From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
To: ast@kernel.org, daniel@iogearbox.net
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
bjorn.topel@intel.com, magnus.karlsson@intel.com,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Subject: [PATCH v5 bpf-next 5/6] bpf: allow for tailcalls in BPF subprograms for x64 JIT
Date: Fri, 24 Jul 2020 19:35:56 +0200 [thread overview]
Message-ID: <20200724173557.5764-6-maciej.fijalkowski@intel.com> (raw)
In-Reply-To: <20200724173557.5764-1-maciej.fijalkowski@intel.com>
Relax verifier's restriction that was meant to forbid tailcall usage
when subprog count was higher than 1.
Also, do not max out the stack depth of program that utilizes tailcalls.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
---
kernel/bpf/verifier.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f4955b4bf8a6..3ea769555246 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4176,10 +4176,12 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
case BPF_FUNC_tail_call:
if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
goto error;
+#if !defined(CONFIG_X86_64) || !defined(CONFIG_BPF_JIT_ALWAYS_ON)
if (env->subprog_cnt > 1) {
verbose(env, "tail_calls are not allowed in programs with bpf-to-bpf calls\n");
return -EINVAL;
}
+#endif
break;
case BPF_FUNC_perf_event_read:
case BPF_FUNC_perf_event_output:
@@ -10284,7 +10286,9 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
* the program array.
*/
prog->cb_access = 1;
+#if !defined(CONFIG_X86_64) || !defined(CONFIG_BPF_JIT_ALWAYS_ON)
env->prog->aux->stack_depth = MAX_BPF_STACK;
+#endif
env->prog->aux->max_pkt_offset = MAX_PACKET_OFF;
/* mark bpf_tail_call as different opcode to avoid
--
2.20.1
next prev parent reply other threads:[~2020-07-24 17:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-24 17:35 [PATCH v5 bpf-next 0/6] bpf: tailcalls in BPF subprograms Maciej Fijalkowski
2020-07-24 17:35 ` [PATCH v5 bpf-next 1/6] bpf, x64: use %rcx instead of %rax for tail call retpolines Maciej Fijalkowski
2020-07-24 17:35 ` [PATCH v5 bpf-next 2/6] bpf: propagate poke descriptors to subprograms Maciej Fijalkowski
2020-07-24 17:35 ` [PATCH v5 bpf-next 3/6] bpf: rename poke descriptor's 'ip' member to 'tailcall_target' Maciej Fijalkowski
2020-07-24 17:35 ` [PATCH v5 bpf-next 4/6] bpf, x64: rework pro/epilogue and tailcall handling in JIT Maciej Fijalkowski
2020-07-28 21:33 ` Daniel Borkmann
2020-07-28 22:07 ` Daniel Borkmann
2020-07-29 16:10 ` Maciej Fijalkowski
2020-07-29 21:10 ` Maciej Fijalkowski
2020-07-30 20:16 ` Daniel Borkmann
2020-07-30 22:58 ` Maciej Fijalkowski
2020-07-24 17:35 ` Maciej Fijalkowski [this message]
2020-07-24 17:35 ` [PATCH v5 bpf-next 6/6] selftests: bpf: add dummy prog for bpf2bpf with tailcall Maciej Fijalkowski
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