From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Michael Neuling To: Chen Gang Subject: Re: [Suggestion] PowerPC: kernel: cross compiling issue with allmodconfig In-reply-to: <514AA0D9.1090509@asianux.com> References: <51428C81.6000204@asianux.com> <25841.1363323174@ale.ozlabs.ibm.com> <5142AE27.7060003@asianux.com> <514AA0D9.1090509@asianux.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Date: Fri, 22 Mar 2013 09:54:46 +1100 Message-ID: <10123.1363906486@ale.ozlabs.ibm.com> Cc: sfr@canb.auug.org.au, matt@ozlabs.org, "linux-kernel@vger.kernel.org" , "paulus@samba.org" , imunsie@au1.ibm.com, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Chen Gang wrote: > Hello All: >=20 > summary: > the root cause is no enough room in exception area (0x5500 -- 0x7000). >=20 > it is caused by the patches "for saving/restre PPR": > they consumed much space of this area (0x5500 -- 0x7000). > for pseries_defconfig and ppc64_defconfig, it is still ok. > but for allmodconfig and "some additional config", it will cause issu= e. >=20 > the solving patch "Make room in exception vector area" can make room la= rger. > it can let "some additional config" ok. > but for allmodconfig, it is still not enough. >=20 >=20 > details > reason: > it is caused by: > commit number: 13e7a8e846c2ea38a552b986ea49332f965bbb7a > commit number: 44e9309f1f357794b7ae93d5f3e3e6f11d2b8a7f > they are "for saving/restore PPR" > by Haren Myneni Thu, 6 Dec 2012 > compiling result: > pseries_defconfig: pass (cpu for POWER7) > ppc64_defconfig: pass (cpu for POWER7) > allmodconfig: failed (cpu for POWER7) >=20 > analysing: > solving patch: > ------------------------------------------------------------------ > commit number: 61383407677aef05928541a00678591abea2d84c > Author: Benjamin Herrenschmidt > Date: Thu Jan 10 17:44:19 2013 +1100 >=20 > powerpc: Make room in exception vector area >=20=20=20=20=20 > The FWNMI region is fixed at 0x7000 and the vector are now > overflowing that with some configurations. Fix that by moving > some hash management code out of that region as it doesn't need > to be that close to the call sites (isn't accessed using > conditional branches). > ------------------------------------------------------------------ >=20 > but for allmodconfig (not only for "some configurations"): > it really can reduce much overflow bytes, > (maybe from hundreds bytes to dozens bytes) > but still not enough (still content overflow bytes) >=20 > additional trying: > after del CONFIG_VSX and CONFIG_PPC_970_NAP in allmodconfig, > (will reduce dozens bytes in the region .0x5500 -- .0x7000) > it can pass compiling (not overflow). >=20 >=20 > next: > I am sorry: > I am not quite familiar with the detail features of powerpc. > it seems I am not the suitable member to continue trying. >=20 > I prefer Benjamin to continue trying (just like what he has done). >=20 > if Benjamin will not do it (e.g. maybe no time to do) > I should continue: "make additional room in exception vector area". > (if get no reply within a week: before 2013-03-28, I should continu= e) >=20 >=20 >=20 > welcome any members' (especially Benjamin) suggestions or completions. This is great, thanks a lot.=20=20 If you want this to be picked up by the maintainer, you'll need to add your signed-off-by. The signed-off-by is to indicate that your happy for it to be included and that you're legally allowed to do so. See http://gerrit.googlecode.com/svn/documentation/2.0/user-signedoffby.html for more info. Mikey >=20 > thanks. >=20 > :-) >=20 >=20 > On 2013=E5=B9=B403=E6=9C=8815=E6=97=A5 13:14, Chen Gang wrote: > > =E4=BA=8E 2013=E5=B9=B403=E6=9C=8815=E6=97=A5 12:52, Michael Neuling = =E5=86=99=E9=81=93: > >> Yep it's a known problem but no one has bothered to fix it since it > >> doesn't happen in a config that anyone cares about like > >> pseries_defconfig and ppc64_defconfig. We've been moving code around = in > >> this area a lot recently hence the breakage. > >> > >> It should be fixed though. Patches welcome. :-) > >=20 > > thanks, and I should try, and very glad to try. > >=20 > > :-) :-) > >=20 > > excuse me, I try to provide related patch within this month (2013-03-= 31), is it ok ? > > the reason is: > > I am not familiar with ppc assembly code, neither ppc kernel, > > so need additional time resource. > > (originally, I worked for x86(_64) core dump analysing for kernel= and user programs) > >=20 > > thanks. > >=20 >=20 >=20 > --=20 > Chen Gang >=20 > Asianux Corporation >=20