
+
 /*
  * Handle floating-point assist faults and traps.
  */
@@ -316,8 +295,6 @@ handle_fpu_swa (int fp_fault, struct pt_regs *regs, unsigned long isr)
        long exception, bundle[2];
        unsigned long fault_ip;
        struct siginfo siginfo;
-       static int fpu_swa_count = 0;
-       static unsigned long last_time;
 
        fault_ip = regs->cr_iip;
        if (!fp_fault && (ia64_psr(regs)->ri == 0))
@@ -325,14 +302,37 @@ handle_fpu_swa (int fp_fault, struct pt_regs *regs, unsigned long isr)
        if (copy_from_user(bundle, (void __user *) fault_ip, sizeof(bundle)))
                return -1;
 
-       if (jiffies - last_time > 5*HZ)
-               fpu_swa_count = 0;
-       if ((fpu_swa_count < 4) && !(current->thread.flags & IA64_THREAD_FPEMU_NOPRINT)) {
-               last_time = jiffies;
-               ++fpu_swa_count;
-               printk(KERN_WARNING
-                      "%s(%d): floating-point assist fault at ip %016lx, isr %016lx\n",
-                      current->comm, current->pid, regs->cr_iip + ia64_psr(regs)->ri, isr);
+       if (!(current->thread.flags & IA64_THREAD_FPEMU_NOPRINT))  {
+               unsigned long count, current_jiffies = jiffies;
+               struct fpu_swa_msg *cp = &__get_cpu_var(cpulast);
+
+               if (unlikely(current_jiffies > cp->time))
+                       cp->count = 0;
+               if (unlikely(cp->count < 5)) {
+                       cp->count++;
+                       cp->time = current_jiffies + 5 * HZ;
+
+                       /* minimize races by grabbing a copy of count BEFORE checking last.time. */
+                       count = last.count;
+                       barrier();
+
+                       /*
+                        * Lower 4 bits are used as a count. Upper bits are a sequence
+                        * number that is updated when count is reset. The cmpxchg will
+                        * fail is seqno has changed. This minimizes mutiple cpus
+                        * reseting the count.
+                        */
+                       if (current_jiffies > last.time)
+                               (void) cmpxchg_acq(&last.count, count, 16 + (count & ~15));
+
+                       /* used fetchadd to atomically update the count */
+                       if ((last.count & 15) < 5 && (ia64_fetchadd(1, &last.count, acq) & 15) < 5) {
+                               last.time = current_jiffies + 5 * HZ;
+                               printk(KERN_WARNING
+                                       "%s(%d): floating-point assist fault at ip %016lx, isr %016lx\n",
+                                       current->comm, current->pid, regs->cr_iip + ia64_psr(regs)->ri, isr);
+                       }
+               }
        }
 
        exception = fp_emulate(fp_fault, bundle, &regs->cr_ipsr, &regs->ar_fpsr, &isr, &regs->pr,