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| author | Alexei Starovoitov <ast@kernel.org> | 2026-01-15 06:08:10 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-01-15 06:08:21 +0300 |
| commit | 9a403a4aea32f1801a7f29b2385ec345d4faaf78 (patch) | |
| tree | 52f62f9a9fbba49a50936ec612be8011e50d2038 | |
| parent | e3d0dbb3b5e8983d3be780199af1e5134c8a9c17 (diff) | |
| parent | 7c8e817e443c118aa303f1bbcec33df8d9e3487a (diff) | |
| download | linux-9a403a4aea32f1801a7f29b2385ec345d4faaf78.tar.xz | |
Merge branch 'bpf-live-registers-computation-with-gotox'
Anton Protopopov says:
====================
bpf: Live registers computation with gotox
While adding a selftest for live registers computation with gotox,
I've noticed that the code is actually incomplete. Namely, the
destination register rX in `gotox rX` wasn't actually considered
as used. Fix this and add a selftest.
v1 -> v2:
* only enable the new selftest on x86 and arm64
v1: https://lore.kernel.org/bpf/20260114113314.32649-1-a.s.protopopov@gmail.com/T/#t
====================
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260114162544.83253-1-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | kernel/bpf/verifier.c | 6 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/compute_live_registers.c | 41 |
2 files changed, 47 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 62ad7c79ce2d..7a375f608263 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -24848,6 +24848,12 @@ static void compute_insn_live_regs(struct bpf_verifier_env *env, case BPF_JMP32: switch (code) { case BPF_JA: + def = 0; + if (BPF_SRC(insn->code) == BPF_X) + use = dst; + else + use = 0; + break; case BPF_JCOND: def = 0; use = 0; diff --git a/tools/testing/selftests/bpf/progs/compute_live_registers.c b/tools/testing/selftests/bpf/progs/compute_live_registers.c index 6884ab99a421..f05e120f3450 100644 --- a/tools/testing/selftests/bpf/progs/compute_live_registers.c +++ b/tools/testing/selftests/bpf/progs/compute_live_registers.c @@ -431,6 +431,47 @@ __naked void subprog1(void) ::: __clobber_all); } +#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) + +SEC("socket") +__log_level(2) +__msg("2: .1........ (07) r1 += 8") +__msg("3: .1........ (79) r2 = *(u64 *)(r1 +0)") +__msg("4: ..2....... (b7) r3 = 1") +__msg("5: ..23...... (b7) r4 = 2") +__msg("6: ..234..... (0d) gotox r2") +__msg("7: ...3...... (bf) r0 = r3") +__msg("8: 0......... (95) exit") +__msg("9: ....4..... (bf) r0 = r4") +__msg("10: 0......... (95) exit") +__naked +void gotox(void) +{ + asm volatile ( + ".pushsection .jumptables,\"\",@progbits;" +"jt0_%=: .quad l0_%= - socket;" + ".quad l1_%= - socket;" + ".size jt0_%=, 16;" + ".global jt0_%=;" + ".popsection;" + + "r1 = jt0_%= ll;" + "r1 += 8;" + "r2 = *(u64 *)(r1 + 0);" + "r3 = 1;" + "r4 = 2;" + ".8byte %[gotox_r2];" +"l0_%=: r0 = r3;" + "exit;" +"l1_%=: r0 = r4;" + "exit;" + : + : __imm_insn(gotox_r2, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_2, BPF_REG_0, 0, 0)) + : __clobber_all); +} + +#endif /* __TARGET_ARCH_x86 || __TARGET_ARCH_arm64 */ + /* to retain debug info for BTF generation */ void kfunc_root(void) { |