diff mbox series

[bpf-next,v2] bpf, docs: Address comments from IETF Area Directors

Message ID 20240623150453.10613-1-dthaler1968@gmail.com (mailing list archive)
State Accepted
Commit 04efaebd72d1d3d9991841051fafc6b195f3676d
Delegated to: BPF
Headers show
Series [bpf-next,v2] bpf, docs: Address comments from IETF Area Directors | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for bpf-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 17 this patch: 17
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 15 maintainers not CCed: jolsa@kernel.org john.fastabend@gmail.com ast@kernel.org haoluo@google.com linux-doc@vger.kernel.org song@kernel.org martin.lau@linux.dev yonghong.song@linux.dev andrii@kernel.org daniel@iogearbox.net eddyz87@gmail.com corbet@lwn.net kpsingh@kernel.org void@manifault.com sdf@google.com
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netdev/deprecated_api success None detected
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netdev/verify_fixes success No Fixes tag
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netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 135 lines checked
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Commit Message

Dave Thaler June 23, 2024, 3:04 p.m. UTC 
This patch does the following to address IETF feedback:

* Remove mention of "program type" and reference future
  docs (and mention platform-specific docs exist) for
  helper functions and BTF. Addresses Roman Danyliw's
  comments based on GENART review from Ines Robles [0].

* Add reference for endianness as requested by John
  Scudder [1].

* Added bit numbers to top of 32-bit wide format diagrams
  as requested by Paul Wouters [2].

* Added more text about why BPF doesn't stand for anything, based
  on text from ebpf.io [3], as requested by Eric Vyncke and
  Gunter Van de Velde [4].

* Replaced "htobe16" (and similar) and the direction-specific
  description with just "be16" (and similar) and a direction-agnostic
  description, to match the direction-agnostic description in
  the Byteswap Instructions section. Based on feedback from Eric
  Vyncke [5].

[0] https://mailarchive.ietf.org/arch/msg/bpf/DvDgDWOiwk05OyNlWlAmELZFPlM/

[1] https://mailarchive.ietf.org/arch/msg/bpf/eKNXpU4jCLjsbZDSw8LjI29M3tM/

[2] https://mailarchive.ietf.org/arch/msg/bpf/hGk8HkYxeZTpdu9qW_MvbGKj7WU/

[3] https://ebpf.io/what-is-ebpf/#what-do-ebpf-and-bpf-stand-for

[4] https://mailarchive.ietf.org/arch/msg/bpf/i93lzdN3ewnzzS_JMbinCIYxAIU/

[5] https://mailarchive.ietf.org/arch/msg/bpf/KBWXbMeDcSrq4vsKR_KkBbV6hI4/

---

1->2: Addressed nits from David Vernet

Signed-off-by: Dave Thaler <dthaler1968@googlemail.com>
---
 .../bpf/standardization/instruction-set.rst   | 80 +++++++++++--------
 1 file changed, 45 insertions(+), 35 deletions(-)

Comments

David Vernet June 23, 2024, 3:43 p.m. UTC | #1 
On Sun, Jun 23, 2024 at 08:04:53AM -0700, Dave Thaler wrote:
> This patch does the following to address IETF feedback:
> 
> * Remove mention of "program type" and reference future
>   docs (and mention platform-specific docs exist) for
>   helper functions and BTF. Addresses Roman Danyliw's
>   comments based on GENART review from Ines Robles [0].
> 
> * Add reference for endianness as requested by John
>   Scudder [1].
> 
> * Added bit numbers to top of 32-bit wide format diagrams
>   as requested by Paul Wouters [2].
> 
> * Added more text about why BPF doesn't stand for anything, based
>   on text from ebpf.io [3], as requested by Eric Vyncke and
>   Gunter Van de Velde [4].
> 
> * Replaced "htobe16" (and similar) and the direction-specific
>   description with just "be16" (and similar) and a direction-agnostic
>   description, to match the direction-agnostic description in
>   the Byteswap Instructions section. Based on feedback from Eric
>   Vyncke [5].
> 
> [0] https://mailarchive.ietf.org/arch/msg/bpf/DvDgDWOiwk05OyNlWlAmELZFPlM/
> 
> [1] https://mailarchive.ietf.org/arch/msg/bpf/eKNXpU4jCLjsbZDSw8LjI29M3tM/
> 
> [2] https://mailarchive.ietf.org/arch/msg/bpf/hGk8HkYxeZTpdu9qW_MvbGKj7WU/
> 
> [3] https://ebpf.io/what-is-ebpf/#what-do-ebpf-and-bpf-stand-for
> 
> [4] https://mailarchive.ietf.org/arch/msg/bpf/i93lzdN3ewnzzS_JMbinCIYxAIU/
> 
> [5] https://mailarchive.ietf.org/arch/msg/bpf/KBWXbMeDcSrq4vsKR_KkBbV6hI4/
> 
> ---
> 
> 1->2: Addressed nits from David Vernet
> 
> Signed-off-by: Dave Thaler <dthaler1968@googlemail.com>

Acked-by: David Vernet <void@manifault.com>

> ---
>  .../bpf/standardization/instruction-set.rst   | 80 +++++++++++--------
>  1 file changed, 45 insertions(+), 35 deletions(-)
> 
> diff --git a/Documentation/bpf/standardization/instruction-set.rst b/Documentation/bpf/standardization/instruction-set.rst
> index 398f27bab..7e636299a 100644
> --- a/Documentation/bpf/standardization/instruction-set.rst
> +++ b/Documentation/bpf/standardization/instruction-set.rst
> @@ -5,12 +5,19 @@
>  BPF Instruction Set Architecture (ISA)
>  ======================================
>  
> -eBPF (which is no longer an acronym for anything), also commonly
> +eBPF, also commonly
>  referred to as BPF, is a technology with origins in the Linux kernel
>  that can run untrusted programs in a privileged context such as an
>  operating system kernel. This document specifies the BPF instruction
>  set architecture (ISA).
>  
> +As a historical note, BPF originally stood for Berkeley Packet Filter,
> +but now that it can do so much more than packet filtering, the acronym
> +no longer makes sense. BPF is now considered a standalone term that
> +does not stand for anything.  The original BPF is sometimes referred to
> +as cBPF (classic BPF) to distinguish it from the now widely deployed
> +eBPF (extended BPF).
> +
>  Documentation conventions
>  =========================
>  
> @@ -18,7 +25,7 @@ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
>  "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
>  "OPTIONAL" in this document are to be interpreted as described in
>  BCP 14 `<https://www.rfc-editor.org/info/rfc2119>`_
> -`RFC8174 <https://www.rfc-editor.org/info/rfc8174>`_
> +`<https://www.rfc-editor.org/info/rfc8174>`_
>  when, and only when, they appear in all capitals, as shown here.
>  
>  For brevity and consistency, this document refers to families
> @@ -59,24 +66,18 @@ numbers.
>  
>  Functions
>  ---------
> -* htobe16: Takes an unsigned 16-bit number in host-endian format and
> -  returns the equivalent number as an unsigned 16-bit number in big-endian
> -  format.
> -* htobe32: Takes an unsigned 32-bit number in host-endian format and
> -  returns the equivalent number as an unsigned 32-bit number in big-endian
> -  format.
> -* htobe64: Takes an unsigned 64-bit number in host-endian format and
> -  returns the equivalent number as an unsigned 64-bit number in big-endian
> -  format.
> -* htole16: Takes an unsigned 16-bit number in host-endian format and
> -  returns the equivalent number as an unsigned 16-bit number in little-endian
> -  format.
> -* htole32: Takes an unsigned 32-bit number in host-endian format and
> -  returns the equivalent number as an unsigned 32-bit number in little-endian
> -  format.
> -* htole64: Takes an unsigned 64-bit number in host-endian format and
> -  returns the equivalent number as an unsigned 64-bit number in little-endian
> -  format.
> +
> +The following byteswap functions are direction-agnostic.  That is,
> +the same function is used for conversion in either direction discussed
> +below.
> +
> +* be16: Takes an unsigned 16-bit number and converts it between
> +  host byte order and big-endian
> +  (`IEN137 <https://www.rfc-editor.org/ien/ien137.txt>`_) byte order.
> +* be32: Takes an unsigned 32-bit number and converts it between
> +  host byte order and big-endian byte order.
> +* be64: Takes an unsigned 64-bit number and converts it between
> +  host byte order and big-endian byte order.
>  * bswap16: Takes an unsigned 16-bit number in either big- or little-endian
>    format and returns the equivalent number with the same bit width but
>    opposite endianness.
> @@ -86,7 +87,12 @@ Functions
>  * bswap64: Takes an unsigned 64-bit number in either big- or little-endian
>    format and returns the equivalent number with the same bit width but
>    opposite endianness.
> -
> +* le16: Takes an unsigned 16-bit number and converts it between
> +  host byte order and little-endian byte order.
> +* le32: Takes an unsigned 32-bit number and converts it between
> +  host byte order and little-endian byte order.
> +* le64: Takes an unsigned 64-bit number and converts it between
> +  host byte order and little-endian byte order.
>  
>  Definitions
>  -----------
> @@ -441,8 +447,8 @@ and MUST be set to 0.
>    =====  ========  =====  =================================================
>    class  source    value  description
>    =====  ========  =====  =================================================
> -  ALU    TO_LE     0      convert between host byte order and little endian
> -  ALU    TO_BE     1      convert between host byte order and big endian
> +  ALU    LE        0      convert between host byte order and little endian
> +  ALU    BE        1      convert between host byte order and big endian
>    ALU64  Reserved  0      do byte swap unconditionally
>    =====  ========  =====  =================================================
>  
> @@ -453,19 +459,19 @@ conformance group.
>  
>  Examples:
>  
> -``{END, TO_LE, ALU}`` with 'imm' = 16/32/64 means::
> +``{END, LE, ALU}`` with 'imm' = 16/32/64 means::
>  
> -  dst = htole16(dst)
> -  dst = htole32(dst)
> -  dst = htole64(dst)
> +  dst = le16(dst)
> +  dst = le32(dst)
> +  dst = le64(dst)
>  
> -``{END, TO_BE, ALU}`` with 'imm' = 16/32/64 means::
> +``{END, BE, ALU}`` with 'imm' = 16/32/64 means::
>  
> -  dst = htobe16(dst)
> -  dst = htobe32(dst)
> -  dst = htobe64(dst)
> +  dst = be16(dst)
> +  dst = be32(dst)
> +  dst = be64(dst)
>  
> -``{END, TO_LE, ALU64}`` with 'imm' = 16/32/64 means::
> +``{END, TO, ALU64}`` with 'imm' = 16/32/64 means::
>  
>    dst = bswap16(dst)
>    dst = bswap32(dst)
> @@ -545,13 +551,17 @@ Helper functions are a concept whereby BPF programs can call into a
>  set of function calls exposed by the underlying platform.
>  
>  Historically, each helper function was identified by a static ID
> -encoded in the 'imm' field.  The available helper functions may differ
> -for each program type, but static IDs are unique across all program types.
> +encoded in the 'imm' field.  Further documentation of helper functions
> +is outside the scope of this document and standardization is left for
> +future work, but use is widely deployed and more information can be
> +found in platform-specific documentation (e.g., Linux kernel documentation).
>  
>  Platforms that support the BPF Type Format (BTF) support identifying
>  a helper function by a BTF ID encoded in the 'imm' field, where the BTF ID
>  identifies the helper name and type.  Further documentation of BTF
> -is outside the scope of this document and is left for future work.
> +is outside the scope of this document and standardization is left for
> +future work, but use is widely deployed and more information can be
> +found in platform-specific documentation (e.g., Linux kernel documentation).
>  
>  Program-local functions
>  ~~~~~~~~~~~~~~~~~~~~~~~
> -- 
> 2.40.1
> 
> -- 
> Bpf mailing list -- bpf@ietf.org
> To unsubscribe send an email to bpf-leave@ietf.org
patchwork-bot+netdevbpf@kernel.org June 23, 2024, 4:20 p.m. UTC | #2 
Hello:

This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Sun, 23 Jun 2024 08:04:53 -0700 you wrote:
> This patch does the following to address IETF feedback:
> 
> * Remove mention of "program type" and reference future
>   docs (and mention platform-specific docs exist) for
>   helper functions and BTF. Addresses Roman Danyliw's
>   comments based on GENART review from Ines Robles [0].
> 
> [...]

Here is the summary with links:
  - [bpf-next,v2] bpf, docs: Address comments from IETF Area Directors
    https://git.kernel.org/bpf/bpf-next/c/04efaebd72d1

You are awesome, thank you!
diff mbox series

Patch

diff --git a/Documentation/bpf/standardization/instruction-set.rst b/Documentation/bpf/standardization/instruction-set.rst
index 398f27bab..7e636299a 100644
--- a/Documentation/bpf/standardization/instruction-set.rst
+++ b/Documentation/bpf/standardization/instruction-set.rst
@@ -5,12 +5,19 @@ 
 BPF Instruction Set Architecture (ISA)
 ======================================
 
-eBPF (which is no longer an acronym for anything), also commonly
+eBPF, also commonly
 referred to as BPF, is a technology with origins in the Linux kernel
 that can run untrusted programs in a privileged context such as an
 operating system kernel. This document specifies the BPF instruction
 set architecture (ISA).
 
+As a historical note, BPF originally stood for Berkeley Packet Filter,
+but now that it can do so much more than packet filtering, the acronym
+no longer makes sense. BPF is now considered a standalone term that
+does not stand for anything.  The original BPF is sometimes referred to
+as cBPF (classic BPF) to distinguish it from the now widely deployed
+eBPF (extended BPF).
+
 Documentation conventions
 =========================
 
@@ -18,7 +25,7 @@  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
 "OPTIONAL" in this document are to be interpreted as described in
 BCP 14 `<https://www.rfc-editor.org/info/rfc2119>`_
-`RFC8174 <https://www.rfc-editor.org/info/rfc8174>`_
+`<https://www.rfc-editor.org/info/rfc8174>`_
 when, and only when, they appear in all capitals, as shown here.
 
 For brevity and consistency, this document refers to families
@@ -59,24 +66,18 @@  numbers.
 
 Functions
 ---------
-* htobe16: Takes an unsigned 16-bit number in host-endian format and
-  returns the equivalent number as an unsigned 16-bit number in big-endian
-  format.
-* htobe32: Takes an unsigned 32-bit number in host-endian format and
-  returns the equivalent number as an unsigned 32-bit number in big-endian
-  format.
-* htobe64: Takes an unsigned 64-bit number in host-endian format and
-  returns the equivalent number as an unsigned 64-bit number in big-endian
-  format.
-* htole16: Takes an unsigned 16-bit number in host-endian format and
-  returns the equivalent number as an unsigned 16-bit number in little-endian
-  format.
-* htole32: Takes an unsigned 32-bit number in host-endian format and
-  returns the equivalent number as an unsigned 32-bit number in little-endian
-  format.
-* htole64: Takes an unsigned 64-bit number in host-endian format and
-  returns the equivalent number as an unsigned 64-bit number in little-endian
-  format.
+
+The following byteswap functions are direction-agnostic.  That is,
+the same function is used for conversion in either direction discussed
+below.
+
+* be16: Takes an unsigned 16-bit number and converts it between
+  host byte order and big-endian
+  (`IEN137 <https://www.rfc-editor.org/ien/ien137.txt>`_) byte order.
+* be32: Takes an unsigned 32-bit number and converts it between
+  host byte order and big-endian byte order.
+* be64: Takes an unsigned 64-bit number and converts it between
+  host byte order and big-endian byte order.
 * bswap16: Takes an unsigned 16-bit number in either big- or little-endian
   format and returns the equivalent number with the same bit width but
   opposite endianness.
@@ -86,7 +87,12 @@  Functions
 * bswap64: Takes an unsigned 64-bit number in either big- or little-endian
   format and returns the equivalent number with the same bit width but
   opposite endianness.
-
+* le16: Takes an unsigned 16-bit number and converts it between
+  host byte order and little-endian byte order.
+* le32: Takes an unsigned 32-bit number and converts it between
+  host byte order and little-endian byte order.
+* le64: Takes an unsigned 64-bit number and converts it between
+  host byte order and little-endian byte order.
 
 Definitions
 -----------
@@ -441,8 +447,8 @@  and MUST be set to 0.
   =====  ========  =====  =================================================
   class  source    value  description
   =====  ========  =====  =================================================
-  ALU    TO_LE     0      convert between host byte order and little endian
-  ALU    TO_BE     1      convert between host byte order and big endian
+  ALU    LE        0      convert between host byte order and little endian
+  ALU    BE        1      convert between host byte order and big endian
   ALU64  Reserved  0      do byte swap unconditionally
   =====  ========  =====  =================================================
 
@@ -453,19 +459,19 @@  conformance group.
 
 Examples:
 
-``{END, TO_LE, ALU}`` with 'imm' = 16/32/64 means::
+``{END, LE, ALU}`` with 'imm' = 16/32/64 means::
 
-  dst = htole16(dst)
-  dst = htole32(dst)
-  dst = htole64(dst)
+  dst = le16(dst)
+  dst = le32(dst)
+  dst = le64(dst)
 
-``{END, TO_BE, ALU}`` with 'imm' = 16/32/64 means::
+``{END, BE, ALU}`` with 'imm' = 16/32/64 means::
 
-  dst = htobe16(dst)
-  dst = htobe32(dst)
-  dst = htobe64(dst)
+  dst = be16(dst)
+  dst = be32(dst)
+  dst = be64(dst)
 
-``{END, TO_LE, ALU64}`` with 'imm' = 16/32/64 means::
+``{END, TO, ALU64}`` with 'imm' = 16/32/64 means::
 
   dst = bswap16(dst)
   dst = bswap32(dst)
@@ -545,13 +551,17 @@  Helper functions are a concept whereby BPF programs can call into a
 set of function calls exposed by the underlying platform.
 
 Historically, each helper function was identified by a static ID
-encoded in the 'imm' field.  The available helper functions may differ
-for each program type, but static IDs are unique across all program types.
+encoded in the 'imm' field.  Further documentation of helper functions
+is outside the scope of this document and standardization is left for
+future work, but use is widely deployed and more information can be
+found in platform-specific documentation (e.g., Linux kernel documentation).
 
 Platforms that support the BPF Type Format (BTF) support identifying
 a helper function by a BTF ID encoded in the 'imm' field, where the BTF ID
 identifies the helper name and type.  Further documentation of BTF
-is outside the scope of this document and is left for future work.
+is outside the scope of this document and standardization is left for
+future work, but use is widely deployed and more information can be
+found in platform-specific documentation (e.g., Linux kernel documentation).
 
 Program-local functions
 ~~~~~~~~~~~~~~~~~~~~~~~