Arch Linux

Earlier this week I submitted a patch for handling *.ko files when using options=('strip' 'debug') in a kernel PKGBUILD. Per Allan McRae's request, I'm submitting a feature request to implement split debug packages for the Arch kernel.

One negative side effect with strip+debug in the current Arch kernel PKGBUILD is that 'vmlinux' needs to stay unstripped in order for module builds to work, i.e.:

> MODPOST 1 modules
> FATAL: vmlinux has no symtab?
> /usr/src/linux-3.13.2-1-ec2/scripts/Makefile.modpost:90: recipe for
> target '__modpost' failed
> make[1]: *** [__modpost] Error 1

Note that even with the corresponding -debug package installed, the module build won't succeed.

So ideally 'vmlinux' will remain unstripped while the kernel modules do get separate debug symbols. I'm not sure I understand why vmlinux is in the main 'linux' package in the first place. I suspect it would be better placed in the linux-headers package, since it's needed for module builds and needs to remain unstripped.

My eventual solution to getting a functionally correct split debug kernel PKGBUILD was:

1. Disable module compression step to allow for splitting debug symbols.
2. Move vmlinux into the linux-headers package.
3. Set options=('!strip') for linux-headers, but options=('strip' 'debug') for the main kernel package.

Patch follows (untested against this PKGBUILD, just provided for demo purposes):

diff --git a/linux/trunk/PKGBUILD b/linux/trunk/PKGBUILD
index 68f4b04..b671789 100644
--- a/linux/trunk/PKGBUILD
+++ b/linux/trunk/PKGBUILD
@@ -11,7 +11,7 @@ arch=('i686' 'x86_64')
url="http://www.kernel.org/"
license=('GPL2')
makedepends=('xmlto' 'docbook-xsl' 'kmod' 'inetutils' 'bc')
-options=('!strip')
+options=('strip' 'debug')
source=("http://www.kernel.org/pub/linux/kernel/v3.x/${_srcname}.tar.xz"
"http://www.kernel.org/pub/linux/kernel/v3.x/patch-${pkgver}.xz"
# the main kernel config files
@@ -169,8 +169,6 @@ _package() {
rm -f "${pkgdir}"/lib/modules/${_kernver}/{source,build}
# remove the firmware
rm -rf "${pkgdir}/lib/firmware"
- # gzip -9 all modules to save 100MB of space
- find "${pkgdir}" -name '*.ko' -exec gzip -9 {} \;
# make room for external modules
ln -s "../extramodules-${_basekernel}${_kernelname:--ARCH}" "${pkgdir}/lib/modules/${_kernver}/extramodules"
# add real version for building modules and running depmod from post_install/upgrade
@@ -183,9 +181,6 @@ _package() {
# move module tree /lib -> /usr/lib
mkdir -p "${pkgdir}/usr"
mv "${pkgdir}/lib" "${pkgdir}/usr/"
-
- # add vmlinux
- install -D -m644 vmlinux "${pkgdir}/usr/lib/modules/${_kernver}/build/vmlinux"
}

_package-headers() {
@@ -193,10 +188,13 @@ _package-headers() {
provides=("kernel26${_kernelname}-headers=${pkgver}")
conflicts=("kernel26${_kernelname}-headers")
replaces=("kernel26${_kernelname}-headers")
+ options=('!strip')

install -dm755 "${pkgdir}/usr/lib/modules/${_kernver}"

cd "${srcdir}/${_srcname}"
+ install -D -m644 vmlinux \
+ "${pkgdir}/usr/lib/modules/${_kernver}/build/vmlinux"
install -D -m644 Makefile \
"${pkgdir}/usr/lib/modules/${_kernver}/build/Makefile"
install -D -m644 kernel/Makefile \