> -----Original Message----- > From: Russell King - ARM Linux [mailto:linux@xxxxxxxxxxxxxxxx] > Sent: Friday, November 14, 2014 7:53 AM > To: Wang, Yalin > > On Fri, Oct 31, 2014 at 01:42:44PM +0800, Wang, Yalin wrote: > > This patch add bitrev.h file to support rbit instruction, so that we > > can do bitrev operation by hardware. > > Signed-off-by: Yalin Wang <yalin.wang@xxxxxxxxxxxxxx> > > --- > > arch/arm/Kconfig | 1 + > > arch/arm/include/asm/bitrev.h | 21 +++++++++++++++++++++ > > 2 files changed, 22 insertions(+) > > create mode 100644 arch/arm/include/asm/bitrev.h > > > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index > > 89c4b5c..be92b3b 100644 > > --- a/arch/arm/Kconfig > > +++ b/arch/arm/Kconfig > > @@ -28,6 +28,7 @@ config ARM > > select HANDLE_DOMAIN_IRQ > > select HARDIRQS_SW_RESEND > > select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT) > > + select HAVE_ARCH_BITREVERSE if (CPU_V7M || CPU_V7) > > Looking at this, this is just wrong. Take a moment to consider what > happens if we build a kernel which supports both ARMv6 _and_ ARMv7 CPUs. > What happens if an ARMv6 CPU tries to execute an rbit instruction? Is it possible to build a kernel that support both CPU_V6 and CPU_V7? I mean in Kconfig, CPU_V6 = y and CPU_V7 = y ? If there is problem like you said, How about this solution: select HAVE_ARCH_BITREVERSE if ((CPU_V7M || CPU_V7) && !CPU_V6) > Second point (which isn't obvious from your submissions on-list) is that > you've loaded the patch system up with patches for other parts of the > kernel tree for which I am not responsible for. As such, I can't take > those patches without the sub-tree maintainer acking them. Also, the > commit text in those patches look weird: > > 6fire: Convert byte_rev_table uses to bitrev8 > > Use the inline function instead of directly indexing the array. > > This allows some architectures with hardware instructions for bit reversals > to eliminate the array. > > Signed-off-by: Joe Perches <(address hidden)> > Signed-off-by: Yalin Wang <(address hidden)> > > Why is Joe signing off on these patches? As his is the first sign-off, one > assumes that he was responsible for creating the patch in the first place, > but there is no From: line marking him as the author. Shouldn't his entry > be an Acked-by: ? > > Confused. For this patch, I just cherry-pick from Joe, If you are not responsible for this part, I will submit to the maintainers for these patches . Sorry for that . -- 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