From c236528e30507834a23058441c072fb69ed224f7 Mon Sep 17 00:00:00 2001 From: Michael Jeanson Date: Wed, 20 Dec 2017 14:41:29 -0500 Subject: [PATCH] jjb: fix modules arm64 crossbuild The ftrace-mod.o special case on arm64 was introduced in 4.13 and removed in 4.15-rc4, it is also being backported in stable branches. See upstream commit: commit be0f272bfc83797f70d44faca86954df62e2bbc0 Author: Ard Biesheuvel Date: Mon Nov 20 17:41:30 2017 +0000 arm64: ftrace: emit ftrace-mod.o contents through code When building the arm64 kernel with both CONFIG_ARM64_MODULE_PLTS and CONFIG_DYNAMIC_FTRACE enabled, the ftrace-mod.o object file is built with the kernel and contains a trampoline that is linked into each module, so that modules can be loaded far away from the kernel and still reach the ftrace entry point in the core kernel with an ordinary relative branch, as is emitted by the compiler instrumentation code dynamic ftrace relies on. In order to be able to build out of tree modules, this object file needs to be included into the linux-headers or linux-devel packages, which is undesirable, as it makes arm64 a special case (although a precedent does exist for 32-bit PPC). Given that the trampoline essentially consists of a PLT entry, let's not bother with a source or object file for it, and simply patch it in whenever the trampoline is being populated, using the existing PLT support routines. Signed-off-by: Michael Jeanson --- scripts/lttng-modules/param-build.sh | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/scripts/lttng-modules/param-build.sh b/scripts/lttng-modules/param-build.sh index 34ad6a9..814489c 100644 --- a/scripts/lttng-modules/param-build.sh +++ b/scripts/lttng-modules/param-build.sh @@ -100,9 +100,9 @@ prepare_lnx_sources() { make arch/powerpc/lib/crtsavres.o CC="$CC" ${koutput} fi - # On arm64 this object is required to build with ftrace support + # On arm64 between 4.13 and 1.15 this object is required to build with ftrace support if [ "${karch}" = "arm64" ]; then - if vergte "$KVERSION" "4.13-rc1"; then + if [ -f "arch/arm64/kernel/ftrace-mod.S" ]; then make arch/arm64/kernel/ftrace-mod.o CC="$CC" ${koutput} fi fi @@ -334,9 +334,9 @@ if [ "${karch}" = "powerpc" ]; then cp -a --parents arch/powerpc/lib/crtsavres.[So] "${LNXHDRDIR}/" fi -# On arm64 this object is required to build with ftrace support +# On arm64 between 4.13 and 1.15 this object is required to build with ftrace support if [ "${karch}" = "arm64" ]; then - if vergte "$KVERSION" "4.13-rc1"; then + if [ -f "arch/arm64/kernel/ftrace-mod.S" ]; then cp -a --parents arch/arm64/kernel/ftrace-mod.[So] "${LNXHDRDIR}/" fi fi -- 2.34.1