Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa...

[linux-2.6-microblaze.git] / arch / mips / kernel / process.c

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 8d85046..9670e70 100644 (file)
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -29,6 +29,7 @@
 #include <linux/kallsyms.h>
 #include <linux/random.h>
 #include <linux/prctl.h>
+#include <linux/nmi.h>
 
 #include <asm/asm.h>
 #include <asm/bootinfo.h>
@@ -655,28 +656,42 @@ unsigned long arch_align_stack(unsigned long sp)
        return sp & ALMASK;
 }
 
-static void arch_dump_stack(void *info)
+static DEFINE_PER_CPU(call_single_data_t, backtrace_csd);
+static struct cpumask backtrace_csd_busy;
+
+static void handle_backtrace(void *info)
 {
-       struct pt_regs *regs;
+       nmi_cpu_backtrace(get_irq_regs());
+       cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy);
+}
 
-       regs = get_irq_regs();
+static void raise_backtrace(cpumask_t *mask)
+{
+       call_single_data_t *csd;
+       int cpu;
 
-       if (regs)
-               show_regs(regs);
+       for_each_cpu(cpu, mask) {
+               /*
+                * If we previously sent an IPI to the target CPU & it hasn't
+                * cleared its bit in the busy cpumask then it didn't handle
+                * our previous IPI & it's not safe for us to reuse the
+                * call_single_data_t.
+                */
+               if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) {
+                       pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n",
+                               cpu);
+                       continue;
+               }
 
-       dump_stack();
+               csd = &per_cpu(backtrace_csd, cpu);
+               csd->func = handle_backtrace;
+               smp_call_function_single_async(cpu, csd);
+       }
 }
 
 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
 {
-       long this_cpu = get_cpu();
-
-       if (cpumask_test_cpu(this_cpu, mask) && !exclude_self)
-               dump_stack();
-
-       smp_call_function_many(mask, arch_dump_stack, NULL, 1);
-
-       put_cpu();
+       nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace);
 }
 
 int mips_get_process_fp_mode(struct task_struct *task)