From 0eb4ef88c53f7169c44b1bd2ace5389981409a60 Mon Sep 17 00:00:00 2001 From: Johan Almbladh Date: Thu, 7 Oct 2021 16:30:06 +0200 Subject: bpf, tests: Add more LD_IMM64 tests This patch adds new tests for the two-instruction LD_IMM64. The new tests verify the operation with immediate values of different byte patterns. Mainly intended to cover JITs that want to be clever when loading 64-bit constants. Signed-off-by: Johan Almbladh Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20211007143006.634308-1-johan.almbladh@anyfinetworks.com --- lib/test_bpf.c | 120 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 117 insertions(+), 3 deletions(-) (limited to 'lib/test_bpf.c') diff --git a/lib/test_bpf.c b/lib/test_bpf.c index b9fc330fc83b..e5b10fdefab5 100644 --- a/lib/test_bpf.c +++ b/lib/test_bpf.c @@ -2134,7 +2134,7 @@ static int bpf_fill_atomic32_cmpxchg_reg_pairs(struct bpf_test *self) * of the immediate value. This is often the case if the native instruction * immediate field width is narrower than 32 bits. */ -static int bpf_fill_ld_imm64(struct bpf_test *self) +static int bpf_fill_ld_imm64_magn(struct bpf_test *self) { int block = 64; /* Increase for more tests per MSB position */ int len = 3 + 8 * 63 * block * 2; @@ -2180,6 +2180,88 @@ static int bpf_fill_ld_imm64(struct bpf_test *self) return 0; } +/* + * Test the two-instruction 64-bit immediate load operation for different + * combinations of bytes. Each byte in the 64-bit word is constructed as + * (base & mask) | (rand() & ~mask), where rand() is a deterministic LCG. + * All patterns (base1, mask1) and (base2, mask2) bytes are tested. + */ +static int __bpf_fill_ld_imm64_bytes(struct bpf_test *self, + u8 base1, u8 mask1, + u8 base2, u8 mask2) +{ + struct bpf_insn *insn; + int len = 3 + 8 * BIT(8); + int pattern, index; + u32 rand = 1; + 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 (pattern = 0; pattern < BIT(8); pattern++) { + u64 imm = 0; + + for (index = 0; index < 8; index++) { + int byte; + + if (pattern & BIT(index)) + byte = (base1 & mask1) | (rand & ~mask1); + else + byte = (base2 & mask2) | (rand & ~mask2); + imm = (imm << 8) | byte; + } + + /* Update our LCG */ + rand = rand * 1664525 + 1013904223; + + /* Perform operation */ + i += __bpf_ld_imm64(&insn[i], R1, imm); + + /* Load reference */ + insn[i++] = BPF_ALU32_IMM(BPF_MOV, R2, imm); + insn[i++] = BPF_ALU32_IMM(BPF_MOV, R3, (u32)(imm >> 32)); + insn[i++] = BPF_ALU64_IMM(BPF_LSH, R3, 32); + insn[i++] = BPF_ALU64_REG(BPF_OR, R2, R3); + + /* Check result */ + insn[i++] = BPF_JMP_REG(BPF_JEQ, R1, R2, 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_ld_imm64_checker(struct bpf_test *self) +{ + return __bpf_fill_ld_imm64_bytes(self, 0, 0xff, 0xff, 0xff); +} + +static int bpf_fill_ld_imm64_pos_neg(struct bpf_test *self) +{ + return __bpf_fill_ld_imm64_bytes(self, 1, 0x81, 0x80, 0x80); +} + +static int bpf_fill_ld_imm64_pos_zero(struct bpf_test *self) +{ + return __bpf_fill_ld_imm64_bytes(self, 1, 0x81, 0, 0xff); +} + +static int bpf_fill_ld_imm64_neg_zero(struct bpf_test *self) +{ + return __bpf_fill_ld_imm64_bytes(self, 0x80, 0x80, 0, 0xff); +} + /* * Exhaustive tests of JMP operations for all combinations of power-of-two * magnitudes of the operands, both for positive and negative values. The @@ -12401,14 +12483,46 @@ static struct bpf_test tests[] = { .fill_helper = bpf_fill_alu32_mod_reg, .nr_testruns = NR_PATTERN_RUNS, }, - /* LD_IMM64 immediate magnitudes */ + /* LD_IMM64 immediate magnitudes and byte patterns */ { "LD_IMM64: all immediate value magnitudes", { }, INTERNAL | FLAG_NO_DATA, { }, { { 0, 1 } }, - .fill_helper = bpf_fill_ld_imm64, + .fill_helper = bpf_fill_ld_imm64_magn, + }, + { + "LD_IMM64: checker byte patterns", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_ld_imm64_checker, + }, + { + "LD_IMM64: random positive and zero byte patterns", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_ld_imm64_pos_zero, + }, + { + "LD_IMM64: random negative and zero byte patterns", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_ld_imm64_neg_zero, + }, + { + "LD_IMM64: random positive and negative byte patterns", + { }, + INTERNAL | FLAG_NO_DATA, + { }, + { { 0, 1 } }, + .fill_helper = bpf_fill_ld_imm64_pos_neg, }, /* 64-bit ATOMIC register combinations */ { -- cgit v1.2.3-59-g8ed1b