Re: [RFC PATCH bpf-next 14/14] selftests/bpf: Add tests for BPF static calls

[Anton Protopopov <aspsk@isovalent.com>]

On 25/03/18 01:53PM, Yonghong Song wrote:
> 
> 
> On 3/18/25 7:33 AM, Anton Protopopov wrote:
> > Add self-tests to test new BPF_STATIC_BRANCH_JA jump instructions
> > and the BPF_STATIC_KEY_UPDATE syscall.
> > 
> > Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
> > ---
> >   .../bpf/prog_tests/bpf_static_keys.c          | 359 ++++++++++++++++++
> >   .../selftests/bpf/progs/bpf_static_keys.c     | 131 +++++++
> >   2 files changed, 490 insertions(+)
> >   create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_static_keys.c
> >   create mode 100644 tools/testing/selftests/bpf/progs/bpf_static_keys.c
> > 
> > diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_static_keys.c b/tools/testing/selftests/bpf/prog_tests/bpf_static_keys.c
> > new file mode 100644
> > index 000000000000..3f105d36743b
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/bpf_static_keys.c
> > @@ -0,0 +1,359 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +#include <test_progs.h>
> > +
> > +#include <sys/syscall.h>
> > +#include <bpf/bpf.h>
> > +
> > +#include "bpf_static_keys.skel.h"
> > +
> > +#define VAL_ON	7
> > +#define VAL_OFF	3
> > +
> > +enum {
> > +	OFF,
> > +	ON
> > +};
> > +
> > +static int _bpf_prog_load(struct bpf_insn *insns, __u32 insn_cnt)
> > +{
> > +	return bpf_prog_load(BPF_PROG_TYPE_XDP, NULL, "GPL", insns, insn_cnt, NULL);
> > +}
> > +
> > +static int _bpf_static_key_update(int map_fd, __u32 on)
> > +{
> > +	LIBBPF_OPTS(bpf_static_key_update_opts, opts);
> > +
> > +	opts.on = on;
> > +
> > +	return bpf_static_key_update(map_fd, &opts);
> > +}
> > +
> > +#define BPF_JMP32_OR_NOP(IMM, OFF)				\
> > +	((struct bpf_insn) {					\
> > +		.code  = BPF_JMP32 | BPF_JA | BPF_K,		\
> > +		.dst_reg = 0,					\
> > +		.src_reg = BPF_STATIC_BRANCH_JA,		\
> > +		.off   = OFF,					\
> > +		.imm   = IMM })
> > +
> > +#define BPF_JMP_OR_NOP(IMM, OFF)				\
> > +	((struct bpf_insn) {					\
> > +		.code  = BPF_JMP | BPF_JA | BPF_K,		\
> > +		.dst_reg = 0,					\
> > +		.src_reg = BPF_STATIC_BRANCH_JA,		\
> > +		.off   = OFF,					\
> > +		.imm   = IMM })
> > +
> > +#define BPF_NOP_OR_JMP32(IMM, OFF)				\
> > +	((struct bpf_insn) {					\
> > +		.code  = BPF_JMP32 | BPF_JA | BPF_K,		\
> > +		.dst_reg = 0,					\
> > +		.src_reg = BPF_STATIC_BRANCH_JA |		\
> > +			   BPF_STATIC_BRANCH_NOP,		\
> > +		.off   = OFF,					\
> > +		.imm   = IMM })
> > +
> > +#define BPF_NOP_OR_JMP(IMM, OFF)				\
> > +	((struct bpf_insn) {					\
> > +		.code  = BPF_JMP | BPF_JA | BPF_K,		\
> > +		.dst_reg = 0,					\
> > +		.src_reg = BPF_STATIC_BRANCH_JA |		\
> > +			   BPF_STATIC_BRANCH_NOP,		\
> > +		.off   = OFF,					\
> > +		.imm   = IMM })
> > +
> > +static const struct bpf_insn insns0[] = {
> > +	BPF_JMP_OR_NOP(0, 1),
> > +	BPF_NOP_OR_JMP(0, 1),
> > +	BPF_JMP32_OR_NOP(1, 0),
> > +	BPF_NOP_OR_JMP32(1, 0),
> > +};
> > +
> 
> [...]
> 
> > +
> > +static void check_bpf_to_bpf_call(struct bpf_static_keys *skel,
> > +				  struct bpf_map *key1,
> > +				  struct bpf_map *key2)
> > +{
> > +	struct bpf_link *link;
> > +
> > +	link = bpf_program__attach(skel->progs.check_bpf_to_bpf_call);
> 
> there is no progcheck_bpf_to_bpf_call. Compilation will fail.

Oops, thanks! I haven't cleaned it out (have it in my dev branch)...
(Compilation will fail in the first place in progs/bpf_static_keys.c, as
`asm(gotol_or_nop)` will not compile.

> > +	if (!ASSERT_OK_PTR(link, "link"))
> > +		return;
> > +
> > +	__check_multiple_keys(skel, key1, key2, 0, 303, 3030, 3333);
> > +
> > +	bpf_link__destroy(link);
> > +}
> > +
> [...]