While at it, fix some typos in the comment.
Cc: Alexei Starovoitov <redacted>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ananth N Mavinakayanahalli <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <redacted>
---
samples/bpf/Makefile | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
@@ -76,16 +76,13 @@ HOSTLOADLIBES_offwaketime += -lelfHOSTLOADLIBES_spintest+=-lelfHOSTLOADLIBES_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:$(src)/%.cclang$(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 $@'
From: Daniel Borkmann <daniel@iogearbox.net> Date: 2016-03-31 18:19:34
On 03/31/2016 07:46 PM, Alexei Starovoitov wrote:
On 3/31/16 4:25 AM, Naveen N. Rao wrote:
quoted
While at it, fix some typos in the comment.
Cc: Alexei Starovoitov <redacted>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ananth N Mavinakayanahalli <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <redacted>
---
samples/bpf/Makefile | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
@@ -76,16 +76,13 @@ HOSTLOADLIBES_offwaketime += -lelfHOSTLOADLIBES_spintest+=-lelfHOSTLOADLIBES_map_perf_test+=-lelf-lrt-# point this to your LLVM backend with bpf support-LLC=$(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)/%.cclang$(NOSTDINC_FLAGS)$(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.
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
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