Message-Id: <20230917-nolibc-syscall-nr-v2-2-03863d509b9a@weissschuh.net>
Date:   Sun, 17 Sep 2023 17:36:17 +0200
From:   Thomas Weißschuh <linux@...ssschuh.net>
To:     Willy Tarreau <w@....eu>, Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Shuah Khan <shuah@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org,
        linux-kselftest@...r.kernel.org,
        Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH v2 2/4] tools/nolibc: avoid unused parameter warnings for
 ENOSYS fallbacks

The ENOSYS fallback code does not use its functions parameters.
This can lead to compiler warnings about unused parameters.

Explicitly avoid these warnings.

Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
 tools/include/nolibc/sys.h | 44 +++++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 17 deletions(-)

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index b478750c9004..8389820e1928 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -43,6 +43,16 @@
 		: __sysret_arg;                         /* return original value */ \
 })
 
+/* Syscall ENOSYS helper: Avoids unused-parameter warnings and provides a
+ * debugging hook.
+ */
+
+static __inline__ int __nolibc_enosys(const char *syscall, ...)
+{
+	(void)syscall;
+	return -ENOSYS;
+}
+
 
 /* Functions in this file only describe syscalls. They're declared static so
  * that the compiler usually decides to inline them while still being allowed
@@ -133,7 +143,7 @@ int sys_chmod(const char *path, mode_t mode)
 #elif defined(__NR_chmod)
 	return my_syscall2(__NR_chmod, path, mode);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, path, mode);
 #endif
 }
 
@@ -156,7 +166,7 @@ int sys_chown(const char *path, uid_t owner, gid_t group)
 #elif defined(__NR_chown)
 	return my_syscall3(__NR_chown, path, owner, group);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, path, owner, group);
 #endif
 }
 
@@ -230,7 +240,7 @@ int sys_dup2(int old, int new)
 #elif defined(__NR_dup2)
 	return my_syscall2(__NR_dup2, old, new);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, old, new);
 #endif
 }
 
@@ -312,7 +322,7 @@ pid_t sys_fork(void)
 #elif defined(__NR_fork)
 	return my_syscall0(__NR_fork);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__);
 #endif
 }
 #endif
@@ -486,7 +496,7 @@ int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
 #ifdef __NR_gettimeofday
 	return my_syscall2(__NR_gettimeofday, tv, tz);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, tv, tz);
 #endif
 }
 
@@ -563,7 +573,7 @@ int sys_link(const char *old, const char *new)
 #elif defined(__NR_link)
 	return my_syscall2(__NR_link, old, new);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, old, new);
 #endif
 }
 
@@ -584,7 +594,7 @@ off_t sys_lseek(int fd, off_t offset, int whence)
 #ifdef __NR_lseek
 	return my_syscall3(__NR_lseek, fd, offset, whence);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, fd, offset, whence);
 #endif
 }
 
@@ -607,7 +617,7 @@ int sys_mkdir(const char *path, mode_t mode)
 #elif defined(__NR_mkdir)
 	return my_syscall2(__NR_mkdir, path, mode);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, path, mode);
 #endif
 }
 
@@ -629,7 +639,7 @@ int sys_rmdir(const char *path)
 #elif defined(__NR_unlinkat)
 	return my_syscall3(__NR_unlinkat, AT_FDCWD, path, AT_REMOVEDIR);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, path);
 #endif
 }
 
@@ -652,7 +662,7 @@ long sys_mknod(const char *path, mode_t mode, dev_t dev)
 #elif defined(__NR_mknod)
 	return my_syscall3(__NR_mknod, path, mode, dev);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, path, mode, dev);
 #endif
 }
 
@@ -742,7 +752,7 @@ int sys_open(const char *path, int flags, mode_t mode)
 #elif defined(__NR_open)
 	return my_syscall3(__NR_open, path, flags, mode);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, path, flags, mode);
 #endif
 }
 
@@ -842,7 +852,7 @@ int sys_poll(struct pollfd *fds, int nfds, int timeout)
 #elif defined(__NR_poll)
 	return my_syscall3(__NR_poll, fds, nfds, timeout);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, fds, nfds, timeout);
 #endif
 }
 
@@ -934,7 +944,7 @@ int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeva
 #endif
 	return my_syscall5(__NR__newselect, nfds, rfds, wfds, efds, timeout);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, nfds, rfds, wfds, efds, timeout);
 #endif
 }
 
@@ -989,7 +999,7 @@ int sys_statx(int fd, const char *path, int flags, unsigned int mask, struct sta
 #ifdef __NR_statx
 	return my_syscall5(__NR_statx, fd, path, flags, mask, buf);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, fd, path, flags, mask, buf);
 #endif
 }
 
@@ -1047,7 +1057,7 @@ int sys_symlink(const char *old, const char *new)
 #elif defined(__NR_symlink)
 	return my_syscall2(__NR_symlink, old, new);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, old, new);
 #endif
 }
 
@@ -1104,7 +1114,7 @@ int sys_unlink(const char *path)
 #elif defined(__NR_unlink)
 	return my_syscall1(__NR_unlink, path);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, path);
 #endif
 }
 
@@ -1127,7 +1137,7 @@ pid_t sys_wait4(pid_t pid, int *status, int options, struct rusage *rusage)
 #ifdef __NR_wait4
 	return my_syscall4(__NR_wait4, pid, status, options, rusage);
 #else
-	return -ENOSYS;
+	return __nolibc_enosys(__func__, pid, status, options, rusage);
 #endif
 }
 

-- 
2.42.0

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