On Fri, Sep 05, 2014 at 12:05:52PM +0100, Russell King - ARM Linux wrote: > On Fri, Sep 05, 2014 at 12:45:47PM +0200, Robert Richter wrote: > > On 05.09.14 10:32:40, Russell King - ARM Linux wrote: > > > On Fri, Sep 05, 2014 at 09:46:42AM +0200, Robert Richter wrote: > > > > From: Radha Mohan Chintakuntla <rchintakun...@cavium.com> > > > > > > > > Increase maximum numbers of cpus to 32. This relates to current > > > > maximal possible cpu number. Increasing this to 64 cpus will be a > > > > separate patch not part of this enablement patches. > > > > > > > > Signed-off-by: Radha Mohan Chintakuntla <rchintakun...@cavium.com> > > > > Signed-off-by: Robert Richter <rrich...@cavium.com> > > > > --- > > > > arch/arm64/Kconfig | 6 ++++++ > > > > 1 file changed, 6 insertions(+) > > > > > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > > > index fd4e81a4e1ce..77fb82b0f684 100644 > > > > --- a/arch/arm64/Kconfig > > > > +++ b/arch/arm64/Kconfig > > > > @@ -134,6 +134,11 @@ source "kernel/Kconfig.freezer" > > > > > > > > menu "Platform selection" > > > > > > > > +config ARCH_THUNDER > > > > + bool "Cavium Inc. Thunder SoC Family" > > > > + help > > > > + This enables support for Cavium's Thunder Family of SoCs. > > > > + > > > > config ARCH_VEXPRESS > > > > bool "ARMv8 software model (Versatile Express)" > > > > select ARCH_REQUIRE_GPIOLIB > > > > @@ -256,6 +261,7 @@ config NR_CPUS > > > > range 2 32 > > > > depends on SMP > > > > # These have to remain sorted largest to smallest > > > > + default "32" if ARCH_THUNDER > > > > default "8" > > > > > > Why do you need ARCH_THUNDER? If it's just to change this default, > > > > No, we need it just to enable all our drivers on the SoC. We want to > > enable the SoC by using defconfig + ARCH_THUNDER. As said in my other > > mail, I put it here to be able to base all other thunder driver patch > > sets on this initial base patch set. Otherwise this particular patch > > and also the dtb patch need to be shipped with all other driver patch > > sets. This might lead to duplicate submissions of the same patch. > > > > With doing defconfig + ARCH_THUNDER we also want to enable the max > > number of cpus that is currently supported. I only enable 32 cpus > > since booting more cpus is untested. There might be problems at the 32 > > cpu boundary. Just setting it to 64 does not mean a kernel will > > actually boot more than 32 cpus. But if it will be ack'ed, I would be > > fine to set NR_CPUS to 32 or 64 in general and independent from > > ARCH_THUNDER. > > > > For simplicity I better drop setting NR_CPUS in this patch. > > So, ARM64 will get a big long list of "config ARCH_foo" options just > to stuff lots of broken select statements into the configuration. Yes, > this may have been the norm with ARM, but it's turned out to be more > of a problem than a solution, especially as it keeps causing Kconfig > warnings when things change in the rest of the kernel tree.
Agreed; this seems more pain than it is worth. > The same is true with defconfigs - Linus threatened to delete all ARM > defconfigs except one at one point. IMO we should continue doing what we've done so far and make the ARM64 defconfig work on everything it can by default, no ARCH_* necessary. That's what most people will build and test and we shouldn't get platform-specific code (well, drivers) breaking the single image. For the extreme configurations (really tiny or really big) custom configuration being necessary is fine. That doesn't have to involve ARCH_* config options. If you want to build a custom config then you should have an idea of what you need. ARCH_* options are only necessary if someone wants a kernel tuned for a specific SoC but doesn't know anything about that SoC. Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
