diff options
author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-12-16 10:14:11 -0500 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-12-17 09:58:13 -0500 |
commit | fa37c025c5bec6704dad714365a7f62d9cb13a36 (patch) | |
tree | dad2b099ef1c4a3c7e52978f35cdf22bb5833f90 /tools | |
parent | afcd4f6235659c611f0e62236f6a7bc0ae08af1e (diff) |
tools: Adopt rounddown_pow_of_two and deps
Will be used to make sure we pass a power of two when automatically
setting up the perf_mmap addr range length, as the kernel code
validating input on /proc/sys/kernel/perf_event_mlock_kb accepts any
integer, if we plain use it to set up the mmap lenght, we may get an
EINVAL when passing a non power of two.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-zflvep0q01dmkruf4o291l4p@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r-- | tools/include/linux/log2.h | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/tools/include/linux/log2.h b/tools/include/linux/log2.h index 141b7665d842..990b138362d6 100644 --- a/tools/include/linux/log2.h +++ b/tools/include/linux/log2.h | |||
@@ -13,6 +13,30 @@ | |||
13 | #define _TOOLS_LINUX_LOG2_H | 13 | #define _TOOLS_LINUX_LOG2_H |
14 | 14 | ||
15 | /* | 15 | /* |
16 | * deal with unrepresentable constant logarithms | ||
17 | */ | ||
18 | extern __attribute__((const, noreturn)) | ||
19 | int ____ilog2_NaN(void); | ||
20 | |||
21 | /* | ||
22 | * non-constant log of base 2 calculators | ||
23 | * - the arch may override these in asm/bitops.h if they can be implemented | ||
24 | * more efficiently than using fls() and fls64() | ||
25 | * - the arch is not required to handle n==0 if implementing the fallback | ||
26 | */ | ||
27 | static inline __attribute__((const)) | ||
28 | int __ilog2_u32(u32 n) | ||
29 | { | ||
30 | return fls(n) - 1; | ||
31 | } | ||
32 | |||
33 | static inline __attribute__((const)) | ||
34 | int __ilog2_u64(u64 n) | ||
35 | { | ||
36 | return fls64(n) - 1; | ||
37 | } | ||
38 | |||
39 | /* | ||
16 | * Determine whether some value is a power of two, where zero is | 40 | * Determine whether some value is a power of two, where zero is |
17 | * *not* considered a power of two. | 41 | * *not* considered a power of two. |
18 | */ | 42 | */ |
@@ -23,4 +47,114 @@ bool is_power_of_2(unsigned long n) | |||
23 | return (n != 0 && ((n & (n - 1)) == 0)); | 47 | return (n != 0 && ((n & (n - 1)) == 0)); |
24 | } | 48 | } |
25 | 49 | ||
50 | /* | ||
51 | * round down to nearest power of two | ||
52 | */ | ||
53 | static inline __attribute__((const)) | ||
54 | unsigned long __rounddown_pow_of_two(unsigned long n) | ||
55 | { | ||
56 | return 1UL << (fls_long(n) - 1); | ||
57 | } | ||
58 | |||
59 | /** | ||
60 | * ilog2 - log of base 2 of 32-bit or a 64-bit unsigned value | ||
61 | * @n - parameter | ||
62 | * | ||
63 | * constant-capable log of base 2 calculation | ||
64 | * - this can be used to initialise global variables from constant data, hence | ||
65 | * the massive ternary operator construction | ||
66 | * | ||
67 | * selects the appropriately-sized optimised version depending on sizeof(n) | ||
68 | */ | ||
69 | #define ilog2(n) \ | ||
70 | ( \ | ||
71 | __builtin_constant_p(n) ? ( \ | ||
72 | (n) < 1 ? ____ilog2_NaN() : \ | ||
73 | (n) & (1ULL << 63) ? 63 : \ | ||
74 | (n) & (1ULL << 62) ? 62 : \ | ||
75 | (n) & (1ULL << 61) ? 61 : \ | ||
76 | (n) & (1ULL << 60) ? 60 : \ | ||
77 | (n) & (1ULL << 59) ? 59 : \ | ||
78 | (n) & (1ULL << 58) ? 58 : \ | ||
79 | (n) & (1ULL << 57) ? 57 : \ | ||
80 | (n) & (1ULL << 56) ? 56 : \ | ||
81 | (n) & (1ULL << 55) ? 55 : \ | ||
82 | (n) & (1ULL << 54) ? 54 : \ | ||
83 | (n) & (1ULL << 53) ? 53 : \ | ||
84 | (n) & (1ULL << 52) ? 52 : \ | ||
85 | (n) & (1ULL << 51) ? 51 : \ | ||
86 | (n) & (1ULL << 50) ? 50 : \ | ||
87 | (n) & (1ULL << 49) ? 49 : \ | ||
88 | (n) & (1ULL << 48) ? 48 : \ | ||
89 | (n) & (1ULL << 47) ? 47 : \ | ||
90 | (n) & (1ULL << 46) ? 46 : \ | ||
91 | (n) & (1ULL << 45) ? 45 : \ | ||
92 | (n) & (1ULL << 44) ? 44 : \ | ||
93 | (n) & (1ULL << 43) ? 43 : \ | ||
94 | (n) & (1ULL << 42) ? 42 : \ | ||
95 | (n) & (1ULL << 41) ? 41 : \ | ||
96 | (n) & (1ULL << 40) ? 40 : \ | ||
97 | (n) & (1ULL << 39) ? 39 : \ | ||
98 | (n) & (1ULL << 38) ? 38 : \ | ||
99 | (n) & (1ULL << 37) ? 37 : \ | ||
100 | (n) & (1ULL << 36) ? 36 : \ | ||
101 | (n) & (1ULL << 35) ? 35 : \ | ||
102 | (n) & (1ULL << 34) ? 34 : \ | ||
103 | (n) & (1ULL << 33) ? 33 : \ | ||
104 | (n) & (1ULL << 32) ? 32 : \ | ||
105 | (n) & (1ULL << 31) ? 31 : \ | ||
106 | (n) & (1ULL << 30) ? 30 : \ | ||
107 | (n) & (1ULL << 29) ? 29 : \ | ||
108 | (n) & (1ULL << 28) ? 28 : \ | ||
109 | (n) & (1ULL << 27) ? 27 : \ | ||
110 | (n) & (1ULL << 26) ? 26 : \ | ||
111 | (n) & (1ULL << 25) ? 25 : \ | ||
112 | (n) & (1ULL << 24) ? 24 : \ | ||
113 | (n) & (1ULL << 23) ? 23 : \ | ||
114 | (n) & (1ULL << 22) ? 22 : \ | ||
115 | (n) & (1ULL << 21) ? 21 : \ | ||
116 | (n) & (1ULL << 20) ? 20 : \ | ||
117 | (n) & (1ULL << 19) ? 19 : \ | ||
118 | (n) & (1ULL << 18) ? 18 : \ | ||
119 | (n) & (1ULL << 17) ? 17 : \ | ||
120 | (n) & (1ULL << 16) ? 16 : \ | ||
121 | (n) & (1ULL << 15) ? 15 : \ | ||
122 | (n) & (1ULL << 14) ? 14 : \ | ||
123 | (n) & (1ULL << 13) ? 13 : \ | ||
124 | (n) & (1ULL << 12) ? 12 : \ | ||
125 | (n) & (1ULL << 11) ? 11 : \ | ||
126 | (n) & (1ULL << 10) ? 10 : \ | ||
127 | (n) & (1ULL << 9) ? 9 : \ | ||
128 | (n) & (1ULL << 8) ? 8 : \ | ||
129 | (n) & (1ULL << 7) ? 7 : \ | ||
130 | (n) & (1ULL << 6) ? 6 : \ | ||
131 | (n) & (1ULL << 5) ? 5 : \ | ||
132 | (n) & (1ULL << 4) ? 4 : \ | ||
133 | (n) & (1ULL << 3) ? 3 : \ | ||
134 | (n) & (1ULL << 2) ? 2 : \ | ||
135 | (n) & (1ULL << 1) ? 1 : \ | ||
136 | (n) & (1ULL << 0) ? 0 : \ | ||
137 | ____ilog2_NaN() \ | ||
138 | ) : \ | ||
139 | (sizeof(n) <= 4) ? \ | ||
140 | __ilog2_u32(n) : \ | ||
141 | __ilog2_u64(n) \ | ||
142 | ) | ||
143 | |||
144 | |||
145 | /** | ||
146 | * rounddown_pow_of_two - round the given value down to nearest power of two | ||
147 | * @n - parameter | ||
148 | * | ||
149 | * round the given value down to the nearest power of two | ||
150 | * - the result is undefined when n == 0 | ||
151 | * - this can be used to initialise global variables from constant data | ||
152 | */ | ||
153 | #define rounddown_pow_of_two(n) \ | ||
154 | ( \ | ||
155 | __builtin_constant_p(n) ? ( \ | ||
156 | (1UL << ilog2(n))) : \ | ||
157 | __rounddown_pow_of_two(n) \ | ||
158 | ) | ||
159 | |||
26 | #endif /* _TOOLS_LINUX_LOG2_H */ | 160 | #endif /* _TOOLS_LINUX_LOG2_H */ |