On Thu Oct 16, 2014 at 23:33:28 +0300, Uwe Geuder wrote:
On 13 October 2014 21:19, Adam Lackorzynski adam@os.inf.tu-dresden.de wrote:
Does the virtual CPU seen by L4Linux need to control/use the SCU or is that something made completely transparent by the virtual cpu offered by L4?
User programs, such as L4Linux, have nothing to do with the SCU, i.e. it is completely transparent.
OK, good.
So I measured again and could not find any effects whether l4x_cpus=3 is present or not.
Next I looked at the code what l4x_cpus= does. And indeed it does nothing. To be more exact all it does is inside #ifdef CONFIG_SMP. You did not explicitly say that I should disable that option, but I still concluded I should do so to get rid of the build failures.
CONFIG_SMP must be enabled.
But as I wrote before, I had not been able to build with that option enabled
Next I looked at our L4Linux configuration and indeed CONFIG_SMP was not set. However after enabling it the kernel does no longer build:
arch/arm/mach-imx/built-in.o: In function `imx_smp_prepare': /home/geuder/projects/c4c/l4-bundle/l4linux/arch/arm/mach-imx/platsmp.c:79: undefined reference to `scu_enable' /home/geuder/projects/c4c/l4-bundle/l4linux/arch/arm/mach-imx/platsmp.c:79: undefined reference to `scu_enable' arch/arm/mach-imx/built-in.o: In function `imx_smp_init_cpus': /home/geuder/projects/c4c/l4-bundle/l4linux/arch/arm/mach-imx/platsmp.c:71: undefined reference to `scu_get_core_count' arch/arm/mach-imx/built-in.o: In function `v7_secondary_startup': /home/geuder/projects/c4c/l4-bundle/l4linux/arch/arm/mach-imx/headsmp.S:33: undefined reference to `v7_invalidate_l1' /home/geuder/projects/c4c/l4-bundle/l4linux/arch/arm/mach-imx/headsmp.S:35: undefined reference to `secondary_startup'
So if CONFIG_SMP is needed to be selected, how can I solve the build problems?
Are there any build issues when you use an unmodified L4Linux, i.e. one that does not have any adaptions for imx?
Adam