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bpf/tests: Add 32 bits only long conditional jump tests

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Commit f1517eb790 ("bpf/tests: Expand branch conversion JIT test")
introduced "Long conditional jump tests" but due to those tests making
use of 64 bits DIV and MOD, they don't get jited on powerpc/32,
leading to the long conditional jump test being skiped for unrelated
reason.

Add 4 new tests that are restricted to 32 bits ALU so that the jump
tests can also be performed on platforms that do no support 64 bits
operations.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/609f87a2d84e032c8d9ccb9ba7aebef893698f1e.1736154762.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy
2025-01-06 10:15:31 +01:00
committed by Daniel Borkmann
parent 8c21f88407
commit 2532608530
1 changed files with 58 additions and 6 deletions
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64
lib/test_bpf.c
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@@ -478,7 +478,7 @@ static int __bpf_ld_imm64(struct bpf_insn insns[2], u8 reg, s64 imm64)
* to overflow the field size of the native instruction, triggering * to overflow the field size of the native instruction, triggering
* a branch conversion mechanism in some JITs. * a branch conversion mechanism in some JITs.
*/ */
static int __bpf_fill_max_jmp(struct bpf_test *self, int jmp, int imm) static int __bpf_fill_max_jmp(struct bpf_test *self, int jmp, int imm, bool alu32)
{ {
struct bpf_insn *insns; struct bpf_insn *insns;
int len = S16_MAX + 5; int len = S16_MAX + 5;
@@ -501,7 +501,7 @@ static int __bpf_fill_max_jmp(struct bpf_test *self, int jmp, int imm)
}; };
int op = ops[(i >> 1) % ARRAY_SIZE(ops)]; int op = ops[(i >> 1) % ARRAY_SIZE(ops)];
if (i & 1) if ((i & 1) || alu32)
insns[i++] = BPF_ALU32_REG(op, R0, R1); insns[i++] = BPF_ALU32_REG(op, R0, R1);
else else
insns[i++] = BPF_ALU64_REG(op, R0, R1); insns[i++] = BPF_ALU64_REG(op, R0, R1);
@@ -516,27 +516,47 @@ static int __bpf_fill_max_jmp(struct bpf_test *self, int jmp, int imm)
} }
/* Branch taken by runtime decision */ /* Branch taken by runtime decision */
static int bpf_fill_max_jmp_taken_32(struct bpf_test *self)
{
return __bpf_fill_max_jmp(self, BPF_JEQ, 1, true);
}
static int bpf_fill_max_jmp_taken(struct bpf_test *self) static int bpf_fill_max_jmp_taken(struct bpf_test *self)
{ {
return __bpf_fill_max_jmp(self, BPF_JEQ, 1); return __bpf_fill_max_jmp(self, BPF_JEQ, 1, false);
} }
/* Branch not taken by runtime decision */ /* Branch not taken by runtime decision */
static int bpf_fill_max_jmp_not_taken_32(struct bpf_test *self)
{
return __bpf_fill_max_jmp(self, BPF_JEQ, 0, true);
}
static int bpf_fill_max_jmp_not_taken(struct bpf_test *self) static int bpf_fill_max_jmp_not_taken(struct bpf_test *self)
{ {
return __bpf_fill_max_jmp(self, BPF_JEQ, 0); return __bpf_fill_max_jmp(self, BPF_JEQ, 0, false);
} }
/* Branch always taken, known at JIT time */ /* Branch always taken, known at JIT time */
static int bpf_fill_max_jmp_always_taken_32(struct bpf_test *self)
{
return __bpf_fill_max_jmp(self, BPF_JGE, 0, true);
}
static int bpf_fill_max_jmp_always_taken(struct bpf_test *self) static int bpf_fill_max_jmp_always_taken(struct bpf_test *self)
{ {
return __bpf_fill_max_jmp(self, BPF_JGE, 0); return __bpf_fill_max_jmp(self, BPF_JGE, 0, false);
} }
/* Branch never taken, known at JIT time */ /* Branch never taken, known at JIT time */
static int bpf_fill_max_jmp_never_taken_32(struct bpf_test *self)
{
return __bpf_fill_max_jmp(self, BPF_JLT, 0, true);
}
static int bpf_fill_max_jmp_never_taken(struct bpf_test *self) static int bpf_fill_max_jmp_never_taken(struct bpf_test *self)
{ {
return __bpf_fill_max_jmp(self, BPF_JLT, 0); return __bpf_fill_max_jmp(self, BPF_JLT, 0, false);
} }
/* ALU result computation used in tests */ /* ALU result computation used in tests */
@@ -14233,6 +14253,38 @@ static struct bpf_test tests[] = {
{ { 0, 0 } }, { { 0, 0 } },
}, },
/* Conditional branch conversions */ /* Conditional branch conversions */
{
"Long conditional jump: taken at runtime (32 bits)",
{ },
INTERNAL | FLAG_NO_DATA,
{ },
{ { 0, 1 } },
.fill_helper = bpf_fill_max_jmp_taken_32,
},
{
"Long conditional jump: not taken at runtime (32 bits)",
{ },
INTERNAL | FLAG_NO_DATA,
{ },
{ { 0, 2 } },
.fill_helper = bpf_fill_max_jmp_not_taken_32,
},
{
"Long conditional jump: always taken, known at JIT time (32 bits)",
{ },
INTERNAL | FLAG_NO_DATA,
{ },
{ { 0, 1 } },
.fill_helper = bpf_fill_max_jmp_always_taken_32,
},
{
"Long conditional jump: never taken, known at JIT time (32 bits)",
{ },
INTERNAL | FLAG_NO_DATA,
{ },
{ { 0, 2 } },
.fill_helper = bpf_fill_max_jmp_never_taken_32,
},
{ {
"Long conditional jump: taken at runtime", "Long conditional jump: taken at runtime",
{ }, { },