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92 lines
2.6 KiB
ArmAsm
92 lines
2.6 KiB
ArmAsm
/* Wrapper around clone system call. RISC-V version.
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Copyright (C) 1996-2020 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 <sys/asm.h>
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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 <tls.h>
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#include "tcb-offsets.h"
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/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
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void *parent_tidptr, void *tls, void *child_tidptr) */
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.text
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LEAF (__clone)
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/* Sanity check arguments. */
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beqz a0,L (invalid) /* No NULL function pointers. */
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beqz a1,L (invalid) /* No NULL stack pointers. */
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addi a1,a1,-16 /* Reserve argument save space. */
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REG_S a0,0(a1) /* Save function pointer. */
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REG_S a3,SZREG(a1) /* Save argument pointer. */
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/* The syscall expects the args to be in different slots. */
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mv a0,a2
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mv a2,a4
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mv a3,a5
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mv a4,a6
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/* Do the system call. */
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li a7,__NR_clone
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scall
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bltz a0,L (error)
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beqz a0,L (thread_start)
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/* Successful return from the parent. */
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ret
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L (invalid):
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li a0, -EINVAL
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/* Something bad happened -- no child created. */
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L (error):
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j __syscall_error
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END (__clone)
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/* Load up the arguments to the function. Put this block of code in
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its own function so that we can terminate the stack trace with our
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debug info. */
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ENTRY (__thread_start)
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L (thread_start):
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/* Terminate call stack by noting ra is undefined. Use a dummy
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.cfi_label to force starting the FDE. */
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.cfi_label .Ldummy
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cfi_undefined (ra)
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/* Restore the arg for user's function. */
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REG_L a1,0(sp) /* Function pointer. */
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REG_L a0,SZREG(sp) /* Argument pointer. */
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/* Call the user's function. */
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jalr a1
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/* Call exit with the function's return value. */
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li a7, __NR_exit
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scall
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END (__thread_start)
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libc_hidden_def (__clone)
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weak_alias (__clone, clone)
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