Pull trivial into release branch

[sfrench/cifs-2.6.git] / arch / mips / kernel / gdb-stub.c

diff --git a/arch/mips/kernel/gdb-stub.c b/arch/mips/kernel/gdb-stub.c
index d4f88e0af24c04fcb51271d50414242418f96ded..6ecbdc1fefd13acdd930998a07c19e633aaab354 100644 (file)
--- a/arch/mips/kernel/gdb-stub.c
+++ b/arch/mips/kernel/gdb-stub.c
@@ -140,6 +140,7 @@
 #include <asm/system.h>
 #include <asm/gdb-stub.h>
 #include <asm/inst.h>
+#include <asm/smp.h>
 
 /*
  * external low-level support routines
@@ -669,6 +670,64 @@ static void kgdb_wait(void *arg)
        local_irq_restore(flags);
 }
 
+/*
+ * GDB stub needs to call kgdb_wait on all processor with interrupts
+ * disabled, so it uses it's own special variant.
+ */
+static int kgdb_smp_call_kgdb_wait(void)
+{
+#ifdef CONFIG_SMP
+       struct call_data_struct data;
+       int i, cpus = num_online_cpus() - 1;
+       int cpu = smp_processor_id();
+
+       /*
+        * Can die spectacularly if this CPU isn't yet marked online
+        */
+       BUG_ON(!cpu_online(cpu));
+
+       if (!cpus)
+               return 0;
+
+       if (spin_is_locked(&smp_call_lock)) {
+               /*
+                * Some other processor is trying to make us do something
+                * but we're not going to respond... give up
+                */
+               return -1;
+               }
+
+       /*
+        * We will continue here, accepting the fact that
+        * the kernel may deadlock if another CPU attempts
+        * to call smp_call_function now...
+        */
+
+       data.func = kgdb_wait;
+       data.info = NULL;
+       atomic_set(&data.started, 0);
+       data.wait = 0;
+
+       spin_lock(&smp_call_lock);
+       call_data = &data;
+       mb();
+
+       /* Send a message to all other CPUs and wait for them to respond */
+       for (i = 0; i < NR_CPUS; i++)
+               if (cpu_online(i) && i != cpu)
+                       core_send_ipi(i, SMP_CALL_FUNCTION);
+
+       /* Wait for response */
+       /* FIXME: lock-up detection, backtrace on lock-up */
+       while (atomic_read(&data.started) != cpus)
+               barrier();
+
+       call_data = NULL;
+       spin_unlock(&smp_call_lock);
+#endif
+
+       return 0;
+}
 
 /*
  * This function does all command processing for interfacing to gdb.  It
@@ -718,7 +777,7 @@ void handle_exception (struct gdb_regs *regs)
        /*
         * force other cpus to enter kgdb
         */
-       smp_call_function(kgdb_wait, NULL, 0, 0);
+       kgdb_smp_call_kgdb_wait();
 
        /*
         * If we're in breakpoint() increment the PC