Wang YanQing b9aa0b35d8 bpf, x32: Fix bug for BPF_ALU64 | BPF_NEG
The current implementation has two errors:

1: The second xor instruction will clear carry flag which
   is necessary for following sbb instruction.
2: The select coding for sbb instruction is wrong, the coding
   is "sbb dreg_hi,ecx", but what we need is "sbb ecx,dreg_hi".

This patch rewrites the implementation and fixes the errors.

This patch fixes below errors reported by bpf/test_verifier in x32
platform when the jit is enabled:

"
0: (b4) w1 = 4
1: (b4) w2 = 4
2: (1f) r2 -= r1
3: (4f) r2 |= r1
4: (87) r2 = -r2
5: (c7) r2 s>>= 63
6: (5f) r1 &= r2
7: (bf) r0 = r1
8: (95) exit
processed 9 insns (limit 131072), stack depth 0
0: (b4) w1 = 4
1: (b4) w2 = 4
2: (1f) r2 -= r1
3: (4f) r2 |= r1
4: (87) r2 = -r2
5: (c7) r2 s>>= 63
6: (5f) r1 &= r2
7: (bf) r0 = r1
8: (95) exit
processed 9 insns (limit 131072), stack depth 0
......
Summary: 1189 PASSED, 125 SKIPPED, 15 FAILED
"

Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-01 23:40:47 +02:00
2019-04-16 15:38:07 +02:00
2019-04-02 18:12:44 -10:00
2019-04-21 10:45:57 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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