> -----Original Message----- > From: Russell King - ARM Linux [mailto:linux@xxxxxxxxxxxxxxxx] > Sent: Friday, January 09, 2015 2:41 AM > To: Wang, Yalin > Cc: 'Will Deacon'; 'Ard Biesheuvel'; 'linux-kernel@xxxxxxxxxxxxxxx'; > 'akinobu.mita@xxxxxxxxx'; 'linux-mm@xxxxxxxxx'; 'Joe Perches'; 'linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx' > Subject: Re: [RFC V6 2/3] arm:add bitrev.h file to support rbit instruction > > On Mon, Nov 17, 2014 at 10:38:58AM +0800, Wang, Yalin wrote: > > Joe has submitted patches to maintainers, So we need wait for them to > > be accepted . > > I ran these patches through my autobuilder, and while most builds didn't > seem to be a problem, the randconfigs found errors: > > /tmp/ccbiuDjS.s:137: Error: selected processor does not support ARM mode > `rbit r3,r2' > /tmp/ccbiuDjS.s:145: Error: selected processor does not support ARM mode > `rbit r0,r1' > make[4]: *** [drivers/iio/amplifiers/ad8366.o] Error 1 > > /tmp/ccFhnoO3.s:6789: Error: selected processor does not support ARM mode > `rbit r2,r2' > make[4]: *** [drivers/mtd/devices/docg3.o] Error 1 > > /tmp/cckMf2pp.s:239: Error: selected processor does not support ARM mode > `rbit ip,ip' > /tmp/cckMf2pp.s:241: Error: selected processor does not support ARM mode > `rbit r2,r2' > /tmp/cckMf2pp.s:248: Error: selected processor does not support ARM mode > `rbit lr,lr' > /tmp/cckMf2pp.s:250: Error: selected processor does not support ARM mode > `rbit r3,r3' > make[5]: *** [drivers/video/fbdev/nvidia/nvidia.o] Error 1 > > /tmp/ccTgULsO.s:1151: Error: selected processor does not support ARM mode > `rbit r1,r1' > /tmp/ccTgULsO.s:1158: Error: selected processor does not support ARM mode > `rbit r0,r0' > /tmp/ccTgULsO.s:1164: Error: selected processor does not support ARM mode > `rbit ip,ip' > /tmp/ccTgULsO.s:1166: Error: selected processor does not support ARM mode > `rbit r3,r3' > /tmp/ccTgULsO.s:1227: Error: selected processor does not support ARM mode > `rbit r5,r5' > /tmp/ccTgULsO.s:1229: Error: selected processor does not support ARM mode > `rbit lr,lr' > /tmp/ccTgULsO.s:1236: Error: selected processor does not support ARM mode > `rbit r0,r0' > /tmp/ccTgULsO.s:1238: Error: selected processor does not support ARM mode > `rbit r3,r3' > make[5]: *** [drivers/video/fbdev/nvidia/nv_accel.o] Error 1 > > The root cause is that the kernel being built is supposed to support both > ARMv7 and ARMv6K CPUs. However, "rbit" is only available on > ARMv6T2 (thumb2) and ARMv7, and not plain ARMv6 or ARMv6K CPUs. > In the patch that you applied: 8205/1 add bitrev.h file to support rbit instruction I have add : + select HAVE_ARCH_BITREVERSE if ((CPU_V7M || CPU_V7) && !CPU_V6) If you build kernel support ARMv6K, should CONFIG_CPU_V6=y, isn't it ? Then will not build hardware rbit instruction, isn't it ? Thanks -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href