linux-stable/tools/testing/selftests/bpf/verifier/atomic_xchg.c
Brendan Jackman 98d666d05a bpf: Add tests for new BPF atomic operations
The prog_test that's added depends on Clang/LLVM features added by
Yonghong in commit 286daafd6512 (was https://reviews.llvm.org/D72184).

Note the use of a define called ENABLE_ATOMICS_TESTS: this is used
to:

 - Avoid breaking the build for people on old versions of Clang
 - Avoid needing separate lists of test objects for no_alu32, where
   atomics are not supported even if Clang has the feature.

The atomics_test.o BPF object is built unconditionally both for
test_progs and test_progs-no_alu32. For test_progs, if Clang supports
atomics, ENABLE_ATOMICS_TESTS is defined, so it includes the proper
test code. Otherwise, progs and global vars are defined anyway, as
stubs; this means that the skeleton user code still builds.

The atomics_test.o userspace object is built once and used for both
test_progs and test_progs-no_alu32. A variable called skip_tests is
defined in the BPF object's data section, which tells the userspace
object whether to skip the atomics test.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210114181751.768687-11-jackmanb@google.com
2021-01-14 18:34:29 -08:00

46 lines
1.2 KiB
C

{
"atomic exchange smoketest - 64bit",
.insns = {
/* val = 3; */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 3),
/* old = atomic_xchg(&val, 4); */
BPF_MOV64_IMM(BPF_REG_1, 4),
BPF_ATOMIC_OP(BPF_DW, BPF_XCHG, BPF_REG_10, BPF_REG_1, -8),
/* if (old != 3) exit(1); */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 3, 2),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
/* if (val != 4) exit(2); */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 4, 2),
BPF_MOV64_IMM(BPF_REG_0, 2),
BPF_EXIT_INSN(),
/* exit(0); */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
},
{
"atomic exchange smoketest - 32bit",
.insns = {
/* val = 3; */
BPF_ST_MEM(BPF_W, BPF_REG_10, -4, 3),
/* old = atomic_xchg(&val, 4); */
BPF_MOV32_IMM(BPF_REG_1, 4),
BPF_ATOMIC_OP(BPF_W, BPF_XCHG, BPF_REG_10, BPF_REG_1, -4),
/* if (old != 3) exit(1); */
BPF_JMP32_IMM(BPF_JEQ, BPF_REG_1, 3, 2),
BPF_MOV32_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
/* if (val != 4) exit(2); */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_10, -4),
BPF_JMP32_IMM(BPF_JEQ, BPF_REG_0, 4, 2),
BPF_MOV32_IMM(BPF_REG_0, 2),
BPF_EXIT_INSN(),
/* exit(0); */
BPF_MOV32_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
},