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Diffstat (limited to 'arch/arc/include/asm/cmpxchg.h')
-rw-r--r--arch/arc/include/asm/cmpxchg.h76
1 files changed, 68 insertions, 8 deletions
diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h
index a444be67cd53..d819de1c5d10 100644
--- a/arch/arc/include/asm/cmpxchg.h
+++ b/arch/arc/include/asm/cmpxchg.h
@@ -44,7 +44,7 @@ __cmpxchg(volatile void *ptr, unsigned long expected, unsigned long new)
return prev;
}
-#else
+#elif !defined(CONFIG_ARC_PLAT_EZNPS)
static inline unsigned long
__cmpxchg(volatile void *ptr, unsigned long expected, unsigned long new)
@@ -64,23 +64,48 @@ __cmpxchg(volatile void *ptr, unsigned long expected, unsigned long new)
return prev;
}
+#else /* CONFIG_ARC_PLAT_EZNPS */
+
+static inline unsigned long
+__cmpxchg(volatile void *ptr, unsigned long expected, unsigned long new)
+{
+ /*
+ * Explicit full memory barrier needed before/after
+ */
+ smp_mb();
+
+ write_aux_reg(CTOP_AUX_GPA1, expected);
+
+ __asm__ __volatile__(
+ " mov r2, %0\n"
+ " mov r3, %1\n"
+ " .word %2\n"
+ " mov %0, r2"
+ : "+r"(new)
+ : "r"(ptr), "i"(CTOP_INST_EXC_DI_R2_R2_R3)
+ : "r2", "r3", "memory");
+
+ smp_mb();
+
+ return new;
+}
+
#endif /* CONFIG_ARC_HAS_LLSC */
#define cmpxchg(ptr, o, n) ((typeof(*(ptr)))__cmpxchg((ptr), \
(unsigned long)(o), (unsigned long)(n)))
/*
- * Since not supported natively, ARC cmpxchg() uses atomic_ops_lock (UP/SMP)
- * just to gaurantee semantics.
- * atomic_cmpxchg() needs to use the same locks as it's other atomic siblings
- * which also happens to be atomic_ops_lock.
- *
- * Thus despite semantically being different, implementation of atomic_cmpxchg()
- * is same as cmpxchg().
+ * atomic_cmpxchg is same as cmpxchg
+ * LLSC: only different in data-type, semantics are exactly same
+ * !LLSC: cmpxchg() has to use an external lock atomic_ops_lock to guarantee
+ * semantics, and this lock also happens to be used by atomic_*()
*/
#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
+#ifndef CONFIG_ARC_PLAT_EZNPS
+
/*
* xchg (reg with memory) based on "Native atomic" EX insn
*/
@@ -143,6 +168,41 @@ static inline unsigned long __xchg(unsigned long val, volatile void *ptr,
#endif
+#else /* CONFIG_ARC_PLAT_EZNPS */
+
+static inline unsigned long __xchg(unsigned long val, volatile void *ptr,
+ int size)
+{
+ extern unsigned long __xchg_bad_pointer(void);
+
+ switch (size) {
+ case 4:
+ /*
+ * Explicit full memory barrier needed before/after
+ */
+ smp_mb();
+
+ __asm__ __volatile__(
+ " mov r2, %0\n"
+ " mov r3, %1\n"
+ " .word %2\n"
+ " mov %0, r2\n"
+ : "+r"(val)
+ : "r"(ptr), "i"(CTOP_INST_XEX_DI_R2_R2_R3)
+ : "r2", "r3", "memory");
+
+ smp_mb();
+
+ return val;
+ }
+ return __xchg_bad_pointer();
+}
+
+#define xchg(ptr, with) ((typeof(*(ptr)))__xchg((unsigned long)(with), (ptr), \
+ sizeof(*(ptr))))
+
+#endif /* CONFIG_ARC_PLAT_EZNPS */
+
/*
* "atomic" variant of xchg()
* REQ: It needs to follow the same serialization rules as other atomic_xxx()