[SPARC64]: Fix endless loop in cheetah_xcall_deliver().

We need to mask out the proper bits when testing the dispatch status
register else we can see unrelated NACK bits from previous cross call
sends.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 6 deletions

diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index 894b506f9636..c39944927f1a 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -476,7 +476,7 @@ static inline void spitfire_xcall_deliver(u64 data0, u64 data1, u64 data2, cpuma
  */
 static void cheetah_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mask)
 {
-        u64 pstate, ver;
+        u64 pstate, ver, busy_mask;
         int nack_busy_id, is_jbus, need_more;
 
         if (cpus_empty(mask))
@@ -508,14 +508,20 @@ retry:
                                "i" (ASI_INTR_W));
 
         nack_busy_id = 0;
+        busy_mask = 0;
         {
                 int i;
 
                 for_each_cpu_mask(i, mask) {
                         u64 target = (i << 14) | 0x70;
 
-                        if (!is_jbus)
+                        if (is_jbus) {
+                                busy_mask |= (0x1UL << (i * 2));
+                        } else {
                                 target |= (nack_busy_id << 24);
+                                busy_mask |= (0x1UL <<
+                                              (nack_busy_id * 2));
+                        }
                         __asm__ __volatile__(
                                 "stxa   %%g0, [%0] %1\n\t"
                                 "membar #Sync\n\t"
@@ -531,15 +537,16 @@ retry:
 
         /* Now, poll for completion. */
         {
-                u64 dispatch_stat;
+                u64 dispatch_stat, nack_mask;
                 long stuck;
 
                 stuck = 100000 * nack_busy_id;
+                nack_mask = busy_mask << 1;
                 do {
                         __asm__ __volatile__("ldxa      [%%g0] %1, %0"
                                              : "=r" (dispatch_stat)
                                              : "i" (ASI_INTR_DISPATCH_STAT));
-                        if (dispatch_stat == 0UL) {
+                        if (!(dispatch_stat & (busy_mask | nack_mask))) {
                                 __asm__ __volatile__("wrpr %0, 0x0, %%pstate"
                                                      : : "r" (pstate));
                                 if (unlikely(need_more)) {
@@ -556,12 +563,12 @@ retry:
                         }
                         if (!--stuck)
                                 break;
-                } while (dispatch_stat & 0x5555555555555555UL);
+                } while (dispatch_stat & busy_mask);
 
                 __asm__ __volatile__("wrpr %0, 0x0, %%pstate"
                                      : : "r" (pstate));
 
-                if ((dispatch_stat & ~(0x5555555555555555UL)) == 0) {
+                if (dispatch_stat & busy_mask) {
                         /* Busy bits will not clear, continue instead
                          * of freezing up on this cpu.
                          */