| Message ID | 7eeb1a1a9910b30782adba9eb5cc47c6ce075223.1721541467.git.tony.ambardar@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | selftests/bpf: Add support for MIPS systems | expand |
On Sun, Jul 21, 2024 at 12:51 AM Tony Ambardar <tony.ambardar@gmail.com> wrote: > > Linking uprobe_multi.c on mips64el fails due to relocation overflows, when > the GOT entries required exceeds the default maximum. Add a specific CFLAGS > (-mxgot) for uprobe_multi.c on MIPS that allows using a larger GOT and > avoids errors such as: > > /tmp/ccBTNQzv.o: in function `bench': > uprobe_multi.c:49:(.text+0x1d7720): relocation truncated to fit: R_MIPS_GOT_DISP against `uprobe_multi_func_08188' > uprobe_multi.c:49:(.text+0x1d7730): relocation truncated to fit: R_MIPS_GOT_DISP against `uprobe_multi_func_08189' > ... > collect2: error: ld returned 1 exit status > > Fixes: 519dfeaf5119 ("selftests/bpf: Add uprobe_multi test program") > Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com> > --- > tools/testing/selftests/bpf/Makefile | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile > index a9c447c63fee..0b4bfbc0ef68 100644 > --- a/tools/testing/selftests/bpf/Makefile > +++ b/tools/testing/selftests/bpf/Makefile > @@ -784,9 +784,12 @@ $(OUTPUT)/veristat: $(OUTPUT)/veristat.o > $(call msg,BINARY,,$@) > $(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@ > > +# Linking uprobe_multi can fail due to relocation overflows on mips. > +uprobe_multi.c-CFLAGS := $(if $(filter mips, $(ARCH)),-mxgot) > + > $(OUTPUT)/uprobe_multi: uprobe_multi.c > $(call msg,BINARY,,$@) > - $(Q)$(CC) $(CFLAGS) -O0 $(LDFLAGS) $^ $(LDLIBS) -o $@ > + $(Q)$(CC) $(CFLAGS) $($<-CFLAGS) -O0 $(LDFLAGS) $^ $(LDLIBS) -o $@ this $($<-CFLAGS) approach is fragile, non-obvious and will break. But there is also no need for this, see: $(OUTPUT)/bench: LDLIBS += -lm make allows to override envvars on a per-target basis, so all you should need is: $(OUTPUT)/uprobe_multi: CFLAGS += $(if $(filter mips, $(ARCH)),-mxgot) $(OUTPUT)/uprobe_multi: uprobe_multi.c ... the rest is the same with no change whatsoever ... > > EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR) \ > prog_tests/tests.h map_tests/tests.h verifier/tests.h \ > -- > 2.34.1 >
On Mon, Jul 22, 2024 at 02:22:53PM -0700, Andrii Nakryiko wrote: > On Sun, Jul 21, 2024 at 12:51 AM Tony Ambardar <tony.ambardar@gmail.com> wrote: [...] > > --- a/tools/testing/selftests/bpf/Makefile > > +++ b/tools/testing/selftests/bpf/Makefile > > @@ -784,9 +784,12 @@ $(OUTPUT)/veristat: $(OUTPUT)/veristat.o > > $(call msg,BINARY,,$@) > > $(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@ > > > > +# Linking uprobe_multi can fail due to relocation overflows on mips. > > +uprobe_multi.c-CFLAGS := $(if $(filter mips, $(ARCH)),-mxgot) > > + > > $(OUTPUT)/uprobe_multi: uprobe_multi.c > > $(call msg,BINARY,,$@) > > - $(Q)$(CC) $(CFLAGS) -O0 $(LDFLAGS) $^ $(LDLIBS) -o $@ > > + $(Q)$(CC) $(CFLAGS) $($<-CFLAGS) -O0 $(LDFLAGS) $^ $(LDLIBS) -o $@ > > this $($<-CFLAGS) approach is fragile, non-obvious and will break. But > there is also no need for this, see: > > $(OUTPUT)/bench: LDLIBS += -lm > > make allows to override envvars on a per-target basis, so all you > should need is: > > > $(OUTPUT)/uprobe_multi: CFLAGS += $(if $(filter mips, $(ARCH)),-mxgot) > $(OUTPUT)/uprobe_multi: uprobe_multi.c > ... the rest is the same with no change whatsoever ... > Great suggestion, thanks for pointing that out! I'll update and send v2. > > > > EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR) \ > > prog_tests/tests.h map_tests/tests.h verifier/tests.h \ > > -- > > 2.34.1 > >
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index a9c447c63fee..0b4bfbc0ef68 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -784,9 +784,12 @@ $(OUTPUT)/veristat: $(OUTPUT)/veristat.o $(call msg,BINARY,,$@) $(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@ +# Linking uprobe_multi can fail due to relocation overflows on mips. +uprobe_multi.c-CFLAGS := $(if $(filter mips, $(ARCH)),-mxgot) + $(OUTPUT)/uprobe_multi: uprobe_multi.c $(call msg,BINARY,,$@) - $(Q)$(CC) $(CFLAGS) -O0 $(LDFLAGS) $^ $(LDLIBS) -o $@ + $(Q)$(CC) $(CFLAGS) $($<-CFLAGS) -O0 $(LDFLAGS) $^ $(LDLIBS) -o $@ EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR) \ prog_tests/tests.h map_tests/tests.h verifier/tests.h \
Linking uprobe_multi.c on mips64el fails due to relocation overflows, when the GOT entries required exceeds the default maximum. Add a specific CFLAGS (-mxgot) for uprobe_multi.c on MIPS that allows using a larger GOT and avoids errors such as: /tmp/ccBTNQzv.o: in function `bench': uprobe_multi.c:49:(.text+0x1d7720): relocation truncated to fit: R_MIPS_GOT_DISP against `uprobe_multi_func_08188' uprobe_multi.c:49:(.text+0x1d7730): relocation truncated to fit: R_MIPS_GOT_DISP against `uprobe_multi_func_08189' ... collect2: error: ld returned 1 exit status Fixes: 519dfeaf5119 ("selftests/bpf: Add uprobe_multi test program") Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com> --- tools/testing/selftests/bpf/Makefile | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)