[PATCH v3 0/3] tools/nolibc: add a new syscall helper

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[PATCH bpf v4 0/2] Fix verifier id...

selftests: -e error: missing...

Zhangjin Wu

7 Jun 2023 7 Jun '23

11:28 a.m.

Willy, Thomas

This is the revision of the v2 syscall helpers [1], it is based on 20230606-nolibc-rv32+stkp7a of [2]. It doesn't conflict with the v4 of -ENOSYS patchset [3], so, it is ok to simply merge both of them.

This revision mainly applied Thomas' method, removed the __syscall() helper and replaced it with __sysret() instead, because __syscall() looks like _syscall() and syscall(), it may mixlead the developers.

Changes from v2 -> v3:

* tools/nolibc: sys.h: add a syscall return helper

* The __syscall() is removed.

* Align the code style of __sysret() with the others, and use __inline__ instead of inline (like stdlib.h) to let it work with the default -std=c89 in tools/testing/selftests/nolibc/Makefile

* tools/nolibc: unistd.h: apply __sysret() helper

As v2.

* tools/nolibc: sys.h: apply __sysret() helper

replaced __syscall() with __sysret() and merged two separated patches of v2 to one.

Did run-user tests for rv32 (with [3]), rv64 and arm64.

BTW, two questions for Thomas,

* This commit 659a49abc9c2 ("tools/nolibc: validate C89 compatibility") enables -std=c89, why not gnu11 used by kernel ? ;-)

* Do we need to tune the order of the macros in unistd.h like this:

#define _syscall(N, ...) __sysret(my_syscall##N(__VA_ARGS__)) #define _syscall_n(N, ...) _syscall(N, __VA_ARGS__) #define __syscall_narg(_0, _1, _2, _3, _4, _5, _6, N, ...) N #define _sycall_narg(...) __syscall_narg(__VA_ARGS__, 6, 5, 4, 3, 2, 1, 0) #define syscall(...) _syscall_n(_sycall_narg(__VA_ARGS__), ##__VA_ARGS__)

Before, It works but seems not put in using order:

#define _syscall(N, ...) __sysret(my_syscall##N(__VA_ARGS__)) #define _sycall_narg(...) __syscall_narg(__VA_ARGS__, 6, 5, 4, 3, 2, 1, 0) #define __syscall_narg(_0, _1, _2, _3, _4, _5, _6, N, ...) N #define _syscall_n(N, ...) _syscall(N, __VA_ARGS__) #define syscall(...) _syscall_n(_sycall_narg(__VA_ARGS__), ##__VA_ARGS__)

Thanks.

Best regards, Zhangjin

--- [1]: https://lore.kernel.org/linux-riscv/cover.1686036862.git.falcon@tinylab.org/ [2]: https://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/nolibc.git [3]: https://lore.kernel.org/linux-riscv/cover.1686128703.git.falcon@tinylab.org/...

Zhangjin Wu (3): tools/nolibc: sys.h: add a syscall return helper tools/nolibc: unistd.h: apply __sysret() helper tools/nolibc: sys.h: apply __sysret() helper

tools/include/nolibc/sys.h | 364 +++++----------------------------- tools/include/nolibc/unistd.h | 11 +- 2 files changed, 55 insertions(+), 320 deletions(-)

-- 2.25.1

Show replies by date

Zhangjin Wu

7 Jun 7 Jun

11:30 a.m.

New subject: [PATCH v3 1/3] tools/nolibc: sys.h: add a syscall return helper

Most of the library routines share the same syscall return logic:

In general, a 0 return value indicates success. A -1 return value indicates an error, and an error number is stored in errno. [1]

Let's add a __sysret() helper for the above logic to simplify the coding and shrink the code lines too.

Thomas suggested to use inline function instead of macro for __sysret().

Willy suggested to make __sysret() be always inline.

[1]: https://man7.org/linux/man-pages/man2/syscall.2.html

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-8... Signed-off-by: Zhangjin Wu falcon@tinylab.org --- tools/include/nolibc/sys.h | 10 ++++++++++ 1 file changed, 10 insertions(+)

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index 856249a11890..150777207468 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -28,6 +28,16 @@ #include "errno.h" #include "types.h"

+/* Syscall return helper, set errno as -ret when ret < 0 */ +static __inline__ __attribute__((unused, always_inline)) +long __sysret(long ret) +{ + if (ret < 0) { + SET_ERRNO(-ret); + ret = -1; + } + return ret; +}

/* 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

Zhangjin Wu

11:31 a.m.

New subject: [PATCH v3 2/3] tools/nolibc: unistd.h: apply __sysret() helper

Use __sysret() to shrink the whole _syscall() to oneline code.

Signed-off-by: Zhangjin Wu falcon@tinylab.org --- tools/include/nolibc/unistd.h | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/tools/include/nolibc/unistd.h b/tools/include/nolibc/unistd.h index c20b2fbf065e..7e3c005d28ba 100644 --- a/tools/include/nolibc/unistd.h +++ b/tools/include/nolibc/unistd.h @@ -56,16 +56,7 @@ int tcsetpgrp(int fd, pid_t pid) return ioctl(fd, TIOCSPGRP, &pid); }

-#define _syscall(N, ...) \ -({ \ - long _ret = my_syscall##N(__VA_ARGS__); \ - if (_ret < 0) { \ - SET_ERRNO(-_ret); \ - _ret = -1; \ - } \ - _ret; \ -}) - +#define _syscall(N, ...) __sysret(my_syscall##N(__VA_ARGS__)) #define _sycall_narg(...) __syscall_narg(__VA_ARGS__, 6, 5, 4, 3, 2, 1, 0) #define __syscall_narg(_0, _1, _2, _3, _4, _5, _6, N, ...) N #define _syscall_n(N, ...) _syscall(N, __VA_ARGS__)

-- 2.25.1

Zhangjin Wu

11:32 a.m.

New subject: [PATCH v3 3/3] tools/nolibc: sys.h: apply __sysret() helper

Use __sysret() to shrink most of the library routines to oneline code.

Removed 266 lines of duplicated code.

Signed-off-by: Zhangjin Wu falcon@tinylab.org --- tools/include/nolibc/sys.h | 354 +++++-------------------------------- 1 file changed, 44 insertions(+), 310 deletions(-)

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index 150777207468..4fbefe5adf93 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -76,13 +76,7 @@ void *sys_brk(void *addr) static __attribute__((unused)) int brk(void *addr) { - void *ret = sys_brk(addr); - - if (!ret) { - SET_ERRNO(ENOMEM); - return -1; - } - return 0; + return __sysret(sys_brk(addr) ? 0 : -ENOMEM); }

static __attribute__((unused)) @@ -112,13 +106,7 @@ int sys_chdir(const char *path) static __attribute__((unused)) int chdir(const char *path) { - int ret = sys_chdir(path); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_chdir(path)); }

@@ -141,13 +129,7 @@ int sys_chmod(const char *path, mode_t mode) static __attribute__((unused)) int chmod(const char *path, mode_t mode) { - int ret = sys_chmod(path, mode); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_chmod(path, mode)); }

@@ -170,13 +152,7 @@ int sys_chown(const char *path, uid_t owner, gid_t group) static __attribute__((unused)) int chown(const char *path, uid_t owner, gid_t group) { - int ret = sys_chown(path, owner, group); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_chown(path, owner, group)); }

@@ -193,13 +169,7 @@ int sys_chroot(const char *path) static __attribute__((unused)) int chroot(const char *path) { - int ret = sys_chroot(path); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_chroot(path)); }

@@ -216,13 +186,7 @@ int sys_close(int fd) static __attribute__((unused)) int close(int fd) { - int ret = sys_close(fd); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_close(fd)); }

@@ -239,13 +203,7 @@ int sys_dup(int fd) static __attribute__((unused)) int dup(int fd) { - int ret = sys_dup(fd); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_dup(fd)); }

@@ -268,13 +226,7 @@ int sys_dup2(int old, int new) static __attribute__((unused)) int dup2(int old, int new) { - int ret = sys_dup2(old, new); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_dup2(old, new)); }

@@ -292,13 +244,7 @@ int sys_dup3(int old, int new, int flags) static __attribute__((unused)) int dup3(int old, int new, int flags) { - int ret = sys_dup3(old, new, flags); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_dup3(old, new, flags)); } #endif

@@ -316,13 +262,7 @@ int sys_execve(const char *filename, char *const argv[], char *const envp[]) static __attribute__((unused)) int execve(const char *filename, char *const argv[], char *const envp[]) { - int ret = sys_execve(filename, argv, envp); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_execve(filename, argv, envp)); }

@@ -369,13 +309,7 @@ pid_t sys_fork(void) static __attribute__((unused)) pid_t fork(void) { - pid_t ret = sys_fork(); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_fork()); }

@@ -392,13 +326,7 @@ int sys_fsync(int fd) static __attribute__((unused)) int fsync(int fd) { - int ret = sys_fsync(fd); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_fsync(fd)); }

@@ -415,13 +343,7 @@ int sys_getdents64(int fd, struct linux_dirent64 *dirp, int count) static __attribute__((unused)) int getdents64(int fd, struct linux_dirent64 *dirp, int count) { - int ret = sys_getdents64(fd, dirp, count); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_getdents64(fd, dirp, count)); }

@@ -459,13 +381,7 @@ pid_t sys_getpgid(pid_t pid) static __attribute__((unused)) pid_t getpgid(pid_t pid) { - pid_t ret = sys_getpgid(pid); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_getpgid(pid)); }

@@ -545,15 +461,7 @@ static unsigned long getauxval(unsigned long key); static __attribute__((unused)) long getpagesize(void) { - long ret; - - ret = getauxval(AT_PAGESZ); - if (!ret) { - SET_ERRNO(ENOENT); - return -1; - } - - return ret; + return __sysret(getauxval(AT_PAGESZ) ?: -ENOENT); }

@@ -570,13 +478,7 @@ int sys_gettimeofday(struct timeval *tv, struct timezone *tz) static __attribute__((unused)) int gettimeofday(struct timeval *tv, struct timezone *tz) { - int ret = sys_gettimeofday(tv, tz); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_gettimeofday(tv, tz)); }

@@ -614,13 +516,7 @@ int sys_ioctl(int fd, unsigned long req, void *value) static __attribute__((unused)) int ioctl(int fd, unsigned long req, void *value) { - int ret = sys_ioctl(fd, req, value); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_ioctl(fd, req, value)); }

/* @@ -636,13 +532,7 @@ int sys_kill(pid_t pid, int signal) static __attribute__((unused)) int kill(pid_t pid, int signal) { - int ret = sys_kill(pid, signal); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_kill(pid, signal)); }

@@ -665,13 +555,7 @@ int sys_link(const char *old, const char *new) static __attribute__((unused)) int link(const char *old, const char *new) { - int ret = sys_link(old, new); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_link(old, new)); }

@@ -688,13 +572,7 @@ off_t sys_lseek(int fd, off_t offset, int whence) static __attribute__((unused)) off_t lseek(int fd, off_t offset, int whence) { - off_t ret = sys_lseek(fd, offset, whence); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_lseek(fd, offset, whence)); }

@@ -717,13 +595,7 @@ int sys_mkdir(const char *path, mode_t mode) static __attribute__((unused)) int mkdir(const char *path, mode_t mode) { - int ret = sys_mkdir(path, mode); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_mkdir(path, mode)); }

@@ -746,13 +618,7 @@ long sys_mknod(const char *path, mode_t mode, dev_t dev) static __attribute__((unused)) int mknod(const char *path, mode_t mode, dev_t dev) { - int ret = sys_mknod(path, mode, dev); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_mknod(path, mode, dev)); }

#ifndef MAP_SHARED @@ -810,13 +676,7 @@ int sys_munmap(void *addr, size_t length) static __attribute__((unused)) int munmap(void *addr, size_t length) { - int ret = sys_munmap(addr, length); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_munmap(addr, length)); }

/* @@ -836,13 +696,7 @@ int mount(const char *src, const char *tgt, const char *fst, unsigned long flags, const void *data) { - int ret = sys_mount(src, tgt, fst, flags, data); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_mount(src, tgt, fst, flags, data)); }

@@ -876,13 +730,7 @@ int open(const char *path, int flags, ...) va_end(args); }

- ret = sys_open(path, flags, mode); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_open(path, flags, mode)); }

@@ -902,13 +750,7 @@ static __attribute__((unused)) int prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5) { - int ret = sys_prctl(option, arg2, arg3, arg4, arg5); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_prctl(option, arg2, arg3, arg4, arg5)); }

@@ -925,13 +767,7 @@ int sys_pivot_root(const char *new, const char *old) static __attribute__((unused)) int pivot_root(const char *new, const char *old) { - int ret = sys_pivot_root(new, old); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_pivot_root(new, old)); }

@@ -960,13 +796,7 @@ int sys_poll(struct pollfd *fds, int nfds, int timeout) static __attribute__((unused)) int poll(struct pollfd *fds, int nfds, int timeout) { - int ret = sys_poll(fds, nfds, timeout); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_poll(fds, nfds, timeout)); }

@@ -983,13 +813,7 @@ ssize_t sys_read(int fd, void *buf, size_t count) static __attribute__((unused)) ssize_t read(int fd, void *buf, size_t count) { - ssize_t ret = sys_read(fd, buf, count); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_read(fd, buf, count)); }

@@ -1007,13 +831,7 @@ ssize_t sys_reboot(int magic1, int magic2, int cmd, void *arg) static __attribute__((unused)) int reboot(int cmd) { - int ret = sys_reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd, 0); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd, 0)); }

@@ -1030,13 +848,7 @@ int sys_sched_yield(void) static __attribute__((unused)) int sched_yield(void) { - int ret = sys_sched_yield(); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_sched_yield()); }

@@ -1076,13 +888,7 @@ int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeva static __attribute__((unused)) int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout) { - int ret = sys_select(nfds, rfds, wfds, efds, timeout); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_select(nfds, rfds, wfds, efds, timeout)); }

@@ -1099,13 +905,7 @@ int sys_setpgid(pid_t pid, pid_t pgid) static __attribute__((unused)) int setpgid(pid_t pid, pid_t pgid) { - int ret = sys_setpgid(pid, pgid); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_setpgid(pid, pgid)); }

@@ -1122,13 +922,7 @@ pid_t sys_setsid(void) static __attribute__((unused)) pid_t setsid(void) { - pid_t ret = sys_setsid(); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_setsid()); }

#if defined(__NR_statx) @@ -1145,13 +939,7 @@ int sys_statx(int fd, const char *path, int flags, unsigned int mask, struct sta static __attribute__((unused)) int statx(int fd, const char *path, int flags, unsigned int mask, struct statx *buf) { - int ret = sys_statx(fd, path, flags, mask, buf); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_statx(fd, path, flags, mask, buf)); } #endif

@@ -1231,13 +1019,7 @@ int sys_stat(const char *path, struct stat *buf) static __attribute__((unused)) int stat(const char *path, struct stat *buf) { - int ret = sys_stat(path, buf); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_stat(path, buf)); }

@@ -1260,13 +1042,7 @@ int sys_symlink(const char *old, const char *new) static __attribute__((unused)) int symlink(const char *old, const char *new) { - int ret = sys_symlink(old, new); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_symlink(old, new)); }

@@ -1300,13 +1076,7 @@ int sys_umount2(const char *path, int flags) static __attribute__((unused)) int umount2(const char *path, int flags) { - int ret = sys_umount2(path, flags); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_umount2(path, flags)); }

@@ -1329,13 +1099,7 @@ int sys_unlink(const char *path) static __attribute__((unused)) int unlink(const char *path) { - int ret = sys_unlink(path); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_unlink(path)); }

@@ -1354,38 +1118,20 @@ pid_t sys_wait4(pid_t pid, int *status, int options, struct rusage *rusage) static __attribute__((unused)) pid_t wait(int *status) { - pid_t ret = sys_wait4(-1, status, 0, NULL); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_wait4(-1, status, 0, NULL)); }

static __attribute__((unused)) pid_t wait4(pid_t pid, int *status, int options, struct rusage *rusage) { - pid_t ret = sys_wait4(pid, status, options, rusage); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_wait4(pid, status, options, rusage)); }

static __attribute__((unused)) pid_t waitpid(pid_t pid, int *status, int options) { - pid_t ret = sys_wait4(pid, status, options, NULL); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_wait4(pid, status, options, NULL)); }

@@ -1402,13 +1148,7 @@ ssize_t sys_write(int fd, const void *buf, size_t count) static __attribute__((unused)) ssize_t write(int fd, const void *buf, size_t count) { - ssize_t ret = sys_write(fd, buf, count); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_write(fd, buf, count)); }

@@ -1425,13 +1165,7 @@ int sys_memfd_create(const char *name, unsigned int flags) static __attribute__((unused)) int memfd_create(const char *name, unsigned int flags) { - ssize_t ret = sys_memfd_create(name, flags); - - if (ret < 0) { - SET_ERRNO(-ret); - ret = -1; - } - return ret; + return __sysret(sys_memfd_create(name, flags)); }

/* make sure to include all global symbols */

-- 2.25.1

Thomas Weißschuh

9:41 p.m.

On 2023-06-07 19:28:58+0800, Zhangjin Wu wrote:

...

Willy, Thomas

This is the revision of the v2 syscall helpers [1], it is based on 20230606-nolibc-rv32+stkp7a of [2]. It doesn't conflict with the v4 of -ENOSYS patchset [3], so, it is ok to simply merge both of them.

This revision mainly applied Thomas' method, removed the __syscall() helper and replaced it with __sysret() instead, because __syscall() looks like _syscall() and syscall(), it may mixlead the developers.

Changes from v2 -> v3:

tools/nolibc: sys.h: add a syscall return helper

The __syscall() is removed.

Align the code style of __sysret() with the others, and use __inline__ instead of inline (like stdlib.h) to let it work with the default -std=c89 in tools/testing/selftests/nolibc/Makefile

tools/nolibc: unistd.h: apply __sysret() helper

As v2.

tools/nolibc: sys.h: apply __sysret() helper

replaced __syscall() with __sysret() and merged two separated patches of v2 to one.

Did run-user tests for rv32 (with [3]), rv64 and arm64.

BTW, two questions for Thomas,

This commit 659a49abc9c2 ("tools/nolibc: validate C89 compatibility") enables -std=c89, why not gnu11 used by kernel ? ;-)

Because nolibc needs to support whatever its users need. As nolibc is header-only all of it needs to work everywhere. C89 should work for everybody :-)

The kernel on the other hand is compiled standalone and is not limited by its users.

See the discussion here:

https://lore.kernel.org/all/20230328-nolibc-c99-v2-0-c989f2289222@weissschuh... https://lore.kernel.org/all/20230328-nolibc-c99-v1-1-a8302fb19f19@weissschuh...

...

Do we need to tune the order of the macros in unistd.h like this:

#define _syscall(N, ...) __sysret(my_syscall##N(__VA_ARGS__)) #define _syscall_n(N, ...) _syscall(N, __VA_ARGS__) #define __syscall_narg(_0, _1, _2, _3, _4, _5, _6, N, ...) N #define _sycall_narg(...) __syscall_narg(__VA_ARGS__, 6, 5, 4, 3, 2, 1, 0) #define syscall(...) _syscall_n(_sycall_narg(__VA_ARGS__), ##__VA_ARGS__)

Before, It works but seems not put in using order:

#define _syscall(N, ...) __sysret(my_syscall##N(__VA_ARGS__)) #define _sycall_narg(...) __syscall_narg(__VA_ARGS__, 6, 5, 4, 3, 2, 1, 0) #define __syscall_narg(_0, _1, _2, _3, _4, _5, _6, N, ...) N #define _syscall_n(N, ...) _syscall(N, __VA_ARGS__) #define syscall(...) _syscall_n(_sycall_narg(__VA_ARGS__), ##__VA_ARGS__)

Not sure it makes a big difference. If you want to change it, go for it.

...

Thanks.

Best regards, Zhangjin

Zhangjin Wu (3): tools/nolibc: sys.h: add a syscall return helper tools/nolibc: unistd.h: apply __sysret() helper tools/nolibc: sys.h: apply __sysret() helper

tools/include/nolibc/sys.h | 364 +++++----------------------------- tools/include/nolibc/unistd.h | 11 +- 2 files changed, 55 insertions(+), 320 deletions(-)

For the full series:

Reviewed-by: Thomas Weißschuh linux@weissschuh.net

Thanks, Thomas

Zhangjin Wu

8 Jun 8 Jun

10:10 a.m.

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On 2023-06-07 19:28:58+0800, Zhangjin Wu wrote:

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Willy, Thomas

This is the revision of the v2 syscall helpers [1], it is based on 20230606-nolibc-rv32+stkp7a of [2]. It doesn't conflict with the v4 of -ENOSYS patchset [3], so, it is ok to simply merge both of them.

This revision mainly applied Thomas' method, removed the __syscall() helper and replaced it with __sysret() instead, because __syscall() looks like _syscall() and syscall(), it may mixlead the developers.

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BTW, two questions for Thomas,

This commit 659a49abc9c2 ("tools/nolibc: validate C89 compatibility") enables -std=c89, why not gnu11 used by kernel ? ;-)

Because nolibc needs to support whatever its users need. As nolibc is header-only all of it needs to work everywhere. C89 should work for everybody :-)

Get it, thanks.

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The kernel on the other hand is compiled standalone and is not limited by its users.

See the discussion here:

https://lore.kernel.org/all/20230328-nolibc-c99-v2-0-c989f2289222@weissschuh... https://lore.kernel.org/all/20230328-nolibc-c99-v1-1-a8302fb19f19@weissschuh...

Thanks very much for sharing the whole history info.

And as the your commit 063b6bc5b39f ("tools/nolibc: use __inline__ syntax") explains, the 'inline' keyword has been used in many headers of include/uapi/, so, how our -std=c89 work with them? I did find the clue eventually, here maybe:

$ grep -n inline scripts/headers_install.sh 11: echo "asm/inline/volatile keywords." 37: s/(^|[[:space:](])(inline|asm|volatile)([[:space:](]|$)/\1__\2__\3/g

The headers_install target helped us convert all of the new keywords to the old ones, it's magic ;-)

So, it should work if people not want to try a -I/path/to/include/uapi/, I did this for musl before, even If we do this, this may help:

diff --git a/tools/include/nolibc/std.h b/tools/include/nolibc/std.h index 933bc0be7e1c..33d546cf9af0 100644 --- a/tools/include/nolibc/std.h +++ b/tools/include/nolibc/std.h @@ -7,6 +7,14 @@ #ifndef _NOLIBC_STD_H #define _NOLIBC_STD_H

+#ifndef NOLIBC_TEST +#ifndef __STDC_VERSION__ +#define inline __inline__ +#define asm __asm__ +#define volatile __volatile__ +#endif +#endif + /* Declare a few quite common macros and types that usually are in stdlib.h, * stdint.h, ctype.h, unistd.h and a few other common locations. Please place * integer type definitions and generic macros here, but avoid OS-specific and diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile index 4a3a105e1fdf..46f061a4458a 100644 --- a/tools/testing/selftests/nolibc/Makefile +++ b/tools/testing/selftests/nolibc/Makefile @@ -78,7 +78,7 @@ endif

CFLAGS_s390 = -m64 CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all)) -CFLAGS ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 \ +CFLAGS ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 -DNOLIBC_TEST \ $(call cc-option,-fno-stack-protector) \ $(CFLAGS_$(ARCH)) $(CFLAGS_STACKPROTECTOR)

Is this worth a new patch? I do think it is not required.

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Do we need to tune the order of the macros in unistd.h like this:

#define _syscall(N, ...) __sysret(my_syscall##N(__VA_ARGS__)) #define _syscall_n(N, ...) _syscall(N, __VA_ARGS__) #define __syscall_narg(_0, _1, _2, _3, _4, _5, _6, N, ...) N #define _sycall_narg(...) __syscall_narg(__VA_ARGS__, 6, 5, 4, 3, 2, 1, 0) #define syscall(...) _syscall_n(_sycall_narg(__VA_ARGS__), ##__VA_ARGS__)

Before, It works but seems not put in using order:

#define _syscall(N, ...) __sysret(my_syscall##N(__VA_ARGS__)) #define _sycall_narg(...) __syscall_narg(__VA_ARGS__, 6, 5, 4, 3, 2, 1, 0) #define __syscall_narg(_0, _1, _2, _3, _4, _5, _6, N, ...) N #define _syscall_n(N, ...) _syscall(N, __VA_ARGS__) #define syscall(...) _syscall_n(_sycall_narg(__VA_ARGS__), ##__VA_ARGS__)

Not sure it makes a big difference. If you want to change it, go for it.

Only switched two of them, oh, just found the '_sycall_narg' did miss a 's' character, it may be really worth a patch now, I know why I focused on the order so much, because the missing 's' made it not aligned well ;-)

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tools/include/nolibc/sys.h | 364 +++++----------------------------- tools/include/nolibc/unistd.h | 11 +- 2 files changed, 55 insertions(+), 320 deletions(-)

For the full series:

Reviewed-by: Thomas Weißschuh linux@weissschuh.net

Thanks a lot, I'm really appreciated.

Best regards, Zhangjin

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Thanks, Thomas

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Thomas Weißschuh
Zhangjin Wu