2 * Spin and read/write lock operations.
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
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.
15 #include <linux/config.h>
16 #include <linux/kernel.h>
17 #include <linux/spinlock.h>
18 #include <linux/module.h>
19 #include <linux/stringify.h>
20 #include <linux/smp.h>
22 #include <asm/hvcall.h>
23 #include <asm/iSeries/HvCall.h>
25 /* waiting for a spinlock... */
26 #if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
28 void __spin_yield(raw_spinlock_t
*lock
)
30 unsigned int lock_value
, holder_cpu
, yield_count
;
31 struct paca_struct
*holder_paca
;
33 lock_value
= lock
->slock
;
36 holder_cpu
= lock_value
& 0xffff;
37 BUG_ON(holder_cpu
>= NR_CPUS
);
38 holder_paca
= &paca
[holder_cpu
];
39 yield_count
= holder_paca
->lppaca
.yield_count
;
40 if ((yield_count
& 1) == 0)
41 return; /* virtual cpu is currently running */
43 if (lock
->slock
!= lock_value
)
44 return; /* something has changed */
45 #ifdef CONFIG_PPC_ISERIES
46 HvCall2(HvCallBaseYieldProcessor
, HvCall_YieldToProc
,
47 ((u64
)holder_cpu
<< 32) | yield_count
);
49 plpar_hcall_norets(H_CONFER
, get_hard_smp_processor_id(holder_cpu
),
55 * Waiting for a read lock or a write lock on a rwlock...
56 * This turns out to be the same for read and write locks, since
57 * we only know the holder if it is write-locked.
59 void __rw_yield(raw_rwlock_t
*rw
)
62 unsigned int holder_cpu
, yield_count
;
63 struct paca_struct
*holder_paca
;
65 lock_value
= rw
->lock
;
67 return; /* no write lock at present */
68 holder_cpu
= lock_value
& 0xffff;
69 BUG_ON(holder_cpu
>= NR_CPUS
);
70 holder_paca
= &paca
[holder_cpu
];
71 yield_count
= holder_paca
->lppaca
.yield_count
;
72 if ((yield_count
& 1) == 0)
73 return; /* virtual cpu is currently running */
75 if (rw
->lock
!= lock_value
)
76 return; /* something has changed */
77 #ifdef CONFIG_PPC_ISERIES
78 HvCall2(HvCallBaseYieldProcessor
, HvCall_YieldToProc
,
79 ((u64
)holder_cpu
<< 32) | yield_count
);
81 plpar_hcall_norets(H_CONFER
, get_hard_smp_processor_id(holder_cpu
),
87 void __raw_spin_unlock_wait(raw_spinlock_t
*lock
)
97 EXPORT_SYMBOL(__raw_spin_unlock_wait
);
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