lockdep: Correctly annotate hardirq context in irq_exit()

[platform/adaptation/renesas_rcar/renesas_kernel.git] / kernel / softirq.c

diff --git a/kernel/softirq.c b/kernel/softirq.c
index dacd0ab..eb0acf4 100644 (file)
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -99,13 +99,13 @@ static void __local_bh_disable(unsigned long ip, unsigned int cnt)
 
        raw_local_irq_save(flags);
        /*
-        * The preempt tracer hooks into add_preempt_count and will break
+        * The preempt tracer hooks into preempt_count_add and will break
         * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
         * is set and before current->softirq_enabled is cleared.
         * We must manually increment preempt_count here and manually
         * call the trace_preempt_off later.
         */
-       preempt_count() += cnt;
+       __preempt_count_add(cnt);
        /*
         * Were softirqs turned off above:
         */
@@ -119,7 +119,7 @@ static void __local_bh_disable(unsigned long ip, unsigned int cnt)
 #else /* !CONFIG_TRACE_IRQFLAGS */
 static inline void __local_bh_disable(unsigned long ip, unsigned int cnt)
 {
-       add_preempt_count(cnt);
+       preempt_count_add(cnt);
        barrier();
 }
 #endif /* CONFIG_TRACE_IRQFLAGS */
@@ -137,7 +137,7 @@ static void __local_bh_enable(unsigned int cnt)
 
        if (softirq_count() == cnt)
                trace_softirqs_on(_RET_IP_);
-       sub_preempt_count(cnt);
+       preempt_count_sub(cnt);
 }
 
 /*
@@ -168,7 +168,7 @@ static inline void _local_bh_enable_ip(unsigned long ip)
         * Keep preemption disabled until we are done with
         * softirq processing:
         */
-       sub_preempt_count(SOFTIRQ_DISABLE_OFFSET - 1);
+       preempt_count_sub(SOFTIRQ_DISABLE_OFFSET - 1);
 
        if (unlikely(!in_interrupt() && local_softirq_pending())) {
                /*
@@ -178,7 +178,7 @@ static inline void _local_bh_enable_ip(unsigned long ip)
                do_softirq();
        }
 
-       dec_preempt_count();
+       preempt_count_dec();
 #ifdef CONFIG_TRACE_IRQFLAGS
        local_irq_enable();
 #endif
@@ -213,14 +213,52 @@ EXPORT_SYMBOL(local_bh_enable_ip);
 #define MAX_SOFTIRQ_TIME  msecs_to_jiffies(2)
 #define MAX_SOFTIRQ_RESTART 10
 
+#ifdef CONFIG_TRACE_IRQFLAGS
+/*
+ * Convoluted means of passing __do_softirq() a message through the various
+ * architecture execute_on_stack() bits.
+ *
+ * When we run softirqs from irq_exit() and thus on the hardirq stack we need
+ * to keep the lockdep irq context tracking as tight as possible in order to
+ * not miss-qualify lock contexts and miss possible deadlocks.
+ */
+static DEFINE_PER_CPU(int, softirq_from_hardirq);
+
+static inline void lockdep_softirq_from_hardirq(void)
+{
+       this_cpu_write(softirq_from_hardirq, 1);
+}
+
+static inline void lockdep_softirq_start(void)
+{
+       if (this_cpu_read(softirq_from_hardirq))
+               trace_hardirq_exit();
+       lockdep_softirq_enter();
+}
+
+static inline void lockdep_softirq_end(void)
+{
+       lockdep_softirq_exit();
+       if (this_cpu_read(softirq_from_hardirq)) {
+               this_cpu_write(softirq_from_hardirq, 0);
+               trace_hardirq_enter();
+       }
+}
+
+#else
+static inline void lockdep_softirq_from_hardirq(void) { }
+static inline void lockdep_softirq_start(void) { }
+static inline void lockdep_softirq_end(void) { }
+#endif
+
 asmlinkage void __do_softirq(void)
 {
-       struct softirq_action *h;
-       __u32 pending;
        unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
-       int cpu;
        unsigned long old_flags = current->flags;
        int max_restart = MAX_SOFTIRQ_RESTART;
+       struct softirq_action *h;
+       __u32 pending;
+       int cpu;
 
        /*
         * Mask out PF_MEMALLOC s current task context is borrowed for the
@@ -233,7 +271,7 @@ asmlinkage void __do_softirq(void)
        account_irq_enter_time(current);
 
        __local_bh_disable(_RET_IP_, SOFTIRQ_OFFSET);
-       lockdep_softirq_enter();
+       lockdep_softirq_start();
 
        cpu = smp_processor_id();
 restart:
@@ -260,7 +298,7 @@ restart:
                                       " exited with %08x?\n", vec_nr,
                                       softirq_to_name[vec_nr], h->action,
                                       prev_count, preempt_count());
-                               preempt_count() = prev_count;
+                               preempt_count_set(prev_count);
                        }
 
                        rcu_bh_qs(cpu);
@@ -280,16 +318,13 @@ restart:
                wakeup_softirqd();
        }
 
-       lockdep_softirq_exit();
-
+       lockdep_softirq_end();
        account_irq_exit_time(current);
        __local_bh_enable(SOFTIRQ_OFFSET);
        WARN_ON_ONCE(in_interrupt());
        tsk_restore_flags(current, old_flags, PF_MEMALLOC);
 }
 
-
-
 asmlinkage void do_softirq(void)
 {
        __u32 pending;
@@ -332,6 +367,7 @@ void irq_enter(void)
 static inline void invoke_softirq(void)
 {
        if (!force_irqthreads) {
+               lockdep_softirq_from_hardirq();
 #ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
                /*
                 * We can safely execute softirq on the current stack if
@@ -377,13 +413,13 @@ void irq_exit(void)
 #endif
 
        account_irq_exit_time(current);
-       trace_hardirq_exit();
-       sub_preempt_count(HARDIRQ_OFFSET);
+       preempt_count_sub(HARDIRQ_OFFSET);
        if (!in_interrupt() && local_softirq_pending())
                invoke_softirq();
 
        tick_irq_exit();
        rcu_irq_exit();
+       trace_hardirq_exit(); /* must be last! */
 }
 
 /*