[PATCH] ARM: imx6: fix SMP compilation again

[arnd@arndb.de (Arnd Bergmann)]

On Tuesday 22 July 2014 16:50:56 Shawn Guo wrote:
> On Tue, Jul 22, 2014 at 10:30:50AM +0200, Arnd Bergmann wrote:
> > My earlier patch 1fc593feaf8e ("ARM: imx: build i.MX6 functions
> > only when needed") fixed a problem with building an i.MX5 kernel,
> > but missed the corner case of building a kernel for i.MX5 with
> > SMP enabled. It is an extremely rare case that has only now
> > happened after many thousands of randconfig kernel builds.
> > 
> > The error message I get is
> > arch/arm/mach-imx/built-in.o: In function `v7_secondary_startup':
> > :(.text+0x5124): undefined reference to `v7_invalidate_l1'
> 
> I cannot reproduce it, and unsure how it happens.
> 
> The v7_invalidate_l1() is defined in arch/arm/mm/cache-v7.S, and should
> be available for i.MX5 build.
> 

Ah, you are right, I got the text wrong here, and I think I now understand
why it didn't happen earlier. Updated patch below (same patch, new
text).

8<-------------
Subject: [PATCH] ARM: imx6: fix SMP compilation again

My earlier patch 1fc593feaf8e ("ARM: imx: build i.MX6 functions
only when needed") fixed a problem with building an i.MX5 kernel,
but now the problem has returned for the case where we allow
ARMv6K SMP builds in multiplatform. With CONFIG_CPU_V7 disabled,
but i.MX3 and SMP enabled, we get this build error:

arch/arm/mach-imx/built-in.o: In function `v7_secondary_startup':
:(.text+0x5124): undefined reference to `v7_invalidate_l1'

This puts the code inside of an "ifdef CONFIG_SMP" to hopefully
do the right thing in all configurations.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index ac88599ca080..23c02932bf84 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -93,9 +93,11 @@ obj-$(CONFIG_HAVE_IMX_ANATOP) += anatop.o
 obj-$(CONFIG_HAVE_IMX_GPC) += gpc.o
 obj-$(CONFIG_HAVE_IMX_MMDC) += mmdc.o
 obj-$(CONFIG_HAVE_IMX_SRC) += src.o
+ifdef CONFIG_SOC_IMX6
 AFLAGS_headsmp.o :=-Wa,-march=armv7-a
 obj-$(CONFIG_SMP) += headsmp.o platsmp.o
 obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o
+endif
 obj-$(CONFIG_SOC_IMX6Q) += clk-imx6q.o mach-imx6q.o
 obj-$(CONFIG_SOC_IMX6SL) += clk-imx6sl.o mach-imx6sl.o
 obj-$(CONFIG_SOC_IMX6SX) += clk-imx6sx.o mach-imx6sx.o