BCQ touch-ups (XCC)
[akaros.git] / kern / src / atomic.c
index 9a49bfc..10d7e25 100644 (file)
@@ -12,6 +12,8 @@
 #include <assert.h>
 #include <hashtable.h>
 #include <smp.h>
+#include <kmalloc.h>
+#include <kdebug.h>
 
 static void increase_lock_depth(uint32_t coreid)
 {
@@ -23,40 +25,101 @@ static void decrease_lock_depth(uint32_t coreid)
        per_cpu_info[coreid].lock_depth--;
 }
 
-#ifdef __CONFIG_SPINLOCK_DEBUG__
+#ifdef CONFIG_SPINLOCK_DEBUG
+
+/* Put locks you want to ignore here. */
+static uintptr_t blacklist_locks[] = {
+       //0xffffffffc03bd000,
+};
+
+/* Could do this on the output side, though noisly locks will crowd us out */
+static bool can_trace(spinlock_t *lock)
+{
+       for (int i = 0; i < ARRAY_SIZE(blacklist_locks); i++) {
+               if (blacklist_locks[i] == (uintptr_t)lock)
+                       return FALSE;
+       }
+       return TRUE;
+}
+
+/* spinlock and trylock call this after locking */
+static void post_lock(spinlock_t *lock, uint32_t coreid)
+{
+       struct per_cpu_info *pcpui = &per_cpu_info[coreid];
+       if ((pcpui->__lock_checking_enabled == 1) && can_trace(lock))
+               pcpui_trace_locks(pcpui, lock);
+       lock->call_site = get_caller_pc();
+       lock->calling_core = coreid;
+       /* TODO consider merging this with __ctx_depth (unused field) */
+       increase_lock_depth(lock->calling_core);
+}
+
 void spin_lock(spinlock_t *lock)
 {
-       uint32_t coreid = core_id();
+       uint32_t coreid = core_id_early();
        struct per_cpu_info *pcpui = &per_cpu_info[coreid];
-       /* TODO: don't print directly.  If we have a lock on the print path that
-        * fails, we'll recurse and/or deadlock */
+       /* Short circuit our lock checking, so we can print or do other things to
+        * announce the failure that require locks.  Also avoids anything else
+        * requiring pcpui initialization. */
+       if (pcpui->__lock_checking_enabled != 1)
+               goto lock;
        if (lock->irq_okay) {
                if (!can_spinwait_irq(pcpui)) {
+                       pcpui->__lock_checking_enabled--;
                        print_kctx_depths("IRQOK");
-                       panic("Lock %08p tried to spin when it shouldn't\n", lock);
+                       panic("Lock %p tried to spin when it shouldn't\n", lock);
+                       pcpui->__lock_checking_enabled++;
                }
        } else {
                if (!can_spinwait_noirq(pcpui)) {
+                       pcpui->__lock_checking_enabled--;
                        print_kctx_depths("NOIRQ");
-                       panic("Lock %08p tried to spin when it shouldn't\n", lock);
+                       panic("Lock %p tried to spin when it shouldn't\n", lock);
+                       pcpui->__lock_checking_enabled++;
                }
        }
-       __spin_lock(lock);
-       lock->call_site = get_caller_pc();
-       lock->calling_core = coreid;
-       /* TODO consider merging this with __ctx_depth (unused field) */
-       increase_lock_depth(lock->calling_core);
+lock:
        __spin_lock(lock);
        /* Memory barriers are handled by the particular arches */
+       post_lock(lock, coreid);
+}
+
+/* Trylock doesn't check for irq/noirq, in case we want to try and lock a
+ * non-irqsave lock from irq context. */
+bool spin_trylock(spinlock_t *lock)
+{
+       uint32_t coreid = core_id_early();
+       bool ret = __spin_trylock(lock);
+       if (ret)
+               post_lock(lock, coreid);
+       return ret;
 }
 
 void spin_unlock(spinlock_t *lock)
 {
        decrease_lock_depth(lock->calling_core);
        /* Memory barriers are handled by the particular arches */
+       assert(spin_locked(lock));
        __spin_unlock(lock);
 }
-#endif /* __CONFIG_SPINLOCK_DEBUG__ */
+
+void spinlock_debug(spinlock_t *lock)
+{
+       uintptr_t pc = lock->call_site;
+       char *func_name;
+
+       if (!pc) {
+               printk("Lock %p: never locked\n", lock);
+               return;
+       }
+       func_name = get_fn_name(pc);
+       printk("Lock %p: currently %slocked.  Last locked at [<%p>] in %s on "
+              "core %d\n", lock, spin_locked(lock) ? "" : "un", pc, func_name,
+              lock->calling_core);
+       kfree(func_name);
+}
+
+#endif /* CONFIG_SPINLOCK_DEBUG */
 
 /* Inits a hashlock. */
 void hashlock_init(struct hashlock *hl, unsigned int nr_entries)