Merge tag 'net-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking updates from Jakub Kicinski:
 "Including fixes from netfilter and bpf.

  Current release - regressions:

   - eth: stmmac: fix failure to probe without MAC interface specified

  Current release - new code bugs:

   - docs: netlink: fix missing classic_netlink doc reference

  Previous releases - regressions:

   - deal with integer overflows in kmalloc_reserve()

   - use sk_forward_alloc_get() in sk_get_meminfo()

   - bpf_sk_storage: fix the missing uncharge in sk_omem_alloc

   - fib: avoid warn splat in flow dissector after packet mangling

   - skb_segment: call zero copy functions before using skbuff frags

   - eth: sfc: check for zero length in EF10 RX prefix

  Previous releases - always broken:

   - af_unix: fix msg_controllen test in scm_pidfd_recv() for
     MSG_CMSG_COMPAT

   - xsk: fix xsk_build_skb() dereferencing possible ERR_PTR()

   - netfilter:
      - nft_exthdr: fix non-linear header modification
      - xt_u32, xt_sctp: validate user space input
      - nftables: exthdr: fix 4-byte stack OOB write
      - nfnetlink_osf: avoid OOB read
      - one more fix for the garbage collection work from last release

   - igmp: limit igmpv3_newpack() packet size to IP_MAX_MTU

   - bpf, sockmap: fix preempt_rt splat when using raw_spin_lock_t

   - handshake: fix null-deref in handshake_nl_done_doit()

   - ip: ignore dst hint for multipath routes to ensure packets are
     hashed across the nexthops

   - phy: micrel:
      - correct bit assignments for cable test errata
      - disable EEE according to the KSZ9477 errata

  Misc:

   - docs/bpf: document compile-once-run-everywhere (CO-RE) relocations

   - Revert "net: macsec: preserve ingress frame ordering", it appears
     to have been developed against an older kernel, problem doesn't
     exist upstream"

* tag 'net-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (95 commits)
  net: enetc: distinguish error from valid pointers in enetc_fixup_clear_rss_rfs()
  Revert "net: team: do not use dynamic lockdep key"
  net: hns3: remove GSO partial feature bit
  net: hns3: fix the port information display when sfp is absent
  net: hns3: fix invalid mutex between tc qdisc and dcb ets command issue
  net: hns3: fix debugfs concurrency issue between kfree buffer and read
  net: hns3: fix byte order conversion issue in hclge_dbg_fd_tcam_read()
  net: hns3: Support query tx timeout threshold by debugfs
  net: hns3: fix tx timeout issue
  net: phy: Provide Module 4 KSZ9477 errata (DS80000754C)
  netfilter: nf_tables: Unbreak audit log reset
  netfilter: ipset: add the missing IP_SET_HASH_WITH_NET0 macro for ip_set_hash_netportnet.c
  netfilter: nft_set_rbtree: skip sync GC for new elements in this transaction
  netfilter: nf_tables: uapi: Describe NFTA_RULE_CHAIN_ID
  netfilter: nfnetlink_osf: avoid OOB read
  netfilter: nftables: exthdr: fix 4-byte stack OOB write
  selftests/bpf: Check bpf_sk_storage has uncharged sk_omem_alloc
  bpf: bpf_sk_storage: Fix the missing uncharge in sk_omem_alloc
  bpf: bpf_sk_storage: Fix invalid wait context lockdep report
  s390/bpf: Pass through tail call counter in trampolines
  ...

7 files changed, 370 insertions, 37 deletions

diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst
index f32db1f44ae9..e43c2fdafcd7 100644
--- a/Documentation/bpf/btf.rst
+++ b/Documentation/bpf/btf.rst
@@ -726,8 +726,8 @@ same as the one describe in :ref:`BTF_Type_String`.
 4.2 .BTF.ext section
 --------------------
 
-The .BTF.ext section encodes func_info and line_info which needs loader
-manipulation before loading into the kernel.
+The .BTF.ext section encodes func_info, line_info and CO-RE relocations
+which needs loader manipulation before loading into the kernel.
 
 The specification for .BTF.ext section is defined at ``tools/lib/bpf/btf.h``
 and ``tools/lib/bpf/btf.c``.
@@ -745,15 +745,20 @@ The current header of .BTF.ext section::
         __u32   func_info_len;
         __u32   line_info_off;
         __u32   line_info_len;
+
+        /* optional part of .BTF.ext header */
+        __u32   core_relo_off;
+        __u32   core_relo_len;
     };
 
 It is very similar to .BTF section. Instead of type/string section, it
-contains func_info and line_info section. See :ref:`BPF_Prog_Load` for details
-about func_info and line_info record format.
+contains func_info, line_info and core_relo sub-sections.
+See :ref:`BPF_Prog_Load` for details about func_info and line_info
+record format.
 
 The func_info is organized as below.::
 
-     func_info_rec_size
+     func_info_rec_size              /* __u32 value */
      btf_ext_info_sec for section #1 /* func_info for section #1 */
      btf_ext_info_sec for section #2 /* func_info for section #2 */
      ...
@@ -773,7 +778,7 @@ Here, num_info must be greater than 0.
 
 The line_info is organized as below.::
 
-     line_info_rec_size
+     line_info_rec_size              /* __u32 value */
      btf_ext_info_sec for section #1 /* line_info for section #1 */
      btf_ext_info_sec for section #2 /* line_info for section #2 */
      ...
@@ -787,6 +792,20 @@ kernel API, the ``insn_off`` is the instruction offset in the unit of ``struct
 bpf_insn``. For ELF API, the ``insn_off`` is the byte offset from the
 beginning of section (``btf_ext_info_sec->sec_name_off``).
 
+The core_relo is organized as below.::
+
+     core_relo_rec_size              /* __u32 value */
+     btf_ext_info_sec for section #1 /* core_relo for section #1 */
+     btf_ext_info_sec for section #2 /* core_relo for section #2 */
+
+``core_relo_rec_size`` specifies the size of ``bpf_core_relo``
+structure when .BTF.ext is generated. All ``bpf_core_relo`` structures
+within a single ``btf_ext_info_sec`` describe relocations applied to
+section named by ``btf_ext_info_sec->sec_name_off``.
+
+See :ref:`Documentation/bpf/llvm_reloc.rst <btf-co-re-relocations>`
+for more information on CO-RE relocations.
+
 4.2 .BTF_ids section
 --------------------
 
diff --git a/Documentation/bpf/index.rst b/Documentation/bpf/index.rst
index 1ff177b89d66..aeaeb35e6d4a 100644
--- a/Documentation/bpf/index.rst
+++ b/Documentation/bpf/index.rst
@@ -29,6 +29,7 @@ that goes into great technical depth about the BPF Architecture.
    bpf_licensing
    test_debug
    clang-notes
+   linux-notes
    other
    redirect
 
diff --git a/Documentation/bpf/standardization/linux-notes.rst b/Documentation/bpf/linux-notes.rst
index 00d2693de025..00d2693de025 100644
--- a/Documentation/bpf/standardization/linux-notes.rst
+++ b/Documentation/bpf/linux-notes.rst
diff --git a/Documentation/bpf/llvm_reloc.rst b/Documentation/bpf/llvm_reloc.rst
index 450e6403fe3d..44188e219d32 100644
--- a/Documentation/bpf/llvm_reloc.rst
+++ b/Documentation/bpf/llvm_reloc.rst
@@ -240,3 +240,307 @@ The .BTF/.BTF.ext sections has R_BPF_64_NODYLD32 relocations::
       Offset             Info             Type               Symbol's Value  Symbol's Name
   000000000000002c  0000000200000004 R_BPF_64_NODYLD32      0000000000000000 .text
   0000000000000040  0000000200000004 R_BPF_64_NODYLD32      0000000000000000 .text
+
+.. _btf-co-re-relocations:
+
+=================
+CO-RE Relocations
+=================
+
+From object file point of view CO-RE mechanism is implemented as a set
+of CO-RE specific relocation records. These relocation records are not
+related to ELF relocations and are encoded in .BTF.ext section.
+See :ref:`Documentation/bpf/btf.rst <BTF_Ext_Section>` for more
+information on .BTF.ext structure.
+
+CO-RE relocations are applied to BPF instructions to update immediate
+or offset fields of the instruction at load time with information
+relevant for target kernel.
+
+Field to patch is selected basing on the instruction class:
+
+* For BPF_ALU, BPF_ALU64, BPF_LD `immediate` field is patched;
+* For BPF_LDX, BPF_STX, BPF_ST `offset` field is patched;
+* BPF_JMP, BPF_JMP32 instructions **should not** be patched.
+
+Relocation kinds
+================
+
+There are several kinds of CO-RE relocations that could be split in
+three groups:
+
+* Field-based - patch instruction with field related information, e.g.
+  change offset field of the BPF_LDX instruction to reflect offset
+  of a specific structure field in the target kernel.
+
+* Type-based - patch instruction with type related information, e.g.
+  change immediate field of the BPF_ALU move instruction to 0 or 1 to
+  reflect if specific type is present in the target kernel.
+
+* Enum-based - patch instruction with enum related information, e.g.
+  change immediate field of the BPF_LD_IMM64 instruction to reflect
+  value of a specific enum literal in the target kernel.
+
+The complete list of relocation kinds is represented by the following enum:
+
+.. code-block:: c
+
+ enum bpf_core_relo_kind {
+	BPF_CORE_FIELD_BYTE_OFFSET = 0,  /* field byte offset */
+	BPF_CORE_FIELD_BYTE_SIZE   = 1,  /* field size in bytes */
+	BPF_CORE_FIELD_EXISTS      = 2,  /* field existence in target kernel */
+	BPF_CORE_FIELD_SIGNED      = 3,  /* field signedness (0 - unsigned, 1 - signed) */
+	BPF_CORE_FIELD_LSHIFT_U64  = 4,  /* bitfield-specific left bitshift */
+	BPF_CORE_FIELD_RSHIFT_U64  = 5,  /* bitfield-specific right bitshift */
+	BPF_CORE_TYPE_ID_LOCAL     = 6,  /* type ID in local BPF object */
+	BPF_CORE_TYPE_ID_TARGET    = 7,  /* type ID in target kernel */
+	BPF_CORE_TYPE_EXISTS       = 8,  /* type existence in target kernel */
+	BPF_CORE_TYPE_SIZE         = 9,  /* type size in bytes */
+	BPF_CORE_ENUMVAL_EXISTS    = 10, /* enum value existence in target kernel */
+	BPF_CORE_ENUMVAL_VALUE     = 11, /* enum value integer value */
+	BPF_CORE_TYPE_MATCHES      = 12, /* type match in target kernel */
+ };
+
+Notes:
+
+* ``BPF_CORE_FIELD_LSHIFT_U64`` and ``BPF_CORE_FIELD_RSHIFT_U64`` are
+  supposed to be used to read bitfield values using the following
+  algorithm:
+
+  .. code-block:: c
+
+     // To read bitfield ``f`` from ``struct s``
+     is_signed = relo(s->f, BPF_CORE_FIELD_SIGNED)
+     off = relo(s->f, BPF_CORE_FIELD_BYTE_OFFSET)
+     sz  = relo(s->f, BPF_CORE_FIELD_BYTE_SIZE)
+     l   = relo(s->f, BPF_CORE_FIELD_LSHIFT_U64)
+     r   = relo(s->f, BPF_CORE_FIELD_RSHIFT_U64)
+     // define ``v`` as signed or unsigned integer of size ``sz``
+     v = *({s|u}<sz> *)((void *)s + off)
+     v <<= l
+     v >>= r
+
+* The ``BPF_CORE_TYPE_MATCHES`` queries matching relation, defined as
+  follows:
+
+  * for integers: types match if size and signedness match;
+  * for arrays & pointers: target types are recursively matched;
+  * for structs & unions:
+
+    * local members need to exist in target with the same name;
+
+    * for each member we recursively check match unless it is already behind a
+      pointer, in which case we only check matching names and compatible kind;
+
+  * for enums:
+
+    * local variants have to have a match in target by symbolic name (but not
+      numeric value);
+
+    * size has to match (but enum may match enum64 and vice versa);
+
+  * for function pointers:
+
+    * number and position of arguments in local type has to match target;
+    * for each argument and the return value we recursively check match.
+
+CO-RE Relocation Record
+=======================
+
+Relocation record is encoded as the following structure:
+
+.. code-block:: c
+
+ struct bpf_core_relo {
+	__u32 insn_off;
+	__u32 type_id;
+	__u32 access_str_off;
+	enum bpf_core_relo_kind kind;
+ };
+
+* ``insn_off`` - instruction offset (in bytes) within a code section
+  associated with this relocation;
+
+* ``type_id`` - BTF type ID of the "root" (containing) entity of a
+  relocatable type or field;
+
+* ``access_str_off`` - offset into corresponding .BTF string section.
+  String interpretation depends on specific relocation kind:
+
+  * for field-based relocations, string encodes an accessed field using
+    a sequence of field and array indices, separated by colon (:). It's
+    conceptually very close to LLVM's `getelementptr <GEP_>`_ instruction's
+    arguments for identifying offset to a field. For example, consider the
+    following C code:
+
+    .. code-block:: c
+
+       struct sample {
+           int a;
+           int b;
+           struct { int c[10]; };
+       } __attribute__((preserve_access_index));
+       struct sample *s;
+
+    * Access to ``s[0].a`` would be encoded as ``0:0``:
+
+      * ``0``: first element of ``s`` (as if ``s`` is an array);
+      * ``0``: index of field ``a`` in ``struct sample``.
+
+    * Access to ``s->a`` would be encoded as ``0:0`` as well.
+    * Access to ``s->b`` would be encoded as ``0:1``:
+
+      * ``0``: first element of ``s``;
+      * ``1``: index of field ``b`` in ``struct sample``.
+
+    * Access to ``s[1].c[5]`` would be encoded as ``1:2:0:5``:
+
+      * ``1``: second element of ``s``;
+      * ``2``: index of anonymous structure field in ``struct sample``;
+      * ``0``: index of field ``c`` in anonymous structure;
+      * ``5``: access to array element #5.
+
+  * for type-based relocations, string is expected to be just "0";
+
+  * for enum value-based relocations, string contains an index of enum
+     value within its enum type;
+
+* ``kind`` - one of ``enum bpf_core_relo_kind``.
+
+.. _GEP: https://llvm.org/docs/LangRef.html#getelementptr-instruction
+
+.. _btf_co_re_relocation_examples:
+
+CO-RE Relocation Examples
+=========================
+
+For the following C code:
+
+.. code-block:: c
+
+ struct foo {
+   int a;
+   int b;
+   unsigned c:15;
+ } __attribute__((preserve_access_index));
+
+ enum bar { U, V };
+
+With the following BTF definitions:
+
+.. code-block::
+
+ ...
+ [2] STRUCT 'foo' size=8 vlen=2
+        'a' type_id=3 bits_offset=0
+        'b' type_id=3 bits_offset=32
+        'c' type_id=4 bits_offset=64 bitfield_size=15
+ [3] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
+ [4] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)
+ ...
+ [16] ENUM 'bar' encoding=UNSIGNED size=4 vlen=2
+        'U' val=0
+        'V' val=1
+
+Field offset relocations are generated automatically when
+``__attribute__((preserve_access_index))`` is used, for example:
+
+.. code-block:: c
+
+  void alpha(struct foo *s, volatile unsigned long *g) {
+    *g = s->a;
+    s->a = 1;
+  }
+
+  00 <alpha>:
+    0:  r3 = *(s32 *)(r1 + 0x0)
+           00:  CO-RE <byte_off> [2] struct foo::a (0:0)
+    1:  *(u64 *)(r2 + 0x0) = r3
+    2:  *(u32 *)(r1 + 0x0) = 0x1
+           10:  CO-RE <byte_off> [2] struct foo::a (0:0)
+    3:  exit
+
+
+All relocation kinds could be requested via built-in functions.
+E.g. field-based relocations:
+
+.. code-block:: c
+
+  void bravo(struct foo *s, volatile unsigned long *g) {
+    *g = __builtin_preserve_field_info(s->b, 0 /* field byte offset */);
+    *g = __builtin_preserve_field_info(s->b, 1 /* field byte size */);
+    *g = __builtin_preserve_field_info(s->b, 2 /* field existence */);
+    *g = __builtin_preserve_field_info(s->b, 3 /* field signedness */);
+    *g = __builtin_preserve_field_info(s->c, 4 /* bitfield left shift */);
+    *g = __builtin_preserve_field_info(s->c, 5 /* bitfield right shift */);
+  }
+
+  20 <bravo>:
+     4:     r1 = 0x4
+            20:  CO-RE <byte_off> [2] struct foo::b (0:1)
+     5:     *(u64 *)(r2 + 0x0) = r1
+     6:     r1 = 0x4
+            30:  CO-RE <byte_sz> [2] struct foo::b (0:1)
+     7:     *(u64 *)(r2 + 0x0) = r1
+     8:     r1 = 0x1
+            40:  CO-RE <field_exists> [2] struct foo::b (0:1)
+     9:     *(u64 *)(r2 + 0x0) = r1
+    10:     r1 = 0x1
+            50:  CO-RE <signed> [2] struct foo::b (0:1)
+    11:     *(u64 *)(r2 + 0x0) = r1
+    12:     r1 = 0x31
+            60:  CO-RE <lshift_u64> [2] struct foo::c (0:2)
+    13:     *(u64 *)(r2 + 0x0) = r1
+    14:     r1 = 0x31
+            70:  CO-RE <rshift_u64> [2] struct foo::c (0:2)
+    15:     *(u64 *)(r2 + 0x0) = r1
+    16:     exit
+
+
+Type-based relocations:
+
+.. code-block:: c
+
+  void charlie(struct foo *s, volatile unsigned long *g) {
+    *g = __builtin_preserve_type_info(*s, 0 /* type existence */);
+    *g = __builtin_preserve_type_info(*s, 1 /* type size */);
+    *g = __builtin_preserve_type_info(*s, 2 /* type matches */);
+    *g = __builtin_btf_type_id(*s, 0 /* type id in this object file */);
+    *g = __builtin_btf_type_id(*s, 1 /* type id in target kernel */);
+  }
+
+  88 <charlie>:
+    17:     r1 = 0x1
+            88:  CO-RE <type_exists> [2] struct foo
+    18:     *(u64 *)(r2 + 0x0) = r1
+    19:     r1 = 0xc
+            98:  CO-RE <type_size> [2] struct foo
+    20:     *(u64 *)(r2 + 0x0) = r1
+    21:     r1 = 0x1
+            a8:  CO-RE <type_matches> [2] struct foo
+    22:     *(u64 *)(r2 + 0x0) = r1
+    23:     r1 = 0x2 ll
+            b8:  CO-RE <local_type_id> [2] struct foo
+    25:     *(u64 *)(r2 + 0x0) = r1
+    26:     r1 = 0x2 ll
+            d0:  CO-RE <target_type_id> [2] struct foo
+    28:     *(u64 *)(r2 + 0x0) = r1
+    29:     exit
+
+Enum-based relocations:
+
+.. code-block:: c
+
+  void delta(struct foo *s, volatile unsigned long *g) {
+    *g = __builtin_preserve_enum_value(*(enum bar *)U, 0 /* enum literal existence */);
+    *g = __builtin_preserve_enum_value(*(enum bar *)V, 1 /* enum literal value */);
+  }
+
+  f0 <delta>:
+    30:     r1 = 0x1 ll
+            f0:  CO-RE <enumval_exists> [16] enum bar::U = 0
+    32:     *(u64 *)(r2 + 0x0) = r1
+    33:     r1 = 0x1 ll
+            108:  CO-RE <enumval_value> [16] enum bar::V = 1
+    35:     *(u64 *)(r2 + 0x0) = r1
+    36:     exit
diff --git a/Documentation/bpf/standardization/abi.rst b/Documentation/bpf/standardization/abi.rst
new file mode 100644
index 000000000000..0c2e10eeb89a
--- /dev/null
+++ b/Documentation/bpf/standardization/abi.rst
@@ -0,0 +1,25 @@
+.. contents::
+.. sectnum::
+
+===================================================
+BPF ABI Recommended Conventions and Guidelines v1.0
+===================================================
+
+This is version 1.0 of an informational document containing recommended
+conventions and guidelines for producing portable BPF program binaries.
+
+Registers and calling convention
+================================
+
+BPF has 10 general purpose registers and a read-only frame pointer register,
+all of which are 64-bits wide.
+
+The BPF calling convention is defined as:
+
+* R0: return value from function calls, and exit value for BPF programs
+* R1 - R5: arguments for function calls
+* R6 - R9: callee saved registers that function calls will preserve
+* R10: read-only frame pointer to access stack
+
+R0 - R5 are scratch registers and BPF programs needs to spill/fill them if
+necessary across calls.
diff --git a/Documentation/bpf/standardization/index.rst b/Documentation/bpf/standardization/index.rst
index 09c6ba055fd7..a50c3baf6345 100644
--- a/Documentation/bpf/standardization/index.rst
+++ b/Documentation/bpf/standardization/index.rst
@@ -12,7 +12,7 @@ for the working group charter, documents, and more.
    :maxdepth: 1
 
    instruction-set
-   linux-notes
+   abi
 
 .. Links:
 .. _IETF BPF Working Group: https://datatracker.ietf.org/wg/bpf/about/
diff --git a/Documentation/bpf/standardization/instruction-set.rst b/Documentation/bpf/standardization/instruction-set.rst
index 4f73e9dc8d9e..c5d53a6e8c79 100644
--- a/Documentation/bpf/standardization/instruction-set.rst
+++ b/Documentation/bpf/standardization/instruction-set.rst
@@ -1,11 +1,11 @@
 .. contents::
 .. sectnum::
 
-========================================
-eBPF Instruction Set Specification, v1.0
-========================================
+=======================================
+BPF Instruction Set Specification, v1.0
+=======================================
 
-This document specifies version 1.0 of the eBPF instruction set.
+This document specifies version 1.0 of the BPF instruction set.
 
 Documentation conventions
 =========================
@@ -97,26 +97,10 @@ Definitions
     A:          10000110
     B: 11111111 10000110
 
-Registers and calling convention
-================================
-
-eBPF has 10 general purpose registers and a read-only frame pointer register,
-all of which are 64-bits wide.
-
-The eBPF calling convention is defined as:
-
-* R0: return value from function calls, and exit value for eBPF programs
-* R1 - R5: arguments for function calls
-* R6 - R9: callee saved registers that function calls will preserve
-* R10: read-only frame pointer to access stack
-
-R0 - R5 are scratch registers and eBPF programs needs to spill/fill them if
-necessary across calls.
-
 Instruction encoding
 ====================
 
-eBPF has two instruction encodings:
+BPF has two instruction encodings:
 
 * the basic instruction encoding, which uses 64 bits to encode an instruction
 * the wide instruction encoding, which appends a second 64-bit immediate (i.e.,
@@ -260,7 +244,7 @@ BPF_END    0xd0   0        byte swap operations (see `Byte swap instructions`_ b
 =========  =====  =======  ==========================================================
 
 Underflow and overflow are allowed during arithmetic operations, meaning
-the 64-bit or 32-bit value will wrap. If eBPF program execution would
+the 64-bit or 32-bit value will wrap. If BPF program execution would
 result in division by zero, the destination register is instead set to zero.
 If execution would result in modulo by zero, for ``BPF_ALU64`` the value of
 the destination register is unchanged whereas for ``BPF_ALU`` the upper
@@ -373,7 +357,7 @@ BPF_JNE   0x5    any  PC += offset if dst != src
 BPF_JSGT  0x6    any  PC += offset if dst > src                    signed
 BPF_JSGE  0x7    any  PC += offset if dst >= src                   signed
 BPF_CALL  0x8    0x0  call helper function by address              see `Helper functions`_
-BPF_CALL  0x8    0x1  call PC += offset                            see `Program-local functions`_
+BPF_CALL  0x8    0x1  call PC += imm                               see `Program-local functions`_
 BPF_CALL  0x8    0x2  call helper function by BTF ID               see `Helper functions`_
 BPF_EXIT  0x9    0x0  return                                       BPF_JMP only
 BPF_JLT   0xa    any  PC += offset if dst < src                    unsigned
@@ -382,7 +366,7 @@ BPF_JSLT  0xc    any  PC += offset if dst < src                    signed
 BPF_JSLE  0xd    any  PC += offset if dst <= src                   signed
 ========  =====  ===  ===========================================  =========================================
 
-The eBPF program needs to store the return value into register R0 before doing a
+The BPF program needs to store the return value into register R0 before doing a
 ``BPF_EXIT``.
 
 Example:
@@ -424,8 +408,8 @@ Program-local functions
 ~~~~~~~~~~~~~~~~~~~~~~~
 Program-local functions are functions exposed by the same BPF program as the
 caller, and are referenced by offset from the call instruction, similar to
-``BPF_JA``.  A ``BPF_EXIT`` within the program-local function will return to
-the caller.
+``BPF_JA``.  The offset is encoded in the imm field of the call instruction.
+A ``BPF_EXIT`` within the program-local function will return to the caller.
 
 Load and store instructions
 ===========================
@@ -502,9 +486,9 @@ Atomic operations
 
 Atomic operations are operations that operate on memory and can not be
 interrupted or corrupted by other access to the same memory region
-by other eBPF programs or means outside of this specification.
+by other BPF programs or means outside of this specification.
 
-All atomic operations supported by eBPF are encoded as store operations
+All atomic operations supported by BPF are encoded as store operations
 that use the ``BPF_ATOMIC`` mode modifier as follows:
 
 * ``BPF_ATOMIC | BPF_W | BPF_STX`` for 32-bit operations
@@ -594,7 +578,7 @@ where
 Maps
 ~~~~
 
-Maps are shared memory regions accessible by eBPF programs on some platforms.
+Maps are shared memory regions accessible by BPF programs on some platforms.
 A map can have various semantics as defined in a separate document, and may or
 may not have a single contiguous memory region, but the 'map_val(map)' is
 currently only defined for maps that do have a single contiguous memory region.
@@ -616,6 +600,6 @@ identified by the given id.
 Legacy BPF Packet access instructions
 -------------------------------------
 
-eBPF previously introduced special instructions for access to packet data that were
+BPF previously introduced special instructions for access to packet data that were
 carried over from classic BPF. However, these instructions are
 deprecated and should no longer be used.