Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 1088 insertions, 0 deletions

diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
new file mode 100644
index 000000000..91fcb75ba
--- /dev/null
+++ b/tools/bpf/bpftool/btf.c
@@ -0,0 +1,1088 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (C) 2019 Facebook */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/err.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/btf.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <bpf/bpf.h>
+#include <bpf/btf.h>
+#include <bpf/hashmap.h>
+#include <bpf/libbpf.h>
+
+#include "json_writer.h"
+#include "main.h"
+
+static const char * const btf_kind_str[NR_BTF_KINDS] = {
+	[BTF_KIND_UNKN]		= "UNKNOWN",
+	[BTF_KIND_INT]		= "INT",
+	[BTF_KIND_PTR]		= "PTR",
+	[BTF_KIND_ARRAY]	= "ARRAY",
+	[BTF_KIND_STRUCT]	= "STRUCT",
+	[BTF_KIND_UNION]	= "UNION",
+	[BTF_KIND_ENUM]		= "ENUM",
+	[BTF_KIND_FWD]		= "FWD",
+	[BTF_KIND_TYPEDEF]	= "TYPEDEF",
+	[BTF_KIND_VOLATILE]	= "VOLATILE",
+	[BTF_KIND_CONST]	= "CONST",
+	[BTF_KIND_RESTRICT]	= "RESTRICT",
+	[BTF_KIND_FUNC]		= "FUNC",
+	[BTF_KIND_FUNC_PROTO]	= "FUNC_PROTO",
+	[BTF_KIND_VAR]		= "VAR",
+	[BTF_KIND_DATASEC]	= "DATASEC",
+	[BTF_KIND_FLOAT]	= "FLOAT",
+	[BTF_KIND_DECL_TAG]	= "DECL_TAG",
+	[BTF_KIND_TYPE_TAG]	= "TYPE_TAG",
+	[BTF_KIND_ENUM64]	= "ENUM64",
+};
+
+static const char *btf_int_enc_str(__u8 encoding)
+{
+	switch (encoding) {
+	case 0:
+		return "(none)";
+	case BTF_INT_SIGNED:
+		return "SIGNED";
+	case BTF_INT_CHAR:
+		return "CHAR";
+	case BTF_INT_BOOL:
+		return "BOOL";
+	default:
+		return "UNKN";
+	}
+}
+
+static const char *btf_var_linkage_str(__u32 linkage)
+{
+	switch (linkage) {
+	case BTF_VAR_STATIC:
+		return "static";
+	case BTF_VAR_GLOBAL_ALLOCATED:
+		return "global";
+	case BTF_VAR_GLOBAL_EXTERN:
+		return "extern";
+	default:
+		return "(unknown)";
+	}
+}
+
+static const char *btf_func_linkage_str(const struct btf_type *t)
+{
+	switch (btf_vlen(t)) {
+	case BTF_FUNC_STATIC:
+		return "static";
+	case BTF_FUNC_GLOBAL:
+		return "global";
+	case BTF_FUNC_EXTERN:
+		return "extern";
+	default:
+		return "(unknown)";
+	}
+}
+
+static const char *btf_str(const struct btf *btf, __u32 off)
+{
+	if (!off)
+		return "(anon)";
+	return btf__name_by_offset(btf, off) ? : "(invalid)";
+}
+
+static int btf_kind_safe(int kind)
+{
+	return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
+}
+
+static int dump_btf_type(const struct btf *btf, __u32 id,
+			 const struct btf_type *t)
+{
+	json_writer_t *w = json_wtr;
+	int kind = btf_kind(t);
+
+	if (json_output) {
+		jsonw_start_object(w);
+		jsonw_uint_field(w, "id", id);
+		jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]);
+		jsonw_string_field(w, "name", btf_str(btf, t->name_off));
+	} else {
+		printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)],
+		       btf_str(btf, t->name_off));
+	}
+
+	switch (kind) {
+	case BTF_KIND_INT: {
+		__u32 v = *(__u32 *)(t + 1);
+		const char *enc;
+
+		enc = btf_int_enc_str(BTF_INT_ENCODING(v));
+
+		if (json_output) {
+			jsonw_uint_field(w, "size", t->size);
+			jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v));
+			jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v));
+			jsonw_string_field(w, "encoding", enc);
+		} else {
+			printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s",
+			       t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v),
+			       enc);
+		}
+		break;
+	}
+	case BTF_KIND_PTR:
+	case BTF_KIND_CONST:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_TYPE_TAG:
+		if (json_output)
+			jsonw_uint_field(w, "type_id", t->type);
+		else
+			printf(" type_id=%u", t->type);
+		break;
+	case BTF_KIND_ARRAY: {
+		const struct btf_array *arr = (const void *)(t + 1);
+
+		if (json_output) {
+			jsonw_uint_field(w, "type_id", arr->type);
+			jsonw_uint_field(w, "index_type_id", arr->index_type);
+			jsonw_uint_field(w, "nr_elems", arr->nelems);
+		} else {
+			printf(" type_id=%u index_type_id=%u nr_elems=%u",
+			       arr->type, arr->index_type, arr->nelems);
+		}
+		break;
+	}
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION: {
+		const struct btf_member *m = (const void *)(t + 1);
+		__u16 vlen = BTF_INFO_VLEN(t->info);
+		int i;
+
+		if (json_output) {
+			jsonw_uint_field(w, "size", t->size);
+			jsonw_uint_field(w, "vlen", vlen);
+			jsonw_name(w, "members");
+			jsonw_start_array(w);
+		} else {
+			printf(" size=%u vlen=%u", t->size, vlen);
+		}
+		for (i = 0; i < vlen; i++, m++) {
+			const char *name = btf_str(btf, m->name_off);
+			__u32 bit_off, bit_sz;
+
+			if (BTF_INFO_KFLAG(t->info)) {
+				bit_off = BTF_MEMBER_BIT_OFFSET(m->offset);
+				bit_sz = BTF_MEMBER_BITFIELD_SIZE(m->offset);
+			} else {
+				bit_off = m->offset;
+				bit_sz = 0;
+			}
+
+			if (json_output) {
+				jsonw_start_object(w);
+				jsonw_string_field(w, "name", name);
+				jsonw_uint_field(w, "type_id", m->type);
+				jsonw_uint_field(w, "bits_offset", bit_off);
+				if (bit_sz) {
+					jsonw_uint_field(w, "bitfield_size",
+							 bit_sz);
+				}
+				jsonw_end_object(w);
+			} else {
+				printf("\n\t'%s' type_id=%u bits_offset=%u",
+				       name, m->type, bit_off);
+				if (bit_sz)
+					printf(" bitfield_size=%u", bit_sz);
+			}
+		}
+		if (json_output)
+			jsonw_end_array(w);
+		break;
+	}
+	case BTF_KIND_ENUM: {
+		const struct btf_enum *v = (const void *)(t + 1);
+		__u16 vlen = BTF_INFO_VLEN(t->info);
+		const char *encoding;
+		int i;
+
+		encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
+		if (json_output) {
+			jsonw_string_field(w, "encoding", encoding);
+			jsonw_uint_field(w, "size", t->size);
+			jsonw_uint_field(w, "vlen", vlen);
+			jsonw_name(w, "values");
+			jsonw_start_array(w);
+		} else {
+			printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
+		}
+		for (i = 0; i < vlen; i++, v++) {
+			const char *name = btf_str(btf, v->name_off);
+
+			if (json_output) {
+				jsonw_start_object(w);
+				jsonw_string_field(w, "name", name);
+				if (btf_kflag(t))
+					jsonw_int_field(w, "val", v->val);
+				else
+					jsonw_uint_field(w, "val", v->val);
+				jsonw_end_object(w);
+			} else {
+				if (btf_kflag(t))
+					printf("\n\t'%s' val=%d", name, v->val);
+				else
+					printf("\n\t'%s' val=%u", name, v->val);
+			}
+		}
+		if (json_output)
+			jsonw_end_array(w);
+		break;
+	}
+	case BTF_KIND_ENUM64: {
+		const struct btf_enum64 *v = btf_enum64(t);
+		__u16 vlen = btf_vlen(t);
+		const char *encoding;
+		int i;
+
+		encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
+		if (json_output) {
+			jsonw_string_field(w, "encoding", encoding);
+			jsonw_uint_field(w, "size", t->size);
+			jsonw_uint_field(w, "vlen", vlen);
+			jsonw_name(w, "values");
+			jsonw_start_array(w);
+		} else {
+			printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
+		}
+		for (i = 0; i < vlen; i++, v++) {
+			const char *name = btf_str(btf, v->name_off);
+			__u64 val = ((__u64)v->val_hi32 << 32) | v->val_lo32;
+
+			if (json_output) {
+				jsonw_start_object(w);
+				jsonw_string_field(w, "name", name);
+				if (btf_kflag(t))
+					jsonw_int_field(w, "val", val);
+				else
+					jsonw_uint_field(w, "val", val);
+				jsonw_end_object(w);
+			} else {
+				if (btf_kflag(t))
+					printf("\n\t'%s' val=%lldLL", name,
+					       (unsigned long long)val);
+				else
+					printf("\n\t'%s' val=%lluULL", name,
+					       (unsigned long long)val);
+			}
+		}
+		if (json_output)
+			jsonw_end_array(w);
+		break;
+	}
+	case BTF_KIND_FWD: {
+		const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union"
+							       : "struct";
+
+		if (json_output)
+			jsonw_string_field(w, "fwd_kind", fwd_kind);
+		else
+			printf(" fwd_kind=%s", fwd_kind);
+		break;
+	}
+	case BTF_KIND_FUNC: {
+		const char *linkage = btf_func_linkage_str(t);
+
+		if (json_output) {
+			jsonw_uint_field(w, "type_id", t->type);
+			jsonw_string_field(w, "linkage", linkage);
+		} else {
+			printf(" type_id=%u linkage=%s", t->type, linkage);
+		}
+		break;
+	}
+	case BTF_KIND_FUNC_PROTO: {
+		const struct btf_param *p = (const void *)(t + 1);
+		__u16 vlen = BTF_INFO_VLEN(t->info);
+		int i;
+
+		if (json_output) {
+			jsonw_uint_field(w, "ret_type_id", t->type);
+			jsonw_uint_field(w, "vlen", vlen);
+			jsonw_name(w, "params");
+			jsonw_start_array(w);
+		} else {
+			printf(" ret_type_id=%u vlen=%u", t->type, vlen);
+		}
+		for (i = 0; i < vlen; i++, p++) {
+			const char *name = btf_str(btf, p->name_off);
+
+			if (json_output) {
+				jsonw_start_object(w);
+				jsonw_string_field(w, "name", name);
+				jsonw_uint_field(w, "type_id", p->type);
+				jsonw_end_object(w);
+			} else {
+				printf("\n\t'%s' type_id=%u", name, p->type);
+			}
+		}
+		if (json_output)
+			jsonw_end_array(w);
+		break;
+	}
+	case BTF_KIND_VAR: {
+		const struct btf_var *v = (const void *)(t + 1);
+		const char *linkage;
+
+		linkage = btf_var_linkage_str(v->linkage);
+
+		if (json_output) {
+			jsonw_uint_field(w, "type_id", t->type);
+			jsonw_string_field(w, "linkage", linkage);
+		} else {
+			printf(" type_id=%u, linkage=%s", t->type, linkage);
+		}
+		break;
+	}
+	case BTF_KIND_DATASEC: {
+		const struct btf_var_secinfo *v = (const void *)(t + 1);
+		const struct btf_type *vt;
+		__u16 vlen = BTF_INFO_VLEN(t->info);
+		int i;
+
+		if (json_output) {
+			jsonw_uint_field(w, "size", t->size);
+			jsonw_uint_field(w, "vlen", vlen);
+			jsonw_name(w, "vars");
+			jsonw_start_array(w);
+		} else {
+			printf(" size=%u vlen=%u", t->size, vlen);
+		}
+		for (i = 0; i < vlen; i++, v++) {
+			if (json_output) {
+				jsonw_start_object(w);
+				jsonw_uint_field(w, "type_id", v->type);
+				jsonw_uint_field(w, "offset", v->offset);
+				jsonw_uint_field(w, "size", v->size);
+				jsonw_end_object(w);
+			} else {
+				printf("\n\ttype_id=%u offset=%u size=%u",
+				       v->type, v->offset, v->size);
+
+				if (v->type < btf__type_cnt(btf)) {
+					vt = btf__type_by_id(btf, v->type);
+					printf(" (%s '%s')",
+					       btf_kind_str[btf_kind_safe(btf_kind(vt))],
+					       btf_str(btf, vt->name_off));
+				}
+			}
+		}
+		if (json_output)
+			jsonw_end_array(w);
+		break;
+	}
+	case BTF_KIND_FLOAT: {
+		if (json_output)
+			jsonw_uint_field(w, "size", t->size);
+		else
+			printf(" size=%u", t->size);
+		break;
+	}
+	case BTF_KIND_DECL_TAG: {
+		const struct btf_decl_tag *tag = (const void *)(t + 1);
+
+		if (json_output) {
+			jsonw_uint_field(w, "type_id", t->type);
+			jsonw_int_field(w, "component_idx", tag->component_idx);
+		} else {
+			printf(" type_id=%u component_idx=%d", t->type, tag->component_idx);
+		}
+		break;
+	}
+	default:
+		break;
+	}
+
+	if (json_output)
+		jsonw_end_object(json_wtr);
+	else
+		printf("\n");
+
+	return 0;
+}
+
+static int dump_btf_raw(const struct btf *btf,
+			__u32 *root_type_ids, int root_type_cnt)
+{
+	const struct btf_type *t;
+	int i;
+
+	if (json_output) {
+		jsonw_start_object(json_wtr);
+		jsonw_name(json_wtr, "types");
+		jsonw_start_array(json_wtr);
+	}
+
+	if (root_type_cnt) {
+		for (i = 0; i < root_type_cnt; i++) {
+			t = btf__type_by_id(btf, root_type_ids[i]);
+			dump_btf_type(btf, root_type_ids[i], t);
+		}
+	} else {
+		const struct btf *base;
+		int cnt = btf__type_cnt(btf);
+		int start_id = 1;
+
+		base = btf__base_btf(btf);
+		if (base)
+			start_id = btf__type_cnt(base);
+
+		for (i = start_id; i < cnt; i++) {
+			t = btf__type_by_id(btf, i);
+			dump_btf_type(btf, i, t);
+		}
+	}
+
+	if (json_output) {
+		jsonw_end_array(json_wtr);
+		jsonw_end_object(json_wtr);
+	}
+	return 0;
+}
+
+static void __printf(2, 0) btf_dump_printf(void *ctx,
+					   const char *fmt, va_list args)
+{
+	vfprintf(stdout, fmt, args);
+}
+
+static int dump_btf_c(const struct btf *btf,
+		      __u32 *root_type_ids, int root_type_cnt)
+{
+	struct btf_dump *d;
+	int err = 0, i;
+
+	d = btf_dump__new(btf, btf_dump_printf, NULL, NULL);
+	if (!d)
+		return -errno;
+
+	printf("#ifndef __VMLINUX_H__\n");
+	printf("#define __VMLINUX_H__\n");
+	printf("\n");
+	printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
+	printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n");
+	printf("#endif\n\n");
+
+	if (root_type_cnt) {
+		for (i = 0; i < root_type_cnt; i++) {
+			err = btf_dump__dump_type(d, root_type_ids[i]);
+			if (err)
+				goto done;
+		}
+	} else {
+		int cnt = btf__type_cnt(btf);
+
+		for (i = 1; i < cnt; i++) {
+			err = btf_dump__dump_type(d, i);
+			if (err)
+				goto done;
+		}
+	}
+
+	printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
+	printf("#pragma clang attribute pop\n");
+	printf("#endif\n");
+	printf("\n");
+	printf("#endif /* __VMLINUX_H__ */\n");
+
+done:
+	btf_dump__free(d);
+	return err;
+}
+
+static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
+
+static struct btf *get_vmlinux_btf_from_sysfs(void)
+{
+	struct btf *base;
+
+	base = btf__parse(sysfs_vmlinux, NULL);
+	if (!base)
+		p_err("failed to parse vmlinux BTF at '%s': %d\n",
+		      sysfs_vmlinux, -errno);
+
+	return base;
+}
+
+#define BTF_NAME_BUFF_LEN 64
+
+static bool btf_is_kernel_module(__u32 btf_id)
+{
+	struct bpf_btf_info btf_info = {};
+	char btf_name[BTF_NAME_BUFF_LEN];
+	int btf_fd;
+	__u32 len;
+	int err;
+
+	btf_fd = bpf_btf_get_fd_by_id(btf_id);
+	if (btf_fd < 0) {
+		p_err("can't get BTF object by id (%u): %s", btf_id, strerror(errno));
+		return false;
+	}
+
+	len = sizeof(btf_info);
+	btf_info.name = ptr_to_u64(btf_name);
+	btf_info.name_len = sizeof(btf_name);
+	err = bpf_btf_get_info_by_fd(btf_fd, &btf_info, &len);
+	close(btf_fd);
+	if (err) {
+		p_err("can't get BTF (ID %u) object info: %s", btf_id, strerror(errno));
+		return false;
+	}
+
+	return btf_info.kernel_btf && strncmp(btf_name, "vmlinux", sizeof(btf_name)) != 0;
+}
+
+static int do_dump(int argc, char **argv)
+{
+	struct btf *btf = NULL, *base = NULL;
+	__u32 root_type_ids[2];
+	int root_type_cnt = 0;
+	bool dump_c = false;
+	__u32 btf_id = -1;
+	const char *src;
+	int fd = -1;
+	int err = 0;
+
+	if (!REQ_ARGS(2)) {
+		usage();
+		return -1;
+	}
+	src = GET_ARG();
+	if (is_prefix(src, "map")) {
+		struct bpf_map_info info = {};
+		__u32 len = sizeof(info);
+
+		if (!REQ_ARGS(2)) {
+			usage();
+			return -1;
+		}
+
+		fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
+		if (fd < 0)
+			return -1;
+
+		btf_id = info.btf_id;
+		if (argc && is_prefix(*argv, "key")) {
+			root_type_ids[root_type_cnt++] = info.btf_key_type_id;
+			NEXT_ARG();
+		} else if (argc && is_prefix(*argv, "value")) {
+			root_type_ids[root_type_cnt++] = info.btf_value_type_id;
+			NEXT_ARG();
+		} else if (argc && is_prefix(*argv, "all")) {
+			NEXT_ARG();
+		} else if (argc && is_prefix(*argv, "kv")) {
+			root_type_ids[root_type_cnt++] = info.btf_key_type_id;
+			root_type_ids[root_type_cnt++] = info.btf_value_type_id;
+			NEXT_ARG();
+		} else {
+			root_type_ids[root_type_cnt++] = info.btf_key_type_id;
+			root_type_ids[root_type_cnt++] = info.btf_value_type_id;
+		}
+	} else if (is_prefix(src, "prog")) {
+		struct bpf_prog_info info = {};
+		__u32 len = sizeof(info);
+
+		if (!REQ_ARGS(2)) {
+			usage();
+			return -1;
+		}
+
+		fd = prog_parse_fd(&argc, &argv);
+		if (fd < 0)
+			return -1;
+
+		err = bpf_prog_get_info_by_fd(fd, &info, &len);
+		if (err) {
+			p_err("can't get prog info: %s", strerror(errno));
+			goto done;
+		}
+
+		btf_id = info.btf_id;
+	} else if (is_prefix(src, "id")) {
+		char *endptr;
+
+		btf_id = strtoul(*argv, &endptr, 0);
+		if (*endptr) {
+			p_err("can't parse %s as ID", *argv);
+			return -1;
+		}
+		NEXT_ARG();
+	} else if (is_prefix(src, "file")) {
+		const char sysfs_prefix[] = "/sys/kernel/btf/";
+
+		if (!base_btf &&
+		    strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 &&
+		    strcmp(*argv, sysfs_vmlinux) != 0)
+			base = get_vmlinux_btf_from_sysfs();
+
+		btf = btf__parse_split(*argv, base ?: base_btf);
+		if (!btf) {
+			err = -errno;
+			p_err("failed to load BTF from %s: %s",
+			      *argv, strerror(errno));
+			goto done;
+		}
+		NEXT_ARG();
+	} else {
+		err = -1;
+		p_err("unrecognized BTF source specifier: '%s'", src);
+		goto done;
+	}
+
+	while (argc) {
+		if (is_prefix(*argv, "format")) {
+			NEXT_ARG();
+			if (argc < 1) {
+				p_err("expecting value for 'format' option\n");
+				err = -EINVAL;
+				goto done;
+			}
+			if (strcmp(*argv, "c") == 0) {
+				dump_c = true;
+			} else if (strcmp(*argv, "raw") == 0) {
+				dump_c = false;
+			} else {
+				p_err("unrecognized format specifier: '%s', possible values: raw, c",
+				      *argv);
+				err = -EINVAL;
+				goto done;
+			}
+			NEXT_ARG();
+		} else {
+			p_err("unrecognized option: '%s'", *argv);
+			err = -EINVAL;
+			goto done;
+		}
+	}
+
+	if (!btf) {
+		if (!base_btf && btf_is_kernel_module(btf_id)) {
+			p_info("Warning: valid base BTF was not specified with -B option, falling back to standard base BTF (%s)",
+			       sysfs_vmlinux);
+			base_btf = get_vmlinux_btf_from_sysfs();
+		}
+
+		btf = btf__load_from_kernel_by_id_split(btf_id, base_btf);
+		if (!btf) {
+			err = -errno;
+			p_err("get btf by id (%u): %s", btf_id, strerror(errno));
+			goto done;
+		}
+	}
+
+	if (dump_c) {
+		if (json_output) {
+			p_err("JSON output for C-syntax dump is not supported");
+			err = -ENOTSUP;
+			goto done;
+		}
+		err = dump_btf_c(btf, root_type_ids, root_type_cnt);
+	} else {
+		err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
+	}
+
+done:
+	close(fd);
+	btf__free(btf);
+	btf__free(base);
+	return err;
+}
+
+static int btf_parse_fd(int *argc, char ***argv)
+{
+	unsigned int id;
+	char *endptr;
+	int fd;
+
+	if (!is_prefix(*argv[0], "id")) {
+		p_err("expected 'id', got: '%s'?", **argv);
+		return -1;
+	}
+	NEXT_ARGP();
+
+	id = strtoul(**argv, &endptr, 0);
+	if (*endptr) {
+		p_err("can't parse %s as ID", **argv);
+		return -1;
+	}
+	NEXT_ARGP();
+
+	fd = bpf_btf_get_fd_by_id(id);
+	if (fd < 0)
+		p_err("can't get BTF object by id (%u): %s",
+		      id, strerror(errno));
+
+	return fd;
+}
+
+static int
+build_btf_type_table(struct hashmap *tab, enum bpf_obj_type type,
+		     void *info, __u32 *len)
+{
+	static const char * const names[] = {
+		[BPF_OBJ_UNKNOWN]	= "unknown",
+		[BPF_OBJ_PROG]		= "prog",
+		[BPF_OBJ_MAP]		= "map",
+	};
+	__u32 btf_id, id = 0;
+	int err;
+	int fd;
+
+	while (true) {
+		switch (type) {
+		case BPF_OBJ_PROG:
+			err = bpf_prog_get_next_id(id, &id);
+			break;
+		case BPF_OBJ_MAP:
+			err = bpf_map_get_next_id(id, &id);
+			break;
+		default:
+			err = -1;
+			p_err("unexpected object type: %d", type);
+			goto err_free;
+		}
+		if (err) {
+			if (errno == ENOENT) {
+				err = 0;
+				break;
+			}
+			p_err("can't get next %s: %s%s", names[type],
+			      strerror(errno),
+			      errno == EINVAL ? " -- kernel too old?" : "");
+			goto err_free;
+		}
+
+		switch (type) {
+		case BPF_OBJ_PROG:
+			fd = bpf_prog_get_fd_by_id(id);
+			break;
+		case BPF_OBJ_MAP:
+			fd = bpf_map_get_fd_by_id(id);
+			break;
+		default:
+			err = -1;
+			p_err("unexpected object type: %d", type);
+			goto err_free;
+		}
+		if (fd < 0) {
+			if (errno == ENOENT)
+				continue;
+			p_err("can't get %s by id (%u): %s", names[type], id,
+			      strerror(errno));
+			err = -1;
+			goto err_free;
+		}
+
+		memset(info, 0, *len);
+		if (type == BPF_OBJ_PROG)
+			err = bpf_prog_get_info_by_fd(fd, info, len);
+		else
+			err = bpf_map_get_info_by_fd(fd, info, len);
+		close(fd);
+		if (err) {
+			p_err("can't get %s info: %s", names[type],
+			      strerror(errno));
+			goto err_free;
+		}
+
+		switch (type) {
+		case BPF_OBJ_PROG:
+			btf_id = ((struct bpf_prog_info *)info)->btf_id;
+			break;
+		case BPF_OBJ_MAP:
+			btf_id = ((struct bpf_map_info *)info)->btf_id;
+			break;
+		default:
+			err = -1;
+			p_err("unexpected object type: %d", type);
+			goto err_free;
+		}
+		if (!btf_id)
+			continue;
+
+		err = hashmap__append(tab, btf_id, id);
+		if (err) {
+			p_err("failed to append entry to hashmap for BTF ID %u, object ID %u: %s",
+			      btf_id, id, strerror(-err));
+			goto err_free;
+		}
+	}
+
+	return 0;
+
+err_free:
+	hashmap__free(tab);
+	return err;
+}
+
+static int
+build_btf_tables(struct hashmap *btf_prog_table,
+		 struct hashmap *btf_map_table)
+{
+	struct bpf_prog_info prog_info;
+	__u32 prog_len = sizeof(prog_info);
+	struct bpf_map_info map_info;
+	__u32 map_len = sizeof(map_info);
+	int err = 0;
+
+	err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info,
+				   &prog_len);
+	if (err)
+		return err;
+
+	err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info,
+				   &map_len);
+	if (err) {
+		hashmap__free(btf_prog_table);
+		return err;
+	}
+
+	return 0;
+}
+
+static void
+show_btf_plain(struct bpf_btf_info *info, int fd,
+	       struct hashmap *btf_prog_table,
+	       struct hashmap *btf_map_table)
+{
+	struct hashmap_entry *entry;
+	const char *name = u64_to_ptr(info->name);
+	int n;
+
+	printf("%u: ", info->id);
+	if (info->kernel_btf)
+		printf("name [%s]  ", name);
+	else if (name && name[0])
+		printf("name %s  ", name);
+	else
+		printf("name <anon>  ");
+	printf("size %uB", info->btf_size);
+
+	n = 0;
+	hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
+		printf("%s%lu", n++ == 0 ? "  prog_ids " : ",", entry->value);
+	}
+
+	n = 0;
+	hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
+		printf("%s%lu", n++ == 0 ? "  map_ids " : ",", entry->value);
+	}
+
+	emit_obj_refs_plain(refs_table, info->id, "\n\tpids ");
+
+	printf("\n");
+}
+
+static void
+show_btf_json(struct bpf_btf_info *info, int fd,
+	      struct hashmap *btf_prog_table,
+	      struct hashmap *btf_map_table)
+{
+	struct hashmap_entry *entry;
+	const char *name = u64_to_ptr(info->name);
+
+	jsonw_start_object(json_wtr);	/* btf object */
+	jsonw_uint_field(json_wtr, "id", info->id);
+	jsonw_uint_field(json_wtr, "size", info->btf_size);
+
+	jsonw_name(json_wtr, "prog_ids");
+	jsonw_start_array(json_wtr);	/* prog_ids */
+	hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
+		jsonw_uint(json_wtr, entry->value);
+	}
+	jsonw_end_array(json_wtr);	/* prog_ids */
+
+	jsonw_name(json_wtr, "map_ids");
+	jsonw_start_array(json_wtr);	/* map_ids */
+	hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
+		jsonw_uint(json_wtr, entry->value);
+	}
+	jsonw_end_array(json_wtr);	/* map_ids */
+
+	emit_obj_refs_json(refs_table, info->id, json_wtr); /* pids */
+
+	jsonw_bool_field(json_wtr, "kernel", info->kernel_btf);
+
+	if (name && name[0])
+		jsonw_string_field(json_wtr, "name", name);
+
+	jsonw_end_object(json_wtr);	/* btf object */
+}
+
+static int
+show_btf(int fd, struct hashmap *btf_prog_table,
+	 struct hashmap *btf_map_table)
+{
+	struct bpf_btf_info info;
+	__u32 len = sizeof(info);
+	char name[64];
+	int err;
+
+	memset(&info, 0, sizeof(info));
+	err = bpf_btf_get_info_by_fd(fd, &info, &len);
+	if (err) {
+		p_err("can't get BTF object info: %s", strerror(errno));
+		return -1;
+	}
+	/* if kernel support emitting BTF object name, pass name pointer */
+	if (info.name_len) {
+		memset(&info, 0, sizeof(info));
+		info.name_len = sizeof(name);
+		info.name = ptr_to_u64(name);
+		len = sizeof(info);
+
+		err = bpf_btf_get_info_by_fd(fd, &info, &len);
+		if (err) {
+			p_err("can't get BTF object info: %s", strerror(errno));
+			return -1;
+		}
+	}
+
+	if (json_output)
+		show_btf_json(&info, fd, btf_prog_table, btf_map_table);
+	else
+		show_btf_plain(&info, fd, btf_prog_table, btf_map_table);
+
+	return 0;
+}
+
+static int do_show(int argc, char **argv)
+{
+	struct hashmap *btf_prog_table;
+	struct hashmap *btf_map_table;
+	int err, fd = -1;
+	__u32 id = 0;
+
+	if (argc == 2) {
+		fd = btf_parse_fd(&argc, &argv);
+		if (fd < 0)
+			return -1;
+	}
+
+	if (argc) {
+		if (fd >= 0)
+			close(fd);
+		return BAD_ARG();
+	}
+
+	btf_prog_table = hashmap__new(hash_fn_for_key_as_id,
+				      equal_fn_for_key_as_id, NULL);
+	btf_map_table = hashmap__new(hash_fn_for_key_as_id,
+				     equal_fn_for_key_as_id, NULL);
+	if (IS_ERR(btf_prog_table) || IS_ERR(btf_map_table)) {
+		hashmap__free(btf_prog_table);
+		hashmap__free(btf_map_table);
+		if (fd >= 0)
+			close(fd);
+		p_err("failed to create hashmap for object references");
+		return -1;
+	}
+	err = build_btf_tables(btf_prog_table, btf_map_table);
+	if (err) {
+		if (fd >= 0)
+			close(fd);
+		return err;
+	}
+	build_obj_refs_table(&refs_table, BPF_OBJ_BTF);
+
+	if (fd >= 0) {
+		err = show_btf(fd, btf_prog_table, btf_map_table);
+		close(fd);
+		goto exit_free;
+	}
+
+	if (json_output)
+		jsonw_start_array(json_wtr);	/* root array */
+
+	while (true) {
+		err = bpf_btf_get_next_id(id, &id);
+		if (err) {
+			if (errno == ENOENT) {
+				err = 0;
+				break;
+			}
+			p_err("can't get next BTF object: %s%s",
+			      strerror(errno),
+			      errno == EINVAL ? " -- kernel too old?" : "");
+			err = -1;
+			break;
+		}
+
+		fd = bpf_btf_get_fd_by_id(id);
+		if (fd < 0) {
+			if (errno == ENOENT)
+				continue;
+			p_err("can't get BTF object by id (%u): %s",
+			      id, strerror(errno));
+			err = -1;
+			break;
+		}
+
+		err = show_btf(fd, btf_prog_table, btf_map_table);
+		close(fd);
+		if (err)
+			break;
+	}
+
+	if (json_output)
+		jsonw_end_array(json_wtr);	/* root array */
+
+exit_free:
+	hashmap__free(btf_prog_table);
+	hashmap__free(btf_map_table);
+	delete_obj_refs_table(refs_table);
+
+	return err;
+}
+
+static int do_help(int argc, char **argv)
+{
+	if (json_output) {
+		jsonw_null(json_wtr);
+		return 0;
+	}
+
+	fprintf(stderr,
+		"Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
+		"       %1$s %2$s dump BTF_SRC [format FORMAT]\n"
+		"       %1$s %2$s help\n"
+		"\n"
+		"       BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
+		"       FORMAT  := { raw | c }\n"
+		"       " HELP_SPEC_MAP "\n"
+		"       " HELP_SPEC_PROGRAM "\n"
+		"       " HELP_SPEC_OPTIONS " |\n"
+		"                    {-B|--base-btf} }\n"
+		"",
+		bin_name, "btf");
+
+	return 0;
+}
+
+static const struct cmd cmds[] = {
+	{ "show",	do_show },
+	{ "list",	do_show },
+	{ "help",	do_help },
+	{ "dump",	do_dump },
+	{ 0 }
+};
+
+int do_btf(int argc, char **argv)
+{
+	return cmd_select(cmds, argc, argv, do_help);
+}