At Thu, 13 Nov 2014 16:05:30 -0800, Joe Perches wrote: > > On Thu, 2014-11-13 at 23:53 +0000, Russell King - ARM Linux wrote: > > 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? > > > > 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? > > Shouldn't his entry be an Acked-by: ? > > I didn't sign off on or ack the "add bitrev.h" patch. > > I created 2 patches that converted direct uses of byte_rev_table > to that bitrev8 static inline. One of them is already in -next > > 7a1283d8f5298437a454ec477384dcd9f9f88bac carl9170: Convert byte_rev_table uses to bitrev8 > > The other hasn't been applied. > > https://lkml.org/lkml/2014/10/28/1056 > > Maybe Takashi Iwai will get around to it one day. It was not clear to me whether I should apply it individually from others in the whole thread. Your description looked as if it makes sense only with ARM's bitrev8 support. So, again: should I apply this now to my tree? Takashi -- 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>