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
98
99
100
101
102
103
104
105
106
107
|
/* -*- c -*-
*
* Copyright (c) 2004-2005 The Trustees of Indiana University.
* All rights reserved.
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2007-2008 Cisco, Inc. All rights reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#include "plpa_config.h"
#include "plpa.h"
#include "plpa_internal.h"
#include <errno.h>
#include <sys/syscall.h>
#include <unistd.h>
#if PLPA_WANT_VALGRIND_SUPPORT
#include "valgrind/memcheck.h"
#endif
/* Cache, just to make things a little more efficient */
static PLPA_NAME(api_type_t) cache = PLPA_NAME_CAPS(PROBE_UNSET);
/* The len value we find - not in public header, but used by the lib */
size_t PLPA_NAME(len) = 0;
int PLPA_NAME(api_probe_init)(void)
{
PLPA_NAME(cpu_set_t) mask;
int rc;
size_t len;
for (len = sizeof(mask); len != 0; len >>= 1) {
rc = syscall(__NR_sched_getaffinity, 0, len, &mask);
if (rc >= 0) {
/* OK, kernel is happy with a get(). Validate w/ a set(). */
/* Note that kernel may have told us the "proper" size */
size_t tmp = (0 != rc) ? ((size_t) rc) : len;
/* Pass mask=NULL, expect errno==EFAULT if tmp was OK
as a length */
#if PLPA_WANT_VALGRIND_SUPPORT
/* Lie to Valgrind and say that this memory is addressible
so that we don't get a false positive here -- we *know*
that 0 is unaddressible; that's the whole point of this
test (to see what error NR_sched_set_affinity will
return). So let's not see a warning from Valgrind from
something that we know is wrong. :-) */
VALGRIND_MAKE_MEM_DEFINED(0, len);
#endif
rc = syscall(__NR_sched_setaffinity, 0, tmp, NULL);
#if PLPA_WANT_VALGRIND_SUPPORT
VALGRIND_MAKE_MEM_UNDEFINED(0, len);
VALGRIND_MAKE_MEM_NOACCESS(0, len);
#endif
if ((rc < 0) && (errno == EFAULT)) {
cache = PLPA_NAME_CAPS(PROBE_OK);
PLPA_NAME(len) = tmp;
rc = 0;
break;
}
}
if (errno == ENOSYS) {
break; /* No point in looping */
}
}
if (rc >= 0) {
/* OK */
} else if (errno == ENOSYS) {
/* Kernel returns ENOSYS because there is no support for
processor affinity */
cache = PLPA_NAME_CAPS(PROBE_NOT_SUPPORTED);
} else {
/* Unknown! */
cache = PLPA_NAME_CAPS(PROBE_UNKNOWN);
}
return 0;
}
int PLPA_NAME(api_probe)(PLPA_NAME(api_type_t) *api_type)
{
int ret;
/* Check to see that we're initialized */
if (!PLPA_NAME(initialized)) {
if (0 != (ret = PLPA_NAME(init)())) {
return ret;
}
}
/* Check for bozo arguments */
if (NULL == api_type) {
return EINVAL;
}
/* All done */
*api_type = cache;
return 0;
}
|
