linux-toradex.git/tools/objtool/include, branch v6.19-rc2

objtool: Add more robust signal error handling, detect and warn about stack overflows

2025-12-03T18:42:37+00:00

When the kernel build fails due to an objtool segfault, the error
message is a bit obtuse and confusing:

  make[5]: *** [scripts/Makefile.build:503: drivers/scsi/qla2xxx/qla2xxx.o] Error 139
                                                                            ^^^^^^^^^
  make[5]: *** Deleting file 'drivers/scsi/qla2xxx/qla2xxx.o'
  make[4]: *** [scripts/Makefile.build:556: drivers/scsi/qla2xxx] Error 2
  make[3]: *** [scripts/Makefile.build:556: drivers/scsi] Error 2
  make[2]: *** [scripts/Makefile.build:556: drivers] Error 2
  make[1]: *** [/home/jpoimboe/git/linux/Makefile:2013: .] Error 2
  make: *** [Makefile:248: __sub-make] Error 2

Add a signal handler to objtool which prints an error message like if
the local stack has overflown (for which there's a chance as objtool
makes heavy use of recursion):

  drivers/scsi/qla2xxx/qla2xxx.o: error: SIGSEGV: objtool stack overflow!

or:

  drivers/scsi/qla2xxx/qla2xxx.o: error: SIGSEGV: objtool crash!

Also, re-raise the signal so the core dump still gets triggered.

[ mingo: Applied a build fix, added more comments and prettified the code. ]

Suggested-by: Ingo Molnar 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Cc: Alexandre Chartre 
Cc: David Laight 
Cc: Linus Torvalds 
Cc: Nathan Chancellor 
Cc: Peter Zijlstra 
Link: https://patch.msgid.link/mi4tihk4dbncn7belrhp6ooudhpw4vdggerktu5333w3gqf3uf@vqlhc3y667mg

objtool: Add wide output for disassembly

2025-11-24T19:40:48+00:00

Add the --wide option to provide a wide output when disassembling.
With this option, the disassembly of alternatives is displayed
side-by-side instead of one above the other.

Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://patch.msgid.link/20251121095340.464045-30-alexandre.chartre@oracle.com

objtool: Add Function to get the name of a CPU feature

2025-11-24T19:39:47+00:00

Add a function to get the name of a CPU feature. The function is
architecture dependent and currently only implemented for x86. The
feature names are automatically generated from the cpufeatures.h
include file.

Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://patch.msgid.link/20251121095340.464045-27-alexandre.chartre@oracle.com

objtool: Provide access to feature and flags of group alternatives

2025-11-21T14:30:14+00:00

Each alternative of a group alternative depends on a specific
feature and flags. Provide access to the feature/flags for each
alternative as an attribute (feature) in struct alt_group.

Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://patch.msgid.link/20251121095340.464045-26-alexandre.chartre@oracle.com

objtool: Add the --disas= action

2025-11-21T14:30:12+00:00

Add the --disas= actions to disassemble the specified
functions. The function pattern can be a single function name (e.g.
--disas foo to disassemble the function with the name "foo"), or a shell
wildcard pattern (e.g. --disas foo* to disassemble all functions with a
name starting with "foo").

Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://patch.msgid.link/20251121095340.464045-18-alexandre.chartre@oracle.com

objtool: Improve tracing of alternative instructions

2025-11-21T14:30:11+00:00

When tracing function validation, improve the reporting of
alternative instruction by more clearly showing the different
alternatives beginning and end.

Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://patch.msgid.link/20251121095340.464045-16-alexandre.chartre@oracle.com

objtool: Add functions to better name alternatives

2025-11-21T14:30:11+00:00

Add the disas_alt_name() and disas_alt_type_name() to provide a
name and a type name for an alternative. This will be used to
better name alternatives when tracing their execution.

Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://patch.msgid.link/20251121095340.464045-15-alexandre.chartre@oracle.com

objtool: Identify the different types of alternatives

2025-11-21T14:30:11+00:00

Alternative code, including jump table and exception table, is represented
with the same struct alternative structure. But there is no obvious way to
identify whether the struct represents alternative instructions, a jump
table or an exception table.

So add a type to struct alternative to clearly identify the type of
alternative.

Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://patch.msgid.link/20251121095340.464045-14-alexandre.chartre@oracle.com

objtool: Improve register reporting during function validation

2025-11-21T14:30:10+00:00

When tracing function validation, instruction state changes can
report changes involving registers. These registers are reported
with the name "r" (e.g. "r3"). Print the CPU specific register
name instead of a generic name (e.g. print "rbx" instead of "r3"
on x86).

Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://patch.msgid.link/20251121095340.464045-13-alexandre.chartre@oracle.com

objtool: Trace instruction state changes during function validation

2025-11-21T14:30:10+00:00

During function validation, objtool maintains a per-instruction state,
in particular to track call frame information. When tracing validation,
print any instruction state changes.

Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://patch.msgid.link/20251121095340.464045-12-alexandre.chartre@oracle.com