On Wed, Apr 24, 2013 at 3:47 PM, Cyrill Gorcunov <gorcunov@xxxxxxxxxx> wrote: > 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. Hi, Sorry, but I don't have access to p4 hardware either. Lin Ming > > Still the patch itself is perfectly fine to me > > Reviewed-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx> > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- 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
