linux-stable.git/arch/mips/net, branch v4.3

MIPS: BPF: Fix load delay slots.

2015-10-02T07:48:57+00:00

The entire bpf_jit_asm.S is written in noreorder mode because "we know
better" according to a comment.  This also prevented the assembler from
throwing in the required NOPs for MIPS I processors which have no
load-use interlock, thus the load's consumer might end up using the
old value of the register from prior to the load.

Fixed by putting the assembler in reorder mode for just the affected
load instructions.  This is not enough for gas to actually try to be
clever by looking at the next instruction and inserting a nop only
when needed but as the comment said "we know better", so getting gas
to unconditionally emit a NOP is just right in this case and prevents
adding further ifdefery.

Signed-off-by: Ralf Baechle

MIPS: BPF: Do all exports of symbols with FEXPORT().

2015-10-01T13:45:44+00:00

FEXPORT also marks the symbol as code using .type symbol, @function.
Without objdump -d will output only a hexdump for code following the
affected symbols.

Signed-off-by: Ralf Baechle

MIPS: BPF: Fix build on pre-R2 little endian CPUs

2015-09-22T17:05:17+00:00

The rotr, seh and wsbh instructions have been introduced with the R2
ISA. Thus the current BPF code fails to build on pre-R2 little endian
CPUs:

    CC      arch/mips/net/bpf_jit.o
    AS      arch/mips/net/bpf_jit_asm.o
  /home/aurel32/linux-4.2/arch/mips/net/bpf_jit_asm.S: Assembler messages:
  /home/aurel32/linux-4.2/arch/mips/net/bpf_jit_asm.S:67: Error: opcode not supported on this processor: mips32 (mips32) `wsbh $8,$19'
  /home/aurel32/linux-4.2/arch/mips/net/bpf_jit_asm.S:68: Error: opcode not supported on this processor: mips32 (mips32) `rotr $19,$8,16'
  /home/aurel32/linux-4.2/arch/mips/net/bpf_jit_asm.S:83: Error: opcode not supported on this processor: mips32 (mips32) `wsbh $8,$19'
  /home/aurel32/linux-4.2/arch/mips/net/bpf_jit_asm.S:84: Error: opcode not supported on this processor: mips32 (mips32) `seh $19,$8'
  /home/aurel32/linux-4.2/arch/mips/net/bpf_jit_asm.S:151: Error: opcode not supported on this processor: mips32 (mips32) `wsbh $8,$12'
  /home/aurel32/linux-4.2/arch/mips/net/bpf_jit_asm.S:153: Error: opcode not supported on this processor: mips32 (mips32) `rotr $19,$8,16'
  /home/aurel32/linux-4.2/arch/mips/net/bpf_jit_asm.S:164: Error: opcode not supported on this processor: mips32 (mips32) `wsbh $19,$12'
  /home/aurel32/linux-4.2/scripts/Makefile.build:294: recipe for target 'arch/mips/net/bpf_jit_asm.o' failed

Fix that by providing equivalent code for these CPUs.

Signed-off-by: Aurelien Jarno 
Reviewed-by: Markos Chandras 
Cc: stable@vger.kernel.org # v4.2+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11098/
Signed-off-by: Ralf Baechle

MIPS: BPF: Avoid unreachable code on little endian

2015-09-22T17:05:17+00:00

On little endian, avoid generating the big endian version of the code
by using #else in addition to #ifdef #endif. Also fix one alignment
issue wrt delay slot.

Signed-off-by: Aurelien Jarno 
Reviewed-by: Markos Chandras 
Cc: stable@vger.kernel.org # v4.2+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11097/
Signed-off-by: Ralf Baechle

MIPS: BPF: Introduce BPF ASM helpers

2015-06-21T19:54:25+00:00

This commit introduces BPF ASM helpers for MIPS and MIPS64 kernels.
The purpose of this patch is to twofold:

1) We are now able to handle negative offsets instead of either
falling back to the interpreter or to simply not do anything and
bail out.

2) Optimize reads from the packet header instead of calling the C
helpers

Because of this patch, we are now able to get rid of quite a bit of
code in the JIT generation process by using MIPS optimized assembly
code. The new assembly code makes the test_bpf testsuite happy with
all 60 test passing successfully compared to the previous
implementation where 2 tests were failing.
Doing some basic analysis in the results between the old
implementation and the new one we can obtain the following
summary running current mainline on an ER8 board (+/- 30us delta is
ignored to prevent noise from kernel scheduling or IRQ latencies):

Summary: 22 tests are faster, 7 are slower and 47 saw no improvement

with the most notable improvement being the tcpdump tests. The 7 tests
that seem to be a bit slower is because they all follow the slow path
(bpf_internal_load_pointer_neg_helper) which is meant to be slow so
that's not a problem.

Signed-off-by: Markos Chandras 
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Hannes Frederic Sowa 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: netdev@vger.kernel.org
Patchwork: http://patchwork.linux-mips.org/patch/10530/
Signed-off-by: Ralf Baechle

MIPS: BPF: Use BPF register names to describe the ABI

2015-06-21T19:54:24+00:00

Use the BPF register names instead of the arch register names to
document how the ABI is structured.

Signed-off-by: Markos Chandras 
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Hannes Frederic Sowa 
Cc: linux-kernel@vger.kernel.org
Patchwork: http://patchwork.linux-mips.org/patch/10529/
Signed-off-by: Ralf Baechle

MIPS: BPF: Move register definition to the BPF header

2015-06-21T19:54:24+00:00

The registers will be used by a subsequent patch introducing
ASM helpers so move them to a common header.

Signed-off-by: Markos Chandras 
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Hannes Frederic Sowa 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/10528/
Signed-off-by: Ralf Baechle

MIPS: net: BPF: Replace RSIZE with SZREG

2015-06-21T19:54:23+00:00

The RSZIE was used to determine the register width but MIPS
already defines SZREG so use that instead.

Cc: netdev@vger.kernel.org
Cc: "David S. Miller" 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Hannes Frederic Sowa 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: netdev@vger.kernel.org
Patchwork: http://patchwork.linux-mips.org/patch/10526/
Signed-off-by: Markos Chandras 
Signed-off-by: Ralf Baechle

MIPS: BPF: Free up some callee-saved registers

2015-06-21T19:54:22+00:00

Move the two scratch registers from s0 and s1 to t4 and t5 in order
to free up some callee-saved registers. We will use these callee-saved
registers to store some permanent data on them in a subsequent patch.

Signed-off-by: Markos Chandras 
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Hannes Frederic Sowa 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/10525/
Signed-off-by: Ralf Baechle

MIPS: BPF: Fix stack pointer allocation

2015-06-06T08:21:10+00:00

Fix stack pointer offset which could potentially corrupt
argument registers in the previous frame. The calculated offset
reflects the size of all the registers we need to preserve so there
is no need for this erroneous subtraction.

[ralf@linux-mips.org: Fixed conflict due to only applying this fix part
of the entire series as part of 4.1 fixes.]

Signed-off-by: Markos Chandras 
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Hannes Frederic Sowa 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/10527/
Signed-off-by: Ralf Baechle