1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
/*
* Spin and read/write lock operations.
*
* Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM
* Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
* Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM
* Rework to support virtual processors
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/stringify.h>
#include <linux/smp.h>
/* waiting for a spinlock... */
#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
#include <asm/hvcall.h>
#include <asm/iseries/hv_call.h>
#include <asm/smp.h>
void __spin_yield(raw_spinlock_t *lock)
{
unsigned int lock_value, holder_cpu, yield_count;
struct paca_struct *holder_paca;
lock_value = lock->slock;
if (lock_value == 0)
return;
holder_cpu = lock_value & 0xffff;
BUG_ON(holder_cpu >= NR_CPUS);
holder_paca = &paca[holder_cpu];
yield_count = holder_paca->lppaca.yield_count;
if ((yield_count & 1) == 0)
return; /* virtual cpu is currently running */
rmb();
if (lock->slock != lock_value)
return; /* something has changed */
#ifdef CONFIG_PPC_ISERIES
HvCall2(HvCallBaseYieldProcessor, HvCall_YieldToProc,
((u64)holder_cpu << 32) | yield_count);
#else
plpar_hcall_norets(H_CONFER, get_hard_smp_processor_id(holder_cpu),
yield_count);
#endif
}
/*
* Waiting for a read lock or a write lock on a rwlock...
* This turns out to be the same for read and write locks, since
* we only know the holder if it is write-locked.
*/
void __rw_yield(raw_rwlock_t *rw)
{
int lock_value;
unsigned int holder_cpu, yield_count;
struct paca_struct *holder_paca;
lock_value = rw->lock;
if (lock_value >= 0)
return; /* no write lock at present */
holder_cpu = lock_value & 0xffff;
BUG_ON(holder_cpu >= NR_CPUS);
holder_paca = &paca[holder_cpu];
yield_count = holder_paca->lppaca.yield_count;
if ((yield_count & 1) == 0)
return; /* virtual cpu is currently running */
rmb();
if (rw->lock != lock_value)
return; /* something has changed */
#ifdef CONFIG_PPC_ISERIES
HvCall2(HvCallBaseYieldProcessor, HvCall_YieldToProc,
((u64)holder_cpu << 32) | yield_count);
#else
plpar_hcall_norets(H_CONFER, get_hard_smp_processor_id(holder_cpu),
yield_count);
#endif
}
#endif
void __raw_spin_unlock_wait(raw_spinlock_t *lock)
{
while (lock->slock) {
HMT_low();
if (SHARED_PROCESSOR)
__spin_yield(lock);
}
HMT_medium();
}
EXPORT_SYMBOL(__raw_spin_unlock_wait);
|
