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Diffstat (limited to 'REORG.TODO/sysdeps/unix/sysv/linux/x86_64/clone.S')
-rw-r--r-- | REORG.TODO/sysdeps/unix/sysv/linux/x86_64/clone.S | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/unix/sysv/linux/x86_64/clone.S b/REORG.TODO/sysdeps/unix/sysv/linux/x86_64/clone.S new file mode 100644 index 0000000000..d5c2d07885 --- /dev/null +++ b/REORG.TODO/sysdeps/unix/sysv/linux/x86_64/clone.S @@ -0,0 +1,107 @@ +/* Copyright (C) 2001-2017 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 + <http://www.gnu.org/licenses/>. */ + +/* 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> + +#define CLONE_VM 0x00000100 + +/* 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 +ENTRY (__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 %r8, %rdx + movq %r9, %r8 + mov 8(%rsp), %R10_LP + movl $SYS_ify(clone),%eax + + /* End FDE now, because in the child the unwind info will be + wrong. */ + cfi_endproc; + syscall + + testq %rax,%rax + jl SYSCALL_ERROR_LABEL + jz L(thread_start) + + ret + +L(thread_start): + cfi_startproc; + /* Clearing frame pointer is insufficient, use CFI. */ + cfi_undefined (rip); + /* Clear the frame pointer. The ABI suggests this be done, to mark + the outermost frame obviously. */ + xorl %ebp, %ebp + + /* 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_endproc; + + cfi_startproc; +PSEUDO_END (__clone) + +libc_hidden_def (__clone) +weak_alias (__clone, clone) |