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selftests/bpf: Some more atomic tests
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Some new verifier tests that hit some important gaps in the parameter
space for atomic ops.

There are already exhaustive tests for the JIT part in
lib/test_bpf.c, but these exercise the verifier too.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211015093318.1273686-1-jackmanb@google.com
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@bjackman
bjackman authored and Alexei Starovoitov committed Oct 21, 2021
1 parent 99aaebf commit 7960d02
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38 changes: 38 additions & 0 deletions tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c
View file
Expand Up @@ -119,3 +119,41 @@
},
.result = ACCEPT,
},
{
"Dest pointer in r0 - fail",
.insns = {
/* val = 0; */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
/* r0 = &val */
BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
/* r0 = atomic_cmpxchg(&val, r0, 1); */
BPF_MOV64_IMM(BPF_REG_1, 1),
BPF_ATOMIC_OP(BPF_DW, BPF_CMPXCHG, BPF_REG_10, BPF_REG_1, -8),
/* if (r0 != 0) exit(1); */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
/* exit(0); */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
},
{
"Dest pointer in r0 - succeed",
.insns = {
/* r0 = &val */
BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
/* val = r0; */
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
/* r0 = atomic_cmpxchg(&val, r0, 0); */
BPF_MOV64_IMM(BPF_REG_1, 0),
BPF_ATOMIC_OP(BPF_DW, BPF_CMPXCHG, BPF_REG_10, BPF_REG_1, -8),
/* r1 = *r0 */
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, -8),
/* exit(0); */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
},
57 changes: 57 additions & 0 deletions tools/testing/selftests/bpf/verifier/atomic_fetch.c
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@@ -0,0 +1,57 @@
#define __ATOMIC_FETCH_OP_TEST(src_reg, dst_reg, operand1, op, operand2, expect) \
{ \
"atomic fetch " #op ", src=" #dst_reg " dst=" #dst_reg, \
.insns = { \
/* u64 val = operan1; */ \
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, operand1), \
/* u64 old = atomic_fetch_add(&val, operand2); */ \
BPF_MOV64_REG(dst_reg, BPF_REG_10), \
BPF_MOV64_IMM(src_reg, operand2), \
BPF_ATOMIC_OP(BPF_DW, op, \
dst_reg, src_reg, -8), \
/* if (old != operand1) exit(1); */ \
BPF_JMP_IMM(BPF_JEQ, src_reg, operand1, 2), \
BPF_MOV64_IMM(BPF_REG_0, 1), \
BPF_EXIT_INSN(), \
/* if (val != result) exit (2); */ \
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -8), \
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, expect, 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_FETCH_OP_TEST(BPF_REG_1, BPF_REG_2, 1, BPF_ADD | BPF_FETCH, 2, 3),
__ATOMIC_FETCH_OP_TEST(BPF_REG_0, BPF_REG_1, 1, BPF_ADD | BPF_FETCH, 2, 3),
__ATOMIC_FETCH_OP_TEST(BPF_REG_1, BPF_REG_0, 1, BPF_ADD | BPF_FETCH, 2, 3),
__ATOMIC_FETCH_OP_TEST(BPF_REG_2, BPF_REG_3, 1, BPF_ADD | BPF_FETCH, 2, 3),
__ATOMIC_FETCH_OP_TEST(BPF_REG_4, BPF_REG_5, 1, BPF_ADD | BPF_FETCH, 2, 3),
__ATOMIC_FETCH_OP_TEST(BPF_REG_9, BPF_REG_8, 1, BPF_ADD | BPF_FETCH, 2, 3),
__ATOMIC_FETCH_OP_TEST(BPF_REG_1, BPF_REG_2, 0x010, BPF_AND | BPF_FETCH, 0x011, 0x010),
__ATOMIC_FETCH_OP_TEST(BPF_REG_0, BPF_REG_1, 0x010, BPF_AND | BPF_FETCH, 0x011, 0x010),
__ATOMIC_FETCH_OP_TEST(BPF_REG_1, BPF_REG_0, 0x010, BPF_AND | BPF_FETCH, 0x011, 0x010),
__ATOMIC_FETCH_OP_TEST(BPF_REG_2, BPF_REG_3, 0x010, BPF_AND | BPF_FETCH, 0x011, 0x010),
__ATOMIC_FETCH_OP_TEST(BPF_REG_4, BPF_REG_5, 0x010, BPF_AND | BPF_FETCH, 0x011, 0x010),
__ATOMIC_FETCH_OP_TEST(BPF_REG_9, BPF_REG_8, 0x010, BPF_AND | BPF_FETCH, 0x011, 0x010),
__ATOMIC_FETCH_OP_TEST(BPF_REG_1, BPF_REG_2, 0x010, BPF_OR | BPF_FETCH, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_0, BPF_REG_1, 0x010, BPF_OR | BPF_FETCH, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_1, BPF_REG_0, 0x010, BPF_OR | BPF_FETCH, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_2, BPF_REG_3, 0x010, BPF_OR | BPF_FETCH, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_4, BPF_REG_5, 0x010, BPF_OR | BPF_FETCH, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_9, BPF_REG_8, 0x010, BPF_OR | BPF_FETCH, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_1, BPF_REG_2, 0x010, BPF_XOR | BPF_FETCH, 0x011, 0x001),
__ATOMIC_FETCH_OP_TEST(BPF_REG_0, BPF_REG_1, 0x010, BPF_XOR | BPF_FETCH, 0x011, 0x001),
__ATOMIC_FETCH_OP_TEST(BPF_REG_1, BPF_REG_0, 0x010, BPF_XOR | BPF_FETCH, 0x011, 0x001),
__ATOMIC_FETCH_OP_TEST(BPF_REG_2, BPF_REG_3, 0x010, BPF_XOR | BPF_FETCH, 0x011, 0x001),
__ATOMIC_FETCH_OP_TEST(BPF_REG_4, BPF_REG_5, 0x010, BPF_XOR | BPF_FETCH, 0x011, 0x001),
__ATOMIC_FETCH_OP_TEST(BPF_REG_9, BPF_REG_8, 0x010, BPF_XOR | BPF_FETCH, 0x011, 0x001),
__ATOMIC_FETCH_OP_TEST(BPF_REG_1, BPF_REG_2, 0x010, BPF_XCHG, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_0, BPF_REG_1, 0x010, BPF_XCHG, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_1, BPF_REG_0, 0x010, BPF_XCHG, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_2, BPF_REG_3, 0x010, BPF_XCHG, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_4, BPF_REG_5, 0x010, BPF_XCHG, 0x011, 0x011),
__ATOMIC_FETCH_OP_TEST(BPF_REG_9, BPF_REG_8, 0x010, BPF_XCHG, 0x011, 0x011),
#undef __ATOMIC_FETCH_OP_TEST
25 changes: 25 additions & 0 deletions tools/testing/selftests/bpf/verifier/atomic_invalid.c
View file
@@ -0,0 +1,25 @@
#define __INVALID_ATOMIC_ACCESS_TEST(op) \
{ \
"atomic " #op " access through non-pointer ", \
.insns = { \
BPF_MOV64_IMM(BPF_REG_0, 1), \
BPF_MOV64_IMM(BPF_REG_1, 0), \
BPF_ATOMIC_OP(BPF_DW, op, BPF_REG_1, BPF_REG_0, -8), \
BPF_MOV64_IMM(BPF_REG_0, 0), \
BPF_EXIT_INSN(), \
}, \
.result = REJECT, \
.errstr = "R1 invalid mem access 'inv'" \
}
__INVALID_ATOMIC_ACCESS_TEST(BPF_ADD),
__INVALID_ATOMIC_ACCESS_TEST(BPF_ADD | BPF_FETCH),
__INVALID_ATOMIC_ACCESS_TEST(BPF_ADD),
__INVALID_ATOMIC_ACCESS_TEST(BPF_ADD | BPF_FETCH),
__INVALID_ATOMIC_ACCESS_TEST(BPF_AND),
__INVALID_ATOMIC_ACCESS_TEST(BPF_AND | BPF_FETCH),
__INVALID_ATOMIC_ACCESS_TEST(BPF_OR),
__INVALID_ATOMIC_ACCESS_TEST(BPF_OR | BPF_FETCH),
__INVALID_ATOMIC_ACCESS_TEST(BPF_XOR),
__INVALID_ATOMIC_ACCESS_TEST(BPF_XOR | BPF_FETCH),
__INVALID_ATOMIC_ACCESS_TEST(BPF_XCHG),
__INVALID_ATOMIC_ACCESS_TEST(BPF_CMPXCHG),

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