| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <tip-fce877e3a429940a986e085a41e8b57f2d922e36@git.kernel.org>
Date: Thu, 4 Feb 2010 09:57:13 GMT
From: tip-bot for Peter Zijlstra <a.p.zijlstra@...llo.nl>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
a.p.zijlstra@...llo.nl, tglx@...utronix.de, mingo@...e.hu
Subject: [tip:perf/core] bitops: Ensure the compile time HWEIGHT is only used for such
Commit-ID: fce877e3a429940a986e085a41e8b57f2d922e36
Gitweb: http://git.kernel.org/tip/fce877e3a429940a986e085a41e8b57f2d922e36
Author: Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Fri, 29 Jan 2010 13:25:12 +0100
Committer: Ingo Molnar <mingo@...e.hu>
CommitDate: Thu, 4 Feb 2010 09:59:50 +0100
bitops: Ensure the compile time HWEIGHT is only used for such
Avoid accidental misuse by failing to compile things
Suggested-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
arch/x86/kernel/cpu/perf_event.c | 10 +++++++---
include/linux/bitops.h | 33 ++++++++++++++++++++++-----------
2 files changed, 29 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 5b91992..96cfc1a 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -93,13 +93,16 @@ struct cpu_hw_events {
struct perf_event *event_list[X86_PMC_IDX_MAX]; /* in enabled order */
};
-#define EVENT_CONSTRAINT(c, n, m) { \
+#define __EVENT_CONSTRAINT(c, n, m, w) {\
{ .idxmsk64[0] = (n) }, \
.code = (c), \
.cmask = (m), \
- .weight = HWEIGHT64((u64)(n)), \
+ .weight = (w), \
}
+#define EVENT_CONSTRAINT(c, n, m) \
+ __EVENT_CONSTRAINT(c, n, m, HWEIGHT(n))
+
#define INTEL_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVTSEL_MASK)
@@ -2622,7 +2625,8 @@ void __init init_hw_perf_events(void)
register_die_notifier(&perf_event_nmi_notifier);
unconstrained = (struct event_constraint)
- EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_events) - 1, 0);
+ __EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_events) - 1,
+ 0, x86_pmu.num_events);
pr_info("... version: %d\n", x86_pmu.version);
pr_info("... bit width: %d\n", x86_pmu.event_bits);
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index ba0fd1e..25b8b2f 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -45,19 +45,30 @@ static inline unsigned long hweight_long(unsigned long w)
return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
}
-#define HWEIGHT8(w) \
- ( (!!((w) & (1ULL << 0))) + \
- (!!((w) & (1ULL << 1))) + \
- (!!((w) & (1ULL << 2))) + \
- (!!((w) & (1ULL << 3))) + \
- (!!((w) & (1ULL << 4))) + \
- (!!((w) & (1ULL << 5))) + \
- (!!((w) & (1ULL << 6))) + \
+/*
+ * Clearly slow versions of the hweightN() functions, their benefit is
+ * of course compile time evaluation of constant arguments.
+ */
+#define HWEIGHT8(w) \
+ ( BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + \
+ (!!((w) & (1ULL << 0))) + \
+ (!!((w) & (1ULL << 1))) + \
+ (!!((w) & (1ULL << 2))) + \
+ (!!((w) & (1ULL << 3))) + \
+ (!!((w) & (1ULL << 4))) + \
+ (!!((w) & (1ULL << 5))) + \
+ (!!((w) & (1ULL << 6))) + \
(!!((w) & (1ULL << 7))) )
-#define HWEIGHT16(w) (HWEIGHT8(w) + HWEIGHT8(w >> 8))
-#define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16(w >> 16))
-#define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32(w >> 32))
+#define HWEIGHT16(w) (HWEIGHT8(w) + HWEIGHT8((w) >> 8))
+#define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16((w) >> 16))
+#define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32((w) >> 32))
+
+/*
+ * Type invariant version that simply casts things to the
+ * largest type.
+ */
+#define HWEIGHT(w) HWEIGHT64((u64)(w))
/**
* rol32 - rotate a 32-bit value left
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists