[MIPS] MT: Improved multithreading support.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/gdb-stub.c b/arch/mips/kernel/gdb-stub.c
index d4f88e0..6ecbdc1 100644
--- 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 @@
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 @@
/*
* 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