On Sat, 2012-07-07 at 01:52 +0800, wfg@xxxxxxxxxxxxxxx wrote:
> Hi Peter,
>
> Should we make the bits "unsigned"?
>
> tree: git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf/core
> head: 6a67943a18c264d5f3df436da38edb3e59adc905
> commit: 3e0091e2b6f8cd59e567f247e345a3a6ad1f6e7e [86/90] perf/x86: Save a few bytes in 'struct x86_pmu'
>
> All sparse warnings:
>
> + arch/x86/kernel/cpu/perf_event.h:377:43: sparse: dubious one-bit signed bitfield
> arch/x86/kernel/cpu/perf_event.h:378:43: sparse: dubious one-bit signed bitfield
> arch/x86/kernel/cpu/perf_event.h:379:43: sparse: dubious one-bit signed bitfield
> arch/x86/kernel/cpu/perf_event.h:380:43: sparse: dubious one-bit signed bitfield
> arch/x86/kernel/cpu/perf_event.h:381:43: sparse: dubious one-bit signed bitfield
>
> vim +377 arch/x86/kernel/cpu/perf_event.h
> 374 /*
> 375 * Intel DebugStore bits
> 376 */
> > 377 int bts :1,
> 378 bts_active :1,
> 379 pebs :1,
> 380 pebs_active :1,
Ha! yes I guess so. Thanks!
---
Subject: perf,x86: Make bitfield unsigned
From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Date: Mon Jul 09 13:50:23 CEST 2012
arch/x86/kernel/cpu/perf_event.h:377:43: sparse: dubious one-bit signed bitfield
Cc: Borislav Petkov <bp@xxxxxxxxx>
Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -374,7 +374,7 @@ struct x86_pmu {
/*
* Intel DebugStore bits
*/
- int bts :1,
+ unsigned int bts :1,
bts_active :1,
pebs :1,
pebs_active :1,
--
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