tcg: Add atomic helpers

Add all of cmpxchg, op_fetch, fetch_op, and xchg.
Handle both endian-ness, and sizes up to 8.
Handle expanding non-atomically, when emulating in serial.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>

1 files changed, 177 insertions, 0 deletions

diff --git a/atomic_template.h b/atomic_template.h
new file mode 100644
index 0000000000..cf83725403
--- /dev/null
+++ b/atomic_template.h
@@ -0,0 +1,177 @@
+/*
+ * Atomic helper templates
+ * Included from tcg-runtime.c and cputlb.c.
+ *
+ * Copyright (c) 2016 Red Hat, Inc
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#if DATA_SIZE == 8
+# define SUFFIX     q
+# define DATA_TYPE  uint64_t
+# define BSWAP      bswap64
+#elif DATA_SIZE == 4
+# define SUFFIX     l
+# define DATA_TYPE  uint32_t
+# define BSWAP      bswap32
+#elif DATA_SIZE == 2
+# define SUFFIX     w
+# define DATA_TYPE  uint16_t
+# define BSWAP      bswap16
+#elif DATA_SIZE == 1
+# define SUFFIX     b
+# define DATA_TYPE  uint8_t
+# define BSWAP
+#else
+# error unsupported data size
+#endif
+
+#if DATA_SIZE >= 4
+# define ABI_TYPE  DATA_TYPE
+#else
+# define ABI_TYPE  uint32_t
+#endif
+
+/* Define host-endian atomic operations.  Note that END is used within
+   the ATOMIC_NAME macro, and redefined below.  */
+#if DATA_SIZE == 1
+# define END
+#elif defined(HOST_WORDS_BIGENDIAN)
+# define END  _be
+#else
+# define END  _le
+#endif
+
+ABI_TYPE ATOMIC_NAME(cmpxchg)(CPUArchState *env, target_ulong addr,
+                              ABI_TYPE cmpv, ABI_TYPE newv EXTRA_ARGS)
+{
+    DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;
+    return atomic_cmpxchg__nocheck(haddr, cmpv, newv);
+}
+
+ABI_TYPE ATOMIC_NAME(xchg)(CPUArchState *env, target_ulong addr,
+                           ABI_TYPE val EXTRA_ARGS)
+{
+    DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;
+    return atomic_xchg__nocheck(haddr, val);
+}
+
+#define GEN_ATOMIC_HELPER(X)                                        \
+ABI_TYPE ATOMIC_NAME(X)(CPUArchState *env, target_ulong addr,       \
+                 ABI_TYPE val EXTRA_ARGS)                           \
+{                                                                   \
+    DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;                           \
+    return atomic_##X(haddr, val);                                  \
+}                                                                   \
+
+GEN_ATOMIC_HELPER(fetch_add)
+GEN_ATOMIC_HELPER(fetch_and)
+GEN_ATOMIC_HELPER(fetch_or)
+GEN_ATOMIC_HELPER(fetch_xor)
+GEN_ATOMIC_HELPER(add_fetch)
+GEN_ATOMIC_HELPER(and_fetch)
+GEN_ATOMIC_HELPER(or_fetch)
+GEN_ATOMIC_HELPER(xor_fetch)
+
+#undef GEN_ATOMIC_HELPER
+#undef END
+
+#if DATA_SIZE > 1
+
+/* Define reverse-host-endian atomic operations.  Note that END is used
+   within the ATOMIC_NAME macro.  */
+#ifdef HOST_WORDS_BIGENDIAN
+# define END  _le
+#else
+# define END  _be
+#endif
+
+ABI_TYPE ATOMIC_NAME(cmpxchg)(CPUArchState *env, target_ulong addr,
+                              ABI_TYPE cmpv, ABI_TYPE newv EXTRA_ARGS)
+{
+    DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;
+    return BSWAP(atomic_cmpxchg__nocheck(haddr, BSWAP(cmpv), BSWAP(newv)));
+}
+
+ABI_TYPE ATOMIC_NAME(xchg)(CPUArchState *env, target_ulong addr,
+                           ABI_TYPE val EXTRA_ARGS)
+{
+    DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;
+    return BSWAP(atomic_xchg__nocheck(haddr, BSWAP(val)));
+}
+
+#define GEN_ATOMIC_HELPER(X)                                        \
+ABI_TYPE ATOMIC_NAME(X)(CPUArchState *env, target_ulong addr,       \
+                 ABI_TYPE val EXTRA_ARGS)                           \
+{                                                                   \
+    DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;                           \
+    return BSWAP(atomic_##X(haddr, BSWAP(val)));                    \
+}
+
+GEN_ATOMIC_HELPER(fetch_and)
+GEN_ATOMIC_HELPER(fetch_or)
+GEN_ATOMIC_HELPER(fetch_xor)
+GEN_ATOMIC_HELPER(and_fetch)
+GEN_ATOMIC_HELPER(or_fetch)
+GEN_ATOMIC_HELPER(xor_fetch)
+
+#undef GEN_ATOMIC_HELPER
+
+/* Note that for addition, we need to use a separate cmpxchg loop instead
+   of bswaps for the reverse-host-endian helpers.  */
+ABI_TYPE ATOMIC_NAME(fetch_add)(CPUArchState *env, target_ulong addr,
+                         ABI_TYPE val EXTRA_ARGS)
+{
+    DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;
+    DATA_TYPE ldo, ldn, ret, sto;
+
+    ldo = atomic_read__nocheck(haddr);
+    while (1) {
+        ret = BSWAP(ldo);
+        sto = BSWAP(ret + val);
+        ldn = atomic_cmpxchg__nocheck(haddr, ldo, sto);
+        if (ldn == ldo) {
+            return ret;
+        }
+        ldo = ldn;
+    }
+}
+
+ABI_TYPE ATOMIC_NAME(add_fetch)(CPUArchState *env, target_ulong addr,
+                         ABI_TYPE val EXTRA_ARGS)
+{
+    DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;
+    DATA_TYPE ldo, ldn, ret, sto;
+
+    ldo = atomic_read__nocheck(haddr);
+    while (1) {
+        ret = BSWAP(ldo) + val;
+        sto = BSWAP(ret);
+        ldn = atomic_cmpxchg__nocheck(haddr, ldo, sto);
+        if (ldn == ldo) {
+            return ret;
+        }
+        ldo = ldn;
+    }
+}
+
+#undef END
+#endif /* DATA_SIZE > 1 */
+
+#undef BSWAP
+#undef ABI_TYPE
+#undef DATA_TYPE
+#undef SUFFIX
+#undef DATA_SIZE