On Wed, Apr 24, 2013 at 09:26:30AM +0200, Ingo Molnar wrote: > > * Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > > And there's quite a lot of them. Even in my (fairly small) config I use on > > my desktop. And the first warnings I see are in x86 code: > > > > arch/x86/kernel/traps.c:405:16: warning: implicit unsigned widening > > cast of a '~' expression > > arch/x86/kernel/cpu/perf_event_p4.c:912:15: warning: implicit unsigned > > widening cast of a '~' expression > > Hm, the perf_event_p4.c code is indeed confused. > > I think the bug is real but probably benign in effect: we allow narrower > values into the MSR register than probably intended. Only a couple of low > bits are reserved AFAICS. > > Here's an (untested!) patch that tries to untangle it all: it just moves > to clean 64-bit types everywhere - these MSRs are 64-bit wide regardless > of whether we run on 32-bit or not. > > Would be nice if someone with a working P4 could test it - Cyrill? [It > should also be double checked whether the high words are really not > reserved and can be written to ...] Hi Ingo! Ufortunately I don't have access to real p4 hardware, thus I'm CC'ing Ming who has been helping a lot in testing this code pieces. Still the patch itself is perfectly fine to me Reviewed-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
