linux-stable.git/tools/objtool/builtin-check.c, branch v5.2

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13

2019-05-21T09:28:45+00:00

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not see http www gnu org licenses

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details [based]
  [from] [clk] [highbank] [c] you should have received a copy of the
  gnu general public license along with this program if not see http
  www gnu org licenses

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 355 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kate Stewart 
Reviewed-by: Jilayne Lovejoy 
Reviewed-by: Steve Winslow 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154041.837383322@linutronix.de
Signed-off-by: Greg Kroah-Hartman

objtool: Add UACCESS validation

2019-04-03T09:02:24+00:00

It is important that UACCESS regions are as small as possible;
furthermore the UACCESS state is not scheduled, so doing anything that
might directly call into the scheduler will cause random code to be
ran with UACCESS enabled.

Teach objtool too track UACCESS state and warn about any CALL made
while UACCESS is enabled. This very much includes the __fentry__()
and __preempt_schedule() calls.

Note that exceptions _do_ save/restore the UACCESS state, and therefore
they can drive preemption. This also means that all exception handlers
must have an otherwise redundant UACCESS disable instruction;
therefore ignore this warning for !STT_FUNC code (exception handlers
are not normal functions).

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Cc: Borislav Petkov 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Signed-off-by: Ingo Molnar

objtool: Add --backtrace support

2019-04-03T09:02:24+00:00

For when you want to know the path that reached your fail state:

  $ ./objtool check --no-fp --backtrace arch/x86/lib/usercopy_64.o
  arch/x86/lib/usercopy_64.o: warning: objtool: .altinstr_replacement+0x3: UACCESS disable without MEMOPs: __clear_user()
  arch/x86/lib/usercopy_64.o: warning: objtool:   __clear_user()+0x3a: (alt)
  arch/x86/lib/usercopy_64.o: warning: objtool:   __clear_user()+0x2e: (branch)
  arch/x86/lib/usercopy_64.o: warning: objtool:   __clear_user()+0x18: (branch)
  arch/x86/lib/usercopy_64.o: warning: objtool:   .altinstr_replacement+0xffffffffffffffff: (branch)
  arch/x86/lib/usercopy_64.o: warning: objtool:   __clear_user()+0x5: (alt)
  arch/x86/lib/usercopy_64.o: warning: objtool:   __clear_user()+0x0: <=== (func)

  0000000000000000 <__clear_user>:
    0:   e8 00 00 00 00          callq  5 <__clear_user+0x5>
                 1: R_X86_64_PLT32       __fentry__-0x4
    5:   90                      nop
    6:   90                      nop
    7:   90                      nop
    8:   48 89 f0                mov    %rsi,%rax
    b:   48 c1 ee 03             shr    $0x3,%rsi
    f:   83 e0 07                and    $0x7,%eax
   12:   48 89 f1                mov    %rsi,%rcx
   15:   48 85 c9                test   %rcx,%rcx
   18:   74 0f                   je     29 <__clear_user+0x29>
   1a:   48 c7 07 00 00 00 00    movq   $0x0,(%rdi)
   21:   48 83 c7 08             add    $0x8,%rdi
   25:   ff c9                   dec    %ecx
   27:   75 f1                   jne    1a <__clear_user+0x1a>
   29:   48 89 c1                mov    %rax,%rcx
   2c:   85 c9                   test   %ecx,%ecx
   2e:   74 0a                   je     3a <__clear_user+0x3a>
   30:   c6 07 00                movb   $0x0,(%rdi)
   33:   48 ff c7                inc    %rdi
   36:   ff c9                   dec    %ecx
   38:   75 f6                   jne    30 <__clear_user+0x30>
   3a:   90                      nop
   3b:   90                      nop
   3c:   90                      nop
   3d:   48 89 c8                mov    %rcx,%rax
   40:   c3                      retq

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Cc: Borislav Petkov 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Signed-off-by: Ingo Molnar

objtool: Add module specific retpoline rules

2018-02-21T08:05:05+00:00

David allowed retpolines in .init.text, except for modules, which will
trip up objtool retpoline validation, fix that.

Requested-by: David Woodhouse 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Thomas Gleixner 
Acked-by: Josh Poimboeuf 
Cc: Andy Lutomirski 
Cc: Arjan van de Ven 
Cc: Borislav Petkov 
Cc: Dan Williams 
Cc: Dave Hansen 
Cc: David Woodhouse 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Signed-off-by: Ingo Molnar

objtool: Add retpoline validation

2018-02-21T08:05:04+00:00

David requested a objtool validation pass for CONFIG_RETPOLINE=y enabled
builds, where it validates no unannotated indirect  jumps or calls are
left.

Add an additional .discard.retpoline_safe section to allow annotating
the few indirect sites that are required and safe.

Requested-by: David Woodhouse 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: David Woodhouse 
Acked-by: Thomas Gleixner 
Acked-by: Josh Poimboeuf 
Cc: Andy Lutomirski 
Cc: Arjan van de Ven 
Cc: Borislav Petkov 
Cc: Dan Williams 
Cc: Dave Hansen 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Signed-off-by: Ingo Molnar

objtool: Use existing global variables for options

2018-02-21T08:05:04+00:00

Use the existing global variables instead of passing them around and
creating duplicate global variables.

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Thomas Gleixner 
Acked-by: Josh Poimboeuf 
Cc: Andy Lutomirski 
Cc: Arjan van de Ven 
Cc: Borislav Petkov 
Cc: Dan Williams 
Cc: Dave Hansen 
Cc: David Woodhouse 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Signed-off-by: Ingo Molnar

objtool: Fix gcov check for older versions of GCC

2017-07-25T09:12:45+00:00

Objtool tries to silence 'unreachable instruction' warnings when it
detects gcov is enabled, because gcov produces a lot of unreachable
instructions and they don't really matter.

However, the 0-day bot is still reporting some unreachable instruction
warnings with CONFIG_GCOV_KERNEL=y on GCC 4.6.4.

As it turns out, objtool's gcov detection doesn't work with older
versions of GCC because they don't create a bunch of symbols with the
'gcov.' prefix like newer versions of GCC do.

Move the gcov check out of objtool and instead just create a new
'--no-unreachable' flag which can be passed in by the kernel Makefile
when CONFIG_GCOV_KERNEL is defined.

Also rename the 'nofp' variable to 'no_fp' for consistency with the new
'no_unreachable' variable.

Reported-by: kbuild test robot 
Signed-off-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: 9cfffb116887 ("objtool: Skip all "unreachable instruction" warnings for gcov kernels")
Link: http://lkml.kernel.org/r/c243dc78eb2ffdabb6e927844dea39b6033cd395.1500939244.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar

objtool: Add ORC unwind table generation

2017-07-18T08:57:43+00:00

Now that objtool knows the states of all registers on the stack for each
instruction, it's straightforward to generate debuginfo for an unwinder
to use.

Instead of generating DWARF, generate a new format called ORC, which is
more suitable for an in-kernel unwinder.  See
Documentation/x86/orc-unwinder.txt for a more detailed description of
this new debuginfo format and why it's preferable to DWARF.

Signed-off-by: Josh Poimboeuf 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Jiri Slaby 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/c9b9f01ba6c5ed2bdc9bb0957b78167fdbf9632e.1499786555.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar

objtool: Move checking code to check.c

2017-06-30T08:19:19+00:00

In preparation for the new 'objtool undwarf generate' command, which
will rely on 'objtool check', move the checking code from
builtin-check.c to check.c where it can be used by other commands.

Signed-off-by: Josh Poimboeuf 
Reviewed-by: Jiri Slaby 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/294c5c695fd73c1a5000bbe5960a7c9bec4ee6b4.1498659915.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar

objtool: Add fortify_panic as __noreturn function

2017-06-16T08:50:59+00:00

CONFIG_FORTIFY_SOURCE=y implements fortify_panic() as a __noreturn function,
so objtool needs to know about it too.

Suggested-by: Daniel Micay 
Tested-by: Stephen Rothwell 
Signed-off-by: Kees Cook 
Signed-off-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1497532835-32704-1-git-send-email-jpoimboe@redhat.com
Signed-off-by: Ingo Molnar