linux-stable.git/tools/objtool, branch v4.19.321

x86/insn: Fix PUSH instruction in x86 instruction decoder opcode map

2024-06-16T11:23:31+00:00

[ Upstream commit 59162e0c11d7257cde15f907d19fefe26da66692 ]

The x86 instruction decoder is used not only for decoding kernel
instructions. It is also used by perf uprobes (user space probes) and by
perf tools Intel Processor Trace decoding. Consequently, it needs to
support instructions executed by user space also.

Opcode 0x68 PUSH instruction is currently defined as 64-bit operand size
only i.e. (d64). That was based on Intel SDM Opcode Map. However that is
contradicted by the Instruction Set Reference section for PUSH in the
same manual.

Remove 64-bit operand size only annotation from opcode 0x68 PUSH
instruction.

Example:

  $ cat pushw.s
  .global  _start
  .text
  _start:
          pushw   $0x1234
          mov     $0x1,%eax   # system call number (sys_exit)
          int     $0x80
  $ as -o pushw.o pushw.s
  $ ld -s -o pushw pushw.o
  $ objdump -d pushw | tail -4
  0000000000401000 <.text>:
    401000:       66 68 34 12             pushw  $0x1234
    401004:       b8 01 00 00 00          mov    $0x1,%eax
    401009:       cd 80                   int    $0x80
  $ perf record -e intel_pt//u ./pushw
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.014 MB perf.data ]

 Before:

  $ perf script --insn-trace=disasm
  Warning:
  1 instruction trace errors
           pushw   10349 [000] 10586.869237014:            401000 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw)           pushw $0x1234
           pushw   10349 [000] 10586.869237014:            401006 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw)           addb %al, (%rax)
           pushw   10349 [000] 10586.869237014:            401008 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw)           addb %cl, %ch
           pushw   10349 [000] 10586.869237014:            40100a [unknown] (/home/ahunter/git/misc/rtit-tests/pushw)           addb $0x2e, (%rax)
   instruction trace error type 1 time 10586.869237224 cpu 0 pid 10349 tid 10349 ip 0x40100d code 6: Trace doesn't match instruction

 After:

  $ perf script --insn-trace=disasm
             pushw   10349 [000] 10586.869237014:            401000 [unknown] (./pushw)           pushw $0x1234
             pushw   10349 [000] 10586.869237014:            401004 [unknown] (./pushw)           movl $1, %eax

Fixes: eb13296cfaf6 ("x86: Instruction decoder API")
Signed-off-by: Adrian Hunter 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20240502105853.5338-3-adrian.hunter@intel.com
Signed-off-by: Sasha Levin

objtool: Add a missing comma to avoid string concatenation

2023-02-06T06:49:45+00:00

commit 1fb466dff904e4a72282af336f2c355f011eec61 upstream.

Recently the kbuild robot reported two new errors:

>> lib/kunit/kunit-example-test.o: warning: objtool: .text.unlikely: unexpected end of section
>> arch/x86/kernel/dumpstack.o: warning: objtool: oops_end() falls through to next function show_opcodes()

I don't know why they did not occur in my test setup but after digging
it I realized I had accidentally dropped a comma in
tools/objtool/check.c when I renamed rewind_stack_do_exit to
rewind_stack_and_make_dead.

Add that comma back to fix objtool errors.

Link: https://lkml.kernel.org/r/202112140949.Uq5sFKR1-lkp@intel.com
Fixes: 0e25498f8cd4 ("exit: Add and use make_task_dead.")
Reported-by: kernel test robot 
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

exit: Add and use make_task_dead.

2023-02-06T06:49:45+00:00

commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream.

There are two big uses of do_exit.  The first is it's design use to be
the guts of the exit(2) system call.  The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.

Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure.  In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.

Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.

As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

objtool: Don't fail on missing symbol table

2021-02-07T13:48:38+00:00

[ Upstream commit 1d489151e9f9d1647110277ff77282fe4d96d09b ]

Thanks to a recent binutils change which doesn't generate unused
symbols, it's now possible for thunk_64.o be completely empty without
CONFIG_PREEMPTION: no text, no data, no symbols.

We could edit the Makefile to only build that file when
CONFIG_PREEMPTION is enabled, but that will likely create confusion
if/when the thunks end up getting used by some other code again.

Just ignore it and move on.

Reported-by: Nathan Chancellor 
Reviewed-by: Nathan Chancellor 
Reviewed-by: Miroslav Benes 
Tested-by: Nathan Chancellor 
Link: https://github.com/ClangBuiltLinux/linux/issues/1254
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Sasha Levin

tools: Factor HOSTCC, HOSTLD, HOSTAR definitions

2021-01-30T12:32:13+00:00

commit c8a950d0d3b926a02c7b2e713850d38217cec3d1 upstream.

Several Makefiles in tools/ need to define the host toolchain variables.
Move their definition to tools/scripts/Makefile.include

Signed-off-by: Jean-Philippe Brucker 
Signed-off-by: Andrii Nakryiko 
Acked-by: Jiri Olsa 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/bpf/20201110164310.2600671-2-jean-philippe@linaro.org
Cc: Alistair Delva 
Signed-off-by: Greg Kroah-Hartman

x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes

2020-12-11T12:25:02+00:00

commit 4e9a5ae8df5b3365183150f6df49e49dece80d8c upstream.

Since insn.prefixes.nbytes can be bigger than the size of
insn.prefixes.bytes[] when a prefix is repeated, the proper check must
be

  insn.prefixes.bytes[i] != 0 and i < 4

instead of using insn.prefixes.nbytes.

Introduce a for_each_insn_prefix() macro for this purpose. Debugged by
Kees Cook .

 [ bp: Massage commit message, sync with the respective header in tools/
   and drop "we". ]

Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints")
Reported-by: syzbot+9b64b619f10f19d19a7c@syzkaller.appspotmail.com
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Borislav Petkov 
Reviewed-by: Srikar Dronamraju 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/160697103739.3146288.7437620795200799020.stgit@devnote2
Signed-off-by: Greg Kroah-Hartman

objtool: Support Clang non-section symbols in ORC generation

2020-11-05T10:08:31+00:00

commit e81e0724432542af8d8c702c31e9d82f57b1ff31 upstream.

When compiling the kernel with AS=clang, objtool produces a lot of
warnings:

  warning: objtool: missing symbol for section .text
  warning: objtool: missing symbol for section .init.text
  warning: objtool: missing symbol for section .ref.text

It then fails to generate the ORC table.

The problem is that objtool assumes text section symbols always exist.
But the Clang assembler is aggressive about removing them.

When generating relocations for the ORC table, objtool always tries to
reference instructions by their section symbol offset.  If the section
symbol doesn't exist, it bails.

Do a fallback: when a section symbol isn't available, reference a
function symbol instead.

Reported-by: Dmitry Golovin 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Borislav Petkov 
Tested-by: Nathan Chancellor 
Reviewed-by: Miroslav Benes 
Acked-by: Peter Zijlstra (Intel) 
Link: https://github.com/ClangBuiltLinux/linux/issues/669
Link: https://lkml.kernel.org/r/9a9cae7fcf628843aabe5a086b1a3c5bf50f42e8.1585761021.git.jpoimboe@redhat.com
Cc: Nick Desaulniers 
Signed-off-by: Greg Kroah-Hartman

objtool: Fix noreturn detection for ignored functions

2020-10-01T11:14:50+00:00

[ Upstream commit db6c6a0df840e3f52c84cc302cc1a08ba11a4416 ]

When a function is annotated with STACK_FRAME_NON_STANDARD, objtool
doesn't validate its code paths.  It also skips sibling call detection
within the function.

But sibling call detection is actually needed for the case where the
ignored function doesn't have any return instructions.  Otherwise
objtool naively marks the function as implicit static noreturn, which
affects the reachability of its callers, resulting in "unreachable
instruction" warnings.

Fix it by just enabling sibling call detection for ignored functions.
The 'insn->ignore' check in add_jump_destinations() is no longer needed
after

  e6da9567959e ("objtool: Don't use ignore flag for fake jumps").

Fixes the following warning:

  arch/x86/kvm/vmx/vmx.o: warning: objtool: vmx_handle_exit_irqoff()+0x142: unreachable instruction

which triggers on an allmodconfig with CONFIG_GCOV_KERNEL unset.

Reported-by: Linus Torvalds 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Borislav Petkov 
Acked-by: Linus Torvalds 
Link: https://lkml.kernel.org/r/5b1e2536cdbaa5246b60d7791b76130a74082c62.1599751464.git.jpoimboe@redhat.com
Signed-off-by: Sasha Levin

kbuild: support LLVM=1 to switch the default tools to Clang/LLVM

2020-09-26T16:01:32+00:00

commit a0d1c951ef08ed24f35129267e3595d86f57f5d3 upstream.

As Documentation/kbuild/llvm.rst implies, building the kernel with a
full set of LLVM tools gets very verbose and unwieldy.

Provide a single switch LLVM=1 to use Clang and LLVM tools instead
of GCC and Binutils. You can pass it from the command line or as an
environment variable.

Please note LLVM=1 does not turn on the integrated assembler. You need
to pass LLVM_IAS=1 to use it. When the upstream kernel is ready for the
integrated assembler, I think we can make it default.

We discussed what we need, and we agreed to go with a simple boolean
flag that switches both target and host tools:

  https://lkml.org/lkml/2020/3/28/494
  https://lkml.org/lkml/2020/4/3/43

Some items discussed, but not adopted:

- LLVM_DIR

  When multiple versions of LLVM are installed, I just thought supporting
  LLVM_DIR=/path/to/my/llvm/bin/ might be useful.

  CC      = $(LLVM_DIR)clang
  LD      = $(LLVM_DIR)ld.lld
    ...

  However, we can handle this by modifying PATH. So, we decided to not do
  this.

- LLVM_SUFFIX

  Some distributions (e.g. Debian) package specific versions of LLVM with
  naming conventions that use the version as a suffix.

  CC      = clang$(LLVM_SUFFIX)
  LD      = ld.lld(LLVM_SUFFIX)
    ...

  will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc.,
  but the suffixed versions in /usr/bin/ are symlinks to binaries in
  /usr/lib/llvm-#/bin/, so this can also be handled by PATH.

Signed-off-by: Masahiro Yamada 
Reviewed-by: Nathan Chancellor 
Tested-by: Nathan Chancellor  # build
Tested-by: Nick Desaulniers 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Nick Desaulniers 
[nd: conflict in exported vars list from not backporting commit
 e83b9f55448a ("kbuild: add ability to generate BTF type info for vmlinux")]
[nd: hunk against Documentation/kbuild/kbuild.rst dropped due to not backporting
 commit cd238effefa2 ("docs: kbuild: convert docs to ReST and rename to *.rst")]
Signed-off-by: Greg Kroah-Hartman

objtool: Ignore empty alternatives

2020-06-22T07:05:09+00:00

[ Upstream commit 7170cf47d16f1ba29eca07fd818870b7af0a93a5 ]

The .alternatives section can contain entries with no original
instructions. Objtool will currently crash when handling such an entry.

Just skip that entry, but still give a warning to discourage useless
entries.

Signed-off-by: Julien Thierry 
Acked-by: Peter Zijlstra (Intel) 
Reviewed-by: Miroslav Benes 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin