linux-toradex.git/arch/arm/net, branch v3.17

net: filter: split 'struct sk_filter' into socket and bpf parts

2014-08-02T22:03:58+00:00

clean up names related to socket filtering and bpf in the following way:
- everything that deals with sockets keeps 'sk_*' prefix
- everything that is pure BPF is changed to 'bpf_*' prefix

split 'struct sk_filter' into
struct sk_filter {
	atomic_t        refcnt;
	struct rcu_head rcu;
	struct bpf_prog *prog;
};
and
struct bpf_prog {
        u32                     jited:1,
                                len:31;
        struct sock_fprog_kern  *orig_prog;
        unsigned int            (*bpf_func)(const struct sk_buff *skb,
                                            const struct bpf_insn *filter);
        union {
                struct sock_filter      insns[0];
                struct bpf_insn         insnsi[0];
                struct work_struct      work;
        };
};
so that 'struct bpf_prog' can be used independent of sockets and cleans up
'unattached' bpf use cases

split SK_RUN_FILTER macro into:
    SK_RUN_FILTER to be used with 'struct sk_filter *' and
    BPF_PROG_RUN to be used with 'struct bpf_prog *'

__sk_filter_release(struct sk_filter *) gains
__bpf_prog_release(struct bpf_prog *) helper function

also perform related renames for the functions that work
with 'struct bpf_prog *', since they're on the same lines:

sk_filter_size -> bpf_prog_size
sk_filter_select_runtime -> bpf_prog_select_runtime
sk_filter_free -> bpf_prog_free
sk_unattached_filter_create -> bpf_prog_create
sk_unattached_filter_destroy -> bpf_prog_destroy
sk_store_orig_filter -> bpf_prog_store_orig_filter
sk_release_orig_filter -> bpf_release_orig_filter
__sk_migrate_filter -> bpf_migrate_filter
__sk_prepare_filter -> bpf_prepare_filter

API for attaching classic BPF to a socket stays the same:
sk_attach_filter(prog, struct sock *)/sk_detach_filter(struct sock *)
and SK_RUN_FILTER(struct sk_filter *, ctx) to execute a program
which is used by sockets, tun, af_packet

API for 'unattached' BPF programs becomes:
bpf_prog_create(struct bpf_prog **)/bpf_prog_destroy(struct bpf_prog *)
and BPF_PROG_RUN(struct bpf_prog *, ctx) to execute a program
which is used by isdn, ppp, team, seccomp, ptp, xt_bpf, cls_bpf, test_bpf

Signed-off-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

net: filter: get rid of BPF_S_* enum

2014-06-02T05:16:58+00:00

This patch finally allows us to get rid of the BPF_S_* enum.
Currently, the code performs unnecessary encode and decode
workarounds in seccomp and filter migration itself when a filter
is being attached in order to overcome BPF_S_* encoding which
is not used anymore by the new interpreter resp. JIT compilers.

Keeping it around would mean that also in future we would need
to extend and maintain this enum and related encoders/decoders.
We can get rid of all that and save us these operations during
filter attaching. Naturally, also JIT compilers need to be updated
by this.

Before JIT conversion is being done, each compiler checks if A
is being loaded at startup to obtain information if it needs to
emit instructions to clear A first. Since BPF extensions are a
subset of BPF_LD | BPF_{W,H,B} | BPF_ABS variants, case statements
for extensions can be removed at that point. To ease and minimalize
code changes in the classic JITs, we have introduced bpf_anc_helper().

Tested with test_bpf on x86_64 (JIT, int), s390x (JIT, int),
arm (JIT, int), i368 (int), ppc64 (JIT, int); for sparc we
unfortunately didn't have access, but changes are analogous to
the rest.

Joint work with Alexei Starovoitov.

Signed-off-by: Daniel Borkmann 
Signed-off-by: Alexei Starovoitov 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: Mircea Gherzan 
Cc: Kees Cook 
Acked-by: Chema Gonzalez 
Signed-off-by: David S. Miller

net: filter: add jited flag to indicate jit compiled filters

2014-03-31T04:45:08+00:00

This patch adds a jited flag into sk_filter struct in order to indicate
whether a filter is currently jited or not. The size of sk_filter is
not being expanded as the 32 bit 'len' member allows upper bits to be
reused since a filter can currently only grow as large as BPF_MAXINSNS.

Therefore, there's enough room also for other in future needed flags to
reuse 'len' field if necessary. The jited flag also allows for having
alternative interpreter functions running as currently, we can only
detect jit compiled filters by testing fp->bpf_func to not equal the
address of sk_run_filter().

Joint work with Alexei Starovoitov.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann 
Cc: Pablo Neira Ayuso 
Signed-off-by: David S. Miller

net: Rename skb->rxhash to skb->hash

2014-03-26T19:58:20+00:00

The packet hash can be considered a property of the packet, not just
on RX path.

This patch changes name of rxhash and l4_rxhash skbuff fields to be
hash and l4_hash respectively. This includes changing uses of the
field in the code which don't call the access functions.

Signed-off-by: Tom Herbert 
Signed-off-by: Eric Dumazet 
Cc: Mahesh Bandewar 
Signed-off-by: David S. Miller

bpf: do not use reciprocal divide

2014-01-16T01:02:08+00:00

At first Jakub Zawadzki noticed that some divisions by reciprocal_divide
were not correct. (off by one in some cases)
http://www.wireshark.org/~darkjames/reciprocal-buggy.c

He could also show this with BPF:
http://www.wireshark.org/~darkjames/set-and-dump-filter-k-bug.c

The reciprocal divide in linux kernel is not generic enough,
lets remove its use in BPF, as it is not worth the pain with
current cpus.

Signed-off-by: Eric Dumazet 
Reported-by: Jakub Zawadzki 
Cc: Mircea Gherzan 
Cc: Daniel Borkmann 
Cc: Hannes Frederic Sowa 
Cc: Matt Evans 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: David S. Miller 
Signed-off-by: David S. Miller

Merge branch 'devel-stable' into for-next

2013-11-12T10:58:59+00:00

Conflicts:
	arch/arm/include/asm/atomic.h
	arch/arm/include/asm/hardirq.h
	arch/arm/kernel/smp.c

ARM: net: fix arm instruction endian-ness in bpf_jit_32.c

2013-10-19T19:46:35+00:00

Use  to correctly transform instruction byte ordering
into in-memory ordering.

Signed-off-by: Ben Dooks 
Reviewed-by: Dave Martin

net: fix unsafe set_memory_rw from softirq

2013-10-07T19:16:45+00:00

on x86 system with net.core.bpf_jit_enable = 1

sudo tcpdump -i eth1 'tcp port 22'

causes the warning:
[   56.766097]  Possible unsafe locking scenario:
[   56.766097]
[   56.780146]        CPU0
[   56.786807]        ----
[   56.793188]   lock(&(&vb->lock)->rlock);
[   56.799593]   
[   56.805889]     lock(&(&vb->lock)->rlock);
[   56.812266]
[   56.812266]  *** DEADLOCK ***
[   56.812266]
[   56.830670] 1 lock held by ksoftirqd/1/13:
[   56.836838]  #0:  (rcu_read_lock){.+.+..}, at: [] vm_unmap_aliases+0x8c/0x380
[   56.849757]
[   56.849757] stack backtrace:
[   56.862194] CPU: 1 PID: 13 Comm: ksoftirqd/1 Not tainted 3.12.0-rc3+ #45
[   56.868721] Hardware name: System manufacturer System Product Name/P8Z77 WS, BIOS 3007 07/26/2012
[   56.882004]  ffffffff821944c0 ffff88080bbdb8c8 ffffffff8175a145 0000000000000007
[   56.895630]  ffff88080bbd5f40 ffff88080bbdb928 ffffffff81755b14 0000000000000001
[   56.909313]  ffff880800000001 ffff880800000000 ffffffff8101178f 0000000000000001
[   56.923006] Call Trace:
[   56.929532]  [] dump_stack+0x55/0x76
[   56.936067]  [] print_usage_bug+0x1f7/0x208
[   56.942445]  [] ? save_stack_trace+0x2f/0x50
[   56.948932]  [] ? check_usage_backwards+0x150/0x150
[   56.955470]  [] mark_lock+0x282/0x2c0
[   56.961945]  [] __lock_acquire+0x45d/0x1d50
[   56.968474]  [] ? __lock_acquire+0x2de/0x1d50
[   56.975140]  [] ? cpumask_next_and+0x55/0x90
[   56.981942]  [] lock_acquire+0x92/0x1d0
[   56.988745]  [] ? vm_unmap_aliases+0x16a/0x380
[   56.995619]  [] _raw_spin_lock+0x41/0x50
[   57.002493]  [] ? vm_unmap_aliases+0x16a/0x380
[   57.009447]  [] vm_unmap_aliases+0x16a/0x380
[   57.016477]  [] ? vm_unmap_aliases+0x8c/0x380
[   57.023607]  [] change_page_attr_set_clr+0xc0/0x460
[   57.030818]  [] ? trace_hardirqs_on+0xd/0x10
[   57.037896]  [] ? kmem_cache_free+0xb0/0x2b0
[   57.044789]  [] ? free_object_rcu+0x93/0xa0
[   57.051720]  [] set_memory_rw+0x2f/0x40
[   57.058727]  [] bpf_jit_free+0x2c/0x40
[   57.065577]  [] sk_filter_release_rcu+0x1a/0x30
[   57.072338]  [] rcu_process_callbacks+0x202/0x7c0
[   57.078962]  [] __do_softirq+0xf7/0x3f0
[   57.085373]  [] run_ksoftirqd+0x35/0x70

cannot reuse jited filter memory, since it's readonly,
so use original bpf insns memory to hold work_struct

defer kfree of sk_filter until jit completed freeing

tested on x86_64 and i386

Signed-off-by: Alexei Starovoitov 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

arm: bpf_jit: can call module_free() from any context

2013-05-20T21:03:50+00:00

Follow-up on module_free()/vfree() that takes care of the rest, so no
longer this workaround with work_struct needed.

Signed-off-by: Daniel Borkmann 
Cc: Al Viro 
Cc: Mircea Gherzan 
Signed-off-by: David S. Miller

filter: bpf_jit_comp: refactor and unify BPF JIT image dump output

2013-03-21T21:25:56+00:00

If bpf_jit_enable > 1, then we dump the emitted JIT compiled image
after creation. Currently, only SPARC and PowerPC has similar output
as in the reference implementation on x86_64. Make a small helper
function in order to reduce duplicated code and make the dump output
uniform across architectures x86_64, SPARC, PPC, ARM (e.g. on ARM
flen, pass and proglen are currently not shown, but would be
interesting to know as well), also for future BPF JIT implementations
on other archs.

Cc: Mircea Gherzan 
Cc: Matt Evans 
Cc: Eric Dumazet 
Cc: David S. Miller 
Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller