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linux-kernel-test/net/core
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Eric Dumazet 0a14842f5a net: filter: Just In Time compiler for x86-64 
In order to speedup packet filtering, here is an implementation of a
JIT compiler for x86_64

It is disabled by default, and must be enabled by the admin.

echo 1 >/proc/sys/net/core/bpf_jit_enable

It uses module_alloc() and module_free() to get memory in the 2GB text
kernel range since we call helpers functions from the generated code.

EAX : BPF A accumulator
EBX : BPF X accumulator
RDI : pointer to skb   (first argument given to JIT function)
RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
r9d : skb->len - skb->data_len (headlen)
r8  : skb->data

To get a trace of generated code, use :

echo 2 >/proc/sys/net/core/bpf_jit_enable

Example of generated code :

# tcpdump -p -n -s 0 -i eth1 host 192.168.20.0/24

flen=18 proglen=147 pass=3 image=ffffffffa00b5000
JIT code: ffffffffa00b5000: 55 48 89 e5 48 83 ec 60 48 89 5d f8 44 8b 4f 60
JIT code: ffffffffa00b5010: 44 2b 4f 64 4c 8b 87 b8 00 00 00 be 0c 00 00 00
JIT code: ffffffffa00b5020: e8 24 7b f7 e0 3d 00 08 00 00 75 28 be 1a 00 00
JIT code: ffffffffa00b5030: 00 e8 fe 7a f7 e0 24 00 3d 00 14 a8 c0 74 49 be
JIT code: ffffffffa00b5040: 1e 00 00 00 e8 eb 7a f7 e0 24 00 3d 00 14 a8 c0
JIT code: ffffffffa00b5050: 74 36 eb 3b 3d 06 08 00 00 74 07 3d 35 80 00 00
JIT code: ffffffffa00b5060: 75 2d be 1c 00 00 00 e8 c8 7a f7 e0 24 00 3d 00
JIT code: ffffffffa00b5070: 14 a8 c0 74 13 be 26 00 00 00 e8 b5 7a f7 e0 24
JIT code: ffffffffa00b5080: 00 3d 00 14 a8 c0 75 07 b8 ff ff 00 00 eb 02 31
JIT code: ffffffffa00b5090: c0 c9 c3

BPF program is 144 bytes long, so native program is almost same size ;)

(000) ldh      [12]
(001) jeq      #0x800           jt 2    jf 8
(002) ld       [26]
(003) and      #0xffffff00
(004) jeq      #0xc0a81400      jt 16   jf 5
(005) ld       [30]
(006) and      #0xffffff00
(007) jeq      #0xc0a81400      jt 16   jf 17
(008) jeq      #0x806           jt 10   jf 9
(009) jeq      #0x8035          jt 10   jf 17
(010) ld       [28]
(011) and      #0xffffff00
(012) jeq      #0xc0a81400      jt 16   jf 13
(013) ld       [38]
(014) and      #0xffffff00
(015) jeq      #0xc0a81400      jt 16   jf 17
(016) ret      #65535
(017) ret      #0

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-04-27 23:05:08 -07:00
..
datagram.c Fix a typo in datagram.c and sctp/socket.c. 2010-12-06 13:10:11 -08:00
dev_addr_lists.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-03-18 10:37:40 -07:00
dev.c bonding: move processing of recv handlers into handle_frame() 2011-04-25 12:00:30 -07:00
drop_monitor.c net: fix incorrect spelling in drop monitor protocol 2011-03-21 18:20:26 -07:00
dst.c net: Add initial_ref arg to dst_alloc(). 2011-02-17 15:44:00 -08:00
ethtool.c net: fix hw_features ethtool_ops->set_flags compatibility 2011-04-21 17:21:43 -07:00
fib_rules.c net: Put flowi_* prefix on AF independent members of struct flowi 2011-03-12 15:08:44 -08:00
filter.c net: filter: Just In Time compiler for x86-64 2011-04-27 23:05:08 -07:00
flow.c net: Make flow cache paths use a const struct flowi. 2011-02-22 18:44:31 -08:00
gen_estimator.c pkt_sched: remov unnecessary bh_disable 2010-09-10 12:47:59 -07:00
gen_stats.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
iovec.c net: Limit socket I/O iovec total length to INT_MAX. 2010-10-28 11:47:52 -07:00
kmap_skb.h
link_watch.c Fix common misspellings 2011-03-31 11:26:23 -03:00
Makefile net: support time stamping in phy devices. 2010-07-18 19:15:26 -07:00
neighbour.c neigh: __rcu annotations 2011-01-20 16:59:34 -08:00
net_namespace.c net: minor cleanup to net_namespace.c. 2011-04-15 15:47:51 -07:00
net-sysfs.c net: rename group sysfs entry to netdev_group 2011-02-09 19:16:15 -08:00
net-sysfs.h xps: Add CONFIG_XPS 2010-11-28 18:24:14 -08:00
net-traces.c netdev: Add tracepoints to netdev layer 2010-09-07 17:51:33 +02:00
netevent.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
netpoll.c inet: constify ip headers and in6_addr 2011-04-22 11:04:14 -07:00
pktgen.c pktgen: Fix set-but-unused variable. 2011-04-17 00:13:16 -07:00
request_sock.c Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-12-08 13:47:38 -08:00
rtnetlink.c Fix common misspellings 2011-03-31 11:26:23 -03:00
scm.c Allow passing O_PATH descriptors via SCM_RIGHTS datagrams 2011-03-15 02:21:45 -04:00
skbuff.c Fix common misspellings 2011-03-31 11:26:23 -03:00
sock.c Fix common misspellings 2011-03-31 11:26:23 -03:00
stream.c net: Fix the condition passed to sk_wait_event() 2010-10-03 20:41:32 -07:00
sysctl_net_core.c net: filter: Just In Time compiler for x86-64 2011-04-27 23:05:08 -07:00
timestamping.c Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-12-17 12:27:22 -08:00
user_dma.c net/core/user_dma.c: Use frag list abstraction interfaces. 2009-06-09 00:19:10 -07:00
utils.c net: return operator cleanup 2010-09-23 14:33:39 -07:00