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Message-Id: <20210914091842.4186267-4-johan.almbladh@anyfinetworks.com>
Date: Tue, 14 Sep 2021 11:18:31 +0200
From: Johan Almbladh <johan.almbladh@...finetworks.com>
To: ast@...nel.org, daniel@...earbox.net, andrii@...nel.org
Cc: kafai@...com, songliubraving@...com, yhs@...com,
john.fastabend@...il.com, kpsingh@...nel.org, iii@...ux.ibm.com,
paul@...ium.io, yangtiezhu@...ngson.cn, netdev@...r.kernel.org,
bpf@...r.kernel.org,
Johan Almbladh <johan.almbladh@...finetworks.com>
Subject: [PATCH bpf v4 03/14] 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 <johan.almbladh@...finetworks.com>
---
lib/test_bpf.c | 260 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 260 insertions(+)
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index f0651dc6450b..f76472c050a7 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;
--
2.30.2
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