Commit | Line | Data |
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40ef8cbc PM |
1 | /* |
2 | * Spin and read/write lock operations. | |
3 | * | |
4 | * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM | |
5 | * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM | |
6 | * Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM | |
7 | * Rework to support virtual processors | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the License, or (at your option) any later version. | |
13 | */ | |
14 | ||
40ef8cbc PM |
15 | #include <linux/kernel.h> |
16 | #include <linux/spinlock.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/stringify.h> | |
734d6524 | 19 | #include <linux/smp.h> |
40ef8cbc PM |
20 | |
21 | /* waiting for a spinlock... */ | |
22 | #if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES) | |
23 | #include <asm/hvcall.h> | |
1da44037 | 24 | #include <asm/iseries/hv_call.h> |
2249ca9d | 25 | #include <asm/smp.h> |
4f896e53 | 26 | #include <asm/firmware.h> |
40ef8cbc PM |
27 | |
28 | void __spin_yield(raw_spinlock_t *lock) | |
29 | { | |
30 | unsigned int lock_value, holder_cpu, yield_count; | |
40ef8cbc PM |
31 | |
32 | lock_value = lock->slock; | |
33 | if (lock_value == 0) | |
34 | return; | |
35 | holder_cpu = lock_value & 0xffff; | |
36 | BUG_ON(holder_cpu >= NR_CPUS); | |
3356bb9f | 37 | yield_count = lppaca[holder_cpu].yield_count; |
40ef8cbc PM |
38 | if ((yield_count & 1) == 0) |
39 | return; /* virtual cpu is currently running */ | |
40 | rmb(); | |
41 | if (lock->slock != lock_value) | |
42 | return; /* something has changed */ | |
4f896e53 SR |
43 | if (firmware_has_feature(FW_FEATURE_ISERIES)) |
44 | HvCall2(HvCallBaseYieldProcessor, HvCall_YieldToProc, | |
45 | ((u64)holder_cpu << 32) | yield_count); | |
1c56f838 | 46 | #ifdef CONFIG_PPC_SPLPAR |
4f896e53 SR |
47 | else |
48 | plpar_hcall_norets(H_CONFER, | |
49 | get_hard_smp_processor_id(holder_cpu), yield_count); | |
1c56f838 | 50 | #endif |
40ef8cbc PM |
51 | } |
52 | ||
53 | /* | |
54 | * Waiting for a read lock or a write lock on a rwlock... | |
55 | * This turns out to be the same for read and write locks, since | |
56 | * we only know the holder if it is write-locked. | |
57 | */ | |
58 | void __rw_yield(raw_rwlock_t *rw) | |
59 | { | |
60 | int lock_value; | |
61 | unsigned int holder_cpu, yield_count; | |
40ef8cbc PM |
62 | |
63 | lock_value = rw->lock; | |
64 | if (lock_value >= 0) | |
65 | return; /* no write lock at present */ | |
66 | holder_cpu = lock_value & 0xffff; | |
67 | BUG_ON(holder_cpu >= NR_CPUS); | |
3356bb9f | 68 | yield_count = lppaca[holder_cpu].yield_count; |
40ef8cbc PM |
69 | if ((yield_count & 1) == 0) |
70 | return; /* virtual cpu is currently running */ | |
71 | rmb(); | |
72 | if (rw->lock != lock_value) | |
73 | return; /* something has changed */ | |
4f896e53 SR |
74 | if (firmware_has_feature(FW_FEATURE_ISERIES)) |
75 | HvCall2(HvCallBaseYieldProcessor, HvCall_YieldToProc, | |
76 | ((u64)holder_cpu << 32) | yield_count); | |
1c56f838 | 77 | #ifdef CONFIG_PPC_SPLPAR |
4f896e53 SR |
78 | else |
79 | plpar_hcall_norets(H_CONFER, | |
80 | get_hard_smp_processor_id(holder_cpu), yield_count); | |
1c56f838 | 81 | #endif |
40ef8cbc PM |
82 | } |
83 | #endif | |
84 | ||
85 | void __raw_spin_unlock_wait(raw_spinlock_t *lock) | |
86 | { | |
87 | while (lock->slock) { | |
88 | HMT_low(); | |
89 | if (SHARED_PROCESSOR) | |
90 | __spin_yield(lock); | |
91 | } | |
92 | HMT_medium(); | |
93 | } | |
94 | ||
95 | EXPORT_SYMBOL(__raw_spin_unlock_wait); |