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- | 1 | # |
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- | 2 | # Copyright (C) 2001-2004 Jakub Jermar |
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- | 3 | # All rights reserved. |
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- | 4 | # |
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- | 5 | # Redistribution and use in source and binary forms, with or without |
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- | 6 | # modification, are permitted provided that the following conditions |
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- | 7 | # are met: |
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- | 8 | # |
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- | 9 | # - Redistributions of source code must retain the above copyright |
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- | 10 | # notice, this list of conditions and the following disclaimer. |
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- | 11 | # - Redistributions in binary form must reproduce the above copyright |
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- | 12 | # notice, this list of conditions and the following disclaimer in the |
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- | 13 | # documentation and/or other materials provided with the distribution. |
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- | 14 | # - The name of the author may not be used to endorse or promote products |
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- | 15 | # derived from this software without specific prior written permission. |
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- | 16 | # |
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- | 17 | # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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- | 18 | # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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- | 19 | # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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- | 20 | # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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- | 21 | # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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- | 22 | # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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- | 23 | # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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- | 24 | # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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- | 25 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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- | 26 | # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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- | 27 | # |
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- | 28 | ||
- | 29 | .text |
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- | 30 | ||
- | 31 | #ifdef CONFIG_SMP |
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- | 32 | ||
- | 33 | .global spinlock_arch |
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- | 34 | ||
- | 35 | # |
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- | 36 | # This is a bus-and-hyperthreading-friendly implementation of spinlock |
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- | 37 | # |
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- | 38 | spinlock_arch: |
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- | 39 | pushl %eax |
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- | 40 | pushl %ebx |
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- | 41 | ||
- | 42 | movl 12(%esp),%ebx |
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- | 43 | ||
- | 44 | 0: |
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- | 45 | #ifdef CONFIG_HT |
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- | 46 | pause # Pentium 4's with HT love this instruction |
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- | 47 | #endif |
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- | 48 | movl (%ebx),%eax |
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- | 49 | testl %eax,%eax |
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- | 50 | jnz 0b # lightweight looping while it is locked |
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- | 51 | incl %eax |
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- | 52 | xchgl %eax,(%ebx) # now use the atomic operation |
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- | 53 | testl %eax,%eax |
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- | 54 | jnz 0b |
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- | 55 | ||
- | 56 | popl %ebx |
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- | 57 | popl %eax |
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- | 58 | ret |
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- | 59 | ||
- | 60 | #endif |