| Age | Commit message (Collapse) | Author |
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Add jited_len to struct bpf_prog. It will be
useful for the struct bpf_prog_info which will
be added in the later patch.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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free up BPF_JMP | BPF_CALL | BPF_X opcode to be used by actual
indirect call by register and use kernel internal opcode to
mark call instruction into bpf_tail_call() helper.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Highlights include:
- Support for direct mapped LPC on POWER9, giving Linux direct access
to devices that may be on there such as a UART.
- Memory hotplug support for the Power9 Radix MMU.
- Add new AUX vectors describing the processor's cache geometry, to
be used by glibc.
- The ability for a guest to ask the hypervisor to resize the guest's
hash table, and in addition support for doing so automatically when
memory is hotplugged into/out-of the guest. This allows the hash
table to be sized based on the current memory usage of the guest,
rather than the maximum possible memory usage.
- Implementation of optprobes (kprobe optimisation) for powerpc.
In addition there's the topic branch shared with the KVM tree, which
includes support for guests to use the Radix MMU on Power9.
Thanks to:
Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju T, Anton
Blanchard, Benjamin Herrenschmidt, Chris Packham, Daniel Axtens,
Daniel Borkmann, David Gibson, Finn Thain, Gautham R. Shenoy, Gavin
Shan, Greg Kurz, Joel Stanley, John Allen, Madhavan Srinivasan,
Mahesh Salgaonkar, Markus Elfring, Michael Neuling, Nathan Fontenot,
Naveen N. Rao, Nicholas Piggin, Paul Mackerras, Ravi Bangoria, Reza
Arbab, Shailendra Singh, Vaibhav Jain, Wei Yongjun"
* tag 'powerpc-4.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (129 commits)
powerpc/mm/radix: Skip ptesync in pte update helpers
powerpc/mm/radix: Use ptep_get_and_clear_full when clearing pte for full mm
powerpc/mm/radix: Update pte update sequence for pte clear case
powerpc/mm: Update PROTFAULT handling in the page fault path
powerpc/xmon: Fix data-breakpoint
powerpc/mm: Fix build break with BOOK3S_64=n and MEMORY_HOTPLUG=y
powerpc/mm: Fix build break when CMA=n && SPAPR_TCE_IOMMU=y
powerpc/mm: Fix build break with RADIX=y & HUGETLBFS=n
powerpc/pseries: Fix typo in parameter description
powerpc/kprobes: Remove kprobe_exceptions_notify()
kprobes: Introduce weak variant of kprobe_exceptions_notify()
powerpc/ftrace: Fix confusing help text for DISABLE_MPROFILE_KERNEL
powerpc/powernv: Fix opal_exit tracepoint opcode
powerpc: Add a prototype for mcount() so it can be versioned
powerpc: Drop GPL from of_node_to_nid() export to match other arches
powerpc/kprobes: Optimize kprobe in kretprobe_trampoline()
powerpc/kprobes: Implement Optprobes
powerpc/kprobes: Fixes for kprobe_lookup_name() on BE
powerpc: Add helper to check if offset is within relative branch range
powerpc/bpf: Introduce __PPC_SH64()
...
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Long standing issue with JITed programs is that stack traces from
function tracing check whether a given address is kernel code
through {__,}kernel_text_address(), which checks for code in core
kernel, modules and dynamically allocated ftrace trampolines. But
what is still missing is BPF JITed programs (interpreted programs
are not an issue as __bpf_prog_run() will be attributed to them),
thus when a stack trace is triggered, the code walking the stack
won't see any of the JITed ones. The same for address correlation
done from user space via reading /proc/kallsyms. This is read by
tools like perf, but the latter is also useful for permanent live
tracing with eBPF itself in combination with stack maps when other
eBPF types are part of the callchain. See offwaketime example on
dumping stack from a map.
This work tries to tackle that issue by making the addresses and
symbols known to the kernel. The lookup from *kernel_text_address()
is implemented through a latched RB tree that can be read under
RCU in fast-path that is also shared for symbol/size/offset lookup
for a specific given address in kallsyms. The slow-path iteration
through all symbols in the seq file done via RCU list, which holds
a tiny fraction of all exported ksyms, usually below 0.1 percent.
Function symbols are exported as bpf_prog_<tag>, in order to aide
debugging and attribution. This facility is currently enabled for
root-only when bpf_jit_kallsyms is set to 1, and disabled if hardening
is active in any mode. The rationale behind this is that still a lot
of systems ship with world read permissions on kallsyms thus addresses
should not get suddenly exposed for them. If that situation gets
much better in future, we always have the option to change the
default on this. Likewise, unprivileged programs are not allowed
to add entries there either, but that is less of a concern as most
such programs types relevant in this context are for root-only anyway.
If enabled, call graphs and stack traces will then show a correct
attribution; one example is illustrated below, where the trace is
now visible in tooling such as perf script --kallsyms=/proc/kallsyms
and friends.
Before:
7fff8166889d bpf_clone_redirect+0x80007f0020ed (/lib/modules/4.9.0-rc8+/build/vmlinux)
f5d80 __sendmsg_nocancel+0xffff006451f1a007 (/usr/lib64/libc-2.18.so)
After:
7fff816688b7 bpf_clone_redirect+0x80007f002107 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fffa0575728 bpf_prog_33c45a467c9e061a+0x8000600020fb (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fffa07ef1fc cls_bpf_classify+0x8000600020dc (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff81678b68 tc_classify+0x80007f002078 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff8164d40b __netif_receive_skb_core+0x80007f0025fb (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff8164d718 __netif_receive_skb+0x80007f002018 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff8164e565 process_backlog+0x80007f002095 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff8164dc71 net_rx_action+0x80007f002231 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff81767461 __softirqentry_text_start+0x80007f0020d1 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff817658ac do_softirq_own_stack+0x80007f00201c (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff810a2c20 do_softirq+0x80007f002050 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff810a2cb5 __local_bh_enable_ip+0x80007f002085 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff8168d452 ip_finish_output2+0x80007f002152 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff8168ea3d ip_finish_output+0x80007f00217d (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff8168f2af ip_output+0x80007f00203f (/lib/modules/4.9.0-rc8+/build/vmlinux)
[...]
7fff81005854 do_syscall_64+0x80007f002054 (/lib/modules/4.9.0-rc8+/build/vmlinux)
7fff817649eb return_from_SYSCALL_64+0x80007f002000 (/lib/modules/4.9.0-rc8+/build/vmlinux)
f5d80 __sendmsg_nocancel+0xffff01c484812007 (/usr/lib64/libc-2.18.so)
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
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Remove the dummy bpf_jit_compile() stubs for eBPF JITs and make
that a single __weak function in the core that can be overridden
similarly to the eBPF one. Also remove stale pr_err() mentions
of bpf_jit_compile.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Introduce __PPC_SH64() as a 64-bit variant to encode shift field in some
of the shift and rotate instructions operating on double-words. Convert
some of the BPF instruction macros to use the same.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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With bpf_jit_binary_alloc(), we allocate at a page granularity and fill
the rest of the space with illegal instructions to mitigate BPF spraying
attacks, while having the actual JIT'ed BPF program at a random location
within the allocated space. Under this scenario, it would be better to
flush the entire allocated buffer rather than just the part containing
the actual program. We already flush the buffer from start to the end of
the BPF program. Extend this to include the illegal instructions after
the BPF program.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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We have a check earlier to ensure we don't proceed if image is NULL. As
such, the redundant check can be removed.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
[Added similar changes for classic BPF JIT]
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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This patch allows XDP prog to extend/remove the packet
data at the head (like adding or removing header). It is
done by adding a new XDP helper bpf_xdp_adjust_head().
It also renames bpf_helper_changes_skb_data() to
bpf_helper_changes_pkt_data() to better reflect
that XDP prog does not work on skb.
This patch adds one "xdp_adjust_head" bit to bpf_prog for the
XDP-capable driver to check if the XDP prog requires
bpf_xdp_adjust_head() support. The driver can then decide
to error out during XDP_SETUP_PROG.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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In line with similar support for other architectures by Daniel Borkmann.
'MOD Default X' from test_bpf without constant blinding:
84 bytes emitted from JIT compiler (pass:3, flen:7)
d0000000058a4688 + <x>:
0: nop
4: nop
8: std r27,-40(r1)
c: std r28,-32(r1)
10: xor r8,r8,r8
14: xor r28,r28,r28
18: mr r27,r3
1c: li r8,66
20: cmpwi r28,0
24: bne 0x0000000000000030
28: li r8,0
2c: b 0x0000000000000044
30: divwu r9,r8,r28
34: mullw r9,r28,r9
38: subf r8,r9,r8
3c: rotlwi r8,r8,0
40: li r8,66
44: ld r27,-40(r1)
48: ld r28,-32(r1)
4c: mr r3,r8
50: blr
... and with constant blinding:
140 bytes emitted from JIT compiler (pass:3, flen:11)
d00000000bd6ab24 + <x>:
0: nop
4: nop
8: std r27,-40(r1)
c: std r28,-32(r1)
10: xor r8,r8,r8
14: xor r28,r28,r28
18: mr r27,r3
1c: lis r2,-22834
20: ori r2,r2,36083
24: rotlwi r2,r2,0
28: xori r2,r2,36017
2c: xoris r2,r2,42702
30: rotlwi r2,r2,0
34: mr r8,r2
38: rotlwi r8,r8,0
3c: cmpwi r28,0
40: bne 0x000000000000004c
44: li r8,0
48: b 0x000000000000007c
4c: divwu r9,r8,r28
50: mullw r9,r28,r9
54: subf r8,r9,r8
58: rotlwi r8,r8,0
5c: lis r2,-17137
60: ori r2,r2,39065
64: rotlwi r2,r2,0
68: xori r2,r2,39131
6c: xoris r2,r2,48399
70: rotlwi r2,r2,0
74: mr r8,r2
78: rotlwi r8,r8,0
7c: ld r27,-40(r1)
80: ld r28,-32(r1)
84: mr r3,r8
88: blr
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Tail calls allow JIT'ed eBPF programs to call into other JIT'ed eBPF
programs. This can be achieved either by:
(1) retaining the stack setup by the first eBPF program and having all
subsequent eBPF programs re-using it, or,
(2) by unwinding/tearing down the stack and having each eBPF program
deal with its own stack as it sees fit.
To ensure that this does not create loops, there is a limit to how many
tail calls can be done (currently 32). This requires the JIT'ed code to
maintain a count of the number of tail calls done so far.
Approach (1) is simple, but requires every eBPF program to have (almost)
the same prologue/epilogue, regardless of whether they need it. This is
inefficient for small eBPF programs which may not sometimes need a
prologue at all. As such, to minimize impact of tail call
implementation, we use approach (2) here which needs each eBPF program
in the chain to use its own prologue/epilogue. This is not ideal when
many tail calls are involved and when all the eBPF programs in the chain
have similar prologue/epilogue. However, the impact is restricted to
programs that do tail calls. Individual eBPF programs are not affected.
We maintain the tail call count in a fixed location on the stack and
updated tail call count values are passed in through this. The very
first eBPF program in a chain sets this up to 0 (the first 2
instructions). Subsequent tail calls skip the first two eBPF JIT
instructions to maintain the count. For programs that don't do tail
calls themselves, the first two instructions are NOPs.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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While at it, ensure that the location of the local save area is
consistent whether or not we setup our own stackframe. This property is
utilised in the next patch that adds support for tail calls.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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PPC64 eBPF JIT compiler.
Enable with:
echo 1 > /proc/sys/net/core/bpf_jit_enable
or
echo 2 > /proc/sys/net/core/bpf_jit_enable
... to see the generated JIT code. This can further be processed with
tools/net/bpf_jit_disasm.
With CONFIG_TEST_BPF=m and 'modprobe test_bpf':
test_bpf: Summary: 305 PASSED, 0 FAILED, [297/297 JIT'ed]
... on both ppc64 BE and LE.
The details of the approach are documented through various comments in
the code.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Break out classic BPF JIT specifics into a separate header in
preparation for eBPF JIT implementation. Note that ppc32 will still need
the classic BPF JIT.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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1. Per the ISA, ADDIS actually uses RT, rather than RS. Though
the result is the same, make the usage clear.
2. The multiply instruction used is a 32-bit multiply. Rename PPC_MUL()
to PPC_MULW() to make the same clear.
3. PPC_STW[U] take the entire 16-bit immediate value and do not require
word-alignment, per the ISA. Change the macros to use IMM_L().
4. A few white-space cleanups to satisfy checkpatch.pl.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Since we will be using the rotate immediate instructions for extended
BPF JIT, let's introduce macros for the same. And since the shift
immediate operations use the rotate immediate instructions, let's redo
those macros to use the newly introduced instructions.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Similar to the LI32() optimization, if the value can be represented
in 32-bits, use LI32(). Also handle loading a few specific forms of
immediate values in an optimum manner.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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The existing LI32() macro can sometimes result in a sign-extended 32-bit
load that does not clear the top 32-bits properly. As an example,
loading 0x7fffffff results in the register containing
0xffffffff7fffffff. While this does not impact classic BPF JIT
implementation (since that only uses the lower word for all operations),
we would like to share this macro between classic BPF JIT and extended
BPF JIT, wherein the entire 64-bit value in the register matters. Fix
this by first doing a shifted LI followed by ORI.
An additional optimization is with loading values between -32768 to -1,
where we now only need a single LI.
The new implementation now generates the same or less number of
instructions.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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The SKF_AD_ALU_XOR_X ancillary is not like the other ancillary data
instructions since it XORs A with X while all the others replace A with
some loaded value. All the BPF JITs fail to clear A if this is used as
the first instruction in a filter. This was found using american fuzzy
lop.
Add a helper to determine if A needs to be cleared given the first
instruction in a filter, and use this in the JITs. Except for ARM, the
rest have only been compile-tested.
Fixes: 3480593131e0 ("net: filter: get rid of BPF_S_* enum")
Signed-off-by: Rabin Vincent <rabin@rab.in>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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As we need to add further flags to the bpf_prog structure, lets migrate
both bools to a bitfield representation. The size of the base structure
(excluding insns) remains unchanged at 40 bytes.
Add also tags for the kmemchecker, so that it doesn't throw false
positives. Even in case gcc would generate suboptimal code, it's not
being accessed in performance critical paths.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Use helpers from the asm-compat.h to wrap up assembly mnemonics
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Nothing needs the module pointer any more, and the next patch will
call it from RCU, where the module itself might no longer exist.
Removing the arg is the safest approach.
This just codifies the use of the module_alloc/module_free pattern
which ftrace and bpf use.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: x86@kernel.org
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: linux-cris-kernel@axis.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: nios2-dev@lists.rocketboards.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Cc: netdev@vger.kernel.org
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Reduce duplicated code by unifying
BPF_ALU | BPF_MOD | BPF_X and BPF_ALU | BPF_DIV | BPF_X
CC: Alexei Starovoitov<alexei.starovoitov@gmail.com>
CC: Daniel Borkmann<dborkman@redhat.com>
CC: Philippe Bergheaud<felix@linux.vnet.ibm.com>
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add BPF extension SKF_AD_HATYPE to ppc JIT to check
the hw type of the interface
Before:
[ 57.723666] test_bpf: #20 LD_HATYPE
[ 57.723675] BPF filter opcode 0020 (@0) unsupported
[ 57.724168] 48 48 PASS
After:
[ 103.053184] test_bpf: #20 LD_HATYPE 7 6 PASS
CC: Alexei Starovoitov<alexei.starovoitov@gmail.com>
CC: Daniel Borkmann<dborkman@redhat.com>
CC: Philippe Bergheaud<felix@linux.vnet.ibm.com>
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
v2: address Alexei's comments
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add BPF extension SKF_AD_PKTTYPE to ppc JIT to load
skb->pkt_type field.
Before:
[ 88.262622] test_bpf: #11 LD_IND_NET 86 97 99 PASS
[ 88.265740] test_bpf: #12 LD_PKTTYPE 109 107 PASS
After:
[ 80.605964] test_bpf: #11 LD_IND_NET 44 40 39 PASS
[ 80.607370] test_bpf: #12 LD_PKTTYPE 9 9 PASS
CC: Alexei Starovoitov<alexei.starovoitov@gmail.com>
CC: Michael Ellerman<mpe@ellerman.id.au>
Cc: Matt Evans <matt@ozlabs.org>
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
v2: Added test rusults
Signed-off-by: David S. Miller <davem@davemloft.net>
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Reported by Mikulas Patocka, kmemcheck currently barks out a
false positive since we don't have special kmemcheck annotation
for bitfields used in bpf_prog structure.
We currently have jited:1, len:31 and thus when accessing len
while CONFIG_KMEMCHECK enabled, kmemcheck throws a warning that
we're reading uninitialized memory.
As we don't need the whole bit universe for pages member, we
can just split it to u16 and use a bool flag for jited instead
of a bitfield.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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With eBPF getting more extended and exposure to user space is on it's way,
hardening the memory range the interpreter uses to steer its command flow
seems appropriate. This patch moves the to be interpreted bytecode to
read-only pages.
In case we execute a corrupted BPF interpreter image for some reason e.g.
caused by an attacker which got past a verifier stage, it would not only
provide arbitrary read/write memory access but arbitrary function calls
as well. After setting up the BPF interpreter image, its contents do not
change until destruction time, thus we can setup the image on immutable
made pages in order to mitigate modifications to that code. The idea
is derived from commit 314beb9bcabf ("x86: bpf_jit_comp: secure bpf jit
against spraying attacks").
This is possible because bpf_prog is not part of sk_filter anymore.
After setup bpf_prog cannot be altered during its life-time. This prevents
any modifications to the entire bpf_prog structure (incl. function/JIT
image pointer).
Every eBPF program (including classic BPF that are migrated) have to call
bpf_prog_select_runtime() to select either interpreter or a JIT image
as a last setup step, and they all are being freed via bpf_prog_free(),
including non-JIT. Therefore, we can easily integrate this into the
eBPF life-time, plus since we directly allocate a bpf_prog, we have no
performance penalty.
Tested with seccomp and test_bpf testsuite in JIT/non-JIT mode and manual
inspection of kernel_page_tables. Brad Spengler proposed the same idea
via Twitter during development of this patch.
Joint work with Hannes Frederic Sowa.
Suggested-by: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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We have to return the boolean here if the tag presents
or not, not just ANDing the TCI with the mask which results to:
[ 709.412097] test_bpf: #18 LD_VLAN_TAG_PRESENT
[ 709.412245] ret 4096 != 1
[ 709.412332] ret 4096 != 1
[ 709.412333] FAIL (2 times)
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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To get a full tag (and not just a VID) we should access the TCI
except the VLAN_TAG_PRESENT field (which means that 802.1q header
is present). Also ensure that the VLAN_TAG_PRESENT stay on its place
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <dborkman@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mircea Gherzan <mgherzan@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Chema Gonzalez <chemag@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <ast@plumgrid.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <therbert@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <edumazet@google.com>
Reported-by: Jakub Zawadzki <darkjames-ws@darkjames.pl>
Cc: Mircea Gherzan <mgherzan@gmail.com>
Cc: Daniel Borkmann <dxchgb@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Matt Evans <matt@ozlabs.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
Pull powerpc updates from Benjamin Herrenschmidt:
"The bulk of this is LE updates. One should now be able to build an LE
kernel and even run some things in it.
I'm still sitting on a handful of patches to enable the new ABI that I
*might* still send this merge window around, but due to the
incertainty (they are pretty fresh) I want to keep them separate.
Other notable changes are some infrastructure bits to better handle
PCI pass-through under KVM, some bits and pieces added to the new
PowerNV platform support such as access to the CPU SCOM bus via sysfs,
and support for EEH error handling on PHB3 (Power8 PCIe).
We also grew arch_get_random_long() for both pseries and powernv when
running on P7+ and P8, exploiting the HW rng.
And finally various embedded updates from freescale"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (154 commits)
powerpc: Fix fatal SLB miss when restoring PPR
powerpc/powernv: Reserve the correct PE number
powerpc/powernv: Add PE to its own PELTV
powerpc/powernv: Add support for indirect XSCOM via debugfs
powerpc/scom: Improve debugfs interface
powerpc/scom: Enable 64-bit addresses
powerpc/boot: Properly handle the base "of" boot wrapper
powerpc/bpf: Support MOD operation
powerpc/bpf: Fix DIVWU instruction opcode
of: Move definition of of_find_next_cache_node into common code.
powerpc: Remove big endianness assumption in of_find_next_cache_node
powerpc/tm: Remove interrupt disable in __switch_to()
powerpc: word-at-a-time optimization for 64-bit Little Endian
powerpc/bpf: BPF JIT compiler for 64-bit Little Endian
powerpc: Only save/restore SDR1 if in hypervisor mode
powerpc/pmu: Fix ADB_PMU_LED_IDE dependencies
powerpc/nvram: Fix endian issue when using the partition length
powerpc/nvram: Fix endian issue when reading the NVRAM size
powerpc/nvram: Scan partitions only once
powerpc/mpc512x: remove unnecessary #if
...
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commit b6069a9570 (filter: add MOD operation) added generic
support for modulus operation in BPF.
This patch brings JIT support for PPC64
Signed-off-by: Vladimir Murzin <murzin.v@gmail.com>
Acked-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This enables the Berkeley Packet Filter JIT compiler
for the PowerPC running in 64bit Little Endian.
Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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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] <Interrupt>
[ 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: [<ffffffff8118f44c>] 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] [<ffffffff8175a145>] dump_stack+0x55/0x76
[ 56.936067] [<ffffffff81755b14>] print_usage_bug+0x1f7/0x208
[ 56.942445] [<ffffffff8101178f>] ? save_stack_trace+0x2f/0x50
[ 56.948932] [<ffffffff810cc0a0>] ? check_usage_backwards+0x150/0x150
[ 56.955470] [<ffffffff810ccb52>] mark_lock+0x282/0x2c0
[ 56.961945] [<ffffffff810ccfed>] __lock_acquire+0x45d/0x1d50
[ 56.968474] [<ffffffff810cce6e>] ? __lock_acquire+0x2de/0x1d50
[ 56.975140] [<ffffffff81393bf5>] ? cpumask_next_and+0x55/0x90
[ 56.981942] [<ffffffff810cef72>] lock_acquire+0x92/0x1d0
[ 56.988745] [<ffffffff8118f52a>] ? vm_unmap_aliases+0x16a/0x380
[ 56.995619] [<ffffffff817628f1>] _raw_spin_lock+0x41/0x50
[ 57.002493] [<ffffffff8118f52a>] ? vm_unmap_aliases+0x16a/0x380
[ 57.009447] [<ffffffff8118f52a>] vm_unmap_aliases+0x16a/0x380
[ 57.016477] [<ffffffff8118f44c>] ? vm_unmap_aliases+0x8c/0x380
[ 57.023607] [<ffffffff810436b0>] change_page_attr_set_clr+0xc0/0x460
[ 57.030818] [<ffffffff810cfb8d>] ? trace_hardirqs_on+0xd/0x10
[ 57.037896] [<ffffffff811a8330>] ? kmem_cache_free+0xb0/0x2b0
[ 57.044789] [<ffffffff811b59c3>] ? free_object_rcu+0x93/0xa0
[ 57.051720] [<ffffffff81043d9f>] set_memory_rw+0x2f/0x40
[ 57.058727] [<ffffffff8104e17c>] bpf_jit_free+0x2c/0x40
[ 57.065577] [<ffffffff81642cba>] sk_filter_release_rcu+0x1a/0x30
[ 57.072338] [<ffffffff811108e2>] rcu_process_callbacks+0x202/0x7c0
[ 57.078962] [<ffffffff81057f17>] __do_softirq+0xf7/0x3f0
[ 57.085373] [<ffffffff81058245>] 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 <ast@plumgrid.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <dborkman@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matt Evans <matt@ozlabs.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <mgherzan@gmail.com>
Cc: Matt Evans <matt@ozlabs.org>
Cc: Eric Dumazet <eric.dumazet@google.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <daniel.borkmann@tik.ee.ethz.ch>
Cc: Matt Evans <matt@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <daniel.borkmann@tik.ee.ethz.ch>
Cc: Matt Evans <matt@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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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 <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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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 <michael@ellerman.id.au>
Acked-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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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 <benh@kernel.crashing.org>
Signed-off-by: Jan Seiffert <kaffeemonster@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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An implementation of a code generator for BPF programs to speed up packet
filtering on PPC64, inspired by Eric Dumazet's x86-64 version.
Filter code is generated as an ABI-compliant function in module_alloc()'d mem
with stackframe & prologue/epilogue generated if required (simple filters don't
need anything more than an li/blr). The filter's local variables, M[], live in
registers. Supports all BPF opcodes, although "complicated" loads from negative
packet offsets (e.g. SKF_LL_OFF) are not yet supported.
There are a couple of further optimisations left for future work; many-pass
assembly with branch-reach reduction and a register allocator to push M[]
variables into volatile registers would improve the code quality further.
This currently supports big-endian 64-bit PowerPC only (but is fairly simple
to port to PPC32 or LE!).
Enabled in the same way as x86-64:
echo 1 > /proc/sys/net/core/bpf_jit_enable
Or, enabled with extra debug output:
echo 2 > /proc/sys/net/core/bpf_jit_enable
Signed-off-by: Matt Evans <matt@ozlabs.org>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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