linux.git/arch/powerpc/net, branch v3.12.45

bpf: do not use reciprocal divide

2014-02-06T19:22:20+00:00

[ Upstream commit aee636c4809fa54848ff07a899b326eb1f9987a2 ]

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 
Signed-off-by: Greg Kroah-Hartman

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

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

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

Followup patch on module_free()/vfree() that takes care of the rest, so
no longer this workaround with work_struct is needed.

Signed-off-by: Daniel Borkmann 
Cc: Al Viro 
Cc: Matt Evans 
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

PPC: net: bpf_jit_comp: add VLAN instructions for BPF JIT

2012-11-18T03:12:47+00:00

This patch is a follow-up for patch "net: filter: add vlan tag access"
to support the new VLAN_TAG/VLAN_TAG_PRESENT accessors in BPF JIT.

Signed-off-by: Daniel Borkmann 
Cc: Matt Evans 
Cc: Benjamin Herrenschmidt 
Acked-by: Matt Evans 
Signed-off-by: David S. Miller

PPC: net: bpf_jit_comp: add XOR instruction for BPF JIT

2012-11-18T03:12:47+00:00

This patch is a follow-up for patch "filter: add XOR instruction for use
with X/K" that implements BPF PowerPC JIT parts for the BPF XOR operation.

Signed-off-by: Daniel Borkmann 
Cc: Matt Evans 
Cc: Benjamin Herrenschmidt 
Acked-by: Matt Evans 
Signed-off-by: David S. Miller

powerpc: Start using ___PPC_RA/B/S/T where necessary

2012-07-10T09:18:25+00:00

Now have ___PPC_RA/B/S/T we can use it in some places.  These are
places where we can't use the existing defines which will soon enforce
R0-R31 usage.

The macros being changed here are being used in inline asm, which
can't convert to enforce the R0-R31 usage.

bpf_jit uses a mix of both generated and non-generated with the same
code, so just convert all these to use the ___PPC_R versions which
won't enforce R usage later.

Signed-off-by: Michael Neuling 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix usage of register macros getting ready for %r0 change

2012-07-10T09:17:55+00:00

Anything that uses a constructed instruction (ie. from ppc-opcode.h),
need to use the new R0 macro, as %r0 is not going to work.

Also convert usages of macros where we are just determining an offset
(usually for a load/store), like:
	std	r14,STK_REG(r14)(r1)
Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since
it's just calculating an offset.

Signed-off-by: Michael Neuling 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix BPF_JIT code to link with multiple TOCs

2012-06-29T04:35:34+00:00

If the kernel is big enough (eg. allyesconfig), the linker may need to
switch TOCs when calling from the BPF JIT code out to the external
helpers (skb_copy_bits() & bpf_internal_load_pointer_neg_helper()).

In order to do that we need to leave space after the bl for the linker
to insert a reload of our TOC pointer.

Signed-off-by: Michael Ellerman 
Acked-by: Matt Evans 
Signed-off-by: Benjamin Herrenschmidt

bpf jit: Let the powerpc jit handle negative offsets

2012-04-30T17:40:50+00:00

Now the helper function from filter.c for negative offsets is exported,
it can be used it in the jit to handle negative offsets.

First modify the asm load helper functions to handle:
- know positive offsets
- know negative offsets
- any offset

then the compiler can be modified to explicitly use these helper
when appropriate.

This fixes the case of a negative X register and allows to lift
the restriction that bpf programs with negative offsets can't
be jited.

Tested-by: Benjamin Herrenschmidt 
Signed-off-by: Jan Seiffert 
Signed-off-by: David S. Miller