linux.git/tools/arch/x86/lib, branch v5.17

tools arch: Update arch/x86/lib/mem{cpy,set}_64.S copies used in 'perf bench mem memcpy'

2022-01-13T13:54:44+00:00

To bring in the change made in this cset:

  f94909ceb1ed4bfd ("x86: Prepare asm files for straight-line-speculation")

It silences these perf tools build warnings, no change in the tools:

  Warning: Kernel ABI header at 'tools/arch/x86/lib/memcpy_64.S' differs from latest version at 'arch/x86/lib/memcpy_64.S'
  diff -u tools/arch/x86/lib/memcpy_64.S arch/x86/lib/memcpy_64.S
  Warning: Kernel ABI header at 'tools/arch/x86/lib/memset_64.S' differs from latest version at 'arch/x86/lib/memset_64.S'
  diff -u tools/arch/x86/lib/memset_64.S arch/x86/lib/memset_64.S

The code generated was checked before and after using 'objdump -d /tmp/build/perf/bench/mem-memcpy-x86-64-asm.o',
no changes.

Cc: Borislav Petkov 
Cc: Peter Zijlstra 
Signed-off-by: Arnaldo Carvalho de Melo

x86/insn: Use get_unaligned() instead of memcpy()

2021-10-06T09:56:37+00:00

Use get_unaligned() instead of memcpy() to access potentially unaligned
memory, which, when accessed through a pointer, leads to undefined
behavior. get_unaligned() describes much better what is happening there
anyway even if memcpy() does the job.

In addition, since perf tool builds with -Werror, it would fire with:

  util/intel-pt-decoder/../../../arch/x86/lib/insn.c: In function '__insn_get_emulate_prefix':
  tools/include/../include/asm-generic/unaligned.h:10:15: error: packed attribute is unnecessary [-Werror=packed]
     10 |  const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \

because -Werror=packed would complain if the packed attribute would have
no effect on the layout of the structure.

In this case, that is intentional so disable the warning only for that
compilation unit.

That part is Reported-by: Stephen Rothwell 

No functional changes.

Fixes: 5ba1071f7554 ("x86/insn, tools/x86: Fix undefined behavior due to potential unaligned accesses")
Suggested-by: Linus Torvalds 
Signed-off-by: Borislav Petkov 
Acked-by: Masami Hiramatsu 
Tested-by: Stephen Rothwell 
Link: https://lkml.kernel.org/r/YVSsIkj9Z29TyUjE@zn.tnic

x86/insn, tools/x86: Fix undefined behavior due to potential unaligned accesses

2021-09-24T10:37:38+00:00

Don't perform unaligned loads in __get_next() and __peek_nbyte_next() as
these are forms of undefined behavior:

"A pointer to an object or incomplete type may be converted to a pointer
to a different object or incomplete type. If the resulting pointer
is not correctly aligned for the pointed-to type, the behavior is
undefined."

(from http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf)

These problems were identified using the undefined behavior sanitizer
(ubsan) with the tools version of the code and perf test.

 [ bp: Massage commit message. ]

Signed-off-by: Numfor Mbiziwo-Tiapo 
Signed-off-by: Ian Rogers 
Signed-off-by: Borislav Petkov 
Acked-by: Masami Hiramatsu 
Link: https://lkml.kernel.org/r/20210923161843.751834-1-irogers@google.com

tools arch: Update arch/x86/lib/mem{cpy,set}_64.S copies used in 'perf bench mem memcpy'

2021-05-10T12:01:00+00:00

To bring in the change made in this cset:

 5e21a3ecad1500e3 ("x86/alternative: Merge include files")

This just silences these perf tools build warnings, no change in the tools:

  Warning: Kernel ABI header at 'tools/arch/x86/lib/memcpy_64.S' differs from latest version at 'arch/x86/lib/memcpy_64.S'
  diff -u tools/arch/x86/lib/memcpy_64.S arch/x86/lib/memcpy_64.S
  Warning: Kernel ABI header at 'tools/arch/x86/lib/memset_64.S' differs from latest version at 'arch/x86/lib/memset_64.S'
  diff -u tools/arch/x86/lib/memset_64.S arch/x86/lib/memset_64.S

Cc: Borislav Petkov 
Cc: Juergen Gross 
Signed-off-by: Arnaldo Carvalho de Melo

tools/insn: Restore the relative include paths for cross building

2021-03-17T19:17:05+00:00

Building perf on ppc causes:

  In file included from util/intel-pt-decoder/intel-pt-insn-decoder.c:15:
  util/intel-pt-decoder/../../../arch/x86/lib/insn.c:14:10: fatal error: asm/inat.h: No such file or directory
     14 | #include  /*__ignore_sync_check__ */
        |          ^~~~~~~~~~~~

Restore the relative include paths so that the compiler can find the
headers.

Fixes: 93281c4a9657 ("x86/insn: Add an insn_decode() API")
Reported-by: Ian Rogers 
Reported-by: Stephen Rothwell 
Signed-off-by: Borislav Petkov 
Tested-by: Ian Rogers 
Tested-by: Stephen Rothwell 
Link: https://lkml.kernel.org/r/20210317150858.02b1bbc8@canb.auug.org.au

x86/insn: Make insn_complete() static

2021-03-15T12:03:46+00:00

... and move it above the only place it is used.

Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/20210304174237.31945-22-bp@alien8.de

x86/insn: Add an insn_decode() API

2021-03-15T10:05:47+00:00

Users of the instruction decoder should use this to decode instruction
bytes. For that, have insn*() helpers return an int value to denote
success/failure. When there's an error fetching the next insn byte and
the insn falls short, return -ENODATA to denote that.

While at it, make insn_get_opcode() more stricter as to whether what has
seen so far is a valid insn and if not.

Copy linux/kconfig.h for the tools-version of the decoder so that it can
use IS_ENABLED().

Also, cast the INSN_MODE_KERN dummy define value to (enum insn_mode)
for tools use of the decoder because perf tool builds with -Werror and
errors out with -Werror=sign-compare otherwise.

Signed-off-by: Borislav Petkov 
Acked-by: Masami Hiramatsu 
Link: https://lkml.kernel.org/r/20210304174237.31945-5-bp@alien8.de

x86/insn: Add a __ignore_sync_check__ marker

2021-03-15T10:00:57+00:00

Add an explicit __ignore_sync_check__ marker which will be used to mark
lines which are supposed to be ignored by file synchronization check
scripts, its advantage being that it explicitly denotes such lines in
the code.

Signed-off-by: Borislav Petkov 
Reviewed-by: Masami Hiramatsu 
Link: https://lkml.kernel.org/r/20210304174237.31945-4-bp@alien8.de

x86/insn: Add @buf_len param to insn_init() kernel-doc comment

2021-03-15T10:00:19+00:00

It wasn't documented so add it. No functional changes.

Signed-off-by: Borislav Petkov 
Acked-by: Masami Hiramatsu 
Link: https://lkml.kernel.org/r/20210304174237.31945-3-bp@alien8.de

x86/insn: Fix vector instruction decoding on big endian cross-compiles

2021-01-14T00:13:17+00:00

Running instruction decoder posttest on an s390 host with an x86 target
with allyesconfig shows errors. Instructions used in a couple of kernel
objects could not be correctly decoded on big endian system.

  insn_decoder_test: warning: objdump says 6 bytes, but insn_get_length() says 5
  insn_decoder_test: warning: Found an x86 instruction decoder bug, please report this.
  insn_decoder_test: warning: ffffffff831eb4e1:    62 d1 fd 48 7f 04 24    vmovdqa64 %zmm0,(%r12)
  insn_decoder_test: warning: objdump says 7 bytes, but insn_get_length() says 6
  insn_decoder_test: warning: Found an x86 instruction decoder bug, please report this.
  insn_decoder_test: warning: ffffffff831eb4e8:    62 51 fd 48 7f 44 24 01         vmovdqa64 %zmm8,0x40(%r12)
  insn_decoder_test: warning: objdump says 8 bytes, but insn_get_length() says 6

This is because in a few places instruction field bytes are set directly
with further usage of "value". To address that introduce and use a
insn_set_byte() helper, which correctly updates "value" on big endian
systems.

Signed-off-by: Vasily Gorbik 
Acked-by: Masami Hiramatsu 
Signed-off-by: Josh Poimboeuf