| Message ID | 20240122113955.45594-1-michal.orzel@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] lib{fdt,elf}: move lib{fdt,elf}-temp.o and their deps to $(targets) | expand |
On Mon, Jan 22, 2024 at 12:39:55PM +0100, Michal Orzel wrote: > At the moment, trying to run xencov read/reset (calling SYSCTL_coverage_op > under the hood) results in a crash. This is due to a profiler trying to > access data in the .init.* sections (libfdt for Arm and libelf for x86) > that are stripped after boot. Normally, the build system compiles any > *.init.o file without COV_FLAGS. However, these two libraries are > handled differently as sections will be renamed to init after linking. > > To override COV_FLAGS to empty for these libraries, lib{fdt,elf}.o were > added to nocov-y. This worked until e321576f4047 ("xen/build: start using > if_changed") that added lib{fdt,elf}-temp.o and their deps to extra-y. > This way, even though these objects appear as prerequisites of > lib{fdt,elf}.o and the settings should propagate to them, make can also > build them as a prerequisite of __build, in which case COV_FLAGS would > still have the unwanted flags. Fix it by switching to $(targets) instead. > > Also, for libfdt, append libfdt.o to nocov-y only if CONFIG_OVERLAY_DTB > is not set. Otherwise, there is no section renaming and we should be able > to run the coverage. > > Fixes: e321576f4047 ("xen/build: start using if_changed") > Signed-off-by: Michal Orzel <michal.orzel@amd.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Thanks,
On 22.01.2024 15:46, Anthony PERARD wrote: > On Mon, Jan 22, 2024 at 12:39:55PM +0100, Michal Orzel wrote: >> At the moment, trying to run xencov read/reset (calling SYSCTL_coverage_op >> under the hood) results in a crash. This is due to a profiler trying to >> access data in the .init.* sections (libfdt for Arm and libelf for x86) >> that are stripped after boot. Normally, the build system compiles any >> *.init.o file without COV_FLAGS. However, these two libraries are >> handled differently as sections will be renamed to init after linking. >> >> To override COV_FLAGS to empty for these libraries, lib{fdt,elf}.o were >> added to nocov-y. This worked until e321576f4047 ("xen/build: start using >> if_changed") that added lib{fdt,elf}-temp.o and their deps to extra-y. >> This way, even though these objects appear as prerequisites of >> lib{fdt,elf}.o and the settings should propagate to them, make can also >> build them as a prerequisite of __build, in which case COV_FLAGS would >> still have the unwanted flags. Fix it by switching to $(targets) instead. >> >> Also, for libfdt, append libfdt.o to nocov-y only if CONFIG_OVERLAY_DTB >> is not set. Otherwise, there is no section renaming and we should be able >> to run the coverage. >> >> Fixes: e321576f4047 ("xen/build: start using if_changed") >> Signed-off-by: Michal Orzel <michal.orzel@amd.com> > > Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com>
diff --git a/xen/common/libelf/Makefile b/xen/common/libelf/Makefile index 8a4522e4e141..917d12b006f7 100644 --- a/xen/common/libelf/Makefile +++ b/xen/common/libelf/Makefile @@ -13,4 +13,4 @@ $(obj)/libelf.o: $(obj)/libelf-temp.o FORCE $(obj)/libelf-temp.o: $(addprefix $(obj)/,$(libelf-objs)) FORCE $(call if_changed,ld) -extra-y += libelf-temp.o $(libelf-objs) +targets += libelf-temp.o $(libelf-objs) diff --git a/xen/common/libfdt/Makefile b/xen/common/libfdt/Makefile index d50487aa6e32..6ce679f98f47 100644 --- a/xen/common/libfdt/Makefile +++ b/xen/common/libfdt/Makefile @@ -5,10 +5,10 @@ SECTIONS := text data $(SPECIAL_DATA_SECTIONS) # For CONFIG_OVERLAY_DTB, libfdt functionalities will be needed during runtime. ifneq ($(CONFIG_OVERLAY_DTB),y) OBJCOPYFLAGS := $(foreach s,$(SECTIONS),--rename-section .$(s)=.init.$(s)) +nocov-y += libfdt.o endif obj-y += libfdt.o -nocov-y += libfdt.o CFLAGS-y += -I$(srctree)/include/xen/libfdt/ @@ -18,4 +18,4 @@ $(obj)/libfdt.o: $(obj)/libfdt-temp.o FORCE $(obj)/libfdt-temp.o: $(addprefix $(obj)/,$(LIBFDT_OBJS)) FORCE $(call if_changed,ld) -extra-y += libfdt-temp.o $(LIBFDT_OBJS) +targets += libfdt-temp.o $(LIBFDT_OBJS)
At the moment, trying to run xencov read/reset (calling SYSCTL_coverage_op under the hood) results in a crash. This is due to a profiler trying to access data in the .init.* sections (libfdt for Arm and libelf for x86) that are stripped after boot. Normally, the build system compiles any *.init.o file without COV_FLAGS. However, these two libraries are handled differently as sections will be renamed to init after linking. To override COV_FLAGS to empty for these libraries, lib{fdt,elf}.o were added to nocov-y. This worked until e321576f4047 ("xen/build: start using if_changed") that added lib{fdt,elf}-temp.o and their deps to extra-y. This way, even though these objects appear as prerequisites of lib{fdt,elf}.o and the settings should propagate to them, make can also build them as a prerequisite of __build, in which case COV_FLAGS would still have the unwanted flags. Fix it by switching to $(targets) instead. Also, for libfdt, append libfdt.o to nocov-y only if CONFIG_OVERLAY_DTB is not set. Otherwise, there is no section renaming and we should be able to run the coverage. Fixes: e321576f4047 ("xen/build: start using if_changed") Signed-off-by: Michal Orzel <michal.orzel@amd.com> --- Changes in v2: - was "coverage: filter out lib{fdt,elf}-temp.o" - switch to $(targets), update rationale --- xen/common/libelf/Makefile | 2 +- xen/common/libfdt/Makefile | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)