linux-toradex.git/kernel/bpf/syscall.c, branch v4.12

bpf: Add strict alignment flag for BPF_PROG_LOAD.

2017-05-11T18:19:00+00:00

Add a new field, "prog_flags", and an initial flag value
BPF_F_STRICT_ALIGNMENT.

When set, the verifier will enforce strict pointer alignment
regardless of the setting of CONFIG_EFFICIENT_UNALIGNED_ACCESS.

The verifier, in this mode, will also use a fixed value of "2" in
place of NET_IP_ALIGN.

This facilitates test cases that will exercise and validate this part
of the verifier even when run on architectures where alignment doesn't
matter.

Signed-off-by: David S. Miller 
Acked-by: Daniel Borkmann

mm, vmalloc: use __GFP_HIGHMEM implicitly

2017-05-09T00:15:13+00:00

__vmalloc* allows users to provide gfp flags for the underlying
allocation.  This API is quite popular

  $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l
  77

The only problem is that many people are not aware that they really want
to give __GFP_HIGHMEM along with other flags because there is really no
reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages
which are mapped to the kernel vmalloc space.  About half of users don't
use this flag, though.  This signals that we make the API unnecessarily
too complex.

This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to
be mapped to the vmalloc space.  Current users which add __GFP_HIGHMEM
are simplified and drop the flag.

Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org
Signed-off-by: Michal Hocko 
Reviewed-by: Matthew Wilcox 
Cc: Al Viro 
Cc: Vlastimil Babka 
Cc: David Rientjes 
Cc: Cristopher Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bpf: map_get_next_key to return first key on NULL

2017-04-25T15:57:45+00:00

When iterating through a map, we need to find a key that does not exist
in the map so map_get_next_key will give us the first key of the map.
This often requires a lot of guessing in production systems.

This patch makes map_get_next_key return the first key when the key
pointer in the parameter is NULL.

Signed-off-by: Teng Qin 
Signed-off-by: Alexei Starovoitov 
Acked-by: Daniel Borkmann 
Signed-off-by: David S. Miller

bpf: remove struct bpf_map_type_list

2017-04-11T18:38:43+00:00

There's no need to have struct bpf_map_type_list since
it just contains a list_head, the type, and the ops
pointer. Since the types are densely packed and not
actually dynamically registered, it's much easier and
smaller to have an array of type->ops pointer. Also
initialize this array statically to remove code needed
to initialize it.

In order to save duplicating the list, move it to the
types header file added by the previous patch and
include it in the same fashion.

Signed-off-by: Johannes Berg 
Acked-by: Alexei Starovoitov 
Acked-by: Daniel Borkmann 
Signed-off-by: David S. Miller

bpf: remove struct bpf_prog_type_list

2017-04-11T18:38:43+00:00

There's no need to have struct bpf_prog_type_list since
it just contains a list_head, the type, and the ops
pointer. Since the types are densely packed and not
actually dynamically registered, it's much easier and
smaller to have an array of type->ops pointer. Also
initialize this array statically to remove code needed
to initialize it.

In order to save duplicating the list, move it to a new
header file and include it in the places needing it.

Signed-off-by: Johannes Berg 
Acked-by: Daniel Borkmann 
Acked-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

bpf: introduce BPF_PROG_TEST_RUN command

2017-04-01T19:45:57+00:00

development and testing of networking bpf programs is quite cumbersome.
Despite availability of user space bpf interpreters the kernel is
the ultimate authority and execution environment.
Current test frameworks for TC include creation of netns, veth,
qdiscs and use of various packet generators just to test functionality
of a bpf program. XDP testing is even more complicated, since
qemu needs to be started with gro/gso disabled and precise queue
configuration, transferring of xdp program from host into guest,
attaching to virtio/eth0 and generating traffic from the host
while capturing the results from the guest.

Moreover analyzing performance bottlenecks in XDP program is
impossible in virtio environment, since cost of running the program
is tiny comparing to the overhead of virtio packet processing,
so performance testing can only be done on physical nic
with another server generating traffic.

Furthermore ongoing changes to user space control plane of production
applications cannot be run on the test servers leaving bpf programs
stubbed out for testing.

Last but not least, the upstream llvm changes are validated by the bpf
backend testsuite which has no ability to test the code generated.

To improve this situation introduce BPF_PROG_TEST_RUN command
to test and performance benchmark bpf programs.

Joint work with Daniel Borkmann.

Signed-off-by: Alexei Starovoitov 
Acked-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Signed-off-by: David S. Miller

bpf: Add hash of maps support

2017-03-22T22:45:45+00:00

This patch adds hash of maps support (hashmap->bpf_map).
BPF_MAP_TYPE_HASH_OF_MAPS is added.

A map-in-map contains a pointer to another map and lets call
this pointer 'inner_map_ptr'.

Notes on deleting inner_map_ptr from a hash map:

1. For BPF_F_NO_PREALLOC map-in-map, when deleting
   an inner_map_ptr, the htab_elem itself will go through
   a rcu grace period and the inner_map_ptr resides
   in the htab_elem.

2. For pre-allocated htab_elem (!BPF_F_NO_PREALLOC),
   when deleting an inner_map_ptr, the htab_elem may
   get reused immediately.  This situation is similar
   to the existing prealloc-ated use cases.

   However, the bpf_map_fd_put_ptr() calls bpf_map_put() which calls
   inner_map->ops->map_free(inner_map) which will go
   through a rcu grace period (i.e. all bpf_map's map_free
   currently goes through a rcu grace period).  Hence,
   the inner_map_ptr is still safe for the rcu reader side.

This patch also includes BPF_MAP_TYPE_HASH_OF_MAPS to the
check_map_prealloc() in the verifier.  preallocation is a
must for BPF_PROG_TYPE_PERF_EVENT.  Hence, even we don't expect
heavy updates to map-in-map, enforcing BPF_F_NO_PREALLOC for map-in-map
is impossible without disallowing BPF_PROG_TYPE_PERF_EVENT from using
map-in-map first.

Signed-off-by: Martin KaFai Lau 
Acked-by: Alexei Starovoitov 
Acked-by: Daniel Borkmann 
Signed-off-by: David S. Miller

bpf: Add array of maps support

2017-03-22T22:45:45+00:00

This patch adds a few helper funcs to enable map-in-map
support (i.e. outer_map->inner_map).  The first outer_map type
BPF_MAP_TYPE_ARRAY_OF_MAPS is also added in this patch.
The next patch will introduce a hash of maps type.

Any bpf map type can be acted as an inner_map.  The exception
is BPF_MAP_TYPE_PROG_ARRAY because the extra level of
indirection makes it harder to verify the owner_prog_type
and owner_jited.

Multi-level map-in-map is not supported (i.e. map->map is ok
but not map->map->map).

When adding an inner_map to an outer_map, it currently checks the
map_type, key_size, value_size, map_flags, max_entries and ops.
The verifier also uses those map's properties to do static analysis.
map_flags is needed because we need to ensure BPF_PROG_TYPE_PERF_EVENT
is using a preallocated hashtab for the inner_hash also.  ops and
max_entries are needed to generate inlined map-lookup instructions.
For simplicity reason, a simple '==' test is used for both map_flags
and max_entries.  The equality of ops is implied by the equality of
map_type.

During outer_map creation time, an inner_map_fd is needed to create an
outer_map.  However, the inner_map_fd's life time does not depend on the
outer_map.  The inner_map_fd is merely used to initialize
the inner_map_meta of the outer_map.

Also, for the outer_map:

* It allows element update and delete from syscall
* It allows element lookup from bpf_prog

The above is similar to the current fd_array pattern.

Signed-off-by: Martin KaFai Lau 
Acked-by: Alexei Starovoitov 
Acked-by: Daniel Borkmann 
Signed-off-by: David S. Miller

bpf: move fixup_bpf_calls() function

2017-03-17T03:44:11+00:00

no functional change.
move fixup_bpf_calls() to verifier.c
it's being refactored in the next patch

Signed-off-by: Alexei Starovoitov 
Acked-by: Daniel Borkmann 
Signed-off-by: David S. Miller

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:29+00:00

We are going to split  out of , which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar