Merge tag 'tegra-for-5.7-asoc' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into asoc-5.7

ASoC: tegra: Fixes for v5.7-rc3

This contains a couple of fixes that are needed to properly

Merge tag 'tegra-for-5.7-asoc' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into asoc-5.7

ASoC: tegra: Fixes for v5.7-rc3

This contains a couple of fixes that are needed to properly reconfigure
the audio clocks on older Tegra devices.

show more ...

Merge branch 'fixes-v5.7' into fixes

Merge drm/drm-next into drm-misc-next

Backmerging required to pull topic/phy-compliance.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-next into drm-intel-next-queued

Backmerging in order to pull "topic/phy-compliance".

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

Merge v5.7-rc1 into drm-misc-fixes

Start the new drm-misc-fixes cycle.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refresh

Resolve these conflicts:

arch/x86/Kconfig
arch/x86/kernel/Makefile

Do a minor "evil merge" to move the KCSAN entry up a

Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refresh

Resolve these conflicts:

arch/x86/Kconfig
arch/x86/kernel/Makefile

Do a minor "evil merge" to move the KCSAN entry up a bit by a few lines
in the Kconfig to reduce the probability of future conflicts.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

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Merge branch 'for-5.7/appleir' into for-linus

- small code cleanups in hid-appleir from Lucas Tanure

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from David Miller:
"Highlights:

1) Fix the iwlwifi regression, from Johannes Berg.

2) Support BSS

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from David Miller:
"Highlights:

1) Fix the iwlwifi regression, from Johannes Berg.

2) Support BSS coloring and 802.11 encapsulation offloading in
hardware, from John Crispin.

3) Fix some potential Spectre issues in qtnfmac, from Sergey
Matyukevich.

4) Add TTL decrement action to openvswitch, from Matteo Croce.

5) Allow paralleization through flow_action setup by not taking the
RTNL mutex, from Vlad Buslov.

6) A lot of zero-length array to flexible-array conversions, from
Gustavo A. R. Silva.

7) Align XDP statistics names across several drivers for consistency,
from Lorenzo Bianconi.

8) Add various pieces of infrastructure for offloading conntrack, and
make use of it in mlx5 driver, from Paul Blakey.

9) Allow using listening sockets in BPF sockmap, from Jakub Sitnicki.

10) Lots of parallelization improvements during configuration changes
in mlxsw driver, from Ido Schimmel.

11) Add support to devlink for generic packet traps, which report
packets dropped during ACL processing. And use them in mlxsw
driver. From Jiri Pirko.

12) Support bcmgenet on ACPI, from Jeremy Linton.

13) Make BPF compatible with RT, from Thomas Gleixnet, Alexei
Starovoitov, and your's truly.

14) Support XDP meta-data in virtio_net, from Yuya Kusakabe.

15) Fix sysfs permissions when network devices change namespaces, from
Christian Brauner.

16) Add a flags element to ethtool_ops so that drivers can more simply
indicate which coalescing parameters they actually support, and
therefore the generic layer can validate the user's ethtool
request. Use this in all drivers, from Jakub Kicinski.

17) Offload FIFO qdisc in mlxsw, from Petr Machata.

18) Support UDP sockets in sockmap, from Lorenz Bauer.

19) Fix stretch ACK bugs in several TCP congestion control modules,
from Pengcheng Yang.

20) Support virtual functiosn in octeontx2 driver, from Tomasz
Duszynski.

21) Add region operations for devlink and use it in ice driver to dump
NVM contents, from Jacob Keller.

22) Add support for hw offload of MACSEC, from Antoine Tenart.

23) Add support for BPF programs that can be attached to LSM hooks,
from KP Singh.

24) Support for multiple paths, path managers, and counters in MPTCP.
From Peter Krystad, Paolo Abeni, Florian Westphal, Davide Caratti,
and others.

25) More progress on adding the netlink interface to ethtool, from
Michal Kubecek"

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2121 commits)
net: ipv6: rpl_iptunnel: Fix potential memory leak in rpl_do_srh_inline
cxgb4/chcr: nic-tls stats in ethtool
net: dsa: fix oops while probing Marvell DSA switches
net/bpfilter: remove superfluous testing message
net: macb: Fix handling of fixed-link node
net: dsa: ksz: Select KSZ protocol tag
netdevsim: dev: Fix memory leak in nsim_dev_take_snapshot_write
net: stmmac: add EHL 2.5Gbps PCI info and PCI ID
net: stmmac: add EHL PSE0 & PSE1 1Gbps PCI info and PCI ID
net: stmmac: create dwmac-intel.c to contain all Intel platform
net: dsa: bcm_sf2: Support specifying VLAN tag egress rule
net: dsa: bcm_sf2: Add support for matching VLAN TCI
net: dsa: bcm_sf2: Move writing of CFP_DATA(5) into slicing functions
net: dsa: bcm_sf2: Check earlier for FLOW_EXT and FLOW_MAC_EXT
net: dsa: bcm_sf2: Disable learning for ASP port
net: dsa: b53: Deny enslaving port 7 for 7278 into a bridge
net: dsa: b53: Prevent tagged VLAN on port 7 for 7278
net: dsa: b53: Restore VLAN entries upon (re)configuration
net: dsa: bcm_sf2: Fix overflow checks
hv_netvsc: Remove unnecessary round_up for recv_completion_cnt
...

show more ...

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Signed-off-by: David S. Miller <davem@davemloft.net>

Merge branch 'bpf-lsm'

KP Singh says:

====================
** Motivation

Google does analysis of rich runtime security data to detect and thwart
threats in real-time. Currently, this is done in cu

Merge branch 'bpf-lsm'

KP Singh says:

====================
** Motivation

Google does analysis of rich runtime security data to detect and thwart
threats in real-time. Currently, this is done in custom kernel modules
but we would like to replace this with something that's upstream and
useful to others.

The current kernel infrastructure for providing telemetry (Audit, Perf
etc.) is disjoint from access enforcement (i.e. LSMs). Augmenting the
information provided by audit requires kernel changes to audit, its
policy language and user-space components. Furthermore, building a MAC
policy based on the newly added telemetry data requires changes to
various LSMs and their respective policy languages.

This patchset allows BPF programs to be attached to LSM hooks This
facilitates a unified and dynamic (not requiring re-compilation of the
kernel) audit and MAC policy.

** Why an LSM?

Linux Security Modules target security behaviours rather than the
kernel's API. For example, it's easy to miss out a newly added system
call for executing processes (eg. execve, execveat etc.) but the LSM
framework ensures that all process executions trigger the relevant hooks
irrespective of how the process was executed.

Allowing users to implement LSM hooks at runtime also benefits the LSM
eco-system by enabling a quick feedback loop from the security community
about the kind of behaviours that the LSM Framework should be targeting.

** How does it work?

The patchset introduces a new eBPF (https://docs.cilium.io/en/v1.6/bpf/)
program type BPF_PROG_TYPE_LSM which can only be attached to LSM hooks.
Loading and attachment of BPF programs requires CAP_SYS_ADMIN.

The new LSM registers nop functions (bpf_lsm_<hook_name>) as LSM hook
callbacks. Their purpose is to provide a definite point where BPF
programs can be attached as BPF_TRAMP_MODIFY_RETURN trampoline programs
for hooks that return an int, and BPF_TRAMP_FEXIT trampoline programs
for void LSM hooks.

Audit logs can be written using a format chosen by the eBPF program to
the perf events buffer or to global eBPF variables or maps and can be
further processed in user-space.

** BTF Based Design

The current design uses BTF:

* https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html
* https://lwn.net/Articles/803258

which allows verifiable read-only structure accesses by field names
rather than fixed offsets. This allows accessing the hook parameters
using a dynamically created context which provides a certain degree of
ABI stability:

// Only declare the structure and fields intended to be used
// in the program
struct vm_area_struct {
unsigned long vm_start;
} __attribute__((preserve_access_index));

// Declare the eBPF program mprotect_audit which attaches to
// to the file_mprotect LSM hook and accepts three arguments.
SEC("lsm/file_mprotect")
int BPF_PROG(mprotect_audit, struct vm_area_struct *vma,
unsigned long reqprot, unsigned long prot, int ret)
{
unsigned long vm_start = vma->vm_start;
return 0;
}

By relocating field offsets, BTF makes a large portion of kernel data
structures readily accessible across kernel versions without requiring a
large corpus of BPF helper functions and requiring recompilation with
every kernel version. The BTF type information is also used by the BPF
verifier to validate memory accesses within the BPF program and also
prevents arbitrary writes to the kernel memory.

The limitations of BTF compatibility are described in BPF Co-Re
(http://vger.kernel.org/bpfconf2019_talks/bpf-core.pdf, i.e. field
renames, #defines and changes to the signature of LSM hooks). This
design imposes that the MAC policy (eBPF programs) be updated when the
inspected kernel structures change outside of BTF compatibility
guarantees. In practice, this is only required when a structure field
used by a current policy is removed (or renamed) or when the used LSM
hooks change. We expect the maintenance cost of these changes to be
acceptable as compared to the design presented in the RFC.

(https://lore.kernel.org/bpf/20190910115527.5235-1-kpsingh@chromium.org/).

** Usage Examples

A simple example and some documentation is included in the patchset.
In order to better illustrate the capabilities of the framework some
more advanced prototype (not-ready for review) code has also been
published separately:

* Logging execution events (including environment variables and
arguments)
https://github.com/sinkap/linux-krsi/blob/patch/v1/examples/samples/bpf/lsm_audit_env.c

* Detecting deletion of running executables:
https://github.com/sinkap/linux-krsi/blob/patch/v1/examples/samples/bpf/lsm_detect_exec_unlink.c

* Detection of writes to /proc/<pid>/mem:
https://github.com/sinkap/linux-krsi/blob/patch/v1/examples/samples/bpf/lsm_audit_env.c

We have updated Google's internal telemetry infrastructure and have
started deploying this LSM on our Linux Workstations. This gives us more
confidence in the real-world applications of such a system.

** Changelog:

- v8 -> v9:
https://lore.kernel.org/bpf/20200327192854.31150-1-kpsingh@chromium.org/
* Fixed a selftest crash when CONFIG_LSM doesn't have "bpf".
* Added James' Ack.
* Rebase.

- v7 -> v8:
https://lore.kernel.org/bpf/20200326142823.26277-1-kpsingh@chromium.org/
* Removed CAP_MAC_ADMIN check from bpf_lsm_verify_prog. LSMs can add it
in their own bpf_prog hook. This can be revisited as a separate patch.
* Added Andrii and James' Ack/Review tags.
* Fixed an indentation issue and missing newlines in selftest error
a cases.
* Updated a comment as suggested by Alexei.
* Updated the documentation to use the newer libbpf API and some other
fixes.
* Rebase

- v6 -> v7:
https://lore.kernel.org/bpf/20200325152629.6904-1-kpsingh@chromium.org/
* Removed __weak from the LSM attachment nops per Kees' suggestion.
Will send a separate patch (if needed) to update the noinline
definition in include/linux/compiler_attributes.h.
* waitpid to wait specifically for the forked child in selftests.
* Comment format fixes in security/... as suggested by Casey.
* Added Acks from Kees and Andrii and Casey's Reviewed-by: tags to
the respective patches.
* Rebase

- v5 -> v6:
https://lore.kernel.org/bpf/20200323164415.12943-1-kpsingh@chromium.org/
* Updated LSM_HOOK macro to define a default value and cleaned up the
BPF LSM hook declarations.
* Added Yonghong's Acks and Kees' Reviewed-by tags.
* Simplification of the selftest code.
* Rebase and fixes suggested by Andrii and Yonghong and some other minor
fixes noticed in internal review.

- v4 -> v5:
https://lore.kernel.org/bpf/20200220175250.10795-1-kpsingh@chromium.org/
* Removed static keys and special casing of BPF calls from the LSM
framework.
* Initialized the BPF callbacks (nops) as proper LSM hooks.
* Updated to using the newly introduced BPF_TRAMP_MODIFY_RETURN
trampolines in https://lkml.org/lkml/2020/3/4/877
* Addressed Andrii's feedback and rebased.

- v3 -> v4:
* Moved away from allocating a separate security_hook_heads and adding a
new special case for arch_prepare_bpf_trampoline to using BPF fexit
trampolines called from the right place in the LSM hook and toggled by
static keys based on the discussion in:
https://lore.kernel.org/bpf/CAG48ez25mW+_oCxgCtbiGMX07g_ph79UOJa07h=o_6B6+Q-u5g@mail.gmail.com/
* Since the code does not deal with security_hook_heads anymore, it goes
from "being a BPF LSM" to "BPF program attachment to LSM hooks".
* Added a new test case which ensures that the BPF programs' return value
is reflected by the LSM hook.

- v2 -> v3 does not change the overall design and has some minor fixes:
* LSM_ORDER_LAST is introduced to represent the behaviour of the BPF LSM
* Fixed the inadvertent clobbering of the LSM Hook error codes
* Added GPL license requirement to the commit log
* The lsm_hook_idx is now the more conventional 0-based index
* Some changes were split into a separate patch ("Load btf_vmlinux only
once per object")
https://lore.kernel.org/bpf/20200117212825.11755-1-kpsingh@chromium.org/
* Addressed Andrii's feedback on the BTF implementation
* Documentation update for using generated vmlinux.h to simplify
programs
* Rebase

- Changes since v1:
https://lore.kernel.org/bpf/20191220154208.15895-1-kpsingh@chromium.org
* Eliminate the requirement to maintain LSM hooks separately in
security/bpf/hooks.h Use BPF trampolines to dynamically allocate
security hooks
* Drop the use of securityfs as bpftool provides the required
introspection capabilities. Update the tests to use the bpf_skeleton
and global variables
* Use O_CLOEXEC anonymous fds to represent BPF attachment in line with
the other BPF programs with the possibility to use bpf program pinning
in the future to provide "permanent attachment".
* Drop the logic based on prog names for handling re-attachment.
* Drop bpf_lsm_event_output from this series and send it as a separate
patch.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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bpf: Introduce BPF_PROG_TYPE_LSM

Introduce types and configs for bpf programs that can be attached to
LSM hooks. The programs can be enabled by the config option
CONFIG_BPF_LSM.

Signed-off-by: KP S

bpf: Introduce BPF_PROG_TYPE_LSM

Introduce types and configs for bpf programs that can be attached to
LSM hooks. The programs can be enabled by the config option
CONFIG_BPF_LSM.

Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Florent Revest <revest@google.com>
Reviewed-by: Thomas Garnier <thgarnie@google.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Link: https://lore.kernel.org/bpf/20200329004356.27286-2-kpsingh@chromium.org

show more ...

Merge branch 'x86/kdump' into locking/kcsan, to resolve conflicts

Conflicts:
arch/x86/purgatory/Makefile

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge drm/drm-next into drm-intel-next-queued

Some DSI and VBT pending patches from Hans will apply
cleanly and with less ugly conflicts if they are rebuilt
on top of other patches that recently lan

Merge drm/drm-next into drm-intel-next-queued

Some DSI and VBT pending patches from Hans will apply
cleanly and with less ugly conflicts if they are rebuilt
on top of other patches that recently landed on drm-next.

Reference: https://patchwork.freedesktop.org/series/70952/
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com

show more ...

Merge tag 'v5.6-rc3' into sched/core, to pick up fixes and dependent patches

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge drm-intel-next-queued into gvt-next

Backmerge to pull in
https://patchwork.freedesktop.org/patch/353621/?series=73544&rev=1

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

Merge v5.6-rc2 into drm-misc-next

Lyude needs some patches in 5.6-rc2 and we didn't bring drm-misc-next
forward yet, so it looks like a good occasion.

Signed-off-by: Maxime Ripard <maxime@cerno.tec

Merge v5.6-rc2 into drm-misc-next

Lyude needs some patches in 5.6-rc2 and we didn't bring drm-misc-next
forward yet, so it looks like a good occasion.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

show more ...

Merge v5.6-rc1 into drm-misc-fixes

We're based on v5.6, need v5.6-rc1 at least. :)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

Merge tag 'v5.5-rc4' into locking/kcsan, to resolve conflicts

Conflicts:
init/main.c
lib/Kconfig.debug

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'linus' into perf/urgent, to synchronize with upstream

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'next' into for-linus

Prepare input updates for 5.6 merge window.

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from David Miller:

1) Add WireGuard

2) Add HE and TWT support to ath11k driver, from John Crispin.

3

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from David Miller:

1) Add WireGuard

2) Add HE and TWT support to ath11k driver, from John Crispin.

3) Add ESP in TCP encapsulation support, from Sabrina Dubroca.

4) Add variable window congestion control to TIPC, from Jon Maloy.

5) Add BCM84881 PHY driver, from Russell King.

6) Start adding netlink support for ethtool operations, from Michal
Kubecek.

7) Add XDP drop and TX action support to ena driver, from Sameeh
Jubran.

8) Add new ipv4 route notifications so that mlxsw driver does not have
to handle identical routes itself. From Ido Schimmel.

9) Add BPF dynamic program extensions, from Alexei Starovoitov.

10) Support RX and TX timestamping in igc, from Vinicius Costa Gomes.

11) Add support for macsec HW offloading, from Antoine Tenart.

12) Add initial support for MPTCP protocol, from Christoph Paasch,
Matthieu Baerts, Florian Westphal, Peter Krystad, and many others.

13) Add Octeontx2 PF support, from Sunil Goutham, Geetha sowjanya, Linu
Cherian, and others.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1469 commits)
net: phy: add default ARCH_BCM_IPROC for MDIO_BCM_IPROC
udp: segment looped gso packets correctly
netem: change mailing list
qed: FW 8.42.2.0 debug features
qed: rt init valid initialization changed
qed: Debug feature: ilt and mdump
qed: FW 8.42.2.0 Add fw overlay feature
qed: FW 8.42.2.0 HSI changes
qed: FW 8.42.2.0 iscsi/fcoe changes
qed: Add abstraction for different hsi values per chip
qed: FW 8.42.2.0 Additional ll2 type
qed: Use dmae to write to widebus registers in fw_funcs
qed: FW 8.42.2.0 Parser offsets modified
qed: FW 8.42.2.0 Queue Manager changes
qed: FW 8.42.2.0 Expose new registers and change windows
qed: FW 8.42.2.0 Internal ram offsets modifications
MAINTAINERS: Add entry for Marvell OcteonTX2 Physical Function driver
Documentation: net: octeontx2: Add RVU HW and drivers overview
octeontx2-pf: ethtool RSS config support
octeontx2-pf: Add basic ethtool support
...

show more ...

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-01-22

The following pull-request contains BPF updates for

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-01-22

The following pull-request contains BPF updates for your *net-next* tree.

We've added 92 non-merge commits during the last 16 day(s) which contain
a total of 320 files changed, 7532 insertions(+), 1448 deletions(-).

The main changes are:

1) function by function verification and program extensions from Alexei.

2) massive cleanup of selftests/bpf from Toke and Andrii.

3) batched bpf map operations from Brian and Yonghong.

4) tcp congestion control in bpf from Martin.

5) bulking for non-map xdp_redirect form Toke.

6) bpf_send_signal_thread helper from Yonghong.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

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Merge tag 'v5.5-rc5' into next

Sync up with mainline to get SPI "delay" API changes.

Merge branch 'tcp-bpf-cc'

Martin Lau says:

====================
This series introduces BPF STRUCT_OPS. It is an infra to allow
implementing some specific kernel's function pointers in BPF.
The fir

Merge branch 'tcp-bpf-cc'

Martin Lau says:

====================
This series introduces BPF STRUCT_OPS. It is an infra to allow
implementing some specific kernel's function pointers in BPF.
The first use case included in this series is to implement
TCP congestion control algorithm in BPF (i.e. implement
struct tcp_congestion_ops in BPF).

There has been attempt to move the TCP CC to the user space
(e.g. CCP in TCP). The common arguments are faster turn around,
get away from long-tail kernel versions in production...etc,
which are legit points.

BPF has been the continuous effort to join both kernel and
userspace upsides together (e.g. XDP to gain the performance
advantage without bypassing the kernel). The recent BPF
advancements (in particular BTF-aware verifier, BPF trampoline,
BPF CO-RE...) made implementing kernel struct ops (e.g. tcp cc)
possible in BPF.

The idea is to allow implementing tcp_congestion_ops in bpf.
It allows a faster turnaround for testing algorithm in the
production while leveraging the existing (and continue growing) BPF
feature/framework instead of building one specifically for
userspace TCP CC.

Please see individual patch for details.

The bpftool support will be posted in follow-up patches.

v4:
- Expose tcp_ca_find() to tcp.h in patch 7.
It is used to check the same bpf-tcp-cc
does not exist to guarantee the register()
will succeed.
- set_memory_ro() and then set_memory_x() only after all
trampolines are written to the image in patch 6. (Daniel)
spinlock is replaced by mutex because set_memory_*
requires sleepable context.

v3:
- Fix kbuild error by considering CONFIG_BPF_SYSCALL (kbuild)
- Support anonymous bitfield in patch 4 (Andrii, Yonghong)
- Push boundary safety check to a specific arch's trampoline function
(in patch 6) (Yonghong).
Reuse the WANR_ON_ONCE check in arch_prepare_bpf_trampoline() in x86.
- Check module field is 0 in udata in patch 6 (Yonghong)
- Check zero holes in patch 6 (Andrii)
- s/_btf_vmlinux/btf/ in patch 5 and 7 (Andrii)
- s/check_xxx/is_xxx/ in patch 7 (Andrii)
- Use "struct_ops/" convention in patch 11 (Andrii)
- Use the skel instead of bpf_object in patch 11 (Andrii)
- libbpf: Decide BPF_PROG_TYPE_STRUCT_OPS at open phase by using
find_sec_def()
- libbpf: Avoid a debug message at open phase (Andrii)
- libbpf: Add bpf_program__(is|set)_struct_ops() for consistency (Andrii)
- libbpf: Add "struct_ops" to section_defs (Andrii)
- libbpf: Some code shuffling in init_kern_struct_ops() (Andrii)
- libbpf: A few safety checks (Andrii)

v2:
- Dropped cubic for now. They will be reposted
once there are more clarity in "jiffies" on both
bpf side (about the helper) and
tcp_cubic side (some of jiffies usages are being replaced
by tp->tcp_mstamp)
- Remove unnecssary check on bitfield support from btf_struct_access()
(Yonghong)
- BTF_TYPE_EMIT macro (Yonghong, Andrii)
- value_name's length check to avoid an unlikely
type match during truncation case (Yonghong)
- BUILD_BUG_ON to ensure no trampoline-image overrun
in the future (Yonghong)
- Simplify get_next_key() (Yonghong)
- Added comment to explain how to check mandatory
func ptr in net/ipv4/bpf_tcp_ca.c (Yonghong)
- Rename "__bpf_" to "bpf_struct_ops_" for value prefix (Andrii)
- Add comment to highlight the bpf_dctcp.c is not necessarily
the same as tcp_dctcp.c. (Alexei, Eric)
- libbpf: Renmae "struct_ops" to ".struct_ops" for elf sec (Andrii)
- libbpf: Expose struct_ops as a bpf_map (Andrii)
- libbpf: Support multiple struct_ops in SEC(".struct_ops") (Andrii)
- libbpf: Add bpf_map__attach_struct_ops() (Andrii)
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS

This patch allows the kernel's struct ops (i.e. func ptr) to be
implemented in BPF. The first use case in this series is the
"struct tcp_congestion_ops" whic

bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS

This patch allows the kernel's struct ops (i.e. func ptr) to be
implemented in BPF. The first use case in this series is the
"struct tcp_congestion_ops" which will be introduced in a
latter patch.

This patch introduces a new prog type BPF_PROG_TYPE_STRUCT_OPS.
The BPF_PROG_TYPE_STRUCT_OPS prog is verified against a particular
func ptr of a kernel struct. The attr->attach_btf_id is the btf id
of a kernel struct. The attr->expected_attach_type is the member
"index" of that kernel struct. The first member of a struct starts
with member index 0. That will avoid ambiguity when a kernel struct
has multiple func ptrs with the same func signature.

For example, a BPF_PROG_TYPE_STRUCT_OPS prog is written
to implement the "init" func ptr of the "struct tcp_congestion_ops".
The attr->attach_btf_id is the btf id of the "struct tcp_congestion_ops"
of the _running_ kernel. The attr->expected_attach_type is 3.

The ctx of BPF_PROG_TYPE_STRUCT_OPS is an array of u64 args saved
by arch_prepare_bpf_trampoline that will be done in the next
patch when introducing BPF_MAP_TYPE_STRUCT_OPS.

"struct bpf_struct_ops" is introduced as a common interface for the kernel
struct that supports BPF_PROG_TYPE_STRUCT_OPS prog. The supporting kernel
struct will need to implement an instance of the "struct bpf_struct_ops".

The supporting kernel struct also needs to implement a bpf_verifier_ops.
During BPF_PROG_LOAD, bpf_struct_ops_find() will find the right
bpf_verifier_ops by searching the attr->attach_btf_id.

A new "btf_struct_access" is also added to the bpf_verifier_ops such
that the supporting kernel struct can optionally provide its own specific
check on accessing the func arg (e.g. provide limited write access).

After btf_vmlinux is parsed, the new bpf_struct_ops_init() is called
to initialize some values (e.g. the btf id of the supporting kernel
struct) and it can only be done once the btf_vmlinux is available.

The R0 checks at BPF_EXIT is excluded for the BPF_PROG_TYPE_STRUCT_OPS prog
if the return type of the prog->aux->attach_func_proto is "void".

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200109003503.3855825-1-kafai@fb.com

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