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Groups > linux.kernel > #1314845 > unrolled thread
| Started by | Wang Nan <wangnan0@huawei.com> |
|---|---|
| First post | 2016-01-22 10:30 +0100 |
| Last post | 2016-01-22 20:10 +0100 |
| Articles | 10 — 6 participants |
Back to article view | Back to linux.kernel
[PATCH 0/2] perf bpf: Fix relocation error Wang Nan <wangnan0@huawei.com> - 2016-01-22 10:30 +0100
[PATCH 1/2] perf test: Add libbpf relocation checker Wang Nan <wangnan0@huawei.com> - 2016-01-22 10:30 +0100
Re: [PATCH 1/2] perf test: Add libbpf relocation checker Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-22 16:50 +0100
Re: [PATCH 1/2] perf test: Add libbpf relocation checker Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2016-01-22 18:10 +0100
clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-22 18:30 +0100
Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker Adam Jackson <ajax@redhat.com> - 2016-01-22 18:40 +0100
Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2016-01-22 18:50 +0100
Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker David Airlie <airlied@redhat.com> - 2016-01-22 22:10 +0100
Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker Daniel Borkmann <daniel@iogearbox.net> - 2016-01-22 19:00 +0100
Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-22 20:10 +0100
| From | Wang Nan <wangnan0@huawei.com> |
|---|---|
| Date | 2016-01-22 10:30 +0100 |
| Subject | [PATCH 0/2] perf bpf: Fix relocation error |
| Message-ID | <qTGcy-25g-19@gated-at.bofh.it> |
Alexei notices me about a bug in llvm [1]. Because of this bug, even a normal BPF program can generate incorrect (or redundant) relocation information. Patch 1 adds a new test case about it (use an buggy BPF script, should fail even LLVM's bug is fixed). Since it is the first test case expected to be fail, test framework is slightly adjusted. Patch 2 adds the checker. [1] https://llvm.org/bugs/show_bug.cgi?id=26243 Wang Nan (2): perf test: Add libbpf relocation checker perf bpf: Check relocation target section tools/lib/bpf/libbpf.c | 34 +++++++++++------- tools/perf/Makefile.perf | 2 +- tools/perf/tests/.gitignore | 1 + tools/perf/tests/Build | 9 ++++- tools/perf/tests/bpf-script-test-relocation.c | 50 +++++++++++++++++++++++++++ tools/perf/tests/bpf.c | 26 +++++++++++--- tools/perf/tests/llvm.c | 17 ++++++--- tools/perf/tests/llvm.h | 5 ++- 8 files changed, 120 insertions(+), 24 deletions(-) create mode 100644 tools/perf/tests/bpf-script-test-relocation.c Cc: Alexei Starovoitov <ast@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Li Zefan <lizefan@huawei.com> Cc: pi3orama@163.com -- 1.8.3.4
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| From | Wang Nan <wangnan0@huawei.com> |
|---|---|
| Date | 2016-01-22 10:30 +0100 |
| Subject | [PATCH 1/2] perf test: Add libbpf relocation checker |
| Message-ID | <qTGcy-25g-27@gated-at.bofh.it> |
| In reply to | #1314845 |
There's a bug in LLVM that it can generate unneeded relocation
information. See [1] and [2]. Libbpf should check the target section
of a relocation symbol.
This patch adds a testcase which reference a global variable (BPF
doesn't support global variable). Before fixing libbpf, the new test
case can be loaded into kernel, the global variable acts like the first
map. It is incorrect.
Result:
# ~/perf test BPF
37: Test BPF filter :
37.1: Test basic BPF filtering : Ok
37.2: Test BPF prologue generation : Ok
37.3: Test BPF relocation checker : FAILED!
# ~/perf test -v BPF
...
libbpf: loading object '[bpf_relocation_test]' from buffer
libbpf: section .strtab, size 126, link 0, flags 0, type=3
libbpf: section .text, size 0, link 0, flags 6, type=1
libbpf: section .data, size 0, link 0, flags 3, type=1
libbpf: section .bss, size 0, link 0, flags 3, type=8
libbpf: section func=sys_write, size 104, link 0, flags 6, type=1
libbpf: found program func=sys_write
libbpf: section .relfunc=sys_write, size 16, link 10, flags 0, type=9
libbpf: section maps, size 16, link 0, flags 3, type=1
libbpf: maps in [bpf_relocation_test]: 16 bytes
libbpf: section license, size 4, link 0, flags 3, type=1
libbpf: license of [bpf_relocation_test] is GPL
libbpf: section version, size 4, link 0, flags 3, type=1
libbpf: kernel version of [bpf_relocation_test] is 40400
libbpf: section .symtab, size 144, link 1, flags 0, type=2
libbpf: map 0 is "my_table"
libbpf: collecting relocating info for: 'func=sys_write'
libbpf: relocation: insn_idx=7
Success unexpectedly: libbpf error when dealing with relocation
test child finished with -1
---- end ----
Test BPF filter subtest 2: FAILED!
[1] https://llvm.org/bugs/show_bug.cgi?id=26243
[2] https://patchwork.ozlabs.org/patch/571385/
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Li Zefan <lizefan@huawei.com>
Cc: pi3orama@163.com
---
tools/perf/Makefile.perf | 2 +-
tools/perf/tests/.gitignore | 1 +
tools/perf/tests/Build | 9 ++++-
tools/perf/tests/bpf-script-test-relocation.c | 50 +++++++++++++++++++++++++++
tools/perf/tests/bpf.c | 26 +++++++++++---
tools/perf/tests/llvm.c | 17 ++++++---
tools/perf/tests/llvm.h | 5 ++-
7 files changed, 98 insertions(+), 12 deletions(-)
create mode 100644 tools/perf/tests/bpf-script-test-relocation.c
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 5d34815..97ce869 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -618,7 +618,7 @@ clean: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clean
$(call QUIET_CLEAN, core-progs) $(RM) $(ALL_PROGRAMS) perf perf-read-vdso32 perf-read-vdsox32
$(call QUIET_CLEAN, core-gen) $(RM) *.spec *.pyc *.pyo */*.pyc */*.pyo $(OUTPUT)common-cmds.h TAGS tags cscope* $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)FEATURE-DUMP $(OUTPUT)util/*-bison* $(OUTPUT)util/*-flex* \
$(OUTPUT)util/intel-pt-decoder/inat-tables.c $(OUTPUT)fixdep \
- $(OUTPUT)tests/llvm-src-{base,kbuild,prologue}.c
+ $(OUTPUT)tests/llvm-src-{base,kbuild,prologue,relocation}.c
$(QUIET_SUBDIR0)Documentation $(QUIET_SUBDIR1) clean
$(python-clean)
diff --git a/tools/perf/tests/.gitignore b/tools/perf/tests/.gitignore
index bf016c4..8cc30e7 100644
--- a/tools/perf/tests/.gitignore
+++ b/tools/perf/tests/.gitignore
@@ -1,3 +1,4 @@
llvm-src-base.c
llvm-src-kbuild.c
llvm-src-prologue.c
+llvm-src-relocation.c
diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index 614899b..1ba628e 100644
--- a/tools/perf/tests/Build
+++ b/tools/perf/tests/Build
@@ -31,7 +31,7 @@ perf-y += sample-parsing.o
perf-y += parse-no-sample-id-all.o
perf-y += kmod-path.o
perf-y += thread-map.o
-perf-y += llvm.o llvm-src-base.o llvm-src-kbuild.o llvm-src-prologue.o
+perf-y += llvm.o llvm-src-base.o llvm-src-kbuild.o llvm-src-prologue.o llvm-src-relocation.o
perf-y += bpf.o
perf-y += topology.o
perf-y += cpumap.o
@@ -59,6 +59,13 @@ $(OUTPUT)tests/llvm-src-prologue.c: tests/bpf-script-test-prologue.c tests/Build
$(Q)sed -e 's/"/\\"/g' -e 's/\(.*\)/"\1\\n"/g' $< >> $@
$(Q)echo ';' >> $@
+$(OUTPUT)tests/llvm-src-relocation.c: tests/bpf-script-test-relocation.c tests/Build
+ $(call rule_mkdir)
+ $(Q)echo '#include <tests/llvm.h>' > $@
+ $(Q)echo 'const char test_llvm__bpf_test_relocation[] =' >> $@
+ $(Q)sed -e 's/"/\\"/g' -e 's/\(.*\)/"\1\\n"/g' $< >> $@
+ $(Q)echo ';' >> $@
+
ifeq ($(ARCH),$(filter $(ARCH),x86 arm arm64))
perf-$(CONFIG_DWARF_UNWIND) += dwarf-unwind.o
endif
diff --git a/tools/perf/tests/bpf-script-test-relocation.c b/tools/perf/tests/bpf-script-test-relocation.c
new file mode 100644
index 0000000..93af774
--- /dev/null
+++ b/tools/perf/tests/bpf-script-test-relocation.c
@@ -0,0 +1,50 @@
+/*
+ * bpf-script-test-relocation.c
+ * Test BPF loader checking relocation
+ */
+#ifndef LINUX_VERSION_CODE
+# error Need LINUX_VERSION_CODE
+# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
+#endif
+#define BPF_ANY 0
+#define BPF_MAP_TYPE_ARRAY 2
+#define BPF_FUNC_map_lookup_elem 1
+#define BPF_FUNC_map_update_elem 2
+
+static void *(*bpf_map_lookup_elem)(void *map, void *key) =
+ (void *) BPF_FUNC_map_lookup_elem;
+static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
+ (void *) BPF_FUNC_map_update_elem;
+
+struct bpf_map_def {
+ unsigned int type;
+ unsigned int key_size;
+ unsigned int value_size;
+ unsigned int max_entries;
+};
+
+#define SEC(NAME) __attribute__((section(NAME), used))
+struct bpf_map_def SEC("maps") my_table = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(int),
+ .value_size = sizeof(int),
+ .max_entries = 1,
+};
+
+int this_is_a_global_val;
+
+SEC("func=sys_write")
+int bpf_func__sys_write(void *ctx)
+{
+ int key = 0;
+ int value = 0;
+
+ /*
+ * Incorrect relocation. Should not allow this program be
+ * loaded into kernel.
+ */
+ bpf_map_update_elem(&this_is_a_global_val, &key, &value, 0);
+ return 0;
+}
+char _license[] SEC("license") = "GPL";
+int _version SEC("version") = LINUX_VERSION_CODE;
diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c
index 33689a0..952ca99 100644
--- a/tools/perf/tests/bpf.c
+++ b/tools/perf/tests/bpf.c
@@ -71,6 +71,15 @@ static struct {
(NR_ITERS + 1) / 4,
},
#endif
+ {
+ LLVM_TESTCASE_BPF_RELOCATION,
+ "Test BPF relocation checker",
+ "[bpf_relocation_test]",
+ "fix 'perf test LLVM' first",
+ "libbpf error when dealing with relocation",
+ NULL,
+ 0,
+ },
};
static int do_test(struct bpf_object *obj, int (*func)(void),
@@ -190,7 +199,7 @@ static int __test__bpf(int idx)
ret = test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz,
bpf_testcase_table[idx].prog_id,
- true);
+ true, NULL);
if (ret != TEST_OK || !obj_buf || !obj_buf_sz) {
pr_debug("Unable to get BPF object, %s\n",
bpf_testcase_table[idx].msg_compile_fail);
@@ -202,14 +211,21 @@ static int __test__bpf(int idx)
obj = prepare_bpf(obj_buf, obj_buf_sz,
bpf_testcase_table[idx].name);
- if (!obj) {
+ if ((!!bpf_testcase_table[idx].target_func) != (!!obj)) {
+ if (!obj)
+ pr_debug("Fail to load BPF object: %s\n",
+ bpf_testcase_table[idx].msg_load_fail);
+ else
+ pr_debug("Success unexpectedly: %s\n",
+ bpf_testcase_table[idx].msg_load_fail);
ret = TEST_FAIL;
goto out;
}
- ret = do_test(obj,
- bpf_testcase_table[idx].target_func,
- bpf_testcase_table[idx].expect_result);
+ if (obj)
+ ret = do_test(obj,
+ bpf_testcase_table[idx].target_func,
+ bpf_testcase_table[idx].expect_result);
out:
bpf__clear();
return ret;
diff --git a/tools/perf/tests/llvm.c b/tools/perf/tests/llvm.c
index 06f45c1..70edcdf 100644
--- a/tools/perf/tests/llvm.c
+++ b/tools/perf/tests/llvm.c
@@ -35,6 +35,7 @@ static int test__bpf_parsing(void *obj_buf __maybe_unused,
static struct {
const char *source;
const char *desc;
+ bool should_load_fail;
} bpf_source_table[__LLVM_TESTCASE_MAX] = {
[LLVM_TESTCASE_BASE] = {
.source = test_llvm__bpf_base_prog,
@@ -48,14 +49,19 @@ static struct {
.source = test_llvm__bpf_test_prologue_prog,
.desc = "Compile source for BPF prologue generation test",
},
+ [LLVM_TESTCASE_BPF_RELOCATION] = {
+ .source = test_llvm__bpf_test_relocation,
+ .desc = "Compile source for BPF relocation test",
+ .should_load_fail = true,
+ },
};
-
int
test_llvm__fetch_bpf_obj(void **p_obj_buf,
size_t *p_obj_buf_sz,
enum test_llvm__testcase idx,
- bool force)
+ bool force,
+ bool *should_load_fail)
{
const char *source;
const char *desc;
@@ -68,6 +74,8 @@ test_llvm__fetch_bpf_obj(void **p_obj_buf,
source = bpf_source_table[idx].source;
desc = bpf_source_table[idx].desc;
+ if (should_load_fail)
+ *should_load_fail = bpf_source_table[idx].should_load_fail;
perf_config(perf_config_cb, NULL);
@@ -136,14 +144,15 @@ int test__llvm(int subtest)
int ret;
void *obj_buf = NULL;
size_t obj_buf_sz = 0;
+ bool should_load_fail = false;
if ((subtest < 0) || (subtest >= __LLVM_TESTCASE_MAX))
return TEST_FAIL;
ret = test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz,
- subtest, false);
+ subtest, false, &should_load_fail);
- if (ret == TEST_OK) {
+ if (ret == TEST_OK && !should_load_fail) {
ret = test__bpf_parsing(obj_buf, obj_buf_sz);
if (ret != TEST_OK) {
pr_debug("Failed to parse test case '%s'\n",
diff --git a/tools/perf/tests/llvm.h b/tools/perf/tests/llvm.h
index 5150b4d..0eaa604 100644
--- a/tools/perf/tests/llvm.h
+++ b/tools/perf/tests/llvm.h
@@ -7,14 +7,17 @@
extern const char test_llvm__bpf_base_prog[];
extern const char test_llvm__bpf_test_kbuild_prog[];
extern const char test_llvm__bpf_test_prologue_prog[];
+extern const char test_llvm__bpf_test_relocation[];
enum test_llvm__testcase {
LLVM_TESTCASE_BASE,
LLVM_TESTCASE_KBUILD,
LLVM_TESTCASE_BPF_PROLOGUE,
+ LLVM_TESTCASE_BPF_RELOCATION,
__LLVM_TESTCASE_MAX,
};
int test_llvm__fetch_bpf_obj(void **p_obj_buf, size_t *p_obj_buf_sz,
- enum test_llvm__testcase index, bool force);
+ enum test_llvm__testcase index, bool force,
+ bool *should_load_fail);
#endif
--
1.8.3.4
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| From | Arnaldo Carvalho de Melo <acme@kernel.org> |
|---|---|
| Date | 2016-01-22 16:50 +0100 |
| Subject | Re: [PATCH 1/2] perf test: Add libbpf relocation checker |
| Message-ID | <qTM8i-5YV-15@gated-at.bofh.it> |
| In reply to | #1314847 |
Em Fri, Jan 22, 2016 at 09:27:20AM +0000, Wang Nan escreveu:
> There's a bug in LLVM that it can generate unneeded relocation
> information. See [1] and [2]. Libbpf should check the target section
> of a relocation symbol.
>
> This patch adds a testcase which reference a global variable (BPF
> doesn't support global variable). Before fixing libbpf, the new test
> case can be loaded into kernel, the global variable acts like the first
> map. It is incorrect.
>
> Result:
> # ~/perf test BPF
> 37: Test BPF filter :
> 37.1: Test basic BPF filtering : Ok
> 37.2: Test BPF prologue generation : Ok
> 37.3: Test BPF relocation checker : FAILED!
So I just got a new notebook, a t450s (heya, will be able to test Intel
PT, etc) and installed fedora 23 on it, cool, there is clang/llvm in it!
And furthermore:
[root@jouet ~]# clang --version
clang version 3.7.0 (tags/RELEASE_370/final)
Target: x86_64-redhat-linux-gnu
Thread model: posix
[root@jouet ~]#
Seems to be the one we need!
But...
[root@jouet ~]# perf test bpf
37: Test BPF filter :
37.1: Test basic BPF filtering : Skip
37.2: Test BPF prologue generation : Skip
[root@jouet ~]#
oh well...
From 'perf test -v bpf':
' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS -DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o -
error: unable to create target: 'No available targets are compatible with this triple, see -version for the available targets.'
----
And after googling 'list clang supported target'
[root@jouet ~]# llc --version
LLVM (http://llvm.org/):
LLVM version 3.7.0
Optimized build.
Built Dec 4 2015 (15:49:18).
Default target: x86_64-redhat-linux-gnu
Host CPU: broadwell
Registered Targets:
aarch64 - AArch64 (little endian)
aarch64_be - AArch64 (big endian)
amdgcn - AMD GCN GPUs
arm - ARM
arm64 - ARM64 (little endian)
armeb - ARM (big endian)
cpp - C++ backend
nvptx - NVIDIA PTX 32-bit
nvptx64 - NVIDIA PTX 64-bit
ppc32 - PowerPC 32
ppc64 - PowerPC 64
ppc64le - PowerPC 64 LE
r600 - AMD GPUs HD2XXX-HD6XXX
systemz - SystemZ
thumb - Thumb
thumbeb - Thumb (big endian)
x86 - 32-bit X86: Pentium-Pro and above
x86-64 - 64-bit X86: EM64T and AMD64
[root@jouet ~]#
Oops, no bpf, so the good thing is that if we uninstall clang and try that test again:
[root@jouet ~]# dnf remove clang llvm
Dependencies resolved.
==============================================================
Package Arch Version Repository Size
==============================================================
Removing:
clang x86_64 3.7.0-3.fc23 @updates 45 M
clang-libs x86_64 3.7.0-3.fc23 @updates 14 M
gcc-c++ x86_64 5.3.1-2.fc23 @updates 24 M
libstdc++-devel x86_64 5.3.1-2.fc23 @updates 9.5 M
llvm x86_64 3.7.0-3.fc23 @updates 4.9 M
Transaction Summary
==============================================================
Remove 5 Packages
When I try it again I get nice instructions on how to install it!
[root@jouet ~]# perf test bpf
37: Test BPF filter :
37.1: Test basic BPF filtering : Skip
37.2: Test BPF prologue generation : Skip
[root@jouet ~]# perf test -v bpf
37: Test BPF filter :
37.1: Test basic BPF filtering :
--- start ---
test child forked, pid 30062
ERROR: unable to find clang.
Hint: Try to install latest clang/llvm to support BPF. Check your $PATH
and 'clang-path' option in [llvm] section of ~/.perfconfig.
LLVM 3.7 or newer is required. Which can be found from http://llvm.org
You may want to try git trunk:
git clone http://llvm.org/git/llvm.git
and
git clone http://llvm.org/git/clang.git
Or fetch the latest clang/llvm 3.7 from pre-built llvm packages for
debian/ubuntu:
http://llvm.org/apt
If you are using old version of clang, change 'clang-bpf-cmd-template'
option in [llvm] section of ~/.perfconfig to:
"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \
-working-directory $WORKING_DIR -c $CLANG_SOURCE \
-emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -"
(Replace /path/to/llc with path to your llc)
Failed to compile test case: 'Basic BPF llvm compiling test'
Unable to get BPF object, fix 'perf test LLVM' first
test child finished with -2
---- end ----
Test BPF filter subtest 0: Skip
37.2: Test BPF prologue generation :
--- force skipped ---
Test BPF filter subtest 1: Skip
[root@jouet ~]#
Lets try it...
- Arnaldo
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| From | Alexei Starovoitov <alexei.starovoitov@gmail.com> |
|---|---|
| Date | 2016-01-22 18:10 +0100 |
| Subject | Re: [PATCH 1/2] perf test: Add libbpf relocation checker |
| Message-ID | <qTNnI-73X-7@gated-at.bofh.it> |
| In reply to | #1315080 |
On Fri, Jan 22, 2016 at 12:40:50PM -0300, Arnaldo Carvalho de Melo wrote: > [root@jouet ~]# llc --version > LLVM (http://llvm.org/): > LLVM version 3.7.0 > Optimized build. > Built Dec 4 2015 (15:49:18). > Default target: x86_64-redhat-linux-gnu > Host CPU: broadwell > > Registered Targets: > aarch64 - AArch64 (little endian) > aarch64_be - AArch64 (big endian) > amdgcn - AMD GCN GPUs > arm - ARM > arm64 - ARM64 (little endian) > armeb - ARM (big endian) > cpp - C++ backend > nvptx - NVIDIA PTX 32-bit > nvptx64 - NVIDIA PTX 64-bit > ppc32 - PowerPC 32 > ppc64 - PowerPC 64 > ppc64le - PowerPC 64 LE > r600 - AMD GPUs HD2XXX-HD6XXX > systemz - SystemZ > thumb - Thumb > thumbeb - Thumb (big endian) > x86 - 32-bit X86: Pentium-Pro and above > x86-64 - 64-bit X86: EM64T and AMD64 > [root@jouet ~]# ouch, so fedorra enabled all sorts of backends, but disabled BPF?! Can somebody talk to redhat packaging folks? clang/llvm enables BPF backend by default.
[toc] | [prev] | [next] | [standalone]
| From | Arnaldo Carvalho de Melo <acme@kernel.org> |
|---|---|
| Date | 2016-01-22 18:30 +0100 |
| Subject | clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker |
| Message-ID | <qTNH4-7bM-17@gated-at.bofh.it> |
| In reply to | #1315137 |
Em Fri, Jan 22, 2016 at 09:07:50AM -0800, Alexei Starovoitov escreveu: > On Fri, Jan 22, 2016 at 12:40:50PM -0300, Arnaldo Carvalho de Melo wrote: > > [root@jouet ~]# llc --version > > LLVM (http://llvm.org/): > > LLVM version 3.7.0 > > Optimized build. > > Built Dec 4 2015 (15:49:18). > > Default target: x86_64-redhat-linux-gnu > > Host CPU: broadwell > > > > Registered Targets: > > aarch64 - AArch64 (little endian) > > aarch64_be - AArch64 (big endian) > > amdgcn - AMD GCN GPUs > > arm - ARM > > arm64 - ARM64 (little endian) > > armeb - ARM (big endian) > > cpp - C++ backend > > nvptx - NVIDIA PTX 32-bit > > nvptx64 - NVIDIA PTX 64-bit > > ppc32 - PowerPC 32 > > ppc64 - PowerPC 64 > > ppc64le - PowerPC 64 LE > > r600 - AMD GPUs HD2XXX-HD6XXX > > systemz - SystemZ > > thumb - Thumb > > thumbeb - Thumb (big endian) > > x86 - 32-bit X86: Pentium-Pro and above > > x86-64 - 64-bit X86: EM64T and AMD64 > > [root@jouet ~]# > > ouch, so fedora enabled all sorts of backends, but disabled BPF?! > Can somebody talk to redhat packaging folks? > clang/llvm enables BPF backend by default. Adding Adam Jackson and Dave Airlie, that last updated llvm. Hi Adam, Dave, the 'bpf' target for clang is being used together with perf to build scriptlets into object code that then gets uploaded to the kernel via sys_bpf(), was the decision not to include 'bpf' just an accident? BTW, this is on a recently installed Fedora 23 machine. - Arnaldo [acme@jouet linux]$ rpm -q --changelog llvm-libs | grep -v ^$ | head -20 * Thu Dec 03 2015 Stephan Bergmann <sbergman@redhat.com> 3.7.0-3 - Resolves: rhbz#1282645 add GCC abi_tag support * Thu Oct 29 2015 Adam Jackson <ajax@redhat.com> 3.7.0-2 - Drop -fno-devirtualize - Link with -static-libstdc++ to work around bundled libstdc++ in Steam * Wed Sep 16 2015 Dave Airlie <airlied@redhat.com> 3.7.0-1 - llvm 3.7.0 * Wed Jul 22 2015 Adam Jackson <ajax@redhat.com> 3.6.2-1 - llvm 3.6.2 * Wed Jun 17 2015 Dave Airlie <airlied@redhat.com> 3.6.1-1 - llvm 3.6.1 * Fri May 29 2015 Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> - 3.6.0-2 - Also require gcc-c++ at runtime (#1021645) * Thu Apr 09 2015 Adam Jackson <ajax@redhat.com> 3.6.0-1 - llvm 3.6.0 * Wed Feb 18 2015 Jonathan Wakely <jwakely@redhat.com> - 3.5.0-11 - Add patch for http://llvm.org/bugs/show_bug.cgi?id=22625 * Wed Feb 18 2015 Richard W.M. Jones <rjones@redhat.com> - 3.5.0-10 - Bump release and rebuild. * Tue Feb 17 2015 Peter Robinson <pbrobinson@fedoraproject.org> 3.5.0-9 [acme@jouet linux]$
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| From | Adam Jackson <ajax@redhat.com> |
|---|---|
| Date | 2016-01-22 18:40 +0100 |
| Subject | Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker |
| Message-ID | <qTNQJ-7gK-1@gated-at.bofh.it> |
| In reply to | #1315157 |
On Fri, 2016-01-22 at 14:22 -0300, Arnaldo Carvalho de Melo wrote:
> the 'bpf' target for clang is being used together with perf to
> build scriptlets into object code that then gets uploaded to the kernel
> via sys_bpf(), was the decision not to include 'bpf' just an accident?
I wouldn't call it a "decision", that would imply intent. The main
reason I explicitly list targets for llvm is to limit the CPU backends
to arches Fedora actually runs on (which itself is because I really
only care about llvmpipe, and am only touching llvm because it's in my
way). Had no idea there was a bpf backend, so never thought to enable
it.
llvm-3.7.0-4.fc2{3,4} are building now with the bpf backend enabled,
I'll create an update for F23 when it's built.
- ajax
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| From | Alexei Starovoitov <alexei.starovoitov@gmail.com> |
|---|---|
| Date | 2016-01-22 18:50 +0100 |
| Subject | Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker |
| Message-ID | <qTO0q-7kv-5@gated-at.bofh.it> |
| In reply to | #1315162 |
On Fri, Jan 22, 2016 at 12:35:42PM -0500, Adam Jackson wrote:
> On Fri, 2016-01-22 at 14:22 -0300, Arnaldo Carvalho de Melo wrote:
>
> > the 'bpf' target for clang is being used together with perf to
> > build scriptlets into object code that then gets uploaded to the kernel
> > via sys_bpf(), was the decision not to include 'bpf' just an accident?
>
> I wouldn't call it a "decision", that would imply intent. The main
> reason I explicitly list targets for llvm is to limit the CPU backends
> to arches Fedora actually runs on (which itself is because I really
> only care about llvmpipe, and am only touching llvm because it's in my
> way). Had no idea there was a bpf backend, so never thought to enable
> it.
>
> llvm-3.7.0-4.fc2{3,4} are building now with the bpf backend enabled,
> I'll create an update for F23 when it's built.
thanks.
if you want to reduce the size of binaries, you can probably disable
nvptx/amdgcn/r600, since I doubt fedora ships with appropriate sdks
that can take advantage of that.
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| From | David Airlie <airlied@redhat.com> |
|---|---|
| Date | 2016-01-22 22:10 +0100 |
| Subject | Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker |
| Message-ID | <qTR7Y-19M-3@gated-at.bofh.it> |
| In reply to | #1315169 |
----- Original Message -----
> From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
> To: "Adam Jackson" <ajax@redhat.com>
> Cc: "Arnaldo Carvalho de Melo" <acme@kernel.org>, "Wang Nan" <wangnan0@huawei.com>, ast@kernel.org,
> linux-kernel@vger.kernel.org, "Daniel Borkmann" <daniel@iogearbox.net>, "Li Zefan" <lizefan@huawei.com>,
> pi3orama@163.com, "Dave Airlie" <airlied@redhat.com>
> Sent: Saturday, 23 January, 2016 3:42:30 AM
> Subject: Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker
>
> On Fri, Jan 22, 2016 at 12:35:42PM -0500, Adam Jackson wrote:
> > On Fri, 2016-01-22 at 14:22 -0300, Arnaldo Carvalho de Melo wrote:
> >
> > > the 'bpf' target for clang is being used together with perf to
> > > build scriptlets into object code that then gets uploaded to the kernel
> > > via sys_bpf(), was the decision not to include 'bpf' just an accident?
> >
> > I wouldn't call it a "decision", that would imply intent. The main
> > reason I explicitly list targets for llvm is to limit the CPU backends
> > to arches Fedora actually runs on (which itself is because I really
> > only care about llvmpipe, and am only touching llvm because it's in my
> > way). Had no idea there was a bpf backend, so never thought to enable
> > it.
> >
> > llvm-3.7.0-4.fc2{3,4} are building now with the bpf backend enabled,
> > I'll create an update for F23 when it's built.
>
> thanks.
> if you want to reduce the size of binaries, you can probably disable
> nvptx/amdgcn/r600, since I doubt fedora ships with appropriate sdks
> that can take advantage of that.
>
amdgcn is the other reason we ship llvm, we could probably drop nvptx.
Dave.
>
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| From | Daniel Borkmann <daniel@iogearbox.net> |
|---|---|
| Date | 2016-01-22 19:00 +0100 |
| Subject | Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker |
| Message-ID | <qTOa6-7nC-1@gated-at.bofh.it> |
| In reply to | #1315162 |
On 01/22/2016 06:35 PM, Adam Jackson wrote:
> On Fri, 2016-01-22 at 14:22 -0300, Arnaldo Carvalho de Melo wrote:
>
>> the 'bpf' target for clang is being used together with perf to
>> build scriptlets into object code that then gets uploaded to the kernel
>> via sys_bpf(), was the decision not to include 'bpf' just an accident?
>
> I wouldn't call it a "decision", that would imply intent. The main
> reason I explicitly list targets for llvm is to limit the CPU backends
> to arches Fedora actually runs on (which itself is because I really
> only care about llvmpipe, and am only touching llvm because it's in my
> way). Had no idea there was a bpf backend, so never thought to enable
> it.
>
> llvm-3.7.0-4.fc2{3,4} are building now with the bpf backend enabled,
> I'll create an update for F23 when it's built.
Awesome, thanks!
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| From | Arnaldo Carvalho de Melo <acme@kernel.org> |
|---|---|
| Date | 2016-01-22 20:10 +0100 |
| Subject | Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker |
| Message-ID | <qTPfQ-8lG-9@gated-at.bofh.it> |
| In reply to | #1315173 |
Em Fri, Jan 22, 2016 at 06:56:02PM +0100, Daniel Borkmann escreveu:
> On 01/22/2016 06:35 PM, Adam Jackson wrote:
> >On Fri, 2016-01-22 at 14:22 -0300, Arnaldo Carvalho de Melo wrote:
> >
> >> the 'bpf' target for clang is being used together with perf to
> >>build scriptlets into object code that then gets uploaded to the kernel
> >>via sys_bpf(), was the decision not to include 'bpf' just an accident?
> >
> >I wouldn't call it a "decision", that would imply intent. The main
> >reason I explicitly list targets for llvm is to limit the CPU backends
> >to arches Fedora actually runs on (which itself is because I really
> >only care about llvmpipe, and am only touching llvm because it's in my
> >way). Had no idea there was a bpf backend, so never thought to enable
> >it.
> >
> >llvm-3.7.0-4.fc2{3,4} are building now with the bpf backend enabled,
> >I'll create an update for F23 when it's built.
>
> Awesome, thanks!
Seconded, thanks for the fast response and for adding the bpf target!
Now that is a good, intentional decision 8-)
- Arnaldo
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