Date:   Mon, 28 Nov 2022 12:44:54 -0300
From:   Pedro Tammela <pctammela@...il.com>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        pabeni@...hat.com, jhs@...atatu.com, xiyou.wangcong@...il.com,
        jiri@...nulli.us, kuniyu@...zon.com,
        Pedro Tammela <pctammela@...atatu.com>
Subject: [PATCH net-next v2 1/3] net/sched: add retpoline wrapper for tc

On kernels compiled with CONFIG_RETPOLINE and CONFIG_NET_TC_INDIRECT_WRAPPER,
optimize actions and filters that are compiled as built-ins into a direct call.
The calls are ordered alphabetically, but new ones should be ideally
added last.

On subsequent patches we expose the classifiers and actions functions
and wire up the wrapper into tc.

Signed-off-by: Pedro Tammela <pctammela@...atatu.com>
---
 include/net/tc_wrapper.h | 232 +++++++++++++++++++++++++++++++++++++++
 net/sched/Kconfig        |  13 +++
 2 files changed, 245 insertions(+)
 create mode 100644 include/net/tc_wrapper.h

diff --git a/include/net/tc_wrapper.h b/include/net/tc_wrapper.h
new file mode 100644
index 000000000000..bd2b4789db2b
--- /dev/null
+++ b/include/net/tc_wrapper.h
@@ -0,0 +1,232 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __NET_TC_WRAPPER_H
+#define __NET_TC_WRAPPER_H
+
+#include <linux/indirect_call_wrapper.h>
+#include <net/pkt_cls.h>
+
+#if IS_ENABLED(CONFIG_RETPOLINE) && IS_ENABLED(CONFIG_NET_TC_INDIRECT_WRAPPER)
+
+#define TC_INDIRECT_SCOPE
+
+/* TC Actions */
+#ifdef CONFIG_NET_CLS_ACT
+
+#define TC_INDIRECT_ACTION_DECLARE(fname)                              \
+	INDIRECT_CALLABLE_DECLARE(int fname(struct sk_buff *skb,       \
+					    const struct tc_action *a, \
+					    struct tcf_result *res))
+
+TC_INDIRECT_ACTION_DECLARE(tcf_bpf_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_connmark_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_csum_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_ct_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_ctinfo_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_gact_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_gate_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_ife_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_ipt_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_mirred_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_mpls_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_nat_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_pedit_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_police_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_sample_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_simp_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_skbedit_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_skbmod_act);
+TC_INDIRECT_ACTION_DECLARE(tcf_vlan_act);
+TC_INDIRECT_ACTION_DECLARE(tunnel_key_act);
+
+static inline int __tc_act(struct sk_buff *skb, const struct tc_action *a,
+			   struct tcf_result *res)
+{
+	if (0) { /* noop */ }
+#if IS_BUILTIN(CONFIG_NET_ACT_BPF)
+	else if (a->ops->act == tcf_bpf_act)
+		return tcf_bpf_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_CONNMARK)
+	else if (a->ops->act == tcf_connmark_act)
+		return tcf_connmark_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_CSUM)
+	else if (a->ops->act == tcf_csum_act)
+		return tcf_csum_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_CT)
+	else if (a->ops->act == tcf_ct_act)
+		return tcf_ct_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_CTINFO)
+	else if (a->ops->act == tcf_ctinfo_act)
+		return tcf_ctinfo_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_GACT)
+	else if (a->ops->act == tcf_gact_act)
+		return tcf_gact_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_GATE)
+	else if (a->ops->act == tcf_gate_act)
+		return tcf_gate_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_IFE)
+	else if (a->ops->act == tcf_ife_act)
+		return tcf_ife_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_IPT)
+	else if (a->ops->act == tcf_ipt_act)
+		return tcf_ipt_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_MIRRED)
+	else if (a->ops->act == tcf_mirred_act)
+		return tcf_mirred_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_MPLS)
+	else if (a->ops->act == tcf_mpls_act)
+		return tcf_mpls_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_NAT)
+	else if (a->ops->act == tcf_nat_act)
+		return tcf_nat_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_PEDIT)
+	else if (a->ops->act == tcf_pedit_act)
+		return tcf_pedit_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_POLICE)
+	else if (a->ops->act == tcf_police_act)
+		return tcf_police_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_SAMPLE)
+	else if (a->ops->act == tcf_sample_act)
+		return tcf_sample_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_SIMP)
+	else if (a->ops->act == tcf_simp_act)
+		return tcf_simp_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_SKBEDIT)
+	else if (a->ops->act == tcf_skbedit_act)
+		return tcf_skbedit_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_SKBMOD)
+	else if (a->ops->act == tcf_skbmod_act)
+		return tcf_skbmod_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_TUNNEL_KEY)
+	else if (a->ops->act == tunnel_key_act)
+		return tunnel_key_act(skb, a, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_ACT_VLAN)
+	else if (a->ops->act == tcf_vlan_act)
+		return tcf_vlan_act(skb, a, res);
+#endif
+	else
+		return a->ops->act(skb, a, res);
+}
+
+#endif /* CONFIG_NET_CLS_ACT */
+
+/* TC Filters */
+#ifdef CONFIG_NET_CLS
+
+#define TC_INDIRECT_FILTER_DECLARE(fname)                               \
+	INDIRECT_CALLABLE_DECLARE(int fname(struct sk_buff *skb,        \
+					    const struct tcf_proto *tp, \
+					    struct tcf_result *res))
+
+TC_INDIRECT_FILTER_DECLARE(basic_classify);
+TC_INDIRECT_FILTER_DECLARE(cls_bpf_classify);
+TC_INDIRECT_FILTER_DECLARE(cls_cgroup_classify);
+TC_INDIRECT_FILTER_DECLARE(fl_classify);
+TC_INDIRECT_FILTER_DECLARE(flow_classify);
+TC_INDIRECT_FILTER_DECLARE(fw_classify);
+TC_INDIRECT_FILTER_DECLARE(mall_classify);
+TC_INDIRECT_FILTER_DECLARE(route4_classify);
+TC_INDIRECT_FILTER_DECLARE(rsvp_classify);
+TC_INDIRECT_FILTER_DECLARE(rsvp6_classify);
+TC_INDIRECT_FILTER_DECLARE(tcindex_classify);
+TC_INDIRECT_FILTER_DECLARE(u32_classify);
+
+static inline int __tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
+				struct tcf_result *res)
+{
+	if (0) { /* noop */ }
+#if IS_BUILTIN(CONFIG_NET_CLS_BASIC)
+	else if (tp->classify == basic_classify)
+		return basic_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_BPF)
+	else if (tp->classify == cls_bpf_classify)
+		return cls_bpf_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_CGROUP)
+	else if (tp->classify == cls_cgroup_classify)
+		return cls_cgroup_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_FLOW)
+	else if (tp->classify == flow_classify)
+		return flow_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_FLOWER)
+	else if (tp->classify == fl_classify)
+		return fl_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_FW)
+	else if (tp->classify == fw_classify)
+		return fw_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_MATCHALL)
+	else if (tp->classify == mall_classify)
+		return mall_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_ROUTE4)
+	else if (tp->classify == route4_classify)
+		return route4_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_RSVP)
+	else if (tp->classify == rsvp_classify)
+		return rsvp_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_RSVP6)
+	else if (tp->classify == rsvp6_classify)
+		return rsvp_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_TCINDEX)
+	else if (tp->classify == tcindex_classify)
+		return tcindex_classify(skb, tp, res);
+#endif
+#if IS_BUILTIN(CONFIG_NET_CLS_U32)
+	else if (tp->classify == u32_classify)
+		return u32_classify(skb, tp, res);
+#endif
+	else
+		return tp->classify(skb, tp, res);
+}
+
+#endif /* CONFIG_NET_CLS */
+
+#else
+
+#define TC_INDIRECT_SCOPE static
+
+#ifdef CONFIG_NET_CLS_ACT
+static inline int __tc_act(struct sk_buff *skb, const struct tc_action *a,
+			   struct tcf_result *res)
+{
+	return a->ops->act(skb, a, res);
+}
+#endif
+
+#ifdef CONFIG_NET_CLS
+static inline int __tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
+				struct tcf_result *res)
+{
+	return tp->classify(skb, tp, res);
+}
+#endif
+
+#endif
+
+#endif /* __NET_TC_WRAPPER_H */
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 1e8ab4749c6c..9bc055f8013e 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -1021,6 +1021,19 @@ config NET_TC_SKB_EXT
 
 	  Say N here if you won't be using tc<->ovs offload or tc chains offload.
 
+config NET_TC_INDIRECT_WRAPPER
+	bool "TC indirect call wrapper"
+	depends on NET_SCHED
+	depends on RETPOLINE
+
+	help
+	  Say Y here to skip indirect calls in the TC datapath for known
+	  builtin classifiers/actions under CONFIG_RETPOLINE kernels.
+
+	  TC may run slower on CPUs with hardware based mitigations.
+
+	  If unsure, say N.
+
 endif # NET_SCHED
 
 config NET_SCH_FIFO
-- 
2.34.1

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