From 68c956fe741757b760aa00fca8725c5651f5f77a Mon Sep 17 00:00:00 2001 From: Johan Almbladh Date: Tue, 14 Sep 2021 11:18:31 +0200 Subject: bpf/tests: Add exhaustive tests of ALU shift values This patch adds a set of tests for ALU64 and ALU32 shift operations to verify correctness for all possible values of the shift value. Mainly intended for JIT testing. Signed-off-by: Johan Almbladh Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210914091842.4186267-4-johan.almbladh@anyfinetworks.com --- lib/test_bpf.c | 260 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 260 insertions(+) diff --git a/lib/test_bpf.c b/lib/test_bpf.c index c865fd584adb..d599c2a8c860 100644 --- a/lib/test_bpf.c +++ b/lib/test_bpf.c @@ -497,6 +497,168 @@ static int bpf_fill_long_jmp(struct bpf_test *self) return 0; } +static int __bpf_ld_imm64(struct bpf_insn insns[2], u8 reg, s64 imm64) +{ + struct bpf_insn tmp[] = {BPF_LD_IMM64(reg, imm64)}; + + memcpy(insns, tmp, sizeof(tmp)); + return 2; +} + +/* Test an ALU shift operation for all valid shift values */ +static int __bpf_fill_alu_shift(struct bpf_test *self, u8 op, + u8 mode, bool alu32) +{ + static const s64 regs[] = { + 0x0123456789abcdefLL, /* dword > 0, word < 0 */ + 0xfedcba9876543210LL, /* dowrd < 0, word > 0 */ + 0xfedcba0198765432LL, /* dowrd < 0, word < 0 */ + 0x0123458967abcdefLL, /* dword > 0, word > 0 */ + }; + int bits = alu32 ? 32 : 64; + int len = (2 + 7 * bits) * ARRAY_SIZE(regs) + 3; + struct bpf_insn *insn; + int imm, k; + int i = 0; + + insn = kmalloc_array(len, sizeof(*insn), GFP_KERNEL); + if (!insn) + return -ENOMEM; + + insn[i++] = BPF_ALU64_IMM(BPF_MOV, R0, 0); + + for (k = 0; k < ARRAY_SIZE(regs); k++) { + s64 reg = regs[k]; + + i += __bpf_ld_imm64(&insn[i], R3, reg); + + for (imm = 0; imm < bits; imm++) { + u64 val; + + /* Perform operation */ + insn[i++] = BPF_ALU64_REG(BPF_MOV, R1, R3); + insn[i++] = BPF_ALU64_IMM(BPF_MOV, R2, imm); + if (alu32) { + if (mode == BPF_K) + insn[i++] = BPF_ALU32_IMM(op, R1, imm); + else + insn[i++] = BPF_ALU32_REG(op, R1, R2); + switch (op) { + case BPF_LSH: + val = (u32)reg << imm; + break; + case BPF_RSH: + val = (u32)reg >> imm; + break; + case BPF_ARSH: + val = (u32)reg >> imm; + if (imm > 0 && (reg & 0x80000000)) + val |= ~(u32)0 << (32 - imm); + break; + } + } else { + if (mode == BPF_K) + insn[i++] = BPF_ALU64_IMM(op, R1, imm); + else + insn[i++] = BPF_ALU64_REG(op, R1, R2); + switch (op) { + case BPF_LSH: + val = (u64)reg << imm; + break; + case BPF_RSH: + val = (u64)reg >> imm; + break; + case BPF_ARSH: + val = (u64)reg >> imm; + if (imm > 0 && reg < 0) + val |= ~(u64)0 << (64 - imm); + break; + } + } + + /* + * When debugging a JIT that fails this test, one + * can write the immediate value to R0 here to find + * out which operand values that fail. + */ + + /* Load reference and check the result */ + i += __bpf_ld_imm64(&insn[i], R4, val); + insn[i++] = BPF_JMP_REG(BPF_JEQ, R1, R4, 1); + insn[i++] = BPF_EXIT_INSN(); + } + } + + insn[i++] = BPF_ALU64_IMM(BPF_MOV, R0, 1); + insn[i++] = BPF_EXIT_INSN(); + + self->u.ptr.insns = insn; + self->u.ptr.len = len; + BUG_ON(i > len); + + return 0; +} + +static int bpf_fill_alu_lsh_imm(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_LSH, BPF_K, false); +} + +static int bpf_fill_alu_rsh_imm(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_RSH, BPF_K, false); +} + +static int bpf_fill_alu_arsh_imm(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_ARSH, BPF_K, false); +} + +static int bpf_fill_alu_lsh_reg(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_LSH, BPF_X, false); +} + +static int bpf_fill_alu_rsh_reg(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_RSH, BPF_X, false); +} + +static int bpf_fill_alu_arsh_reg(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_ARSH, BPF_X, false); +} + +static int bpf_fill_alu32_lsh_imm(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_LSH, BPF_K, true); +} + +static int bpf_fill_alu32_rsh_imm(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_RSH, BPF_K, true); +} + +static int bpf_fill_alu32_arsh_imm(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_ARSH, BPF_K, true); +} + +static int bpf_fill_alu32_lsh_reg(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_LSH, BPF_X, true); +} + +static int bpf_fill_alu32_rsh_reg(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_RSH, BPF_X, true); +} + +static int bpf_fill_alu32_arsh_reg(struct bpf_test *self) +{ + return __bpf_fill_alu_shift(self, BPF_ARSH, BPF_X, true); +} + static struct bpf_test tests[] = { { "TAX", @@ -8414,6 +8576,104 @@ static struct bpf_test tests[] = { {}, { { 0, 2 } }, }, + /* Exhaustive test of ALU64 shift operations */ + { + "ALU64_LSH_K: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu_lsh_imm, + }, + { + "ALU64_RSH_K: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu_rsh_imm, + }, + { + "ALU64_ARSH_K: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu_arsh_imm, + }, + { + "ALU64_LSH_X: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu_lsh_reg, + }, + { + "ALU64_RSH_X: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu_rsh_reg, + }, + { + "ALU64_ARSH_X: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu_arsh_reg, + }, + /* Exhaustive test of ALU32 shift operations */ + { + "ALU32_LSH_K: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu32_lsh_imm, + }, + { + "ALU32_RSH_K: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu32_rsh_imm, + }, + { + "ALU32_ARSH_K: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu32_arsh_imm, + }, + { + "ALU32_LSH_X: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu32_lsh_reg, + }, + { + "ALU32_RSH_X: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu32_rsh_reg, + }, + { + "ALU32_ARSH_X: all shift values", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_alu32_arsh_reg, + }, }; static struct net_device dev; -- cgit v1.2.3-59-g8ed1b