Hi Zhangjin,
On Wed, Jul 12, 2023 at 05:16:34PM +0800, Zhangjin Wu wrote:
__NR_statx has been added from v4.10:
commit a528d35e8bfc ("statx: Add a system call to make enhanced file info available")It has been supported by all of the platforms since at least from v4.20 and glibc 2.28.
Let's remove the old arch related and dependent sys_stat support completely.
This is friendly to the future new architecture porting.
As I previously said, I'd like that we at least preserve compatibility with supported stable branches. 4.14 and 4.19 are still supported, so does this mean that if I rebuild my preinit against the updated nolibc it will fail to boot on such older systems for the archs that we support?
Because if it means that in order to support all currently active kernels, one must only build from an older copy of the lib, that becomes a disservice to its development and usage. Thus if you checked that aarch64, arm, i386, mips, riscv, s390 and x86_64 had already adopted statx by 4.14, then I'm fine and we can drop stat(), but then it must be mentioned in the commit message, because here it's not explicit.
Yeah, we used 'git blame' before and found the last related change is v4.20, but it is not really the first change.
Just read the statx manpage again:
https://man7.org/linux/man-pages/man2/statx.2.html
It shows something about "Linux 4.11, glibc 2.28.
And 'git grep' shows it is true:
$ git grep -r statx v4.11 arch/ include/uapi/asm-generic/unistd.h | grep -E "aarch64|arm|mips|s390|x86|:include/uapi" v4.11:arch/arm/tools/syscall.tbl:397 common statx sys_statx v4.11:arch/arm64/include/asm/unistd32.h:#define __NR_statx 397 v4.11:arch/arm64/include/asm/unistd32.h:__SYSCALL(__NR_statx, sys_statx) v4.11:arch/mips/include/uapi/asm/unistd.h:#define __NR_statx (__NR_Linux + 366) v4.11:arch/mips/include/uapi/asm/unistd.h:#define __NR_statx (__NR_Linux + 326) v4.11:arch/mips/include/uapi/asm/unistd.h:#define __NR_statx (__NR_Linux + 330) v4.11:arch/mips/kernel/scall32-o32.S: PTR sys_statx v4.11:arch/mips/kernel/scall64-64.S: PTR sys_statx v4.11:arch/mips/kernel/scall64-n32.S: PTR sys_statx /* 6330 */ v4.11:arch/mips/kernel/scall64-o32.S: PTR sys_statx v4.11:arch/s390/include/uapi/asm/unistd.h:#define __NR_statx 379 v4.11:arch/s390/kernel/compat_wrapper.c:COMPAT_SYSCALL_WRAP5(statx, int, dfd, const char __user *, path, unsigned, flags, unsigned, mask, struct statx __user *, buffer); v4.11:arch/s390/kernel/syscalls.S:SYSCALL(sys_statx,compat_sys_statx) v4.11:arch/x86/entry/syscalls/syscall_32.tbl:383 i386 statx sys_statx v4.11:arch/x86/entry/syscalls/syscall_64.tbl:332 common statx sys_statx v4.11:include/uapi/asm-generic/unistd.h:#define __NR_statx 291 v4.11:include/uapi/asm-generic/unistd.h:__SYSCALL(__NR_statx, sys_statx)
both riscv and loongarch use the generic unistd.h, so, all of our supported archs should work as-is. riscv itself is added from v4.15, loongarch itself is added from v5.19.
The powerpc we plan to support is from v4.11:
$ git grep -r statx v4.11 arch/powerpc/ v4.11:arch/powerpc/include/asm/systbl.h:SYSCALL(statx) v4.11:arch/powerpc/include/uapi/asm/unistd.h:#define __NR_statx 383
So, let's simply correct the commit message (the old v4.10 has a wrong -1 offset, I wrongly used 'git show a528d35e8bfc:Makefile' before).
sys_statx has been supported from Linux v4.11 and glibc 2.28:
$ git grep -r statx v4.11 arch/ include/uapi/asm-generic/unistd.h
Both riscv (firstly added from v4.15) and loongarch (firstly added from v5.19) use the generic unistd.h, the others are supported from arch/.
Let's remove the old arch related and dependent sys_stat support completely.
Since the current oldest stable branch is v4.14, so, using statx instead of sys_stat preserves compatibility with all of the supported stable branches.
This is friendly to the future new architecture porting.
Best regards, Zhangjin
Thanks! Willy