[PATCH v5 03/16] xen: Implement common byte{order,swap}.h

[Andrew Cooper <andrew.cooper3@citrix.com>]

From: Lin Liu <lin.liu@citrix.com>

The current swab??() infrastructure is unecesserily complicated, and can be
repated entirely with compiler builtins.

All supported compilers provide __BYTE_ORDER__ and __builtin_bswap??().

Nothing in Xen cares about the values of __{BIG,LITTLE}_ENDIAN; just that one
of them is defined.  Therefore, centralise their definitions in xen/config.h

Signed-off-by: Lin Liu <lin.liu@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Anthony PERARD <anthony.perard@vates.tech>
CC: Michal Orzel <michal.orzel@amd.com>
CC: Jan Beulich <jbeulich@suse.com>
CC: Julien Grall <julien@xen.org>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
CC: Bertrand Marquis <bertrand.marquis@arm.com>
CC: Shawn Anastasio <sanastasio@raptorengineering.com>
CC: Oleksii Kurochko <oleksii.kurochko@gmail.com>
CC: Daniel P. Smith <dpsmith@apertussolutions.com>
CC: Lin Liu <lin.liu@citrix.com>

v5:
 * Rebase substantially
 * Drop PASTE().  It doesn't work when BITS_PER_LONG isn't a plain integer
 * Simplify in light of new toolchain baseline
---
 xen/include/xen/byteorder.h               | 44 +++++++++++++++++++++++
 xen/include/xen/byteorder/big_endian.h    |  4 ---
 xen/include/xen/byteorder/little_endian.h |  4 ---
 xen/include/xen/byteswap.h                | 15 ++++++++
 xen/include/xen/config.h                  |  6 ++++
 5 files changed, 65 insertions(+), 8 deletions(-)
 create mode 100644 xen/include/xen/byteorder.h
 create mode 100644 xen/include/xen/byteswap.h

diff --git a/xen/include/xen/byteorder.h b/xen/include/xen/byteorder.h
new file mode 100644
index 000000000000..570a7fe027e5
--- /dev/null
+++ b/xen/include/xen/byteorder.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef XEN_BYTEORDER_H
+#define XEN_BYTEORDER_H
+
+#include <xen/byteswap.h>
+#include <xen/types.h>
+
+#if defined(__LITTLE_ENDIAN)
+
+# define cpu_to_le64(x) (uint64_t)(x)
+# define le64_to_cpu(x) (uint64_t)(x)
+# define cpu_to_le32(x) (uint32_t)(x)
+# define le32_to_cpu(x) (uint32_t)(x)
+# define cpu_to_le16(x) (uint16_t)(x)
+# define le16_to_cpu(x) (uint16_t)(x)
+
+# define cpu_to_be64(x) bswap64(x)
+# define be64_to_cpu(x) bswap64(x)
+# define cpu_to_be32(x) bswap32(x)
+# define be32_to_cpu(x) bswap32(x)
+# define cpu_to_be16(x) bswap16(x)
+# define be16_to_cpu(x) bswap16(x)
+
+#elif defined(__BIG_ENDIAN)
+
+# define cpu_to_le64(x) bswap64(x)
+# define le64_to_cpu(x) bswap64(x)
+# define cpu_to_le32(x) bswap32(x)
+# define le32_to_cpu(x) bswap32(x)
+# define cpu_to_le16(x) bswap16(x)
+# define le16_to_cpu(x) bswap16(x)
+
+# define cpu_to_be64(x) (uint64_t)(x)
+# define be64_to_cpu(x) (uint64_t)(x)
+# define cpu_to_be32(x) (uint32_t)(x)
+# define be32_to_cpu(x) (uint32_t)(x)
+# define cpu_to_be16(x) (uint16_t)(x)
+# define be16_to_cpu(x) (uint16_t)(x)
+
+#else
+# error Unknown Endianness
+#endif /* __*_ENDIAN */
+
+#endif /* XEN_BYTEORDER_H */
diff --git a/xen/include/xen/byteorder/big_endian.h b/xen/include/xen/byteorder/big_endian.h
index 9cfb567d51d5..512291c76f1b 100644
--- a/xen/include/xen/byteorder/big_endian.h
+++ b/xen/include/xen/byteorder/big_endian.h
@@ -1,10 +1,6 @@
 #ifndef __XEN_BYTEORDER_BIG_ENDIAN_H__
 #define __XEN_BYTEORDER_BIG_ENDIAN_H__
 
-#ifndef __BIG_ENDIAN
-#define __BIG_ENDIAN 4321
-#endif
-
 #include <xen/types.h>
 #include <xen/byteorder/swab.h>
 
diff --git a/xen/include/xen/byteorder/little_endian.h b/xen/include/xen/byteorder/little_endian.h
index 96c80eab2b12..bd1afc6a67c3 100644
--- a/xen/include/xen/byteorder/little_endian.h
+++ b/xen/include/xen/byteorder/little_endian.h
@@ -1,10 +1,6 @@
 #ifndef __XEN_BYTEORDER_LITTLE_ENDIAN_H__
 #define __XEN_BYTEORDER_LITTLE_ENDIAN_H__
 
-#ifndef __LITTLE_ENDIAN
-#define __LITTLE_ENDIAN 1234
-#endif
-
 #include <xen/types.h>
 #include <xen/byteorder/swab.h>
 
diff --git a/xen/include/xen/byteswap.h b/xen/include/xen/byteswap.h
new file mode 100644
index 000000000000..46d93f88eac9
--- /dev/null
+++ b/xen/include/xen/byteswap.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef XEN_BYTESWAP_H
+#define XEN_BYTESWAP_H
+
+#define bswap16(x) __builtin_bswap16(x)
+#define bswap32(x) __builtin_bswap32(x)
+#define bswap64(x) __builtin_bswap64(x)
+
+#if BITS_PER_LONG == 64
+# define bswapl(x) bswap64(x)
+#elif BITS_PER_LONG == 32
+# define bswapl(x) bswap32(x)
+#endif
+
+#endif /* XEN_BYTESWAP_H */
diff --git a/xen/include/xen/config.h b/xen/include/xen/config.h
index d888b2314daf..6815a0ef0c1a 100644
--- a/xen/include/xen/config.h
+++ b/xen/include/xen/config.h
@@ -98,4 +98,10 @@
 #define ZERO_BLOCK_PTR ((void *)-1L)
 #endif
 
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define __LITTLE_ENDIAN
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define __BIG_ENDIAN
+#endif
+
 #endif /* __XEN_CONFIG_H__ */
-- 
2.39.5