Merge tag 'v5.13-rc2' into spi-5.13

Linux 5.13-rc2

4 files changed, 57 insertions, 14 deletions

diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst
index 0e15f9b05c9d..437de2a7a5de 100644
--- a/Documentation/bpf/bpf_design_QA.rst
+++ b/Documentation/bpf/bpf_design_QA.rst
@@ -258,3 +258,18 @@ Q: Can BPF functionality such as new program or map types, new
 helpers, etc be added out of kernel module code?
 
 A: NO.
+
+Q: Directly calling kernel function is an ABI?
+----------------------------------------------
+Q: Some kernel functions (e.g. tcp_slow_start) can be called
+by BPF programs.  Do these kernel functions become an ABI?
+
+A: NO.
+
+The kernel function protos will change and the bpf programs will be
+rejected by the verifier.  Also, for example, some of the bpf-callable
+kernel functions have already been used by other kernel tcp
+cc (congestion-control) implementations.  If any of these kernel
+functions has changed, both the in-tree and out-of-tree kernel tcp cc
+implementations have to be changed.  The same goes for the bpf
+programs and they have to be adjusted accordingly.
diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst
index 2ed89abbf9a4..253496af8fef 100644
--- a/Documentation/bpf/bpf_devel_QA.rst
+++ b/Documentation/bpf/bpf_devel_QA.rst
@@ -29,7 +29,7 @@ list:
 This may also include issues related to XDP, BPF tracing, etc.
 
 Given netdev has a high volume of traffic, please also add the BPF
-maintainers to Cc (from kernel MAINTAINERS_ file):
+maintainers to Cc (from kernel ``MAINTAINERS`` file):
 
 * Alexei Starovoitov <ast@kernel.org>
 * Daniel Borkmann <daniel@iogearbox.net>
@@ -234,11 +234,11 @@ be subject to change.
 
 Q: samples/bpf preference vs selftests?
 ---------------------------------------
-Q: When should I add code to `samples/bpf/`_ and when to BPF kernel
-selftests_ ?
+Q: When should I add code to ``samples/bpf/`` and when to BPF kernel
+selftests_?
 
 A: In general, we prefer additions to BPF kernel selftests_ rather than
-`samples/bpf/`_. The rationale is very simple: kernel selftests are
+``samples/bpf/``. The rationale is very simple: kernel selftests are
 regularly run by various bots to test for kernel regressions.
 
 The more test cases we add to BPF selftests, the better the coverage
@@ -246,9 +246,9 @@ and the less likely it is that those could accidentally break. It is
 not that BPF kernel selftests cannot demo how a specific feature can
 be used.
 
-That said, `samples/bpf/`_ may be a good place for people to get started,
+That said, ``samples/bpf/`` may be a good place for people to get started,
 so it might be advisable that simple demos of features could go into
-`samples/bpf/`_, but advanced functional and corner-case testing rather
+``samples/bpf/``, but advanced functional and corner-case testing rather
 into kernel selftests.
 
 If your sample looks like a test case, then go for BPF kernel selftests
@@ -449,6 +449,19 @@ from source at
 
 https://github.com/acmel/dwarves
 
+pahole starts to use libbpf definitions and APIs since v1.13 after the
+commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
+It works well with the git repository because the libbpf submodule will
+use "git submodule update --init --recursive" to update.
+
+Unfortunately, the default github release source code does not contain
+libbpf submodule source code and this will cause build issues, the tarball
+from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
+github, you can get the source tarball with corresponding libbpf submodule
+codes from
+
+https://fedorapeople.org/~acme/dwarves
+
 Some distros have pahole version 1.16 packaged already, e.g.
 Fedora, Gentoo.
 
@@ -645,10 +658,9 @@ when:
 
 .. Links
 .. _Documentation/process/: https://www.kernel.org/doc/html/latest/process/
-.. _MAINTAINERS: ../../MAINTAINERS
 .. _netdev-FAQ: ../networking/netdev-FAQ.rst
-.. _samples/bpf/: ../../samples/bpf/
-.. _selftests: ../../tools/testing/selftests/bpf/
+.. _selftests:
+   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/
 .. _Documentation/dev-tools/kselftest.rst:
    https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html
 .. _Documentation/bpf/btf.rst: btf.rst
diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst
index 44dc789de2b4..846354cd2d69 100644
--- a/Documentation/bpf/btf.rst
+++ b/Documentation/bpf/btf.rst
@@ -84,6 +84,7 @@ sequentially and type id is assigned to each recognized type starting from id
     #define BTF_KIND_FUNC_PROTO     13      /* Function Proto       */
     #define BTF_KIND_VAR            14      /* Variable     */
     #define BTF_KIND_DATASEC        15      /* Section      */
+    #define BTF_KIND_FLOAT          16      /* Floating point       */
 
 Note that the type section encodes debug info, not just pure types.
 ``BTF_KIND_FUNC`` is not a type, and it represents a defined subprogram.
@@ -95,8 +96,8 @@ Each type contains the following common data::
         /* "info" bits arrangement
          * bits  0-15: vlen (e.g. # of struct's members)
          * bits 16-23: unused
-         * bits 24-27: kind (e.g. int, ptr, array...etc)
-         * bits 28-30: unused
+         * bits 24-28: kind (e.g. int, ptr, array...etc)
+         * bits 29-30: unused
          * bit     31: kind_flag, currently used by
          *             struct, union and fwd
          */
@@ -452,6 +453,18 @@ map definition.
   * ``offset``: the in-section offset of the variable
   * ``size``: the size of the variable in bytes
 
+2.2.16 BTF_KIND_FLOAT
+~~~~~~~~~~~~~~~~~~~~~
+
+``struct btf_type`` encoding requirement:
+ * ``name_off``: any valid offset
+ * ``info.kind_flag``: 0
+ * ``info.kind``: BTF_KIND_FLOAT
+ * ``info.vlen``: 0
+ * ``size``: the size of the float type in bytes: 2, 4, 8, 12 or 16.
+
+No additional type data follow ``btf_type``.
+
 3. BTF Kernel API
 *****************
 
diff --git a/Documentation/bpf/index.rst b/Documentation/bpf/index.rst
index 4f2874b729c3..a702f67dd45f 100644
--- a/Documentation/bpf/index.rst
+++ b/Documentation/bpf/index.rst
@@ -12,9 +12,6 @@ BPF instruction-set.
 The Cilium project also maintains a `BPF and XDP Reference Guide`_
 that goes into great technical depth about the BPF Architecture.
 
-The primary info for the bpf syscall is available in the `man-pages`_
-for `bpf(2)`_.
-
 BPF Type Format (BTF)
 =====================
 
@@ -35,6 +32,12 @@ Two sets of Questions and Answers (Q&A) are maintained.
    bpf_design_QA
    bpf_devel_QA
 
+Syscall API
+===========
+
+The primary info for the bpf syscall is available in the `man-pages`_
+for `bpf(2)`_. For more information about the userspace API, see
+Documentation/userspace-api/ebpf/index.rst.
 
 Helper functions
 ================