Merge tag 'objtool-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

- klp-build livepatch module generation (Josh Poimboeuf)

Int

Merge tag 'objtool-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

- klp-build livepatch module generation (Josh Poimboeuf)

Introduce new objtool features and a klp-build script to generate
livepatch modules using a source .patch as input.

This builds on concepts from the longstanding out-of-tree kpatch
project which began in 2012 and has been used for many years to
generate livepatch modules for production kernels. However, this is a
complete rewrite which incorporates hard-earned lessons from 12+
years of maintaining kpatch.

Key improvements compared to kpatch-build:

- Integrated with objtool: Leverages objtool's existing control-flow
graph analysis to help detect changed functions.

- Works on vmlinux.o: Supports late-linked objects, making it
compatible with LTO, IBT, and similar.

- Simplified code base: ~3k fewer lines of code.

- Upstream: No more out-of-tree #ifdef hacks, far less cruft.

- Cleaner internals: Vastly simplified logic for
symbol/section/reloc inclusion and special section extraction.

- Robust __LINE__ macro handling: Avoids false positive binary diffs
caused by the __LINE__ macro by introducing a fix-patch-lines
script which injects #line directives into the source .patch to
preserve the original line numbers at compile time.

- Disassemble code with libopcodes instead of running objdump
(Alexandre Chartre)

- Disassemble support (-d option to objtool) by Alexandre Chartre,
which supports the decoding of various Linux kernel code generation
specials such as alternatives:

17ef: sched_balance_find_dst_group+0x62f mov 0x34(%r9),%edx
17f3: sched_balance_find_dst_group+0x633 | <alternative.17f3> | X86_FEATURE_POPCNT
17f3: sched_balance_find_dst_group+0x633 | call 0x17f8 <__sw_hweight64> | popcnt %rdi,%rax
17f8: sched_balance_find_dst_group+0x638 cmp %eax,%edx

... jump table alternatives:

1895: sched_use_asym_prio+0x5 test $0x8,%ch
1898: sched_use_asym_prio+0x8 je 0x18a9 <sched_use_asym_prio+0x19>
189a: sched_use_asym_prio+0xa | <jump_table.189a> | JUMP
189a: sched_use_asym_prio+0xa | jmp 0x18ae <sched_use_asym_prio+0x1e> | nop2
189c: sched_use_asym_prio+0xc mov $0x1,%eax
18a1: sched_use_asym_prio+0x11 and $0x80,%ecx

... exception table alternatives:

native_read_msr:
5b80: native_read_msr+0x0 mov %edi,%ecx
5b82: native_read_msr+0x2 | <ex_table.5b82> | EXCEPTION
5b82: native_read_msr+0x2 | rdmsr | resume at 0x5b84 <native_read_msr+0x4>
5b84: native_read_msr+0x4 shl $0x20,%rdx

.... x86 feature flag decoding (also see the X86_FEATURE_POPCNT
example in sched_balance_find_dst_group() above):

2faaf: start_thread_common.constprop.0+0x1f jne 0x2fba4 <start_thread_common.constprop.0+0x114>
2fab5: start_thread_common.constprop.0+0x25 | <alternative.2fab5> | X86_FEATURE_ALWAYS | X86_BUG_NULL_SEG
2fab5: start_thread_common.constprop.0+0x25 | jmp 0x2faba <.altinstr_aux+0x2f4> | jmp 0x4b0 <start_thread_common.constprop.0+0x3f> | nop5
2faba: start_thread_common.constprop.0+0x2a mov $0x2b,%eax

... NOP sequence shortening:

1048e2: snapshot_write_finalize+0xc2 je 0x104917 <snapshot_write_finalize+0xf7>
1048e4: snapshot_write_finalize+0xc4 nop6
1048ea: snapshot_write_finalize+0xca nop11
1048f5: snapshot_write_finalize+0xd5 nop11
104900: snapshot_write_finalize+0xe0 mov %rax,%rcx
104903: snapshot_write_finalize+0xe3 mov 0x10(%rdx),%rax

... and much more.

- Function validation tracing support (Alexandre Chartre)

- Various -ffunction-sections fixes (Josh Poimboeuf)

- Clang AutoFDO (Automated Feedback-Directed Optimizations) support
(Josh Poimboeuf)

- Misc fixes and cleanups (Borislav Petkov, Chen Ni, Dylan Hatch, Ingo
Molnar, John Wang, Josh Poimboeuf, Pankaj Raghav, Peter Zijlstra,
Thorsten Blum)

* tag 'objtool-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (129 commits)
objtool: Fix segfault on unknown alternatives
objtool: Build with disassembly can fail when including bdf.h
objtool: Trim trailing NOPs in alternative
objtool: Add wide output for disassembly
objtool: Compact output for alternatives with one instruction
objtool: Improve naming of group alternatives
objtool: Add Function to get the name of a CPU feature
objtool: Provide access to feature and flags of group alternatives
objtool: Fix address references in alternatives
objtool: Disassemble jump table alternatives
objtool: Disassemble exception table alternatives
objtool: Print addresses with alternative instructions
objtool: Disassemble group alternatives
objtool: Print headers for alternatives
objtool: Preserve alternatives order
objtool: Add the --disas=<function-pattern> action
objtool: Do not validate IBT for .return_sites and .call_sites
objtool: Improve tracing of alternative instructions
objtool: Add functions to better name alternatives
objtool: Identify the different types of alternatives
...

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objtool: Fix segfault on unknown alternatives

So 'objtool --link -d vmlinux.o' gets surprised by this endbr64+endbr64 pattern
in ___bpf_prog_run():

___bpf_prog_run:
1e7680: ___bpf_prog_run+0x0

objtool: Fix segfault on unknown alternatives

So 'objtool --link -d vmlinux.o' gets surprised by this endbr64+endbr64 pattern
in ___bpf_prog_run():

___bpf_prog_run:
1e7680: ___bpf_prog_run+0x0 push %r12
1e7682: ___bpf_prog_run+0x2 mov %rdi,%r12
1e7685: ___bpf_prog_run+0x5 push %rbp
1e7686: ___bpf_prog_run+0x6 xor %ebp,%ebp
1e7688: ___bpf_prog_run+0x8 push %rbx
1e7689: ___bpf_prog_run+0x9 mov %rsi,%rbx
1e768c: ___bpf_prog_run+0xc movzbl (%rbx),%esi
1e768f: ___bpf_prog_run+0xf movzbl %sil,%edx
1e7693: ___bpf_prog_run+0x13 mov %esi,%eax
1e7695: ___bpf_prog_run+0x15 mov 0x0(,%rdx,8),%rdx
1e769d: ___bpf_prog_run+0x1d jmp 0x1e76a2 <__x86_indirect_thunk_rdx>
1e76a2: ___bpf_prog_run+0x22 endbr64
1e76a6: ___bpf_prog_run+0x26 endbr64
1e76aa: ___bpf_prog_run+0x2a mov 0x4(%rbx),%edx

And crashes due to blindly dereferencing alt->insn->alt_group.

Bail out on NULL ->alt_group, which produces this warning and continues
with the disassembly, instead of a segfault:

.git/O/vmlinux.o: warning: objtool: <alternative.1e769d>: failed to disassemble alternative

Cc: Alexandre Chartre <alexandre.chartre@oracle.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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objtool: Trim trailing NOPs in alternative

When disassembling alternatives replace trailing NOPs with a single
indication of the number of bytes covered with NOPs.

Signed-off-by: Alexandre Chartre

objtool: Trim trailing NOPs in alternative

When disassembling alternatives replace trailing NOPs with a single
indication of the number of bytes covered with NOPs.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-31-alexandre.chartre@oracle.com

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objtool: Add wide output for disassembly

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

objtool: Add wide output for disassembly

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 <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-30-alexandre.chartre@oracle.com

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objtool: Compact output for alternatives with one instruction

When disassembling, if an instruction has alternatives which are all
made of a single instruction then print each alternative on a singl

objtool: Compact output for alternatives with one instruction

When disassembling, if an instruction has alternatives which are all
made of a single instruction then print each alternative on a single
line (instruction + description) so that the output is more compact.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-29-alexandre.chartre@oracle.com

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objtool: Improve naming of group alternatives

Improve the naming of group alternatives by showing the feature name and
flags used by the alternative.

Signed-off-by: Alexandre Chartre <alexandre.cha

objtool: Improve naming of group alternatives

Improve the naming of group alternatives by showing the feature name and
flags used by the alternative.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-28-alexandre.chartre@oracle.com

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objtool: Fix address references in alternatives

When using the --disas option, alternatives are disassembled but
address references in non-default alternatives can be incorrect.

The problem is that

objtool: Fix address references in alternatives

When using the --disas option, alternatives are disassembled but
address references in non-default alternatives can be incorrect.

The problem is that alternatives are shown as if they were replacing the
original code of the alternative. So if an alternative is referencing
an address inside the alternative then the reference has to be
adjusted to the location of the original code.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-25-alexandre.chartre@oracle.com

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objtool: Disassemble jump table alternatives

When using the --disas option, also disassemble jump tables.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlst

objtool: Disassemble jump table alternatives

When using the --disas option, also disassemble jump tables.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-24-alexandre.chartre@oracle.com

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objtool: Disassemble exception table alternatives

When using the --disas option, also disassemble exception tables
(EX_TABLE).

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed

objtool: Disassemble exception table alternatives

When using the --disas option, also disassemble exception tables
(EX_TABLE).

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-23-alexandre.chartre@oracle.com

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objtool: Print addresses with alternative instructions

All alternatives are disassemble side-by-side when using the --disas
option. However the address of each instruction is not printed because
ins

objtool: Print addresses with alternative instructions

All alternatives are disassemble side-by-side when using the --disas
option. However the address of each instruction is not printed because
instructions from different alternatives are not necessarily aligned.

Change this behavior to print the address of each instruction. Spaces
will appear between instructions from the same alternative when
instructions from different alternatives do not have the same alignment.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-22-alexandre.chartre@oracle.com

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objtool: Disassemble group alternatives

When using the --disas option, disassemble all group alternatives.
Jump tables and exception tables (which are handled as alternatives)
are not disassembled a

objtool: Disassemble group alternatives

When using the --disas option, disassemble all group alternatives.
Jump tables and exception tables (which are handled as alternatives)
are not disassembled at the moment.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-21-alexandre.chartre@oracle.com

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objtool: Print headers for alternatives

When using the --disas option, objtool doesn't currently disassemble
any alternative. Print an header for each alternative. This identifies
places where alter

objtool: Print headers for alternatives

When using the --disas option, objtool doesn't currently disassemble
any alternative. Print an header for each alternative. This identifies
places where alternatives are present but alternative code is still
not disassembled at the moment.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-20-alexandre.chartre@oracle.com

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objtool: Add the --disas=<function-pattern> action

Add the --disas=<function-pattern> actions to disassemble the specified
functions. The function pattern can be a single function name (e.g.
--disas

objtool: Add the --disas=<function-pattern> action

Add the --disas=<function-pattern> 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 <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-18-alexandre.chartre@oracle.com

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objtool: Add functions to better name alternatives

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 alternati

objtool: Add functions to better name alternatives

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 <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-15-alexandre.chartre@oracle.com

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objtool: Add option to trace function validation

Add an option to trace and have information during the validation
of specified functions. Functions are specified with the --trace
option which can b

objtool: Add option to trace function validation

Add an option to trace and have information during the validation
of specified functions. Functions are specified with the --trace
option which can be a single function name (e.g. --trace foo to
trace the function with the name "foo"), or a shell wildcard
pattern (e.g. --trace foo* to trace all functions with a name
starting with "foo").

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-11-alexandre.chartre@oracle.com

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objtool: Disassemble instruction on warning or backtrace

When an instruction warning (WARN_INSN) or backtrace (BT_INSN) is issued,
disassemble the instruction to provide more context.

Signed-off-by

objtool: Disassemble instruction on warning or backtrace

When an instruction warning (WARN_INSN) or backtrace (BT_INSN) is issued,
disassemble the instruction to provide more context.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-8-alexandre.chartre@oracle.com

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objtool: Store instruction disassembly result

When disassembling an instruction store the result instead of directly
printing it.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Sig

objtool: Store instruction disassembly result

When disassembling an instruction store the result instead of directly
printing it.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-7-alexandre.chartre@oracle.com

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objtool: Print symbol during disassembly

Print symbols referenced during disassembly instead of just printing
raw addresses. Also handle address relocation.

Signed-off-by: Alexandre Chartre <alexan

objtool: Print symbol during disassembly

Print symbols referenced during disassembly instead of just printing
raw addresses. Also handle address relocation.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-6-alexandre.chartre@oracle.com

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objtool: Disassemble code with libopcodes instead of running objdump

objtool executes the objdump command to disassemble code. Use libopcodes
instead to have more control about the disassembly scope

objtool: Disassemble code with libopcodes instead of running objdump

objtool executes the objdump command to disassemble code. Use libopcodes
instead to have more control about the disassembly scope and output.
If libopcodes is not present then objtool is built without disassembly
support.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-4-alexandre.chartre@oracle.com

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objtool: Create disassembly context

Create a structure to store information for disassembling functions.
For now, it is just a wrapper around an objtool file.

Signed-off-by: Alexandre Chartre <alex

objtool: Create disassembly context

Create a structure to store information for disassembling functions.
For now, it is just a wrapper around an objtool file.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-3-alexandre.chartre@oracle.com

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objtool: Move disassembly functions to a separated file

objtool disassembles functions which have warnings. Move the code
to do that to a dedicated file. The code is just moved, it is not
changed.

objtool: Move disassembly functions to a separated file

objtool disassembles functions which have warnings. Move the code
to do that to a dedicated file. The code is just moved, it is not
changed.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-2-alexandre.chartre@oracle.com

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