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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 <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211007143006.634308-1-johan.almbladh@anyfinetworks.com
This commit is contained in:
Johan Almbladh 2021-10-07 16:30:06 +02:00 committed by Daniel Borkmann
parent bbf731b3f4
commit 0eb4ef88c5
1 changed files with 117 additions and 3 deletions
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120
lib/test_bpf.c
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@ -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 */
{