linux.git/arch/mips/net, branch v4.14.124

MIPS: eBPF: Fix icache flush end address

2019-03-05T16:58:03+00:00

commit d1a2930d8a992fb6ac2529449f81a0056e1b98d1 upstream.

The MIPS eBPF JIT calls flush_icache_range() in order to ensure the
icache observes the code that we just wrote. Unfortunately it gets the
end address calculation wrong due to some bad pointer arithmetic.

The struct jit_ctx target field is of type pointer to u32, and as such
adding one to it will increment the address being pointed to by 4 bytes.
Therefore in order to find the address of the end of the code we simply
need to add the number of 4 byte instructions emitted, but we mistakenly
add the number of instructions multiplied by 4. This results in the call
to flush_icache_range() operating on a memory region 4x larger than
intended, which is always wasteful and can cause crashes if we overrun
into an unmapped page.

Fix this by correcting the pointer arithmetic to remove the bogus
multiplication, and use braces to remove the need for a set of brackets
whilst also making it obvious that the target field is a pointer.

Signed-off-by: Paul Burton 
Fixes: b6bd53f9c4e8 ("MIPS: Add missing file for eBPF JIT.")
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Martin KaFai Lau 
Cc: Song Liu 
Cc: Yonghong Song 
Cc: netdev@vger.kernel.org
Cc: bpf@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: Daniel Borkmann 
Signed-off-by: Greg Kroah-Hartman

MIPS: eBPF: Always return sign extended 32b values

2019-02-27T09:08:01+00:00

commit 13443154f6cac61d148471ede6d7f1f6b5ea946a upstream.

The function prototype used to call JITed eBPF code (ie. the type of the
struct bpf_prog bpf_func field) returns an unsigned int. The MIPS n64
ABI that MIPS64 kernels target defines that 32 bit integers should
always be sign extended when passed in registers as either arguments or
return values.

This means that when returning any value which may not already be sign
extended (ie. of type REG_64BIT or REG_32BIT_ZERO_EX) we need to perform
that sign extension in order to comply with the n64 ABI. Without this we
see strange looking test failures from test_bpf.ko, such as:

  test_bpf: #65 ALU64_MOV_X:
    dst = 4294967295 jited:1 ret -1 != -1 FAIL (1 times)

Although the return value printed matches the expected value, this is
only because printf is only examining the least significant 32 bits of
the 64 bit register value we returned. The register holding the expected
value is sign extended whilst the v0 register was set to a zero extended
value by our JITed code, so when compared by a conditional branch
instruction the values are not equal.

We already handle this when the return value register is of type
REG_32BIT_ZERO_EX, so simply extend this to also cover REG_64BIT.

Signed-off-by: Paul Burton 
Fixes: b6bd53f9c4e8 ("MIPS: Add missing file for eBPF JIT.")
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: Daniel Borkmann 
Signed-off-by: Greg Kroah-Hartman

MIPS: bpf: Fix a typo in build_one_insn()

2017-11-01T00:09:17+00:00

Fix a typo in build_one_insn().

Fixes: b6bd53f9c4e8 ("MIPS: Add missing file for eBPF JIT.")
Signed-off-by: Wei Yongjun 
Cc:  # 4.13+
Patchwork: https://patchwork.linux-mips.org/patch/17491/
Signed-off-by: James Hogan

MIPS: bpf: Fix uninitialised target compiler error

2017-10-09T12:53:38+00:00

Compiling ebpf_jit.c with gcc 4.9 results in a (likely spurious)
compiler warning, as gcc has detected that the variable "target" may be
used uninitialised. Since -Werror is active, this is treated as an error
and causes a kernel build failure whenever CONFIG_MIPS_EBPF_JIT is
enabled.

arch/mips/net/ebpf_jit.c: In function 'build_one_insn':
arch/mips/net/ebpf_jit.c:1118:80: error: 'target' may be used
uninitialized in this function [-Werror=maybe-uninitialized]
    emit_instr(ctx, j, target);
                                                                                ^
cc1: all warnings being treated as errors

Fix this by initialising "target" to 0. If it really is used
uninitialised this would result in a jump to 0 and a detectable run time
failure.

Signed-off-by: Matt Redfearn 
Fixes: b6bd53f9c4e8 ("MIPS: Add missing file for eBPF JIT.")
Cc: James Hogan 
Cc: David Daney 
Cc: David S. Miller 
Cc: Colin Ian King 
Cc: Daniel Borkmann 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc:  # v4.13+
Patchwork: https://patchwork.linux-mips.org/patch/17375/
Signed-off-by: Ralf Baechle

MIPS,bpf: fix missing break in switch statement

2017-08-22T23:18:00+00:00

There is a missing break causing a fall-through and setting
ctx.use_bbit_insns to the wrong value. Fix this by adding the
missing break.

Detected with cppcheck:
"Variable 'ctx.use_bbit_insns' is reassigned a value before the old
one has been used. 'break;' missing?"

Fixes: 8d8d18c3283f ("MIPS,bpf: Fix using smp_processor_id() in preemptible splat.")
Signed-off-by: Colin Ian King 
Acked-by: David Daney 
Signed-off-by: David S. Miller

MIPS,bpf: Cache value of BPF_OP(insn->code) in eBPF JIT.

2017-08-21T17:31:34+00:00

The code looks a little cleaner if we replace BPF_OP(insn->code) with
the local variable bpf_op.  Caching the value this way also saves 300
bytes (about 1%) in the code size of the JIT.

Signed-off-by: David Daney 
Signed-off-by: David S. Miller

MIPS, bpf: Implement JLT, JLE, JSLT and JSLE ops in the eBPF JIT.

2017-08-21T17:31:34+00:00

Signed-off-by: David Daney 
Signed-off-by: David S. Miller

MIPS,bpf: Fix using smp_processor_id() in preemptible splat.

2017-08-21T17:31:34+00:00

If the kernel is configured with preemption enabled we were getting
warning stack traces for use of current_cpu_type().

Fix by moving the test between preempt_disable()/preempt_enable() and
caching the results of the CPU type tests for use during code
generation.

Signed-off-by: David Daney 
Signed-off-by: David S. Miller

MIPS: Add missing file for eBPF JIT.

2017-08-04T18:23:58+00:00

Inexplicably, commit f381bf6d82f0 ("MIPS: Add support for eBPF JIT.")
lost a file somewhere on its path to Linus' tree.  Add back the
missing ebpf_jit.c so that we can build with CONFIG_BPF_JIT selected.

This version of ebpf_jit.c is identical to the original except for two
minor change need to resolve conflicts with changes merged from the
BPF branch:

A) Set prog->jited_len = image_size;
B) Use BPF_TAIL_CALL instead of BPF_CALL | BPF_X

Fixes: f381bf6d82f0 ("MIPS: Add support for eBPF JIT.")
Signed-off-by: David Daney 
Acked-by: Daniel Borkmann 
Signed-off-by: David S. Miller

MIPS: Add support for eBPF JIT.

2017-06-28T10:22:39+00:00

Since the eBPF machine has 64-bit registers, we only support this in
64-bit kernels.  As of the writing of this commit log test-bpf is showing:

  test_bpf: Summary: 316 PASSED, 0 FAILED, [308/308 JIT'ed]

All current test cases are successfully compiled.

Many examples in samples/bpf are usable, specifically tracex5 which
uses tail calls works.

Signed-off-by: David Daney 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Markos Chandras 
Cc: Matt Redfearn 
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16369/
Signed-off-by: Ralf Baechle