[PATCH v2 1/4] tools/nolibc: sys.h: add __syscall() and __sysret() helpers

[Zhangjin Wu <falcon@tinylab.org>]

most of the library routines share the same code model, let's add two
helpers to simplify the coding and shrink the code lines too.

One added for syscall return, one added for syscall call.

Thomas suggested to use inline function instead of macro for __sysret(),
and he also helped to simplify the __syscall() a lot.

Willy suggested to make __sysret() be always inline.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/linux-riscv/ZH1+hkhiA2+ItSvX@1wt.eu/
Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/linux-riscv/ea4e7442-7223-4211-ba29-70821e907888@t-8ch.de/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/include/nolibc/sys.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index 5464f93e863e..c12c14db056e 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -28,6 +28,18 @@
 #include "errno.h"
 #include "types.h"
 
+/* Syscall return helper, set errno as -ret when ret < 0 */
+static inline __attribute__((always_inline)) long __sysret(long ret)
+{
+	if (ret < 0) {
+		SET_ERRNO(-ret);
+		ret = -1;
+	}
+	return ret;
+}
+
+/* Syscall call helper, use syscall name instead of syscall number */
+#define __syscall(name, ...) __sysret(sys_##name(__VA_ARGS__))
 
 /* Functions in this file only describe syscalls. They're declared static so
  * that the compiler usually decides to inline them while still being allowed
-- 
2.25.1