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	The rpm-pkg make target currently suffers from a few issues related to
debuginfo:
1. debuginfo for things built into the kernel (vmlinux) is not available
   in any RPM produced by make rpm-pkg. This makes using tools like
   systemtap against a make rpm-pkg kernel impossible.
2. debug source for the kernel is not available. This means that
   commands like 'disas /s' in gdb, which display source intermixed with
   assembly, can only print file names/line numbers which then must be
   painstakingly resolved to actual source in a separate editor.
3. debuginfo for modules is available, but it remains bundled with the
   .ko files that contain module code, in the main kernel RPM. This is a
   waste of space for users who do not need to debug the kernel (i.e.
   most users).
Address all of these issues by additionally building a debuginfo RPM
when the kernel configuration allows for it, in line with standard
patterns followed by RPM distributors. With these changes:
1. systemtap now works (when these changes are backported to 6.11, since
   systemtap lags a bit behind in compatibility), as verified by the
   following simple test script:
   # stap -e 'probe kernel.function("do_sys_open").call { printf("%s\n", $$parms); }'
   dfd=0xffffffffffffff9c filename=0x7fe18800b160 flags=0x88800 mode=0x0
   ...
2. disas /s works correctly in gdb, with source and disassembly
   interspersed:
   # gdb vmlinux --batch -ex 'disas /s blk_op_str'
   Dump of assembler code for function blk_op_str:
   block/blk-core.c:
   125     {
      0xffffffff814c8740 <+0>:     endbr64
   127
   128             if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
      0xffffffff814c8744 <+4>:     mov    $0xffffffff824a7378,%rax
      0xffffffff814c874b <+11>:    cmp    $0x23,%edi
      0xffffffff814c874e <+14>:    ja     0xffffffff814c8768 <blk_op_str+40>
      0xffffffff814c8750 <+16>:    mov    %edi,%edi
   126             const char *op_str = "UNKNOWN";
      0xffffffff814c8752 <+18>:    mov    $0xffffffff824a7378,%rdx
   127
   128             if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
      0xffffffff814c8759 <+25>:    mov    -0x7dfa0160(,%rdi,8),%rax
   126             const char *op_str = "UNKNOWN";
      0xffffffff814c8761 <+33>:    test   %rax,%rax
      0xffffffff814c8764 <+36>:    cmove  %rdx,%rax
   129                     op_str = blk_op_name[op];
   130
   131             return op_str;
   132     }
      0xffffffff814c8768 <+40>:    jmp    0xffffffff81d01360 <__x86_return_thunk>
   End of assembler dump.
3. The size of the main kernel package goes down substantially,
   especially if many modules are built (quite typical). Here is a
   comparison of installed size of the kernel package (configured with
   allmodconfig, dwarf4 debuginfo, and module compression turned off)
   before and after this patch:
   # rpm -qi kernel-6.13* | grep -E '^(Version|Size)'
   Version     : 6.13.0postpatch+
   Size        : 1382874089
   Version     : 6.13.0prepatch+
   Size        : 17870795887
   This is a ~92% size reduction.
Note that a debuginfo package can only be produced if the following
configs are set:
- CONFIG_DEBUG_INFO=y
- CONFIG_MODULE_COMPRESS=n
- CONFIG_DEBUG_INFO_SPLIT=n
The first of these is obvious - we can't produce debuginfo if the build
does not generate it. The second two requirements can in principle be
removed, but doing so is difficult with the current approach, which uses
a generic rpmbuild script find-debuginfo.sh that processes all packaged
executables. If we want to remove those requirements the best path
forward is likely to add some debuginfo extraction/installation logic to
the modules_install target (controllable by flags). That way, it's
easier to operate on modules before they're compressed, and the logic
can be reused by all packaging targets.
Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
		
	
			
		
			
				
	
	
		
			173 lines
		
	
	
	
		
			6 KiB
		
	
	
	
		
			RPMSpec
		
	
	
	
	
	
			
		
		
	
	
			173 lines
		
	
	
	
		
			6 KiB
		
	
	
	
		
			RPMSpec
		
	
	
	
	
	
# _arch is undefined if /usr/lib/rpm/platform/*/macros was not included.
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%{!?_arch: %define _arch dummy}
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%{!?make: %define make make}
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%define makeflags %{?_smp_mflags} ARCH=%{ARCH}
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Name: kernel
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Summary: The Linux Kernel
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Version: %(echo %{KERNELRELEASE} | sed -e 's/-/_/g')
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Release: %{pkg_release}
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License: GPL
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Group: System Environment/Kernel
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Vendor: The Linux Community
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URL: https://www.kernel.org
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Source0: linux.tar.gz
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Source1: config
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Source2: diff.patch
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Provides: kernel-%{KERNELRELEASE}
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BuildRequires: bc binutils bison dwarves
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BuildRequires: (elfutils-libelf-devel or libelf-devel) flex
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BuildRequires: gcc make openssl openssl-devel perl python3 rsync
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%description
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The Linux Kernel, the operating system core itself
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%package headers
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Summary: Header files for the Linux kernel for use by glibc
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Group: Development/System
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Obsoletes: kernel-headers < %{version}
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Provides: kernel-headers = %{version}
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%description headers
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Kernel-headers includes the C header files that specify the interface
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between the Linux kernel and userspace libraries and programs.  The
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header files define structures and constants that are needed for
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building most standard programs and are also needed for rebuilding the
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glibc package.
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%if %{with_devel}
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%package devel
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Summary: Development package for building kernel modules to match the %{version} kernel
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Group: System Environment/Kernel
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AutoReqProv: no
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%description -n kernel-devel
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This package provides kernel headers and makefiles sufficient to build modules
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against the %{version} kernel package.
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%endif
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%if %{with_debuginfo}
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# list of debuginfo-related options taken from distribution kernel.spec
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# files
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%undefine _include_minidebuginfo
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%undefine _find_debuginfo_dwz_opts
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%undefine _unique_build_ids
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%undefine _unique_debug_names
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%undefine _unique_debug_srcs
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%undefine _debugsource_packages
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%undefine _debuginfo_subpackages
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%global _find_debuginfo_opts -r
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%global _missing_build_ids_terminate_build 1
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%global _no_recompute_build_ids 1
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%{debug_package}
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%endif
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# some (but not all) versions of rpmbuild emit %%debug_package with
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# %%install. since we've already emitted it manually, that would cause
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# a package redefinition error. ensure that doesn't happen
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%define debug_package %{nil}
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# later, we make all modules executable so that find-debuginfo.sh strips
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# them up. but they don't actually need to be executable, so remove the
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# executable bit, taking care to do it _after_ find-debuginfo.sh has run
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%define __spec_install_post \
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	%{?__debug_package:%{__debug_install_post}} \
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	%{__arch_install_post} \
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	%{__os_install_post} \
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	find %{buildroot}/lib/modules/%{KERNELRELEASE} -name "*.ko" -type f \\\
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		| xargs --no-run-if-empty chmod u-x
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%prep
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%setup -q -n linux
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cp %{SOURCE1} .config
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patch -p1 < %{SOURCE2}
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%build
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%{make} %{makeflags} KERNELRELEASE=%{KERNELRELEASE} KBUILD_BUILD_VERSION=%{release}
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%install
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mkdir -p %{buildroot}/lib/modules/%{KERNELRELEASE}
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cp $(%{make} %{makeflags} -s image_name) %{buildroot}/lib/modules/%{KERNELRELEASE}/vmlinuz
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# DEPMOD=true makes depmod no-op. We do not package depmod-generated files.
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%{make} %{makeflags} INSTALL_MOD_PATH=%{buildroot} DEPMOD=true modules_install
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%{make} %{makeflags} INSTALL_HDR_PATH=%{buildroot}/usr headers_install
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cp System.map %{buildroot}/lib/modules/%{KERNELRELEASE}
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cp .config %{buildroot}/lib/modules/%{KERNELRELEASE}/config
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if %{make} %{makeflags} run-command KBUILD_RUN_COMMAND='test -d ${srctree}/arch/${SRCARCH}/boot/dts' 2>/dev/null; then
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	%{make} %{makeflags} INSTALL_DTBS_PATH=%{buildroot}/lib/modules/%{KERNELRELEASE}/dtb dtbs_install
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fi
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ln -fns /usr/src/kernels/%{KERNELRELEASE} %{buildroot}/lib/modules/%{KERNELRELEASE}/build
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%if %{with_devel}
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%{make} %{makeflags} run-command KBUILD_RUN_COMMAND='${srctree}/scripts/package/install-extmod-build %{buildroot}/usr/src/kernels/%{KERNELRELEASE}'
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%endif
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{
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	echo "/lib/modules/%{KERNELRELEASE}"
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	for x in alias alias.bin builtin.alias.bin builtin.bin dep dep.bin \
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				devname softdep symbols symbols.bin weakdep; do
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		echo "%ghost /lib/modules/%{KERNELRELEASE}/modules.${x}"
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	done
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	for x in System.map config vmlinuz; do
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		echo "%ghost /boot/${x}-%{KERNELRELEASE}"
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	done
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	if [ -d "%{buildroot}/lib/modules/%{KERNELRELEASE}/dtb" ];then
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		find "%{buildroot}/lib/modules/%{KERNELRELEASE}/dtb" -printf "%%%ghost /boot/dtb-%{KERNELRELEASE}/%%P\n"
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	fi
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	echo "%exclude /lib/modules/%{KERNELRELEASE}/build"
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} > %{buildroot}/kernel.list
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# make modules executable so that find-debuginfo.sh strips them. this
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# will be undone later in %%__spec_install_post
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find %{buildroot}/lib/modules/%{KERNELRELEASE} -name "*.ko" -type f \
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	| xargs --no-run-if-empty chmod u+x
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%if %{with_debuginfo}
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# copying vmlinux directly to the debug directory means it will not get
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# stripped (but its source paths will still be collected + fixed up)
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mkdir -p %{buildroot}/usr/lib/debug/lib/modules/%{KERNELRELEASE}
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cp vmlinux %{buildroot}/usr/lib/debug/lib/modules/%{KERNELRELEASE}
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%endif
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%clean
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rm -rf %{buildroot}
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rm -f debugfiles.list debuglinks.list debugsourcefiles.list debugsources.list \
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	elfbins.list
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%post
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if [ -x /usr/bin/kernel-install ]; then
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	/usr/bin/kernel-install add %{KERNELRELEASE} /lib/modules/%{KERNELRELEASE}/vmlinuz
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fi
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for file in vmlinuz System.map config; do
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	if ! cmp --silent "/lib/modules/%{KERNELRELEASE}/${file}" "/boot/${file}-%{KERNELRELEASE}"; then
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		cp "/lib/modules/%{KERNELRELEASE}/${file}" "/boot/${file}-%{KERNELRELEASE}"
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	fi
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done
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if [ -d "/lib/modules/%{KERNELRELEASE}/dtb" ] && \
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   ! diff -rq "/lib/modules/%{KERNELRELEASE}/dtb" "/boot/dtb-%{KERNELRELEASE}" >/dev/null 2>&1; then
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	rm -rf "/boot/dtb-%{KERNELRELEASE}"
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	cp -r "/lib/modules/%{KERNELRELEASE}/dtb" "/boot/dtb-%{KERNELRELEASE}"
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fi
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if [ ! -e "/lib/modules/%{KERNELRELEASE}/modules.dep" ]; then
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	/usr/sbin/depmod %{KERNELRELEASE}
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fi
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%preun
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if [ -x /usr/bin/kernel-install ]; then
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kernel-install remove %{KERNELRELEASE}
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fi
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%files -f %{buildroot}/kernel.list
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%defattr (-, root, root)
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%exclude /kernel.list
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%files headers
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%defattr (-, root, root)
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/usr/include
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%if %{with_devel}
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%files devel
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%defattr (-, root, root)
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/usr/src/kernels/%{KERNELRELEASE}
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/lib/modules/%{KERNELRELEASE}/build
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%endif
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