On 02/03/23 13:10, Pavel Kozlov via Libc-alpha wrote:
> From: Pavel Kozlov <pavel.koz...@synopsys.com>
>
> Use the clone3 wrapper on ARC. It doesn't care about stack alignment.
> All callers should provide an aligned stack.
> It follows the internal signature:
>
> extern int clone3 (struct clone_args *__cl_args, size_t __size,
> int (*__func) (void *__arg), void *__arg);
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zane...@linaro.org>
> ---
> Checked on arc-linux-gnu. Previously observed tst-misaling-clone-internal
> test fail was because I used outdated master branch.
> Full testsuite runs without regressions.
> But I also see fail of the new tst-spawn7, as already repoted at [1].
>
> [1]
> https://sourceware.org/pipermail/libc-alpha/2023-February/145937.html
>
> sysdeps/unix/sysv/linux/arc/clone3.S | 90 ++++++++++++++++++++++++++++
> sysdeps/unix/sysv/linux/arc/sysdep.h | 2 +
> 2 files changed, 92 insertions(+)
> create mode 100644 sysdeps/unix/sysv/linux/arc/clone3.S
>
> diff --git a/sysdeps/unix/sysv/linux/arc/clone3.S
> b/sysdeps/unix/sysv/linux/arc/clone3.S
> new file mode 100644
> index 000000000000..87a8272a3977
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/arc/clone3.S
> @@ -0,0 +1,90 @@
> +/* The clone3 syscall wrapper. Linux/arc version.
> + Copyright (C) 2023 Free Software Foundation, Inc.
> +
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <sysdep.h>
> +#define _ERRNO_H 1
> +#include <bits/errno.h>
> +
> +/* The userland implementation is:
> + int clone3 (struct clone_args *cl_args, size_t size,
> + int (*func)(void *arg), void *arg);
> +
> + the kernel entry is:
> + int clone3 (struct clone_args *cl_args, size_t size);
> +
> + The parameters are passed in registers from userland:
> + r0: cl_args
> + r1: size
> + r2: func
> + r3: arg */
> +
> +ENTRY(__clone3)
> +
> + /* Save args for the child. */
> + mov r10, r0 /* cl_args */
> + mov r11, r2 /* func */
> + mov r12, r3 /* args */
> +
> + /* Sanity check args. */
> + breq r10, 0, L (__sys_err) /* No NULL cl_args pointer. */
> + breq r11, 0, L (__sys_err) /* No NULL function pointer. */
> +
> + /* Do the system call, the kernel expects:
> + r8: system call number
> + r0: cl_args
> + r1: size */
> + mov r0, r10
> + mov r8, __NR_clone3
> + ARC_TRAP_INSN
> +
> + cmp r0, 0
> + beq thread_start_clone3 /* Child returns. */
> + blt L (__sys_err2)
> + j [blink] /* Parent returns. */
> +
> +L (__sys_err):
> + mov r0, -EINVAL
> +L (__sys_err2):
> + b __syscall_error
> +PSEUDO_END (__clone3)
> +
> +
> + .align 4
> + .type thread_start_clone3, %function
> +thread_start_clone3:
> + cfi_startproc
> + /* Terminate call stack by noting ra is undefined. */
> + cfi_undefined (blink)
> +
> + /* Child jumps off to @fn with @arg as argument. */
> + jl.d [r11]
> + mov r0, r12
> +
> + /* exit() with result from @fn (already in r0). */
> + mov r8, __NR_exit
> + ARC_TRAP_INSN
> +
> + /* In case it ever came back. */
> + flag 1
> +
> + cfi_endproc
> + .size thread_start_clone3, .-thread_start_clone3
> +
> +libc_hidden_def (__clone3)
> +weak_alias (__clone3, clone3)
> diff --git a/sysdeps/unix/sysv/linux/arc/sysdep.h
> b/sysdeps/unix/sysv/linux/arc/sysdep.h
> index dd6fe73445f9..88dc1dff017f 100644
> --- a/sysdeps/unix/sysv/linux/arc/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/arc/sysdep.h
> @@ -141,6 +141,8 @@ hidden_proto (__syscall_error)
>
> # define ARC_TRAP_INSN "trap_s 0 \n\t"
>
> +# define HAVE_CLONE3_WRAPPER 1
> +
> # undef INTERNAL_SYSCALL_NCS
> # define INTERNAL_SYSCALL_NCS(number, nr_args, args...) \
> ({ \
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