| Message ID | 1346598341-20434-1-git-send-email-arnout@mind.be |
|---|---|
| State | Rejected |
| Headers | show |
Arnout, All, On Sunday 02 September 2012 17:05:41 Arnout Vandecappelle (Essensium/Mind) wrote: > Buildroot currently requires a defconfig to be supplied for the kernel: > either a custom supplied one, or one from the kernel tree. However, > the kernel can (usually) also select a default defconfig, based on > the architecture. So make this option available to buildroot. > > We also make this the default, so the user can compile a kernel with > minimal effort. > > Microblaze currently (linux-3.5) doesn't have a default defconfig. > Older versions also lack it for some architectures (e.g. mips was > introduced in 2.6.35) but that's nearly impossible to check for at > buildroot level. > > Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr> Regards, Yann E. MORIN.
Dear Arnout Vandecappelle (Essensium/Mind), On Sun, 2 Sep 2012 17:05:41 +0200, Arnout Vandecappelle (Essensium/Mind) wrote: > Buildroot currently requires a defconfig to be supplied for the kernel: > either a custom supplied one, or one from the kernel tree. However, > the kernel can (usually) also select a default defconfig, based on > the architecture. So make this option available to buildroot. > > We also make this the default, so the user can compile a kernel with > minimal effort. > > Microblaze currently (linux-3.5) doesn't have a default defconfig. > Older versions also lack it for some architectures (e.g. mips was > introduced in 2.6.35) but that's nearly impossible to check for at > buildroot level. > > Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> I'm not sure I agree with this one. On many architectures, the default defconfig doesn't necessarily make sense. For example, on ARM, the default defconfig is versatile, which is very unlikely to match the user's hardware. In the current situation, if the user only enables the "Linux kernel", he gets an error at build time telling him that building a kernel without specifying a configuration is not possible. I think this is a sane behavior that should be preserved. With this patch, the user will enable "Linux kernel", not notice that it should be configured, do the build, and then try to boot the kernel on some hardware platform... and get something that doesn't work at all. So I believe here that "compiling a kernel with minimal effort" is not possible. You _have_ to select a configuration. The only architecture on which I believe this would make sense are i386 and x86_64, because the kernel only provides one defconfig for each of them. In this case, something like: config BR2_LINUX_KERNEL_DEFCONFIG string "Defconfig name" depends on BR2_LINUX_KERNEL_USE_DEFCONFIG + default "i386" if BR2_i386 + default "x86_64" if BR2_x86_64 would be sufficient. Even though some defconfig contain so many options enabled that they take ages to build, and are a bit irrelevant to build a kernel for an embedded system, but that's a different story. Best regards, Thomas
diff --git a/linux/Config.in b/linux/Config.in index 9c63215..1165bc9 100644 --- a/linux/Config.in +++ b/linux/Config.in @@ -101,7 +101,13 @@ config BR2_LINUX_KERNEL_PATCH choice prompt "Kernel configuration" - default BR2_LINUX_KERNEL_USE_DEFCONFIG + # microblaze doesn't have an in-kernel defconfig (as of 3.5) + default BR2_LINUX_KERNEL_USE_DEFCONFIG if BR2_microblazeel || BR2_microblazebe + default BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG + +config BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG + bool "Using the default supplied by the kernel" + depends on !(BR2_microblazeel || BR2_microblazebe) config BR2_LINUX_KERNEL_USE_DEFCONFIG bool "Using a defconfig" diff --git a/linux/linux.mk b/linux/linux.mk index c4bdf90..a248ae4 100644 --- a/linux/linux.mk +++ b/linux/linux.mk @@ -146,6 +146,13 @@ endef LINUX_POST_PATCH_HOOKS += LINUX_APPLY_PATCHES +ifeq ($(BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG),y) + +define LINUX_BASE_CONFIGURE_CMDS + $(TARGET_MAKE_ENV) $(MAKE1) $(LINUX_MAKE_FLAGS) -C $(@D) defconfig +endef + +else # BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG ifeq ($(BR2_LINUX_KERNEL_USE_DEFCONFIG),y) KERNEL_SOURCE_CONFIG = $(KERNEL_ARCH_PATH)/configs/$(call qstrip,$(BR2_LINUX_KERNEL_DEFCONFIG))_defconfig @@ -153,10 +160,16 @@ else ifeq ($(BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG),y) KERNEL_SOURCE_CONFIG = $(BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE) endif -define LINUX_CONFIGURE_CMDS +define LINUX_BASE_CONFIGURE_CMDS cp $(KERNEL_SOURCE_CONFIG) $(KERNEL_ARCH_PATH)/configs/buildroot_defconfig $(TARGET_MAKE_ENV) $(MAKE1) $(LINUX_MAKE_FLAGS) -C $(@D) buildroot_defconfig rm $(KERNEL_ARCH_PATH)/configs/buildroot_defconfig +endef + +endif # BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG + +define LINUX_CONFIGURE_CMDS + $(LINUX_BASE_CONFIGURE_CMDS) $(if $(BR2_ARM_EABI), $(call KCONFIG_ENABLE_OPT,CONFIG_AEABI,$(@D)/.config), $(call KCONFIG_DISABLE_OPT,CONFIG_AEABI,$(@D)/.config))
Buildroot currently requires a defconfig to be supplied for the kernel: either a custom supplied one, or one from the kernel tree. However, the kernel can (usually) also select a default defconfig, based on the architecture. So make this option available to buildroot. We also make this the default, so the user can compile a kernel with minimal effort. Microblaze currently (linux-3.5) doesn't have a default defconfig. Older versions also lack it for some architectures (e.g. mips was introduced in 2.6.35) but that's nearly impossible to check for at buildroot level. Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> --- linux/Config.in | 8 +++++++- linux/linux.mk | 15 ++++++++++++++- 2 files changed, 21 insertions(+), 2 deletions(-)