git: 30253da1a982 - main - atomic: Add some type checking to plain atomic_load/store helpers

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=30253da1a982285b0ae6e89e22369a61cf9266eb

commit 30253da1a982285b0ae6e89e22369a61cf9266eb
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2022-07-25 21:48:46 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2022-07-25 21:52:58 +0000

    atomic: Add some type checking to plain atomic_load/store helpers
    
    Reviewed by:    rpokala, mjg, imp, kib
    MFC after:      2 weeks
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D35828
---
 sys/sys/atomic_common.h | 88 ++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 66 insertions(+), 22 deletions(-)

diff --git a/sys/sys/atomic_common.h b/sys/sys/atomic_common.h
index e3969b241a8c..a34198fda88a 100644
--- a/sys/sys/atomic_common.h
+++ b/sys/sys/atomic_common.h
@@ -36,39 +36,83 @@
 #error do not include this header, use machine/atomic.h
 #endif
 
-#define	atomic_load_char(p)	(*(volatile u_char *)(p))
-#define	atomic_load_short(p)	(*(volatile u_short *)(p))
-#define	atomic_load_int(p)	(*(volatile u_int *)(p))
-#define	atomic_load_long(p)	(*(volatile u_long *)(p))
-#define	atomic_load_ptr(p)	(*(volatile __typeof(*p) *)(p))
-#define	atomic_load_8(p)	(*(volatile uint8_t *)(p))
-#define	atomic_load_16(p)	(*(volatile uint16_t *)(p))
-#define	atomic_load_32(p)	(*(volatile uint32_t *)(p))
-#ifdef _LP64
-#define	atomic_load_64(p)	(*(volatile uint64_t *)(p))
-#endif
+#include <sys/cdefs.h>
+#include <sys/types.h>
 
-#define	atomic_store_char(p, v)		\
+#define	__atomic_load_char_relaxed(p)	(*(volatile u_char *)(p))
+#define	__atomic_load_short_relaxed(p)	(*(volatile u_short *)(p))
+#define	__atomic_load_int_relaxed(p)	(*(volatile u_int *)(p))
+#define	__atomic_load_long_relaxed(p)	(*(volatile u_long *)(p))
+#define	__atomic_load_8_relaxed(p)	(*(volatile uint8_t *)(p))
+#define	__atomic_load_16_relaxed(p)	(*(volatile uint16_t *)(p))
+#define	__atomic_load_32_relaxed(p)	(*(volatile uint32_t *)(p))
+#define	__atomic_load_64_relaxed(p)	(*(volatile uint64_t *)(p))
+
+#define	__atomic_store_char_relaxed(p, v)	\
     (*(volatile u_char *)(p) = (u_char)(v))
-#define	atomic_store_short(p, v)		\
+#define	__atomic_store_short_relaxed(p, v)	\
     (*(volatile u_short *)(p) = (u_short)(v))
-#define	atomic_store_int(p, v)		\
+#define	__atomic_store_int_relaxed(p, v)	\
     (*(volatile u_int *)(p) = (u_int)(v))
-#define	atomic_store_long(p, v)		\
+#define	__atomic_store_long_relaxed(p, v)	\
     (*(volatile u_long *)(p) = (u_long)(v))
-#define	atomic_store_ptr(p, v)		\
-    (*(volatile __typeof(*p) *)(p) = (v))
-#define	atomic_store_8(p, v)		\
+#define	__atomic_store_8_relaxed(p, v)		\
     (*(volatile uint8_t *)(p) = (uint8_t)(v))
-#define	atomic_store_16(p, v)		\
+#define	__atomic_store_16_relaxed(p, v)		\
     (*(volatile uint16_t *)(p) = (uint16_t)(v))
-#define	atomic_store_32(p, v)		\
+#define	__atomic_store_32_relaxed(p, v)		\
     (*(volatile uint32_t *)(p) = (uint32_t)(v))
-#ifdef _LP64
-#define	atomic_store_64(p, v)		\
+#define	__atomic_store_64_relaxed(p, v)		\
     (*(volatile uint64_t *)(p) = (uint64_t)(v))
+
+/*
+ * When _Generic is available, try to provide some type checking.
+ */
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \
+    __has_extension(c_generic_selections)
+#define	__atomic_load_generic(p, t, ut, n)	\
+	_Generic(*(p),				\
+	    t: __atomic_load_ ## n ## _relaxed(p), ut: __atomic_load_ ## n ## _relaxed(p))
+#define	__atomic_store_generic(p, v, t, ut, n)	\
+	_Generic(*(p),				\
+	    t: __atomic_store_ ## n ## _relaxed(p, v), ut: __atomic_store_ ## n ## _relaxed(p, v))
+#else
+#define	__atomic_load_generic(p, t, ut, n)	__atomic_load_ ## n ## _relaxed(p)
+#define	__atomic_store_generic(p, v, t, ut, n)	__atomic_store_ ## n ## _relaxed(p, v)
 #endif
 
+#define	atomic_load_char(p)	__atomic_load_generic(p, char, u_char, char)
+#define	atomic_load_short(p)	__atomic_load_generic(p, short, u_short, short)
+#define	atomic_load_int(p)	__atomic_load_generic(p, int, u_int, int)
+#define	atomic_load_long(p)	__atomic_load_generic(p, long, u_long, long)
+#define	atomic_load_8(p)	__atomic_load_generic(p, int8_t, uint8_t, 8)
+#define	atomic_load_16(p)	__atomic_load_generic(p, int16_t, uint16_t, 16)
+#define	atomic_load_32(p)	__atomic_load_generic(p, int32_t, uint32_t, 32)
+#ifdef __LP64__
+#define	atomic_load_64(p)	__atomic_load_generic(p, int64_t, uint64_t, 64)
+#endif
+#define	atomic_store_char(p, v)			\
+	__atomic_store_generic(p, v, char, u_char, char)
+#define	atomic_store_short(p, v)		\
+	__atomic_store_generic(p, v, short, u_short, short)
+#define	atomic_store_int(p, v)			\
+	__atomic_store_generic(p, v, int, u_int, int)
+#define	atomic_store_long(p, v)			\
+	__atomic_store_generic(p, v, long, u_long, long)
+#define	atomic_store_8(p, v)			\
+	__atomic_store_generic(p, v, int8_t, uint8_t, 8)
+#define	atomic_store_16(p, v)			\
+	__atomic_store_generic(p, v, int16_t, uint16_t, 16)
+#define	atomic_store_32(p, v)			\
+	__atomic_store_generic(p, v, int32_t, uint32_t, 32)
+#ifdef __LP64__
+#define	atomic_store_64(p, v)			\
+	__atomic_store_generic(p, v, int64_t, uint64_t, 64)
+#endif
+
+#define	atomic_load_ptr(p)	(*(volatile __typeof(*p) *)(p))
+#define	atomic_store_ptr(p, v)	(*(volatile __typeof(*p) *)(p) = (v))
+
 /*
  * Currently all architectures provide acquire and release fences on their own,
  * but they don't provide consume. Kludge below allows relevant code to stop