linux-toradex.git/tools/include/linux/objtool.h, branch v5.19-rc3

x86/ftrace: Remove OBJECT_FILES_NON_STANDARD usage

2022-06-06T18:50:22+00:00

The file-wide OBJECT_FILES_NON_STANDARD annotation is used with
CONFIG_FRAME_POINTER to tell objtool to skip the entire file when frame
pointers are enabled.  However that annotation is now deprecated because
it doesn't work with IBT, where objtool runs on vmlinux.o instead of
individual translation units.

Instead, use more fine-grained function-specific annotations:

- The 'save_mcount_regs' macro does funny things with the frame pointer.
  Use STACK_FRAME_NON_STANDARD_FP to tell objtool to ignore the
  functions using it.

- The return_to_handler() "function" isn't actually a callable function.
  Instead of being called, it's returned to.  The real return address
  isn't on the stack, so unwinding is already doomed no matter which
  unwinder is used.  So just remove the STT_FUNC annotation, telling
  objtool to ignore it.  That also removes the implicit
  ANNOTATE_NOENDBR, which now needs to be made explicit.

Fixes the following warning:

  vmlinux.o: warning: objtool: __fentry__+0x16: return with modified stack frame

Fixes: ed53a0d97192 ("x86/alternative: Use .ibt_endbr_seal to seal indirect calls")
Reported-by: kernel test robot 
Signed-off-by: Josh Poimboeuf 
Link: https://lore.kernel.org/r/b7a7a42fe306aca37826043dac89e113a1acdbac.1654268610.git.jpoimboe@kernel.org

Merge tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-05-24T17:36:38+00:00

Pull objtool updates from Ingo Molnar:

 - Comprehensive interface overhaul:
   =================================

   Objtool's interface has some issues:

     - Several features are done unconditionally, without any way to
       turn them off. Some of them might be surprising. This makes
       objtool tricky to use, and prevents porting individual features
       to other arches.

     - The config dependencies are too coarse-grained. Objtool
       enablement is tied to CONFIG_STACK_VALIDATION, but it has several
       other features independent of that.

     - The objtool subcmds ("check" and "orc") are clumsy: "check" is
       really a subset of "orc", so it has all the same options.

       The subcmd model has never really worked for objtool, as it only
       has a single purpose: "do some combination of things on an object
       file".

     - The '--lto' and '--vmlinux' options are nonsensical and have
       surprising behavior.

   Overhaul the interface:

      - get rid of subcmds

      - make all features individually selectable

      - remove and/or clarify confusing/obsolete options

      - update the documentation

      - fix some bugs found along the way

 - Fix x32 regression

 - Fix Kbuild cleanup bugs

 - Add scripts/objdump-func helper script to disassemble a single
   function from an object file.

 - Rewrite scripts/faddr2line to be section-aware, by basing it on
   'readelf', moving it away from 'nm', which doesn't handle multiple
   sections well, which can result in decoding failure.

 - Rewrite & fix symbol handling - which had a number of bugs wrt.
   object files that don't have global symbols - which is rare but
   possible. Also fix a bunch of symbol handling bugs found along the
   way.

* tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  objtool: Fix objtool regression on x32 systems
  objtool: Fix symbol creation
  scripts/faddr2line: Fix overlapping text section failures
  scripts: Create objdump-func helper script
  objtool: Remove libsubcmd.a when make clean
  objtool: Remove inat-tables.c when make clean
  objtool: Update documentation
  objtool: Remove --lto and --vmlinux in favor of --link
  objtool: Add HAVE_NOINSTR_VALIDATION
  objtool: Rename "VMLINUX_VALIDATION" -> "NOINSTR_VALIDATION"
  objtool: Make noinstr hacks optional
  objtool: Make jump label hack optional
  objtool: Make static call annotation optional
  objtool: Make stack validation frame-pointer-specific
  objtool: Add CONFIG_OBJTOOL
  objtool: Extricate sls from stack validation
  objtool: Rework ibt and extricate from stack validation
  objtool: Make stack validation optional
  objtool: Add option to print section addresses
  objtool: Don't print parentheses in function addresses
  ...

objtool: Fix STACK_FRAME_NON_STANDARD reloc type

2022-05-06T20:20:43+00:00

STACK_FRAME_NON_STANDARD results in inconsistent relocation types
depending on .c or .S usage:

  Relocation section '.rela.discard.func_stack_frame_non_standard' at offset 0x3c01090 contains 5 entries:
  Offset             Info             Type               Symbol's Value  Symbol's Name + Addend
  0000000000000000  00020c2200000002 R_X86_64_PC32          0000000000047b40 do_suspend_lowlevel + 0
  0000000000000008  0002461e00000001 R_X86_64_64            00000000000480a0 machine_real_restart + 0
  0000000000000010  0000001400000001 R_X86_64_64            0000000000000000 .rodata + b3d4
  0000000000000018  0002444600000002 R_X86_64_PC32          00000000000678a0 __efi64_thunk + 0
  0000000000000020  0002659d00000001 R_X86_64_64            0000000000113160 __crash_kexec + 0

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Borislav Petkov 
Link: https://lore.kernel.org/r/20220506121631.508692613@infradead.org

objtool: Add CONFIG_OBJTOOL

2022-04-22T10:32:03+00:00

Now that stack validation is an optional feature of objtool, add
CONFIG_OBJTOOL and replace most usages of CONFIG_STACK_VALIDATION with
it.

CONFIG_STACK_VALIDATION can now be considered to be frame-pointer
specific.  CONFIG_UNWINDER_ORC is already inherently valid for live
patching, so no need to "validate" it.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Miroslav Benes 
Link: https://lkml.kernel.org/r/939bf3d85604b2a126412bf11af6e3bd3b872bcb.1650300597.git.jpoimboe@redhat.com

x86,objtool: Move the ASM_REACHABLE annotation to objtool.h

2022-03-15T09:32:45+00:00

Because we need a variant for .S files too.

Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/Yi9gOW9f1GGwwUD6@hirez.programming.kicks-ass.net

x86/ibt: Add ANNOTATE_NOENDBR

2022-03-15T09:32:33+00:00

In order to have objtool warn about code references to !ENDBR
instruction, we need an annotation to allow this for non-control-flow
instances -- consider text range checks, text patching, or return
trampolines etc.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Kees Cook 
Acked-by: Josh Poimboeuf 
Link: https://lore.kernel.org/r/20220308154317.578968224@infradead.org

objtool: Add frame-pointer-specific function ignore

2021-10-01T01:24:07+00:00

Add a CONFIG_FRAME_POINTER-specific version of
STACK_FRAME_NON_STANDARD() for the case where a function is
intentionally missing frame pointer setup, but otherwise needs
objtool/ORC coverage when frame pointers are disabled.

Link: https://lkml.kernel.org/r/163163047364.489837.17377799909553689661.stgit@devnote2

Signed-off-by: Josh Poimboeuf 
Reviewed-by: Masami Hiramatsu 
Tested-by: Masami Hiramatsu 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

objtool: Combine UNWIND_HINT_RET_OFFSET and UNWIND_HINT_FUNC

2021-01-26T17:12:00+00:00

The ORC metadata generated for UNWIND_HINT_FUNC isn't actually very
func-like.  With certain usages it can cause stack state mismatches
because it doesn't set the return address (CFI_RA).

Also, users of UNWIND_HINT_RET_OFFSET no longer need to set a custom
return stack offset.  Instead they just need to specify a func-like
situation, so the current ret_offset code is hacky for no good reason.

Solve both problems by simplifying the RET_OFFSET handling and
converting it into a more useful UNWIND_HINT_FUNC.

If we end up needing the old 'ret_offset' functionality again in the
future, we should be able to support it pretty easily with the addition
of a custom 'sp_offset' in UNWIND_HINT_FUNC.

Signed-off-by: Josh Poimboeuf 
Link: https://lore.kernel.org/r/db9d1f5d79dddfbb3725ef6d8ec3477ad199948d.1611263462.git.jpoimboe@redhat.com

objtool: Add asm version of STACK_FRAME_NON_STANDARD