[IA64] Support multiple CPUs going through OS_MCA
[sfrench/cifs-2.6.git] / arch / ia64 / kernel / mca.c
index 1ead5ea6c5ce71afaf259eb6629abc8f65a0c11e..4b5daa3cc0feab6723764d67a7c221e74e5b3eb3 100644 (file)
@@ -57,6 +57,9 @@
  *
  * 2006-09-15 Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
  *           Add printing support for MCA/INIT.
+ *
+ * 2007-04-27 Russ Anderson <rja@sgi.com>
+ *           Support multiple cpus going through OS_MCA in the same event.
  */
 #include <linux/types.h>
 #include <linux/init.h>
@@ -96,7 +99,6 @@
 #endif
 
 /* Used by mca_asm.S */
-u32                            ia64_mca_serialize;
 DEFINE_PER_CPU(u64, ia64_mca_data); /* == __per_cpu_mca[smp_processor_id()] */
 DEFINE_PER_CPU(u64, ia64_mca_per_cpu_pte); /* PTE to map per-CPU area */
 DEFINE_PER_CPU(u64, ia64_mca_pal_pte);     /* PTE to map PAL code */
@@ -963,11 +965,12 @@ ia64_mca_modify_original_stack(struct pt_regs *regs,
                goto no_mod;
        }
 
+       if (r13 != sos->prev_IA64_KR_CURRENT) {
+               msg = "inconsistent previous current and r13";
+               goto no_mod;
+       }
+
        if (!mca_recover_range(ms->pmsa_iip)) {
-               if (r13 != sos->prev_IA64_KR_CURRENT) {
-                       msg = "inconsistent previous current and r13";
-                       goto no_mod;
-               }
                if ((r12 - r13) >= KERNEL_STACK_SIZE) {
                        msg = "inconsistent r12 and r13";
                        goto no_mod;
@@ -1187,6 +1190,13 @@ all_in:
  *     further MCA logging is enabled by clearing logs.
  *     Monarch also has the duty of sending wakeup-IPIs to pull the
  *     slave processors out of rendezvous spinloop.
+ *
+ *     If multiple processors call into OS_MCA, the first will become
+ *     the monarch.  Subsequent cpus will be recorded in the mca_cpu
+ *     bitmask.  After the first monarch has processed its MCA, it
+ *     will wake up the next cpu in the mca_cpu bitmask and then go
+ *     into the rendezvous loop.  When all processors have serviced
+ *     their MCA, the last monarch frees up the rest of the processors.
  */
 void
 ia64_mca_handler(struct pt_regs *regs, struct switch_stack *sw,
@@ -1196,16 +1206,32 @@ ia64_mca_handler(struct pt_regs *regs, struct switch_stack *sw,
        struct task_struct *previous_current;
        struct ia64_mca_notify_die nd =
                { .sos = sos, .monarch_cpu = &monarch_cpu };
+       static atomic_t mca_count;
+       static cpumask_t mca_cpu;
 
+       if (atomic_add_return(1, &mca_count) == 1) {
+               monarch_cpu = cpu;
+               sos->monarch = 1;
+       } else {
+               cpu_set(cpu, mca_cpu);
+               sos->monarch = 0;
+       }
        mprintk(KERN_INFO "Entered OS MCA handler. PSP=%lx cpu=%d "
                "monarch=%ld\n", sos->proc_state_param, cpu, sos->monarch);
 
        previous_current = ia64_mca_modify_original_stack(regs, sw, sos, "MCA");
-       monarch_cpu = cpu;
+
        if (notify_die(DIE_MCA_MONARCH_ENTER, "MCA", regs, (long)&nd, 0, 0)
                        == NOTIFY_STOP)
                ia64_mca_spin(__FUNCTION__);
-       ia64_wait_for_slaves(cpu, "MCA");
+       if (sos->monarch) {
+               ia64_wait_for_slaves(cpu, "MCA");
+       } else {
+               ia64_mc_info.imi_rendez_checkin[cpu] = IA64_MCA_RENDEZ_CHECKIN_CONCURRENT_MCA;
+               while (cpu_isset(cpu, mca_cpu))
+                       cpu_relax();    /* spin until monarch wakes us */
+               ia64_mc_info.imi_rendez_checkin[cpu] = IA64_MCA_RENDEZ_CHECKIN_NOTDONE;
+        }
 
        /* Wakeup all the processors which are spinning in the rendezvous loop.
         * They will leave SAL, then spin in the OS with interrupts disabled
@@ -1244,6 +1270,26 @@ ia64_mca_handler(struct pt_regs *regs, struct switch_stack *sw,
                        == NOTIFY_STOP)
                ia64_mca_spin(__FUNCTION__);
 
+
+       if (atomic_dec_return(&mca_count) > 0) {
+               int i;
+
+               /* wake up the next monarch cpu,
+                * and put this cpu in the rendez loop.
+                */
+               ia64_mc_info.imi_rendez_checkin[cpu] = IA64_MCA_RENDEZ_CHECKIN_CONCURRENT_MCA;
+               for_each_online_cpu(i) {
+                       if (cpu_isset(i, mca_cpu)) {
+                               monarch_cpu = i;
+                               cpu_clear(i, mca_cpu);  /* wake next cpu */
+                               while (monarch_cpu != -1)
+                                       cpu_relax();    /* spin until last cpu leaves */
+                               ia64_mc_info.imi_rendez_checkin[cpu] = IA64_MCA_RENDEZ_CHECKIN_NOTDONE;
+                               set_curr_task(cpu, previous_current);
+                               return;
+                       }
+               }
+       }
        set_curr_task(cpu, previous_current);
        monarch_cpu = -1;
 }