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From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org, Christian Brauner <brauner@kernel.org>
Subject: [PATCH v2 8/9] mips: Add the clone3 wrapper
Date: Fri, 30 Sep 2022 16:26:12 -0300	[thread overview]
Message-ID: <20220930192613.3491147-9-adhemerval.zanella@linaro.org> (raw)
In-Reply-To: <20220930192613.3491147-1-adhemerval.zanella@linaro.org>

It follows the internal signature:

extern int clone3 (struct clone_args *__cl_args, size_t __size,
                   int (*__func) (void *__arg), void *__arg);

And x86_64 semantics to return EINVAL if either cl_args or func
is NULL.  The stack is 16-byte aligned prior executing func.

Checked on mips64el-linux-gnueabihf and mipsel-linux-gnu.
---
 sysdeps/unix/sysv/linux/mips/clone3.S | 147 ++++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/mips/sysdep.h |   2 +
 2 files changed, 149 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..bd493e344b
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mips/clone3.S
@@ -0,0 +1,147 @@
+/* The clone3 syscall wrapper.  Linux/mips version.
+   Copyright (C) 2022 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.  */
+
+	/* Align stack to 8/16 bytes per the ABI.  */
+#if _MIPS_SIM == _ABIO32
+	li		t1, -8
+#else
+	li		t1, -16
+#endif
+	and		sp, sp, t1
+
+	/* 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 2515dadc26..3f464925e7 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
-- 
2.34.1


  parent reply	other threads:[~2022-09-30 19:26 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-30 19:26 [PATCH v2 0/9] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella
2022-09-30 19:26 ` [PATCH v2 1/9] linux: Do not reset signal handler in posix_spawn if it is already SIG_DFL Adhemerval Zanella
2023-01-11 21:06   ` Carlos O'Donell
2022-09-30 19:26 ` [PATCH v2 2/9] linux: Add clone3 CLONE_CLEAR_SIGHAND optimization to posix_spawn Adhemerval Zanella
2023-01-11 21:06   ` Carlos O'Donell
2022-09-30 19:26 ` [PATCH v2 3/9] powerpc64le: Add the clone3 wrapper Adhemerval Zanella
2022-09-30 19:26 ` [PATCH v2 4/9] aarch64: " Adhemerval Zanella
2022-11-02 12:12   ` Szabolcs Nagy
2022-11-03 13:15     ` Adhemerval Zanella Netto
2022-11-03 14:01       ` Szabolcs Nagy
2022-11-03 16:22         ` Adhemerval Zanella Netto
2022-11-03 16:31           ` Szabolcs Nagy
2022-11-03 16:39             ` Adhemerval Zanella Netto
2022-11-03 16:52               ` Szabolcs Nagy
2022-11-03 16:55                 ` Adhemerval Zanella Netto
2022-11-03 20:55                   ` H.J. Lu
2022-11-03 21:28                     ` Adhemerval Zanella Netto
2022-11-03 21:22                   ` Adhemerval Zanella Netto
2022-11-03 21:58                     ` H.J. Lu
2022-11-04 12:32                       ` Adhemerval Zanella Netto
2022-09-30 19:26 ` [PATCH v2 5/9] s390x: " Adhemerval Zanella
2022-09-30 19:26 ` [PATCH v2 6/9] riscv: " Adhemerval Zanella
2022-09-30 19:26 ` [PATCH v2 7/9] arm: " Adhemerval Zanella
2022-09-30 19:26 ` Adhemerval Zanella [this message]
2022-09-30 19:26 ` [PATCH v2 9/9] Linux: optimize clone3 internal usage Adhemerval Zanella
2023-01-11 21:12   ` Carlos O'Donell
2022-10-27 16:48 ` [PATCH v2 0/9] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella Netto
2023-01-11 21:11 ` Carlos O'Donell

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