| /* Wrapper around clone system call. RISC-V version. |
| Copyright (C) 1996-2018 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 <sys/asm.h> |
| #include <sysdep.h> |
| #define _ERRNO_H 1 |
| #include <bits/errno.h> |
| #include <tls.h> |
| #include "tcb-offsets.h" |
| |
| /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, |
| void *parent_tidptr, void *tls, void *child_tidptr) */ |
| |
| .text |
| LEAF (__clone) |
| |
| /* Sanity check arguments. */ |
| beqz a0,L (invalid) /* No NULL function pointers. */ |
| beqz a1,L (invalid) /* No NULL stack pointers. */ |
| |
| addi a1,a1,-16 /* Reserve argument save space. */ |
| REG_S a0,0(a1) /* Save function pointer. */ |
| REG_S a3,SZREG(a1) /* Save argument pointer. */ |
| |
| /* The syscall expects the args to be in different slots. */ |
| mv a0,a2 |
| mv a2,a4 |
| mv a3,a5 |
| mv a4,a6 |
| |
| /* Do the system call. */ |
| li a7,__NR_clone |
| scall |
| |
| bltz a0,L (error) |
| beqz a0,L (thread_start) |
| |
| /* Successful return from the parent. */ |
| ret |
| |
| L (invalid): |
| li a0, -EINVAL |
| /* Something bad happened -- no child created. */ |
| L (error): |
| j __syscall_error |
| END (__clone) |
| |
| /* Load up the arguments to the function. Put this block of code in |
| its own function so that we can terminate the stack trace with our |
| debug info. */ |
| |
| ENTRY (__thread_start) |
| L (thread_start): |
| /* Restore the arg for user's function. */ |
| REG_L a1,0(sp) /* Function pointer. */ |
| REG_L a0,SZREG(sp) /* Argument pointer. */ |
| |
| /* Call the user's function. */ |
| jalr a1 |
| |
| /* Call exit with the function's return value. */ |
| li a7, __NR_exit |
| scall |
| |
| END (__thread_start) |
| |
| libc_hidden_def (__clone) |
| weak_alias (__clone, clone) |
