[Buildroot] [PATCH v4] linux-headers: allow use of headers from kernel "package" selected

[Yann E. MORIN <yann.morin.1998@free.fr>]

Karoly, All,

On 2015-03-01 18:17 +0100, Karoly Kasza spake thusly:
> This change makes it possible to use exactly the same sources for both
> headers during toolchain building and for kernel building itself, even
> if custom kernel is selected.
> 
> That way users can be sure that ABI mismatch won't happen between toolchain
> and kernel.
> 
> Signed-off-by: Karoly Kasza <kaszak@gmail.com>

We've discussed this at length, both on this threads and on IRC, and
we've come to the conclusion that the implementation you proposed is not
acceptable.

However, Peter suggested an alternate path, and I've implemented a proof
of concept that seems to be working quite OK. I'll refine it and post it
on the list soonish.

In the meantime, we've marked your patch as "changes requested" on
Patchwork.

Thanks for spawning the discussion! :-)

Regards,
Yann E. MORIN.

> ---
> 
> Changes v3 -> v4:
>   - Rebased to cleanly apply again
> 
>  linux/Config.in                        |    1 +
>  linux/linux.mk                         |    7 +++++++
>  package/linux-headers/Config.in.host   |   14 ++++++++++++--
>  package/linux-headers/linux-headers.mk |    9 +++++++++
>  4 files changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/linux/Config.in b/linux/Config.in
> index c981493..30faaaf 100644
> --- a/linux/Config.in
> +++ b/linux/Config.in
> @@ -26,6 +26,7 @@ config BR2_LINUX_KERNEL_LATEST_VERSION
>  config BR2_LINUX_KERNEL_SAME_AS_HEADERS
>  	bool "Same as toolchain kernel headers"
>  	depends on BR2_TOOLCHAIN_BUILDROOT
> +	depends on !BR2_KERNEL_HEADERS_SAME_AS_KERNEL
>  	help
>  	  This option will re-use the same kernel sources as the one
>  	  that have been used for the kernel headers of the
> diff --git a/linux/linux.mk b/linux/linux.mk
> index 0b8c912..29d93db 100644
> --- a/linux/linux.mk
> +++ b/linux/linux.mk
> @@ -8,6 +8,9 @@ LINUX_VERSION = $(call qstrip,$(BR2_LINUX_KERNEL_VERSION))
>  LINUX_LICENSE = GPLv2
>  LINUX_LICENSE_FILES = COPYING
>  
> +# Compute variables as a function, so linux-headers can call it when needed
> +define BR2_LINUX_COMPUTE_VARS
> +
>  # Compute LINUX_SOURCE and LINUX_SITE from the configuration
>  ifeq ($(BR2_LINUX_KERNEL_CUSTOM_TARBALL),y)
>  LINUX_TARBALL = $(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION))
> @@ -40,6 +43,10 @@ LINUX_SITE := $(LINUX_SITE)/testing/
>  endif # -rc
>  endif
>  
> +endef
> +
> +$(eval $(BR2_LINUX_COMPUTE_VARS))
> +
>  LINUX_PATCHES = $(call qstrip,$(BR2_LINUX_KERNEL_PATCH))
>  
>  LINUX_INSTALL_IMAGES = YES
> diff --git a/package/linux-headers/Config.in.host b/package/linux-headers/Config.in.host
> index 2755f2f..7a06224 100644
> --- a/package/linux-headers/Config.in.host
> +++ b/package/linux-headers/Config.in.host
> @@ -5,6 +5,7 @@ comment "Kernel Header Options"
>  
>  choice
>  	prompt "Kernel Headers"
> +	default BR2_KERNEL_HEADERS_SAME_AS_KERNEL if BR2_LINUX_KERNEL
>  	default BR2_KERNEL_HEADERS_3_18
>  	help
>  	  Select the version of kernel header files you wish to use.
> @@ -69,6 +70,13 @@ choice
>  
>  	config BR2_KERNEL_HEADERS_VERSION
>  		bool "Manually specified Linux version"
> +
> +	config BR2_KERNEL_HEADERS_SAME_AS_KERNEL
> +		bool "Use Linux kernel specified for target"
> +		depends on BR2_LINUX_KERNEL
> +		help
> +		  Use the Linux kernel specified for the target in
> +		  the Kernel menu.
>  endchoice
>  
>  config BR2_DEFAULT_KERNEL_VERSION
> @@ -80,10 +88,12 @@ config BR2_DEFAULT_KERNEL_VERSION
>  
>  choice
>  	bool "Custom kernel headers series"
> -	depends on BR2_KERNEL_HEADERS_VERSION
> +	depends on BR2_KERNEL_HEADERS_VERSION || BR2_KERNEL_HEADERS_SAME_AS_KERNEL
>  	default BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_REALLY_OLD
>  	help
> -	  Set to the kernel headers series you manually set above.
> +	  Set to the kernel headers series you manually entered in
> +	  "linux version" field or matching version of specific kernel selected
> +	  for building in "kernel" section.
>  
>  	  This is used to hide/show some packages that have strict
>  	  requirements on the version of kernel headers.
> diff --git a/package/linux-headers/linux-headers.mk b/package/linux-headers/linux-headers.mk
> index d770927..b4a1c8d 100644
> --- a/package/linux-headers/linux-headers.mk
> +++ b/package/linux-headers/linux-headers.mk
> @@ -7,6 +7,14 @@
>  # This package is used to provide Linux kernel headers for the
>  # internal toolchain backend.
>  
> +ifeq ($(BR2_KERNEL_HEADERS_SAME_AS_KERNEL),y)
> +# Force computing the variables from the Kernel package
> +$(eval $(BR2_LINUX_COMPUTE_VARS))
> +LINUX_HEADERS_VERSION = $(call qstrip,$(BR2_LINUX_KERNEL_VERSION))
> +LINUX_HEADERS_SOURCE = $(LINUX_SOURCE)
> +LINUX_HEADERS_SITE = $(LINUX_SITE)
> +LINUX_HEADERS_SITE_METHOD = $(LINUX_SITE_METHOD)
> +else
>  LINUX_HEADERS_VERSION = $(call qstrip,$(BR2_DEFAULT_KERNEL_HEADERS))
>  ifeq ($(findstring x2.6.,x$(LINUX_HEADERS_VERSION)),x2.6.)
>  LINUX_HEADERS_SITE = $(BR2_KERNEL_MIRROR)/linux/kernel/v2.6
> @@ -14,6 +22,7 @@ else
>  LINUX_HEADERS_SITE = $(BR2_KERNEL_MIRROR)/linux/kernel/v3.x
>  endif
>  LINUX_HEADERS_SOURCE = linux-$(LINUX_HEADERS_VERSION).tar.xz
> +endif
>  
>  LINUX_HEADERS_INSTALL_STAGING = YES
>  
> -- 
> 1.7.10.4
> 
> _______________________________________________
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> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

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