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116 lines
3.0 KiB
ArmAsm
116 lines
3.0 KiB
ArmAsm
/* Copyright (C) 1996-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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/* clone() is even more special than fork() as it mucks with stacks
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and invokes a function in the right context after its all over. */
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#include <sysdep.h>
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#define _ERRNO_H 1
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#include <bits/errno.h>
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#include <asm-syntax.h>
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/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
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pid_t *ptid, struct user_desc *tls, pid_t *ctid); */
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#define PARMS 4 /* no space for saved regs */
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#define FUNC PARMS
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#define STACK FUNC+4
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#define FLAGS STACK+4
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#define ARG FLAGS+4
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#define PTID ARG+4
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#define TLS PTID+4
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#define CTID TLS+4
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#define __NR_clone 120
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#define SYS_clone 120
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.text
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ENTRY (__clone)
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/* Sanity check arguments. */
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movl $-EINVAL,%eax
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movl FUNC(%esp),%ecx /* no NULL function pointers */
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testl %ecx,%ecx
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jz SYSCALL_ERROR_LABEL
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movl STACK(%esp),%ecx /* no NULL stack pointers */
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testl %ecx,%ecx
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jz SYSCALL_ERROR_LABEL
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/* Insert the argument onto the new stack. Make sure the new
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thread is started with an alignment of (mod 16). */
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andl $0xfffffff0, %ecx
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subl $28,%ecx
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movl ARG(%esp),%eax /* no negative argument counts */
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movl %eax,12(%ecx)
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/* Save the function pointer as the zeroth argument.
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It will be popped off in the child in the ebx frobbing below. */
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movl FUNC(%esp),%eax
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movl %eax,8(%ecx)
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/* Don't leak any information. */
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movl $0,4(%ecx)
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/* Do the system call */
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pushl %ebx
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cfi_adjust_cfa_offset (4)
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pushl %esi
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cfi_adjust_cfa_offset (4)
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pushl %edi
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cfi_adjust_cfa_offset (4)
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movl TLS+12(%esp),%esi
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cfi_rel_offset (esi, 4)
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movl PTID+12(%esp),%edx
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movl FLAGS+12(%esp),%ebx
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cfi_rel_offset (ebx, 8)
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movl CTID+12(%esp),%edi
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cfi_rel_offset (edi, 0)
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movl $SYS_ify(clone),%eax
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/* Remember the flag value. */
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movl %ebx, (%ecx)
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/* End FDE now, because in the child the unwind info will be
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wrong. */
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cfi_endproc
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int $0x80
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popl %edi
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popl %esi
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popl %ebx
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test %eax,%eax
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jl SYSCALL_ERROR_LABEL
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jz L(thread_start)
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ret
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L(thread_start):
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cfi_startproc;
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/* Clearing frame pointer is insufficient, use CFI. */
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cfi_undefined (eip);
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/* Note: %esi is zero. */
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movl %esi,%ebp /* terminate the stack frame */
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call *%ebx
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movl %eax, %ebx
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movl $SYS_ify(exit), %eax
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ENTER_KERNEL
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PSEUDO_END (__clone)
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libc_hidden_def (__clone)
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weak_alias (__clone, clone)
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