| 1 | /* Copyright (C) 2012-2024 Free Software Foundation, Inc. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | |
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| 4 | The GNU C Library is free software; you can redistribute it and/or |
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| 5 | modify it under the terms of the GNU Lesser General Public |
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| 6 | License as published by the Free Software Foundation; either |
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| 7 | version 2.1 of the License, or (at your option) any later version. |
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| 8 | |
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| 9 | The GNU C Library is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | Lesser General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU Lesser General Public |
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| 15 | License along with the GNU C Library; if not, see |
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| 16 | <https://www.gnu.org/licenses/>. */ |
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| 17 | |
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| 18 | #include <sysdep.h> |
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| 19 | #include <shlib-compat.h> |
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| 20 | |
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| 21 | ENTRY(__pthread_spin_lock) |
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| 22 | /* Always return zero. */ |
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| 23 | xor %eax, %eax |
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| 24 | LOCK |
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| 25 | decl 0(%rdi) |
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| 26 | jne 1f |
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| 27 | ret |
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| 28 | |
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| 29 | .align 16 |
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| 30 | 1: |
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| 31 | /* `rep nop` == `pause`. */ |
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| 32 | rep |
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| 33 | nop |
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| 34 | cmpl %eax, 0(%rdi) |
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| 35 | jle 1b |
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| 36 | /* Just repeat the `lock decl` logic here. The code size save |
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| 37 | of jumping back to entry doesn't change how many 16-byte |
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| 38 | chunks (default function alignment) that the code fits in. */ |
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| 39 | LOCK |
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| 40 | decl 0(%rdi) |
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| 41 | jne 1b |
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| 42 | ret |
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| 43 | END(__pthread_spin_lock) |
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| 44 | versioned_symbol (libc, __pthread_spin_lock, pthread_spin_lock, GLIBC_2_34) |
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| 45 | |
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| 46 | #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_2, GLIBC_2_34) |
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| 47 | compat_symbol (libpthread, __pthread_spin_lock, pthread_spin_lock, GLIBC_2_2) |
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| 48 | #endif |
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| 49 | |
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