Re: [PATCH 5/5] mips: Add the clone3 wrapper

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

Ping.

On 03/02/23 14:12, Adhemerval Zanella wrote:
> It follows the internal signature:
> 
> extern int clone3 (struct clone_args *__cl_args, size_t __size,
>                    int (*__func) (void *__arg), void *__arg);
> 
> Checked on mips64el-linux-gnueabihf and mipsel-linux-gnu.
> ---
>  sysdeps/unix/sysv/linux/mips/clone3.S | 139 ++++++++++++++++++++++++++
>  sysdeps/unix/sysv/linux/mips/sysdep.h |   2 +
>  2 files changed, 141 insertions(+)
>  create mode 100644 sysdeps/unix/sysv/linux/mips/clone3.S
> 
> diff --git a/sysdeps/unix/sysv/linux/mips/clone3.S b/sysdeps/unix/sysv/linux/mips/clone3.S
> new file mode 100644
> index 0000000000..492d6d8b77
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/mips/clone3.S
> @@ -0,0 +1,139 @@
> +/* The clone3 syscall wrapper.  Linux/mips 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 <sys/asm.h>
> +#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:
> +   a0/$4: cl_args
> +   a1/$5: size
> +   a2/$6: func
> +   a3/$7: arg  */
> +
> +	.text
> +	.set		nomips16
> +#if _MIPS_SIM == _ABIO32
> +# define EXTRA_LOCALS 1
> +#else
> +# define EXTRA_LOCALS 0
> +#endif
> +#define FRAMESZ ((NARGSAVE*SZREG)+ALSZ)&ALMASK
> +GPOFF= FRAMESZ-(1*SZREG)
> +NESTED(__clone3, SZREG, sp)
> +#ifdef __PIC__
> +	SETUP_GP
> +#endif
> +#if FRAMESZ
> +	PTR_SUBU sp, FRAMESZ
> +	cfi_adjust_cfa_offset (FRAMESZ)
> +#endif
> +	SETUP_GP64_STACK (GPOFF, __clone)
> +#ifdef __PIC__
> +	SAVE_GP (GPOFF)
> +#endif
> +#ifdef PROF
> +	.set	noat
> +	move	$1,ra
> +	jal	_mcount
> +	.set	at
> +#endif
> +
> +	/* Sanity check args.  */
> +	li	v0, EINVAL
> +	beqz	a0, L(error)	/* No NULL cl_args pointer.  */
> +	beqz	a2, L(error)	/* No NULL function pointer.  */
> +
> +	move	$8, a3		/* a3 is set to 0/1 for syscall success/error
> +				   while a4/$8 is returned unmodified.  */
> +
> +	/* Do the system call, the kernel expects:
> +	   v0: system call number
> +	   a0: cl_args
> +	   a1: size  */
> +	li		v0, __NR_clone3
> +	cfi_endproc
> +	syscall
> +
> +	bnez		a3, L(error)
> +	beqz		v0, L(thread_start_clone3)
> +
> +	/* Successful return from the parent */
> +	cfi_startproc
> +#if FRAMESZ
> +	cfi_adjust_cfa_offset (FRAMESZ)
> +#endif
> +	SETUP_GP64_STACK_CFI (GPOFF)
> +	cfi_remember_state
> +	RESTORE_GP64_STACK
> +#if FRAMESZ
> +	PTR_ADDU	sp, FRAMESZ
> +	cfi_adjust_cfa_offset (-FRAMESZ)
> +#endif
> +	ret
> +
> +L(error):
> +	cfi_restore_state
> +#ifdef __PIC__
> +	PTR_LA		t9,__syscall_error
> +	RESTORE_GP64_STACK
> +	PTR_ADDU	sp, FRAMESZ
> +	cfi_adjust_cfa_offset (-FRAMESZ)
> +	jr		t9
> +#else
> +	RESTORE_GP64_STACK
> +	PTR_ADDU	sp, FRAMESZ
> +	cfi_adjust_cfa_offset (-FRAMESZ)
> +	j		__syscall_error
> +#endif
> +END (__clone3)
> +
> +/* Load up the arguments to the function.  Put this block of code in
> +   its own function so that we can terminate the stack trace with our
> +   debug info.  */
> +
> +ENTRY(__thread_start_clone3)
> +L(thread_start_clone3):
> +	cfi_undefined ($31)
> +	/* cp is already loaded.  */
> +	SAVE_GP (GPOFF)
> +	/* The stackframe has been created on entry of clone3.  */
> +
> +	/* Restore the arg for user's function.  */
> +	move		t9, a2		/* Function pointer.  */
> +	move		a0, $8		/* Argument pointer.  */
> +
> +	/* Call the user's function.  */
> +	jal		t9
> +
> +	move		a0, v0
> +	li		v0, __NR_exit
> +	syscall
> +END(__thread_start_clone3)
> +
> +libc_hidden_def (__clone3)
> +weak_alias (__clone3, clone3)
> diff --git a/sysdeps/unix/sysv/linux/mips/sysdep.h b/sysdeps/unix/sysv/linux/mips/sysdep.h
> index ff84a91b31..673aa08b57 100644
> --- a/sysdeps/unix/sysv/linux/mips/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/mips/sysdep.h
> @@ -28,3 +28,5 @@
>  #endif
>  #define HAVE_GETTIMEOFDAY_VSYSCALL      "__vdso_gettimeofday"
>  #define HAVE_CLOCK_GETRES_VSYSCALL      "__vdso_clock_getres"
> +
> +#define HAVE_CLONE3_WRAPPER		1