From bf9ee5ca114921718da280de46046dbc43722641 Mon Sep 17 00:00:00 2001
From: Andrew Waterman <waterman@cs.berkeley.edu>
Date: Tue, 23 Feb 2016 12:44:42 -0800
Subject: simplify pk atomics and add atomic_or

---
 pk/atomic.h | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/pk/atomic.h b/pk/atomic.h
index 37f43e5..e4610de 100644
--- a/pk/atomic.h
+++ b/pk/atomic.h
@@ -13,27 +13,25 @@
 typedef struct { int lock; } spinlock_t;
 #define SPINLOCK_INIT {0}
 
-#define mb() __sync_synchronize()
+#define mb() asm volatile ("fence" ::: "memory")
 #define atomic_set(ptr, val) (*(volatile typeof(*(ptr)) *)(ptr) = val)
 #define atomic_read(ptr) (*(volatile typeof(*(ptr)) *)(ptr))
 
 #ifdef __riscv_atomic
 # define atomic_add(ptr, inc) __sync_fetch_and_add(ptr, inc)
+# define atomic_or(ptr, inc) __sync_fetch_and_or(ptr, inc)
 # define atomic_swap(ptr, swp) __sync_lock_test_and_set(ptr, swp)
 # define atomic_cas(ptr, cmp, swp) __sync_val_compare_and_swap(ptr, cmp, swp)
 #else
-# define atomic_add(ptr, inc) ({ \
+# define atomic_binop(ptr, inc, op) ({ \
   long flags = disable_irqsave(); \
-  typeof(*(ptr)) res = *(volatile typeof(*(ptr)) *)(ptr); \
-  *(volatile typeof(ptr))(ptr) = res + (inc); \
-  enable_irqrestore(flags); \
-  res; })
-# define atomic_swap(ptr, swp) ({ \
-  long flags = disable_irqsave(); \
-  typeof(*(ptr)) res = *(volatile typeof(*(ptr)) *)(ptr); \
-  *(volatile typeof(ptr))(ptr) = (swp); \
+  typeof(*(ptr)) res = atomic_read(ptr); \
+  atomic_set(ptr, op); \
   enable_irqrestore(flags); \
   res; })
+# define atomic_add(ptr, inc) atomic_binop(ptr, inc, res + (inc))
+# define atomic_or(ptr, inc) atomic_binop(ptr, inc, res | (inc))
+# define atomic_swap(ptr, inc) atomic_binop(ptr, inc, (inc))
 # define atomic_cas(ptr, cmp, swp) ({ \
   long flags = disable_irqsave(); \
   typeof(*(ptr)) res = *(volatile typeof(*(ptr)) *)(ptr); \
-- 
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