[SPARC64]: Wrap SMP IPIs with irq_enter()/irq_exit().

Otherwise all sorts of bad things can happen, including
spurious softlockup reports.

Other platforms have this same bug, in one form or
another, just don't see the issue because they
don't sleep as long as sparc64 can in NOHZ.

Thanks to some brilliant debugging by Peter Zijlstra.

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

diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index 524b88920947d268233825aefec54b549d0ba21f..409dd71f2738c88f59ae367bdc93aceb2e83455a 100644 (file)
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -866,14 +866,21 @@ void smp_call_function_client(int irq, struct pt_regs *regs)
        void *info = call_data->info;
 
        clear_softint(1 << irq);
+
+       irq_enter();
+
+       if (!call_data->wait) {
+               /* let initiator proceed after getting data */
+               atomic_inc(&call_data->finished);
+       }
+
+       func(info);
+
+       irq_exit();
+
        if (call_data->wait) {
                /* let initiator proceed only after completion */
-               func(info);
                atomic_inc(&call_data->finished);
-       } else {
-               /* let initiator proceed after getting data */
-               atomic_inc(&call_data->finished);
-               func(info);
        }
 }
 
@@ -1032,7 +1039,9 @@ void smp_receive_signal(int cpu)
 
 void smp_receive_signal_client(int irq, struct pt_regs *regs)
 {
+       irq_enter();
        clear_softint(1 << irq);
+       irq_exit();
 }
 
 void smp_new_mmu_context_version_client(int irq, struct pt_regs *regs)
@@ -1040,6 +1049,8 @@ void smp_new_mmu_context_version_client(int irq, struct pt_regs *regs)
        struct mm_struct *mm;
        unsigned long flags;
 
+       irq_enter();
+
        clear_softint(1 << irq);
 
        /* See if we need to allocate a new TLB context because
@@ -1059,6 +1070,8 @@ void smp_new_mmu_context_version_client(int irq, struct pt_regs *regs)
        load_secondary_context(mm);
        __flush_tlb_mm(CTX_HWBITS(mm->context),
                       SECONDARY_CONTEXT);
+
+       irq_exit();
 }
 
 void smp_new_mmu_context_version(void)
@@ -1217,6 +1230,8 @@ void smp_penguin_jailcell(int irq, struct pt_regs *regs)
 {
        clear_softint(1 << irq);
 
+       irq_enter();
+
        preempt_disable();
 
        __asm__ __volatile__("flushw");
@@ -1229,6 +1244,8 @@ void smp_penguin_jailcell(int irq, struct pt_regs *regs)
        prom_world(0);
 
        preempt_enable();
+
+       irq_exit();
 }
 
 /* /proc/profile writes can call this, don't __init it please. */