some more x86_64 source

1 files changed, 116 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/x86_64/clone.S b/libc/sysdeps/linux/x86_64/clone.S
new file mode 100644
index 000000000..9d244d018
--- /dev/null
+++ b/libc/sysdeps/linux/x86_64/clone.S
@@ -0,0 +1,116 @@
+/* Copyright (C) 2001, 2002, 2003, 2004 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* clone() is even more special than fork() as it mucks with stacks
+   and invokes a function in the right context after its all over.  */
+
+#define _ERRNO_H	1
+#include <bits/errno.h>
+
+#define CLONE_VM	0x00000100
+#define CLONE_THREAD	0x00010000
+
+/* The userland implementation is:
+   int clone (int (*fn)(void *arg), void *child_stack, int flags, void *arg),
+   the kernel entry is:
+   int clone (long flags, void *child_stack).
+
+   The parameters are passed in register and on the stack from userland:
+   rdi: fn
+   rsi: child_stack
+   rdx:	flags
+   rcx: arg
+   r8d:	TID field in parent
+   r9d: thread pointer
+%esp+8:	TID field in child
+
+   The kernel expects:
+   rax: system call number
+   rdi: flags
+   rsi: child_stack
+   rdx: TID field in parent
+   r10: TID field in child
+   r8:	thread pointer  */
+
+
+        .text
+.globl __clone;
+.type	__clone,@function
+.align 4;
+__clone:
+	/* Sanity check arguments.  */
+	movq	$-EINVAL,%rax
+	testq	%rdi,%rdi		/* no NULL function pointers */
+	jz	__syscall_error
+	testq	%rsi,%rsi		/* no NULL stack pointers */
+	jz	__syscall_error
+
+	/* Insert the argument onto the new stack.  */
+	subq	$16,%rsi
+	movq	%rcx,8(%rsi)
+
+	/* Save the function pointer.  It will be popped off in the
+	   child in the ebx frobbing below.  */
+	movq	%rdi,0(%rsi)
+
+	/* Do the system call.  */
+	movq	%rdx, %rdi
+	movq	%r8, %rdx
+	movq	%r9, %r8
+	movq	8(%rsp), %r10
+	movq	$__NR_clone,%rax
+
+	syscall
+
+	testq	%rax,%rax
+	jl	__syscall_error
+	jz	L(thread_start)
+
+L(pseudo_end):
+	ret
+
+L(thread_start):
+	/* Clear the frame pointer.  The ABI suggests this be done, to mark
+	   the outermost frame obviously.  */
+	xorq	%rbp, %rbp
+
+#ifdef RESET_PID
+	testq	$CLONE_THREAD, %rdi
+	jne	1f
+	testq	$CLONE_VM, %rdi
+	movl	$-1, %eax
+	jne	2f
+	movq	__NR_getpid, %rax
+	syscall
+2:	movl	%eax, %fs:PID
+	movl	%eax, %fs:TID
+1:
+#endif
+
+	/* Set up arguments for the function call.  */
+	popq	%rax		/* Function to call.  */
+	popq	%rdi		/* Argument.  */
+	call	*%rax
+	/* Call exit with return value from function call. */
+	movq	%rax, %rdi
+	call	HIDDEN_JUMPTARGET (_exit)
+
+	cfi_startproc;
+PSEUDO_END (BP_SYM (__clone))
+
+weak_alias (BP_SYM (__clone), BP_SYM (clone))