linux.git/tools/objtool, branch v5.11.8

objtool: Fix ".cold" section suffix check for newer versions of GCC

2021-03-04T11:14:45+00:00

[ Upstream commit 34ca59e109bdf69704c33b8eeffaa4c9f71076e5 ]

With my version of GCC 9.3.1 the ".cold" subfunctions no longer have a
numbered suffix, so the trailing period is no longer there.

Presumably this doesn't yet trigger a user-visible bug since most of the
subfunction detection logic is duplicated.   I only found it when
testing vmlinux.o validation.

Fixes: 54262aa28301 ("objtool: Fix sibling call detection")
Signed-off-by: Josh Poimboeuf 
Link: https://lore.kernel.org/r/ca0b5a57f08a2fbb48538dd915cc253b5edabb40.1611263461.git.jpoimboe@redhat.com
Signed-off-by: Sasha Levin

objtool: Fix retpoline detection in asm code

2021-03-04T11:14:45+00:00

[ Upstream commit 1f9a1b74942485a0a29e7c4a9a9f2fe8aea17766 ]

The JMP_NOSPEC macro branches to __x86_retpoline_*() rather than the
__x86_indirect_thunk_*() wrappers used by C code.  Detect jumps to
__x86_retpoline_*() as retpoline dynamic jumps.

Presumably this doesn't trigger a user-visible bug.  I only found it
when testing vmlinux.o validation.

Fixes: 39b735332cb8 ("objtool: Detect jumps to retpoline thunks")
Signed-off-by: Josh Poimboeuf 
Link: https://lore.kernel.org/r/31f5833e2e4f01e3d755889ac77e3661e906c09f.1611263461.git.jpoimboe@redhat.com
Signed-off-by: Sasha Levin

objtool: Fix error handling for STD/CLD warnings

2021-03-04T11:14:45+00:00

[ Upstream commit 6f567c9300a5ebd7b18c26dda1c8d6ffbdd0debd ]

Actually return an error (and display a backtrace, if requested) for
directional bit warnings.

Fixes: 2f0f9e9ad7b3 ("objtool: Add Direction Flag validation")
Signed-off-by: Josh Poimboeuf 
Link: https://lore.kernel.org/r/dc70f2adbc72f09526f7cab5b6feb8bf7f6c5ad4.1611263461.git.jpoimboe@redhat.com
Signed-off-by: Sasha Levin

objtool: Don't fail on missing symbol table

2021-01-21T21:49:58+00:00

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

objtool: Don't fail the kernel build on fatal errors

2021-01-21T21:49:39+00:00

This is basically a revert of commit 644592d32837 ("objtool: Fail the
kernel build on fatal errors").

That change turned out to be more trouble than it's worth.  Failing the
build is an extreme measure which sometimes gets too much attention and
blocks CI build testing.

These fatal-type warnings aren't yet as rare as we'd hope, due to the
ever-increasing matrix of supported toolchains/plugins and their
fast-changing nature as of late.

Also, there are more people (and bots) looking for objtool warnings than
ever before, so even non-fatal warnings aren't likely to be ignored for
long.

Suggested-by: Nick Desaulniers 
Reviewed-by: Miroslav Benes 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Kamalesh Babulal 
Signed-off-by: Josh Poimboeuf

objtool: Don't add empty symbols to the rbtree

2021-01-13T22:56:37+00:00

Building with the Clang assembler shows the following warning:

  arch/x86/kernel/ftrace_64.o: warning: objtool: missing symbol for insn at offset 0x16

The Clang assembler strips section symbols.  That ends up giving
objtool's find_func_containing() much more test coverage than normal.
Turns out, find_func_containing() doesn't work so well for overlapping
symbols:

     2: 000000000000000e     0 NOTYPE  LOCAL  DEFAULT    2 fgraph_trace
     3: 000000000000000f     0 NOTYPE  LOCAL  DEFAULT    2 trace
     4: 0000000000000000   165 FUNC    GLOBAL DEFAULT    2 __fentry__
     5: 000000000000000e     0 NOTYPE  GLOBAL DEFAULT    2 ftrace_stub

The zero-length NOTYPE symbols are inside __fentry__(), confusing the
rbtree search for any __fentry__() offset coming after a NOTYPE.

Try to avoid this problem by not adding zero-length symbols to the
rbtree.  They're rare and aren't needed in the rbtree anyway.

One caveat, this actually might not end up being the right fix.
Non-empty overlapping symbols, if they exist, could have the same
problem.  But that would need bigger changes, let's see if we can get
away with the easy fix for now.

Reported-by: Arnd Bergmann 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Josh Poimboeuf

Merge tag 'objtool-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-12-27T17:08:23+00:00

Pull objtool fix from Ingo Molnar:
 "Fix a segfault that occurs when built with Clang"

* tag 'objtool-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix seg fault with Clang non-section symbols

objtool: Fix seg fault with Clang non-section symbols

2020-12-16T13:35:46+00:00

The Clang assembler likes to strip section symbols, which means objtool
can't reference some text code by its section.  This confuses objtool
greatly, causing it to seg fault.

The fix is similar to what was done before, for ORC reloc generation:

  e81e07244325 ("objtool: Support Clang non-section symbols in ORC generation")

Factor out that code into a common helper and use it for static call
reloc generation as well.

Reported-by: Arnd Bergmann 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Miroslav Benes 
Link: https://github.com/ClangBuiltLinux/linux/issues/1207
Link: https://lkml.kernel.org/r/ba6b6c0f0dd5acbba66e403955a967d9fdd1726a.1607983452.git.jpoimboe@redhat.com

tools: Factor HOSTCC, HOSTLD, HOSTAR definitions

2020-11-11T20:18:22+00:00

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

Merge tag 'objtool-core-2020-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-10-14T17:13:37+00:00

Pull objtool updates from Ingo Molnar:
 "Most of the changes are cleanups and reorganization to make the
  objtool code more arch-agnostic. This is in preparation for non-x86
  support.

  Other changes:

   - KASAN fixes

   - Handle unreachable trap after call to noreturn functions better

   - Ignore unreachable fake jumps

   - Misc smaller fixes & cleanups"

* tag 'objtool-core-2020-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  perf build: Allow nested externs to enable BUILD_BUG() usage
  objtool: Allow nested externs to enable BUILD_BUG()
  objtool: Permit __kasan_check_{read,write} under UACCESS
  objtool: Ignore unreachable trap after call to noreturn functions
  objtool: Handle calling non-function symbols in other sections
  objtool: Ignore unreachable fake jumps
  objtool: Remove useless tests before save_reg()
  objtool: Decode unwind hint register depending on architecture
  objtool: Make unwind hint definitions available to other architectures
  objtool: Only include valid definitions depending on source file type
  objtool: Rename frame.h -> objtool.h
  objtool: Refactor jump table code to support other architectures
  objtool: Make relocation in alternative handling arch dependent
  objtool: Abstract alternative special case handling
  objtool: Move macros describing structures to arch-dependent code
  objtool: Make sync-check consider the target architecture
  objtool: Group headers to check in a single list
  objtool: Define 'struct orc_entry' only when needed
  objtool: Skip ORC entry creation for non-text sections
  objtool: Move ORC logic out of check()
  ...