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| author |  Yonghong Song <yonghong.song@linux.dev>
| 2023-07-27 18:12:31 -0700 |
|---|---|---|
| committer |  Alexei Starovoitov <ast@kernel.org>
| 2023-07-27 18:52:33 -0700 |
| commit | 4cd58e9af8b9d9fff6b7145e742abbfcda0af4af (patch) | |
| tree | 2b6a5c2980c745a2b0096f544a17b6d82bb0fc89 /arch/x86/net | |
| parent | bpf: Fix jit blinding with new sdiv/smov insns (diff) | |
| download | linux-4cd58e9af8b9d9fff6b7145e742abbfcda0af4af.tar.gz linux-4cd58e9af8b9d9fff6b7145e742abbfcda0af4af.tar.bz2 linux-4cd58e9af8b9d9fff6b7145e742abbfcda0af4af.zip | |
bpf: Support new 32bit offset jmp instruction
Add interpreter/jit/verifier support for 32bit offset jmp instruction.
If a conditional jmp instruction needs more than 16bit offset,
it can be simulated with a conditional jmp + a 32bit jmp insn.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011231.3716103-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'arch/x86/net')
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index a89b62eb2b40..a5930042139d 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1815,16 +1815,24 @@ emit_cond_jmp: /* Convert BPF opcode to x86 */ break; case BPF_JMP | BPF_JA: - if (insn->off == -1) - /* -1 jmp instructions will always jump - * backwards two bytes. Explicitly handling - * this case avoids wasting too many passes - * when there are long sequences of replaced - * dead code. - */ - jmp_offset = -2; - else - jmp_offset = addrs[i + insn->off] - addrs[i]; + case BPF_JMP32 | BPF_JA: + if (BPF_CLASS(insn->code) == BPF_JMP) { + if (insn->off == -1) + /* -1 jmp instructions will always jump + * backwards two bytes. Explicitly handling + * this case avoids wasting too many passes + * when there are long sequences of replaced + * dead code. + */ + jmp_offset = -2; + else + jmp_offset = addrs[i + insn->off] - addrs[i]; + } else { + if (insn->imm == -1) + jmp_offset = -2; + else + jmp_offset = addrs[i + insn->imm] - addrs[i]; + } if (!jmp_offset) { /* |