forked from pool/dwarves
Jan Engelhardt
13b18b0184
- add libbpf-Fix-libbpf-hashmap-on-I-LP32-architectures.patch OBS-URL: https://build.opensuse.org/request/show/831403 OBS-URL: https://build.opensuse.org/package/show/devel:tools/dwarves?expand=0&rev=41
46 lines
1.6 KiB
Diff
46 lines
1.6 KiB
Diff
From: Jakub Bogusz <qboosh@pld-linux.org>
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Date: Thu, 9 Jul 2020 15:57:23 -0700
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Subject: libbpf: Fix libbpf hashmap on (I)LP32 architectures
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Git-commit: b2f9f1535bb93ee5fa2ea30ac1c26fa0d676154c
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Patch-mainline: 5.8-rc5
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References: x86_32 crashes fix
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On ILP32, 64-bit result was shifted by value calculated for 32-bit long type
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and returned value was much outside hashmap capacity.
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As advised by Andrii Nakryiko, this patch uses different hashing variant for
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architectures with size_t shorter than long long.
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Fixes: e3b924224028 ("libbpf: add resizable non-thread safe internal hashmap")
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Signed-off-by: Jakub Bogusz <qboosh@pld-linux.org>
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Signed-off-by: Andrii Nakryiko <andriin@fb.com>
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Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Link: https://lore.kernel.org/bpf/20200709225723.1069937-1-andriin@fb.com
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Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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---
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lib/bpf/src/hashmap.h | 10 +++++++++-
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1 file changed, 9 insertions(+), 1 deletion(-)
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--- a/lib/bpf/src/hashmap.h
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+++ b/lib/bpf/src/hashmap.h
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@@ -16,11 +16,19 @@
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#include <bits/reg.h>
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#endif
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#include "libbpf_internal.h"
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+#include <limits.h>
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static inline size_t hash_bits(size_t h, int bits)
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{
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/* shuffle bits and return requested number of upper bits */
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- return (h * 11400714819323198485llu) >> (__WORDSIZE - bits);
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+#if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)
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+ /* LP64 case */
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+ return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);
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+#elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__)
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+ return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits);
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+#else
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+# error "Unsupported size_t size"
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+#endif
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}
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typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
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