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1 | # |
1 | # |
2 | # Copyright (C) 2001-2004 Jakub Jermar |
2 | # Copyright (c) 2001-2004 Jakub Jermar |
3 | # All rights reserved. |
3 | # All rights reserved. |
4 | # |
4 | # |
5 | # Redistribution and use in source and binary forms, with or without |
5 | # Redistribution and use in source and binary forms, with or without |
6 | # modification, are permitted provided that the following conditions |
6 | # modification, are permitted provided that the following conditions |
7 | # are met: |
7 | # are met: |
8 | # |
8 | # |
9 | # - Redistributions of source code must retain the above copyright |
9 | # - Redistributions of source code must retain the above copyright |
10 | # notice, this list of conditions and the following disclaimer. |
10 | # notice, this list of conditions and the following disclaimer. |
11 | # - Redistributions in binary form must reproduce the above copyright |
11 | # - Redistributions in binary form must reproduce the above copyright |
12 | # notice, this list of conditions and the following disclaimer in the |
12 | # notice, this list of conditions and the following disclaimer in the |
13 | # documentation and/or other materials provided with the distribution. |
13 | # documentation and/or other materials provided with the distribution. |
14 | # - The name of the author may not be used to endorse or promote products |
14 | # - The name of the author may not be used to endorse or promote products |
15 | # derived from this software without specific prior written permission. |
15 | # derived from this software without specific prior written permission. |
16 | # |
16 | # |
17 | # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | # |
27 | # |
28 | 28 | ||
29 | .text |
29 | .text |
30 | 30 | ||
31 | #ifdef CONFIG_SMP |
31 | #ifdef CONFIG_SMP |
32 | 32 | ||
33 | .global spinlock_arch |
33 | .global spinlock_arch |
34 | 34 | ||
35 | # |
35 | # |
36 | # This is a bus-and-hyperthreading-friendly implementation of spinlock |
36 | # This is a bus-and-hyperthreading-friendly implementation of spinlock |
37 | # |
37 | # |
38 | spinlock_arch: |
38 | spinlock_arch: |
39 | pushl %eax |
39 | pushl %eax |
40 | pushl %ebx |
40 | pushl %ebx |
41 | 41 | ||
42 | movl 12(%esp),%ebx |
42 | movl 12(%esp),%ebx |
43 | 43 | ||
44 | 0: |
44 | 0: |
45 | #ifdef CONFIG_HT |
45 | #ifdef CONFIG_HT |
46 | pause # Pentium 4's with HT love this instruction |
46 | pause # Pentium 4's with HT love this instruction |
47 | #endif |
47 | #endif |
48 | movl (%ebx),%eax |
48 | movl (%ebx),%eax |
49 | testl %eax,%eax |
49 | testl %eax,%eax |
50 | jnz 0b # lightweight looping while it is locked |
50 | jnz 0b # lightweight looping while it is locked |
51 | incl %eax |
51 | incl %eax |
52 | xchgl %eax,(%ebx) # now use the atomic operation |
52 | xchgl %eax,(%ebx) # now use the atomic operation |
53 | testl %eax,%eax |
53 | testl %eax,%eax |
54 | jnz 0b |
54 | jnz 0b |
55 | 55 | ||
56 | popl %ebx |
56 | popl %ebx |
57 | popl %eax |
57 | popl %eax |
58 | ret |
58 | ret |
59 | 59 | ||
60 | #endif |
60 | #endif |
61 | 61 |