]>
Commit | Line | Data |
---|---|---|
49505f6f JB |
1 | Fix libbpf hashmap on (I)LP32 architectures |
2 | ||
3 | On ILP32, 64-bit result was shifted by value calculated for 32-bit long type | |
4 | and returned value was much outside hashmap capacity. | |
5 | As advised by Andrii Nakryiko, this patch uses different hashing variant for | |
6 | architectures with size_t shorter than long long. | |
7 | ||
a02a39f3 JB |
8 | --- linux-5.7/tools/lib/bpf/hashmap.h.orig 2020-06-01 01:49:15.000000000 +0200 |
9 | +++ linux-5.7/tools/lib/bpf/hashmap.h 2020-06-21 15:22:07.298466419 +0200 | |
49505f6f | 10 | @@ -11,14 +11,18 @@ |
a02a39f3 JB |
11 | #include <stdbool.h> |
12 | #include <stddef.h> | |
49505f6f JB |
13 | #include <limits.h> |
14 | -#ifndef __WORDSIZE | |
15 | -#define __WORDSIZE (__SIZEOF_LONG__ * 8) | |
a02a39f3 | 16 | -#endif |
a02a39f3 JB |
17 | |
18 | static inline size_t hash_bits(size_t h, int bits) | |
19 | { | |
20 | /* shuffle bits and return requested number of upper bits */ | |
21 | - return (h * 11400714819323198485llu) >> (__WORDSIZE - bits); | |
49505f6f JB |
22 | +#if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__) |
23 | + /* LP64 case */ | |
a02a39f3 | 24 | + return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits); |
49505f6f JB |
25 | +#elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__) |
26 | + return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits); | |
27 | +#else | |
28 | +# error "Unsupported size_t size" | |
29 | +#endif | |
a02a39f3 JB |
30 | } |
31 | ||
32 | typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx); |