From f3b55abb6d5a522228e136c3bc4a9a716d5d8a54 Mon Sep 17 00:00:00 2001 From: Jiong Wang Date: Fri, 24 May 2019 23:25:20 +0100 Subject: [PATCH] selftests: bpf: adjust several test_verifier helpers for insn insertion - bpf_fill_ld_abs_vlan_push_pop: Prevent zext happens inside PUSH_CNT loop. This could happen because of BPF_LD_ABS (32-bit def) + BPF_JMP (64-bit use), or BPF_LD_ABS + EXIT (64-bit use of R0). So, change BPF_JMP to BPF_JMP32 and redefine R0 at exit path to cut off the data-flow from inside the loop. - bpf_fill_jump_around_ld_abs: Jump range is limited to 16 bit. every ld_abs is replaced by 6 insns, but on arches like arm, ppc etc, there will be one BPF_ZEXT inserted to extend the error value of the inlined ld_abs sequence which then contains 7 insns. so, set the dividend to 7 so the testcase could work on all arches. - bpf_fill_scale1/bpf_fill_scale2: Both contains ~1M BPF_ALU32_IMM which will trigger ~1M insn patcher call because of hi32 randomization later when BPF_F_TEST_RND_HI32 is set for bpf selftests. Insn patcher is not efficient that 1M call to it will hang computer. So , change to BPF_ALU64_IMM to avoid hi32 randomization. Signed-off-by: Jiong Wang Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/test_verifier.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 6e2fec84c929..fa9b5bfe5d9f 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -138,32 +138,36 @@ static void bpf_fill_ld_abs_vlan_push_pop(struct bpf_test *self) loop: for (j = 0; j < PUSH_CNT; j++) { insn[i++] = BPF_LD_ABS(BPF_B, 0); - insn[i] = BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0x34, len - i - 2); + /* jump to error label */ + insn[i] = BPF_JMP32_IMM(BPF_JNE, BPF_REG_0, 0x34, len - i - 3); i++; insn[i++] = BPF_MOV64_REG(BPF_REG_1, BPF_REG_6); insn[i++] = BPF_MOV64_IMM(BPF_REG_2, 1); insn[i++] = BPF_MOV64_IMM(BPF_REG_3, 2); insn[i++] = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_skb_vlan_push), - insn[i] = BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, len - i - 2); + insn[i] = BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, len - i - 3); i++; } for (j = 0; j < PUSH_CNT; j++) { insn[i++] = BPF_LD_ABS(BPF_B, 0); - insn[i] = BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0x34, len - i - 2); + insn[i] = BPF_JMP32_IMM(BPF_JNE, BPF_REG_0, 0x34, len - i - 3); i++; insn[i++] = BPF_MOV64_REG(BPF_REG_1, BPF_REG_6); insn[i++] = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_skb_vlan_pop), - insn[i] = BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, len - i - 2); + insn[i] = BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, len - i - 3); i++; } if (++k < 5) goto loop; - for (; i < len - 1; i++) - insn[i] = BPF_ALU32_IMM(BPF_MOV, BPF_REG_0, 0xbef); + for (; i < len - 3; i++) + insn[i] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_0, 0xbef); + insn[len - 3] = BPF_JMP_A(1); + /* error label */ + insn[len - 2] = BPF_MOV32_IMM(BPF_REG_0, 0); insn[len - 1] = BPF_EXIT_INSN(); self->prog_len = len; } @@ -171,8 +175,13 @@ loop: static void bpf_fill_jump_around_ld_abs(struct bpf_test *self) { struct bpf_insn *insn = self->fill_insns; - /* jump range is limited to 16 bit. every ld_abs is replaced by 6 insns */ - unsigned int len = (1 << 15) / 6; + /* jump range is limited to 16 bit. every ld_abs is replaced by 6 insns, + * but on arches like arm, ppc etc, there will be one BPF_ZEXT inserted + * to extend the error value of the inlined ld_abs sequence which then + * contains 7 insns. so, set the dividend to 7 so the testcase could + * work on all arches. + */ + unsigned int len = (1 << 15) / 7; int i = 0; insn[i++] = BPF_MOV64_REG(BPF_REG_6, BPF_REG_1); @@ -232,7 +241,7 @@ static void bpf_fill_scale1(struct bpf_test *self) * within 1m limit add MAX_TEST_INSNS - MAX_JMP_SEQ - 1 MOVs and 1 EXIT */ while (i < MAX_TEST_INSNS - MAX_JMP_SEQ - 1) - insn[i++] = BPF_ALU32_IMM(BPF_MOV, BPF_REG_0, 42); + insn[i++] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_0, 42); insn[i] = BPF_EXIT_INSN(); self->prog_len = i + 1; self->retval = 42; @@ -264,7 +273,7 @@ static void bpf_fill_scale2(struct bpf_test *self) * within 1m limit add MAX_TEST_INSNS - MAX_JMP_SEQ - 1 MOVs and 1 EXIT */ while (i < MAX_TEST_INSNS - MAX_JMP_SEQ - 1) - insn[i++] = BPF_ALU32_IMM(BPF_MOV, BPF_REG_0, 42); + insn[i++] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_0, 42); insn[i] = BPF_EXIT_INSN(); self->prog_len = i + 1; self->retval = 42; -- 2.11.0