This patch adds a test for the 64-bit immediate load, a two-instruction
operation, to verify correctness for all possible magnitudes of the
immediate operand. Mainly intended for JIT testing.
Signed-off-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx>
---
lib/test_bpf.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index c25e99a461de..6a04447171c7 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -1104,6 +1104,60 @@ static int bpf_fill_alu32_mod_reg(struct bpf_test *self)
return __bpf_fill_alu32_reg(self, BPF_MOD);
}
+/*
+ * Test the two-instruction 64-bit immediate load operation for all
+ * power-of-two magnitudes of the immediate operand. For each MSB, a block
+ * of immediate values centered around the power-of-two MSB are tested,
+ * both for positive and negative values. The test is designed to verify
+ * the operation for JITs that emit different code depending on the magnitude
+ * 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)
+{
+ int block = 64; /* Increase for more tests per MSB position */
+ int len = 3 + 8 * 63 * block * 2;
+ struct bpf_insn *insn;
+ int bit, adj, sign;
+ 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 (bit = 0; bit <= 62; bit++) {
+ for (adj = -block / 2; adj < block / 2; adj++) {
+ for (sign = -1; sign <= 1; sign += 2) {
+ s64 imm = sign * ((1LL << bit) + adj);
+
+ /* 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;
+}
/*
* Exhaustive tests of JMP operations for all combinations of power-of-two
@@ -10245,6 +10299,15 @@ static struct bpf_test tests[] = {
.fill_helper = bpf_fill_alu32_mod_reg,
.nr_testruns = NR_PATTERN_RUNS,
},
+ /* LD_IMM64 immediate magnitudes */
+ {
+ "LD_IMM64: all immediate value magnitudes",
+ { },
+ INTERNAL | FLAG_NO_DATA,
+ { },
+ { { 0, 1 } },
+ .fill_helper = bpf_fill_ld_imm64,
+ },
/* JMP immediate magnitudes */
{
"JMP_JSET_K: all immediate value magnitudes",
--
2.30.2
