| 1 | /* Wrapper around clone system call. |
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| 2 | Copyright (C) 1997-2024 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include <sysdep.h> |
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| 20 | #define _ERRNO_H 1 |
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| 21 | #include <bits/errno.h> |
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| 22 | |
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| 23 | /* This is the only really unusual system call in PPC linux, but not |
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| 24 | because of any weirdness in the system call itself; because of |
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| 25 | all the freaky stuff we have to do to make the call useful. */ |
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| 26 | |
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| 27 | /* int [r3] clone(int (*fn)(void *arg) [r3], void *child_stack [r4], |
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| 28 | int flags [r5], void *arg [r6], void *parent_tid [r7], |
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| 29 | void *tls [r8], void *child_tid [r9]); */ |
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| 30 | |
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| 31 | ENTRY (__clone) |
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| 32 | |
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| 33 | /* Check for child_stack == NULL || fn == NULL. */ |
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| 34 | cmpwi cr0,r4,0 |
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| 35 | cmpwi cr1,r3,0 |
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| 36 | cror cr0*4+eq,cr1*4+eq,cr0*4+eq |
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| 37 | beq- cr0,L(badargs) |
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| 38 | |
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| 39 | /* Set up stack frame for parent. */ |
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| 40 | stwu r1,-32(r1) |
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| 41 | cfi_adjust_cfa_offset (32) |
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| 42 | stmw r28,16(r1) |
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| 43 | |
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| 44 | /* Set up stack frame for child. */ |
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| 45 | clrrwi r4,r4,4 |
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| 46 | li r0,0 |
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| 47 | stwu r0,-16(r4) |
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| 48 | |
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| 49 | /* Save fn, args, stack across syscall. */ |
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| 50 | mr r30,r3 /* Function in r30. */ |
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| 51 | mr r28,r5 |
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| 52 | mr r31,r6 /* Argument in r31. */ |
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| 53 | |
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| 54 | /* 'flags' argument is first parameter to clone syscall. (The other |
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| 55 | argument is the stack pointer, already in r4.) */ |
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| 56 | mr r3,r5 |
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| 57 | |
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| 58 | /* Move the parent_tid, child_tid and tls arguments. */ |
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| 59 | mr r5,r7 |
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| 60 | mr r6,r8 |
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| 61 | mr r7,r9 |
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| 62 | |
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| 63 | /* End FDE now, because in the child the unwind info will be |
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| 64 | wrong. */ |
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| 65 | cfi_endproc |
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| 66 | |
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| 67 | /* Do the call. */ |
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| 68 | DO_CALL(SYS_ify(clone)) |
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| 69 | |
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| 70 | /* Check for child process. */ |
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| 71 | cmpwi cr1,r3,0 |
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| 72 | crandc cr1*4+eq,cr1*4+eq,cr0*4+so |
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| 73 | bne- cr1,L(parent) /* The '-' is to minimise the race. */ |
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| 74 | |
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| 75 | /* Call procedure. */ |
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| 76 | mtctr r30 |
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| 77 | mr r3,r31 |
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| 78 | bctrl |
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| 79 | DO_CALL(SYS_ify(exit)) |
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| 80 | |
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| 81 | L(parent): |
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| 82 | /* Parent. Restore registers & return. */ |
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| 83 | lmw r28,16(r1) |
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| 84 | addi r1,r1,32 |
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| 85 | bnslr+ |
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| 86 | b __syscall_error@local |
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| 87 | |
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| 88 | L(badargs): |
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| 89 | li r3,EINVAL |
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| 90 | b __syscall_error@local |
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| 91 | |
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| 92 | cfi_startproc |
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| 93 | END (__clone) |
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| 94 | |
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| 95 | libc_hidden_def (__clone) |
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| 96 | weak_alias (__clone, clone) |
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| 97 | |
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