From: Arnd Bergmann Date: Thu, 17 Dec 2015 16:45:47 +0000 (+0100) Subject: ARM: make default platform work for NOMMU X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=70722803de91a7670979dcb5748631b4e3c1b219;p=deliverable%2Flinux.git ARM: make default platform work for NOMMU Moving ARCH_VERSATILE into ARCH_MULTIPLATFORM means that it no longer works as the default target for MMU-less kernels. While we might want to get that working again in the future, it's also a rather bad default, and it makes sense to make ARM_SINGLE_V7M the default because that is what realistically all NOMMU users on ARM are using, and it actually is what gets selected by default in the absence of versatile in the choice statement. Related to this, 'allnoconfig' kernels fail to link with the new default, as they do not include a machine record: arm-linux-gnueabi-ld: no machine record defined For ARCH_MULTIPLATFORM kernels, we avoid this error by using a default machine descriptor that works for all trivial platforms, like ARCH_VIRT. The same reasoning applies for ARM_SINGLE_V7M, as that can also boot with empty machine descriptors both on qemu and on real hardware, as long as all the drivers are present. We could also follow up with a patch to remove the existing machine descriptors for the ARMv7M platforms, the only callback pointer the four platforms contain today is the armv7m_restart handler and we can simply make that the default for v7M with an add-on patch. Signed-off-by: Arnd Bergmann --- diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 72c1df041ae8..a0fda44551ec 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -313,7 +313,7 @@ config MMU # choice prompt "ARM system type" - default ARCH_VERSATILE if !MMU + default ARM_SINGLE_ARMV7M if !MMU default ARCH_MULTIPLATFORM if MMU config ARCH_MULTIPLATFORM diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 65addcbf5b30..2e26016a91a5 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -211,7 +211,7 @@ const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys) { const struct machine_desc *mdesc, *mdesc_best = NULL; -#ifdef CONFIG_ARCH_MULTIPLATFORM +#if defined(CONFIG_ARCH_MULTIPLATFORM) || defined(CONFIG_ARM_SINGLE_ARMV7M) DT_MACHINE_START(GENERIC_DT, "Generic DT based system") MACHINE_END