diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/x86_64/clone.S')
-rw-r--r-- | sysdeps/unix/sysv/linux/x86_64/clone.S | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/x86_64/clone.S b/sysdeps/unix/sysv/linux/x86_64/clone.S new file mode 100644 index 0000000..a2c2c9a --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86_64/clone.S @@ -0,0 +1,86 @@ +/* Copyright (C) 2001 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. */ + +#include <sysdep.h> +#define _ERRNO_H 1 +#include <bits/errno.h> +#include <asm-syntax.h> +#include <bp-sym.h> +#include <bp-asm.h> + +/* 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 from userland: + rdi: fn + rsi: child_stack + rdx: flags + rcx: arg + + The kernel expects: + rax: system call number + rdi: flags + rsi: child_stack */ + + + .text +ENTRY (BP_SYM (__clone)) + /* Sanity check arguments. */ + movq $-EINVAL,%rax + testq %rdi,%rdi /* no NULL function pointers */ + jz SYSCALL_ERROR_LABEL + testq %rsi,%rsi /* no NULL stack pointers */ + jz SYSCALL_ERROR_LABEL + + /* 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 $SYS_ify(clone),%rax + syscall + + testq %rax,%rax + jl SYSCALL_ERROR_LABEL + jz thread_start + +L(pseudo_end): + ret + +thread_start: + /* 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 JUMPTARGET (_exit) + +PSEUDO_END (BP_SYM (__clone)) + +weak_alias (BP_SYM (__clone), BP_SYM (clone)) |