| Message ID | ba23d688b3550c3f22dd0dd6d5cb1233c2f34816.1459423412.git.naveen.n.rao@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Not Applicable |
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On 3/31/16 4:25 AM, Naveen N. Rao wrote: > While at it, fix some typos in the comment. > > Cc: Alexei Starovoitov <ast@fb.com> > Cc: David S. Miller <davem@davemloft.net> > Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> > --- > samples/bpf/Makefile | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile > index 502c9fc..88bc5a0 100644 > --- a/samples/bpf/Makefile > +++ b/samples/bpf/Makefile > @@ -76,16 +76,13 @@ HOSTLOADLIBES_offwaketime += -lelf > HOSTLOADLIBES_spintest += -lelf > HOSTLOADLIBES_map_perf_test += -lelf -lrt > > -# point this to your LLVM backend with bpf support > -LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc > - > -# asm/sysreg.h inline assmbly used by it is incompatible with llvm. > -# But, ehere is not easy way to fix it, so just exclude it since it is > +# asm/sysreg.h - inline assembly used by it is incompatible with llvm. > +# But, there is no easy way to fix it, so just exclude it since it is > # useless for BPF samples. > $(obj)/%.o: $(src)/%.c > clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ > -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ > - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@ > + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=obj -o $@ > clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ > -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ > - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=asm -o $@.s > + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=asm -o $@.s that was a workaround when clang/llvm didn't have bpf support. Now clang 3.7 and 3.8 have bpf built-in, so make sense to remove manual calls to llc completely. Just use 'clang -target bpf -O2 -D... -c $< -o $@'
On 03/31/2016 07:46 PM, Alexei Starovoitov wrote: > On 3/31/16 4:25 AM, Naveen N. Rao wrote: >> While at it, fix some typos in the comment. >> >> Cc: Alexei Starovoitov <ast@fb.com> >> Cc: David S. Miller <davem@davemloft.net> >> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> >> Cc: Michael Ellerman <mpe@ellerman.id.au> >> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> >> --- >> samples/bpf/Makefile | 11 ++++------- >> 1 file changed, 4 insertions(+), 7 deletions(-) >> >> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile >> index 502c9fc..88bc5a0 100644 >> --- a/samples/bpf/Makefile >> +++ b/samples/bpf/Makefile >> @@ -76,16 +76,13 @@ HOSTLOADLIBES_offwaketime += -lelf >> HOSTLOADLIBES_spintest += -lelf >> HOSTLOADLIBES_map_perf_test += -lelf -lrt >> >> -# point this to your LLVM backend with bpf support >> -LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc >> - >> -# asm/sysreg.h inline assmbly used by it is incompatible with llvm. >> -# But, ehere is not easy way to fix it, so just exclude it since it is >> +# asm/sysreg.h - inline assembly used by it is incompatible with llvm. >> +# But, there is no easy way to fix it, so just exclude it since it is >> # useless for BPF samples. >> $(obj)/%.o: $(src)/%.c >> clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ >> -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ >> - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@ >> + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=obj -o $@ >> clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ >> -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ >> - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=asm -o $@.s >> + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=asm -o $@.s > > that was a workaround when clang/llvm didn't have bpf support. > Now clang 3.7 and 3.8 have bpf built-in, so make sense to remove > manual calls to llc completely. > Just use 'clang -target bpf -O2 -D... -c $< -o $@' +1, the clang part in that Makefile should also more correctly be called with '-target bpf' as it turns out (despite llc with '-march=bpf' ...). Better to use clang directly as suggested by Alexei.
On 2016/03/31 08:19PM, Daniel Borkmann wrote: > On 03/31/2016 07:46 PM, Alexei Starovoitov wrote: > >On 3/31/16 4:25 AM, Naveen N. Rao wrote: > >> clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ > >> -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ > >>- -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@ > >>+ -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=obj -o $@ > >> clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ > >> -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ > >>- -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=asm -o $@.s > >>+ -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=asm -o $@.s > > > >that was a workaround when clang/llvm didn't have bpf support. > >Now clang 3.7 and 3.8 have bpf built-in, so make sense to remove > >manual calls to llc completely. > >Just use 'clang -target bpf -O2 -D... -c $< -o $@' > > +1, the clang part in that Makefile should also more correctly be called > with '-target bpf' as it turns out (despite llc with '-march=bpf' ...). > Better to use clang directly as suggested by Alexei. I'm likely missing something obvious, but I cannot get this to work. With this diff: $(obj)/%.o: $(src)/%.c clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@ - clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ - -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=asm -o $@.s + -O2 -target bpf -c $< -o $@ I see far too many errors thrown starting with: clang -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.8.2/include -I./arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -Iinclude -I./arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I./include/uapi -Iinclude/generated/uapi -include ./include/linux/kconfig.h \ -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ -O2 -target bpf -c samples/bpf/map_perf_test_kern.c -o samples/bpf/map_perf_test_kern.o In file included from samples/bpf/map_perf_test_kern.c:7: In file included from include/linux/skbuff.h:17: In file included from include/linux/kernel.h:10: In file included from include/linux/bitops.h:36: In file included from ./arch/x86/include/asm/bitops.h:500: ./arch/x86/include/asm/arch_hweight.h:31:10: error: invalid output constraint '=a' in asm : "="REG_OUT (res) ^ ./arch/x86/include/asm/arch_hweight.h:59:10: error: invalid output constraint '=a' in asm : "="REG_OUT (res) What am I missing? - Naveen
On 4/1/16 7:37 AM, Naveen N. Rao wrote: > On 2016/03/31 08:19PM, Daniel Borkmann wrote: >> On 03/31/2016 07:46 PM, Alexei Starovoitov wrote: >>> On 3/31/16 4:25 AM, Naveen N. Rao wrote: >>>> clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ >>>> -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ >>>> - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@ >>>> + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=obj -o $@ >>>> clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ >>>> -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ >>>> - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=asm -o $@.s >>>> + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=asm -o $@.s >>> >>> that was a workaround when clang/llvm didn't have bpf support. >>> Now clang 3.7 and 3.8 have bpf built-in, so make sense to remove >>> manual calls to llc completely. >>> Just use 'clang -target bpf -O2 -D... -c $< -o $@' >> >> +1, the clang part in that Makefile should also more correctly be called >> with '-target bpf' as it turns out (despite llc with '-march=bpf' ...). >> Better to use clang directly as suggested by Alexei. > > I'm likely missing something obvious, but I cannot get this to work. > With this diff: > > $(obj)/%.o: $(src)/%.c > clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ > -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ > - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@ > - clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ > - -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ > - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=asm -o $@.s > + -O2 -target bpf -c $< -o $@ > > I see far too many errors thrown starting with: > ./arch/x86/include/asm/arch_hweight.h:31:10: error: invalid output constraint '=a' in asm > : "="REG_OUT (res) ahh. yes. when processing kernel headers clang has to assume x86 style inline asm, though all of these functions will be ignored. I don't have a quick fix for this yet. Let's go back to your original change $(LLC)->llc
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 502c9fc..88bc5a0 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -76,16 +76,13 @@ HOSTLOADLIBES_offwaketime += -lelf HOSTLOADLIBES_spintest += -lelf HOSTLOADLIBES_map_perf_test += -lelf -lrt -# point this to your LLVM backend with bpf support -LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc - -# asm/sysreg.h inline assmbly used by it is incompatible with llvm. -# But, ehere is not easy way to fix it, so just exclude it since it is +# asm/sysreg.h - inline assembly used by it is incompatible with llvm. +# But, there is no easy way to fix it, so just exclude it since it is # useless for BPF samples. $(obj)/%.o: $(src)/%.c clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@ + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=obj -o $@ clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=asm -o $@.s + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=asm -o $@.s
While at it, fix some typos in the comment. Cc: Alexei Starovoitov <ast@fb.com> Cc: David S. Miller <davem@davemloft.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> --- samples/bpf/Makefile | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-)