Accepting request 931976 from home:gbelinassi

- Add ExtraBuildFlags for build flags that cannot be passed to configure.

------------------( below changes from previous sr )---------------------------
- Pass livepatchable flags directly to make.
- Add optional support for livepatches (JSC #SLE-20049).
- Generate ipa-clones tarball artifact when livepatch support is enabled.

Userspace Livepatching allows your application to be updated without restarting. For a library to be livepatchable, it has to be compiled with special flags (-fpatchable-functions-entry=X,Y).

To aid the development of livepatches, ipa-clones are also generated in the build process and packed into a livepatch-devel package. This package is meant to be used by developers during their workflow: these files contains log of changes that gcc did in the compiled code that may change code layout, which must be accounted when developing a livepatch. For instance, livepatching a function which is inlined requires livepatching every function that calls it. Tools that use such files already exists in kernel-livepatching and we aim porting them to userspace livepatching as well.

OBS-URL: https://build.opensuse.org/request/show/931976
OBS-URL: https://build.opensuse.org/package/show/Base:System/glibc?expand=0&rev=606

glibc.changes

@@ -1,3 +1,10 @@
+-------------------------------------------------------------------
+Wed Nov 16 17:22:28 UTC 2021 - Giuliano Belinassi <giuliano.belinassi@suse.com>
+
+- Add ExtraBuildFlags for build flags that cannot be passed to configure.
+- Add support for livepatches (JSC #SLE-20049).
+- Generate ipa-clones tarball artifact when livepatching is enabled.
+
 -------------------------------------------------------------------
 Wed Nov 10 13:39:26 UTC 2021 - Andreas Schwab <schwab@suse.de>
 

glibc.spec

@@ -16,6 +16,24 @@
 #
 
 
+%if 0%{?sle_version} >= 150400 || 0%{?suse_version} >= 1550
+%define livepatchable 1
+
+# Set variables for livepatching.
+%define _other %{_topdir}/OTHER
+%define tar_basename glibc-livepatch-%{version}-%{release}
+%define tar_package_name %{tar_basename}.%{_arch}.tar.xz
+%define clones_dest_dir %{tar_basename}/%{_arch}
+%else
+# Unsupported operating system.
+%define livepatchable 0
+%endif
+
+%ifnarch x86_64
+# Unsupported architectures must have livepatch disabled.
+%define livepatchable 0
+%endif
+
 # Run with osc --with=fast_build to have a shorter turnaround
 # It will avoid building some parts of glibc
 %bcond_with    fast_build
@@ -61,6 +79,7 @@ ExclusiveArch:  do_not_build
 %define build_main 0
 %define build_utils 1
 %define build_testsuite 0
+%define livepatchable 0
 %endif
 %if "%flavor" == "testsuite"
 %if %{with ringdisabled}
@@ -69,6 +88,7 @@ ExclusiveArch:  do_not_build
 %define build_main 0
 %define build_utils 0
 %define build_testsuite 1
+%define livepatchable 0
 %endif
 %if 0%{?cross_arch:1}
 %define build_main 0
@@ -613,6 +633,7 @@ BuildFlags+=" -march=i686 -mtune=generic"
 %endif
 BuildCC="%__cc"
 BuildCCplus="%__cxx"
+
 #
 #now overwrite for some architectures
 #
@@ -658,6 +679,15 @@ BuildCCplus=%{cross_arch}-suse-linux-g++
 %endif
 %endif
 
+# Add build flags that cannot be passed to configure.
+ExtraBuildFlags=
+%if %{livepatchable}
+# Append necessary flags for livepatch support, if enabled. Do it on make, else
+# on configure GCC will report that it can't write the ipa-clones to /dev/ and
+# configure will fail to detect that gcc support several flags.
+ExtraBuildFlags+="-fpatchable-function-entry=16,14 -fdump-ipa-clones"
+%endif
+
 #
 # Build base glibc
 #
@@ -725,7 +755,7 @@ esac
     exit $rc;
   }
 
-make %{?_smp_mflags}
+make %{?_smp_mflags} CFLAGS="$BuildFlags $ExtraBuildFlags"
 cd ..
 
 #
@@ -824,6 +854,32 @@ make %{?_smp_mflags} -C cc-base check-abi
 %endif
 
 %install
+%if %{livepatchable}
+
+# Ipa-clones are files generated by gcc which logs changes made across
+# functions, and we need to know such changes to build livepatches
+# correctly. These files are intended to be used by the livepatch
+# developers and may be retrieved by using `osc getbinaries`.
+#
+# Create list of ipa-clones.
+find . -name "*.ipa-clones" ! -empty | sed 's/^\.\///g' |  sort > ipa-clones.list
+
+# Create ipa-clones destination folder and move clones there.
+mkdir -p ipa-clones/%{clones_dest_dir}
+while read f; do
+  _dest=ipa-clones/%{clones_dest_dir}/$f
+  mkdir -p ${_dest%/*}
+  cp $f $_dest
+done < ipa-clones.list
+
+# Create tarball with ipa-clones.
+tar cfJ %{tar_package_name} -C ipa-clones %{tar_basename}
+
+# Copy tarball to the OTHER folder to store it as artifact.
+cp %{tar_package_name} %{_other}
+
+%endif # livepatchable
+
 %if !%{build_testsuite}
 
 %if %{with usrmerged}