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Add test for percpu btf_type_tag. Similar to the "user" tag, we test
the following cases:
1. __percpu struct field.
2. __percpu as function parameter.
3. per_cpu_ptr() accepts dynamically allocated __percpu memory.
Because the test for "user" and the test for "percpu" are very similar,
a little bit of refactoring has been done in btf_tag.c. Basically, both
tests share the same function for loading vmlinux and module btf.
Example output from log:
> ./test_progs -v -t btf_tag
libbpf: prog 'test_percpu1': BPF program load failed: Permission denied
libbpf: prog 'test_percpu1': -- BEGIN PROG LOAD LOG --
...
; g = arg->a;
1: (61) r1 = *(u32 *)(r1 +0)
R1 is ptr_bpf_testmod_btf_type_tag_1 access percpu memory: off=0
...
test_btf_type_tag_mod_percpu:PASS:btf_type_tag_percpu 0 nsec
#26/6 btf_tag/btf_type_tag_percpu_mod1:OK
libbpf: prog 'test_percpu2': BPF program load failed: Permission denied
libbpf: prog 'test_percpu2': -- BEGIN PROG LOAD LOG --
...
; g = arg->p->a;
2: (61) r1 = *(u32 *)(r1 +0)
R1 is ptr_bpf_testmod_btf_type_tag_1 access percpu memory: off=0
...
test_btf_type_tag_mod_percpu:PASS:btf_type_tag_percpu 0 nsec
#26/7 btf_tag/btf_type_tag_percpu_mod2:OK
libbpf: prog 'test_percpu_load': BPF program load failed: Permission denied
libbpf: prog 'test_percpu_load': -- BEGIN PROG LOAD LOG --
...
; g = (__u64)cgrp->rstat_cpu->updated_children;
2: (79) r1 = *(u64 *)(r1 +48)
R1 is ptr_cgroup_rstat_cpu access percpu memory: off=48
...
test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu_load 0 nsec
#26/8 btf_tag/btf_type_tag_percpu_vmlinux_load:OK
load_btfs:PASS:could not load vmlinux BTF 0 nsec
test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu 0 nsec
test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu_helper 0 nsec
#26/9 btf_tag/btf_type_tag_percpu_vmlinux_helper:OK
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-5-haoluo@google.com
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Added a selftest with three__user usages: a __user pointer-type argument
in bpf_testmod, a __user pointer-type struct member in bpf_testmod,
and a __user pointer-type struct member in vmlinux. In all cases,
directly accessing the user memory will result verification failure.
$ ./test_progs -v -n 22/3
...
libbpf: prog 'test_user1': BPF program load failed: Permission denied
libbpf: prog 'test_user1': -- BEGIN PROG LOAD LOG --
R1 type=ctx expected=fp
0: R1=ctx(id=0,off=0,imm=0) R10=fp0
; int BPF_PROG(test_user1, struct bpf_testmod_btf_type_tag_1 *arg)
0: (79) r1 = *(u64 *)(r1 +0)
func 'bpf_testmod_test_btf_type_tag_user_1' arg0 has btf_id 136561 type STRUCT 'bpf_testmod_btf_type_tag_1'
1: R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,off=0,imm=0)
; g = arg->a;
1: (61) r1 = *(u32 *)(r1 +0)
R1 invalid mem access 'user_ptr_'
...
#22/3 btf_tag/btf_type_tag_user_mod1:OK
$ ./test_progs -v -n 22/4
...
libbpf: prog 'test_user2': BPF program load failed: Permission denied
libbpf: prog 'test_user2': -- BEGIN PROG LOAD LOG --
R1 type=ctx expected=fp
0: R1=ctx(id=0,off=0,imm=0) R10=fp0
; int BPF_PROG(test_user2, struct bpf_testmod_btf_type_tag_2 *arg)
0: (79) r1 = *(u64 *)(r1 +0)
func 'bpf_testmod_test_btf_type_tag_user_2' arg0 has btf_id 136563 type STRUCT 'bpf_testmod_btf_type_tag_2'
1: R1_w=ptr_bpf_testmod_btf_type_tag_2(id=0,off=0,imm=0)
; g = arg->p->a;
1: (79) r1 = *(u64 *)(r1 +0) ; R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,off=0,imm=0)
; g = arg->p->a;
2: (61) r1 = *(u32 *)(r1 +0)
R1 invalid mem access 'user_ptr_'
...
#22/4 btf_tag/btf_type_tag_user_mod2:OK
$ ./test_progs -v -n 22/5
...
libbpf: prog 'test_sys_getsockname': BPF program load failed: Permission denied
libbpf: prog 'test_sys_getsockname': -- BEGIN PROG LOAD LOG --
R1 type=ctx expected=fp
0: R1=ctx(id=0,off=0,imm=0) R10=fp0
; int BPF_PROG(test_sys_getsockname, int fd, struct sockaddr *usockaddr,
0: (79) r1 = *(u64 *)(r1 +8)
func '__sys_getsockname' arg1 has btf_id 2319 type STRUCT 'sockaddr'
1: R1_w=user_ptr_sockaddr(id=0,off=0,imm=0)
; g = usockaddr->sa_family;
1: (69) r1 = *(u16 *)(r1 +0)
R1 invalid mem access 'user_ptr_'
...
#22/5 btf_tag/btf_type_tag_user_vmlinux:OK
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220127154616.659314-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The uapi btf.h contains the following declaration:
struct btf_decl_tag {
__s32 component_idx;
};
The skeleton will also generate a struct with name
"btf_decl_tag" for bpf program btf_decl_tag.c.
Rename btf_decl_tag.c to test_btf_decl_tag.c so
the corresponding skeleton struct name becomes
"test_btf_decl_tag". This way, we could include
uapi btf.h in prog_tests/btf_tag.c.
There is no functionality change for this patch.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220127154611.656699-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The following is the main btf_type_tag usage in the
C test:
#define __tag1 __attribute__((btf_type_tag("tag1")))
#define __tag2 __attribute__((btf_type_tag("tag2")))
struct btf_type_tag_test {
int __tag1 * __tag1 __tag2 *p;
} g;
The bpftool raw dump with related types:
[4] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
[11] STRUCT 'btf_type_tag_test' size=8 vlen=1
'p' type_id=14 bits_offset=0
[12] TYPE_TAG 'tag1' type_id=16
[13] TYPE_TAG 'tag2' type_id=12
[14] PTR '(anon)' type_id=13
[15] TYPE_TAG 'tag1' type_id=4
[16] PTR '(anon)' type_id=15
[17] VAR 'g' type_id=11, linkage=global
With format C dump, we have
struct btf_type_tag_test {
int __attribute__((btf_type_tag("tag1"))) * __attribute__((btf_type_tag("tag1"))) __attribute__((btf_type_tag("tag2"))) *p;
};
The result C code is identical to the original definition except macro's are gone.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211112012646.1508231-1-yhs@fb.com
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Rename progs/tag.c to progs/btf_decl_tag.c so we can introduce
progs/btf_type_tag.c in the next patch.
Also create a subtest for btf_decl_tag in prog_tests/btf_tag.c
so we can introduce btf_type_tag subtest in the next patch.
I also took opportunity to remove the check whether __has_attribute
is defined or not in progs/btf_decl_tag.c since all recent
clangs should already support this macro.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211112012641.1507144-1-yhs@fb.com
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Commit c240ba287890 ("selftests/bpf: Add a test with a bpf
program with btf_tag attributes") added btf_tag selftest
to test BTF_KIND_TAG generation from C source code, and to
test kernel validation of generated BTF types.
But if an old clang (clang 13 or earlier) is used, the
following compiler warning may be seen:
progs/tag.c:23:20: warning: unknown attribute 'btf_tag' ignored
and the test itself is marked OK. The compiler warning is bad
and the test itself shouldn't be marked OK.
This patch added the check for btf_tag attribute support.
If btf_tag is not supported by the clang, the attribute will
not be used in the code and the test will be marked as skipped.
For example, with clang 13:
./test_progs -t btf_tag
#21 btf_tag:SKIP
Summary: 1/0 PASSED, 1 SKIPPED, 0 FAILED
The selftests/README.rst is updated to clarify when the btf_tag
test may be skipped.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210915061036.2577971-1-yhs@fb.com
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Add a bpf program with btf_tag attributes. The program is
loaded successfully with the kernel. With the command
bpftool btf dump file ./tag.o
the following dump shows that tags are properly encoded:
[8] STRUCT 'key_t' size=12 vlen=3
'a' type_id=2 bits_offset=0
'b' type_id=2 bits_offset=32
'c' type_id=2 bits_offset=64
[9] TAG 'tag1' type_id=8 component_id=-1
[10] TAG 'tag2' type_id=8 component_id=-1
[11] TAG 'tag1' type_id=8 component_id=1
[12] TAG 'tag2' type_id=8 component_id=1
...
[21] FUNC_PROTO '(anon)' ret_type_id=2 vlen=1
'x' type_id=2
[22] FUNC 'foo' type_id=21 linkage=static
[23] TAG 'tag1' type_id=22 component_id=0
[24] TAG 'tag2' type_id=22 component_id=0
[25] TAG 'tag1' type_id=22 component_id=-1
[26] TAG 'tag2' type_id=22 component_id=-1
...
[29] VAR 'total' type_id=27, linkage=global
[30] TAG 'tag1' type_id=29 component_id=-1
[31] TAG 'tag2' type_id=29 component_id=-1
If an old clang compiler, which does not support btf_tag attribute,
is used, these btf_tag attributes will be silently ignored.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210914223058.248949-1-yhs@fb.com
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