Toolchain and infrastructure:
- Pass '-Zunstable-options' flag required by the future Rust 1.95.0.
- Fix 'objtool' warning for Rust 1.84.0.
'kernel' crate:
- 'irq' module: add missing bound detected by the future Rust 1.95.0.
- 'list' module: add missing 'unsafe' blocks and placeholder safety
comments to macros (an issue for future callers within the crate).
'pin-init' crate:
- Clean Clippy warning that changed behavior in the future Rust 1.95.0.
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Merge tag 'rust-fixes-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Pass '-Zunstable-options' flag required by the future Rust 1.95.0
- Fix 'objtool' warning for Rust 1.84.0
'kernel' crate:
- 'irq' module: add missing bound detected by the future Rust 1.95.0
- 'list' module: add missing 'unsafe' blocks and placeholder safety
comments to macros (an issue for future callers within the crate)
'pin-init' crate:
- Clean Clippy warning that changed behavior in the future Rust
1.95.0"
* tag 'rust-fixes-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: list: Add unsafe blocks for container_of and safety comments
rust: pin-init: replace clippy `expect` with `allow`
rust: irq: add `'static` bounds to irq callbacks
objtool/rust: add one more `noreturn` Rust function
rust: kbuild: pass `-Zunstable-options` for Rust 1.95.0
clock interface, taming the include hell by splitting the pv_ops structure
and removing of a bunch of obsolete code. Work by Juergen Gross.
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Merge tag 'x86_paravirt_for_v7.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 paravirt updates from Borislav Petkov:
- A nice cleanup to the paravirt code containing a unification of the
paravirt clock interface, taming the include hell by splitting the
pv_ops structure and removing of a bunch of obsolete code (Juergen
Gross)
* tag 'x86_paravirt_for_v7.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
x86/paravirt: Use XOR r32,r32 to clear register in pv_vcpu_is_preempted()
x86/paravirt: Remove trailing semicolons from alternative asm templates
x86/pvlocks: Move paravirt spinlock functions into own header
x86/paravirt: Specify pv_ops array in paravirt macros
x86/paravirt: Allow pv-calls outside paravirt.h
objtool: Allow multiple pv_ops arrays
x86/xen: Drop xen_mmu_ops
x86/xen: Drop xen_cpu_ops
x86/xen: Drop xen_irq_ops
x86/paravirt: Move pv_native_*() prototypes to paravirt.c
x86/paravirt: Introduce new paravirt-base.h header
x86/paravirt: Move paravirt_sched_clock() related code into tsc.c
x86/paravirt: Use common code for paravirt_steal_clock()
riscv/paravirt: Use common code for paravirt_steal_clock()
loongarch/paravirt: Use common code for paravirt_steal_clock()
arm64/paravirt: Use common code for paravirt_steal_clock()
arm/paravirt: Use common code for paravirt_steal_clock()
sched: Move clock related paravirt code to kernel/sched
paravirt: Remove asm/paravirt_api_clock.h
x86/paravirt: Move thunk macros to paravirt_types.h
...
`objtool` with Rust 1.84.0 reports:
rust/kernel.o: error: objtool: _RNvXNtNtCsaRPFapPOzLs_6kernel3str9parse_intaNtNtB2_7private12FromStrRadix14from_str_radix()
falls through to next function _RNvXNtNtCsaRPFapPOzLs_6kernel3str9parse_intaNtNtB2_7private12FromStrRadix16from_u64_negated()
This is very similar to commit c18f35e490 ("objtool/rust: add one more
`noreturn` Rust function"), which added `from_ascii_radix_panic` for Rust
1.86.0, except that Rust 1.84.0 ends up needing `from_str_radix_panic`.
Thus add it to the list to fix the warning.
Cc: FUJITA Tomonori <fujita.tomonori@gmail.com>
Fixes: 51d9ee90ea ("rust: str: add radix prefixed integer parsing functions")
Reported-by: Alice Ryhl <aliceryhl@google.com>
Link: https://rust-for-linux.zulipchat.com/#narrow/channel/291565/topic/x/with/572427627
Tested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260206204336.38462-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
- Bump up the Clang minimum version requirements
for livepatch builds, due to Clang assembler
section handling bugs causing silent
miscompilations.
- Strip livepatching symbol artifacts from
non-livepatch modules.
- Fix livepatch build warnings when certain
Clang LTO options are enabled.
- Fix livepatch build error when
CONFIG_MEM_ALLOC_PROFILING_DEBUG=y.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'objtool-urgent-2026-02-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull objtool fixes from Ingo Molnar::
- Bump up the Clang minimum version requirements for livepatch
builds, due to Clang assembler section handling bugs causing
silent miscompilations
- Strip livepatching symbol artifacts from non-livepatch modules
- Fix livepatch build warnings when certain Clang LTO options
are enabled
- Fix livepatch build error when CONFIG_MEM_ALLOC_PROFILING_DEBUG=y
* tag 'objtool-urgent-2026-02-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool/klp: Fix unexported static call key access for manually built livepatch modules
objtool/klp: Fix symbol correlation for orphaned local symbols
livepatch: Free klp_{object,func}_ext data after initialization
livepatch: Fix having __klp_objects relics in non-livepatch modules
livepatch/klp-build: Require Clang assembler >= 20
Enabling CONFIG_MEM_ALLOC_PROFILING_DEBUG with CONFIG_SAMPLE_LIVEPATCH
results in the following error:
samples/livepatch/livepatch-shadow-fix1.o: error: objtool: static_call: can't find static_call_key symbol: __SCK__WARN_trap
This is caused an extra file->klp sanity check which was added by commit
164c9201e1 ("objtool: Add base objtool support for livepatch
modules"). That check was intended to ensure that livepatch modules
built with klp-build always have full access to their static call keys.
However, it failed to account for the fact that manually built livepatch
modules (i.e., not built with klp-build) might need access to unexported
static call keys, for which read-only access is typically allowed for
modules.
While the livepatch-shadow-fix1 module doesn't explicitly use any static
calls, it does have a memory allocation, which can cause
CONFIG_MEM_ALLOC_PROFILING_DEBUG to insert a WARN() call. And WARN() is
now an unexported static call as of commit 860238af7a ("x86_64/bug:
Inline the UD1").
Fix it by removing the overzealous file->klp check, restoring the
original behavior for manually built livepatch modules.
Fixes: 164c9201e1 ("objtool: Add base objtool support for livepatch modules")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Song Liu <song@kernel.org>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patch.msgid.link/0bd3ae9a53c3d743417fe842b740a7720e2bcd1c.1770058775.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
The klp_object_ext and klp_func_ext data, which are stored in the
__klp_objects and __klp_funcs sections, respectively, are not needed
after they are used to create the actual klp_object and klp_func
instances. This operation is implemented by the init function in
scripts/livepatch/init.c.
Prefix the two sections with ".init" so they are freed after the module
is initializated.
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Link: https://patch.msgid.link/20260123102825.3521961-3-petr.pavlu@suse.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Instead of having the pv spinlock function definitions in paravirt.h,
move them into the new header paravirt-spinlock.h.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260105110520.21356-22-jgross@suse.com
Having a single large pv_ops array has the main disadvantage of needing all
prototypes of the single array members in one header file. This is adding up
to the need to include lots of otherwise unrelated headers.
In order to allow multiple smaller pv_ops arrays dedicated to one area of the
kernel each, allow multiple arrays in objtool.
For better performance limit the possible names of the arrays to start with
"pv_ops".
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260105110520.21356-19-jgross@suse.com
Instead of having a pre-filled array xen_mmu_ops for Xen PV paravirt
functions, drop the array and assign each element individually.
This is in preparation of reducing the paravirt include hell by
splitting paravirt.h into multiple more fine grained header files,
which will in turn require to split up the pv_ops vector as well.
Dropping the pre-filled array makes life easier for objtool to
detect missing initializers in multiple pv_ops_ arrays.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://patch.msgid.link/20260105110520.21356-18-jgross@suse.com
Instead of having a pre-filled array xen_cpu_ops for Xen PV paravirt
functions, drop the array and assign each element individually.
This is in preparation of reducing the paravirt include hell by
splitting paravirt.h into multiple more fine grained header files,
which will in turn require to split up the pv_ops vector as well.
Dropping the pre-filled array makes life easier for objtool to
detect missing initializers in multiple pv_ops_ arrays.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://patch.msgid.link/20260105110520.21356-17-jgross@suse.com
Instead of having a pre-filled array xen_irq_ops for Xen PV paravirt
functions, drop the array and assign each element individually.
This is in preparation of reducing the paravirt include hell by
splitting paravirt.h into multiple more fine grained header files,
which will in turn require to split up the pv_ops vector as well.
Dropping the pre-filled array makes life easier for objtool to
detect missing initializers in multiple pv_ops_ arrays.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://patch.msgid.link/20260105110520.21356-16-jgross@suse.com
Fix the following warning:
rust/kernel.o: warning: objtool: _RNvXNtNtCs1ewLyjEZ7Le_6kernel3str9parse_intaNtNtB2_7private12FromStrRadix14from_str_radix()
falls through to next function _RNvXNtNtCs1ewLyjEZ7Le_6kernel3str9parse_intaNtNtB2_7private12FromStrRadix16from_u64_negated()
The commit 51d9ee90ea ("rust: str: add radix prefixed integer
parsing functions") introduces u64::from_str_radix(), whose
implementation contains a panic path for out-of-range radix values.
The panic helper is core::num::from_ascii_radix_panic().
Note that radix is derived from strip_radix() here and is always
within the valid range, so kernel never panics.
Fixes: 51d9ee90ea ("rust: str: add radix prefixed integer parsing functions")
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20251223113538.1016078-1-fujita.tomonori@gmail.com
[ Reworded typo. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
On an allmodconfig kernel compiled with Clang, objtool is segfaulting in
drivers/scsi/qla2xxx/qla2xxx.o due to a stack overflow in
validate_branch().
Due in part to KASAN being enabled, the qla2xxx code has a large number
of conditional jumps, causing objtool to go quite deep in its recursion.
By far the biggest offender of stack usage is the recently added
'prev_state' stack variable in validate_insn(), coming in at 328 bytes.
Move that variable (and its tracing usage) to handle_insn_ops() and make
handle_insn_ops() noinline to keep its stack frame outside the recursive
call chain.
Reported-by: Nathan Chancellor <nathan@kernel.org>
Fixes: fcb268b47a ("objtool: Trace instruction state changes during function validation")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://patch.msgid.link/21bb161c23ca0d8c942a960505c0d327ca2dc7dc.1764691895.git.jpoimboe@kernel.org
Closes: https://lore.kernel.org/20251201202329.GA3225984@ax162
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 <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/20251121095340.464045-26-alexandre.chartre@oracle.com
Preserve the order in which alternatives are defined. Currently
objtool stores alternatives in a list in reverse order.
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/20251121095340.464045-19-alexandre.chartre@oracle.com
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
The .return_sites and .call_sites sections reference text addresses,
but not with the intent to indirect branch to them, so they don't
need to be validated for IBT.
This is useful when running objtool on object files which already
have .return_sites or .call_sites sections, for example to re-run
objtool after it has reported an error or a warning.
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/20251121095340.464045-17-alexandre.chartre@oracle.com
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 <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/20251121095340.464045-16-alexandre.chartre@oracle.com
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 <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/20251121095340.464045-14-alexandre.chartre@oracle.com
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 <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/20251121095340.464045-12-alexandre.chartre@oracle.com
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
Keep track of the maximum length of symbol names. This will help
formatting the code flow between different functions.
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/20251121095340.464045-10-alexandre.chartre@oracle.com
The code to validate a branch loops through all instructions of the
branch and validate each instruction. Move the code to validate an
instruction to a separated function.
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/20251121095340.464045-9-alexandre.chartre@oracle.com
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
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
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
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
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
This reverts commit 9c7dc1dd89.
The check-function-names.sh script now provides the function name
checking functionality for all architectures, making the objtool check
redundant.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/c7d549d4de8bd1490d106b99630eea5efc69a4dd.1763669451.git.jpoimboe@kernel.org
The .cold function parent/child correlation logic has two passes: one in
read_symbols() and one in add_jump_destinations().
The second pass was added with commit cd77849a69 ("objtool: Fix GCC 8
cold subfunction detection for aliased functions") to ensure that if the
parent symbol had aliases then the canonical symbol was chosen as the
parent.
That solution was rather clunky, not to mention incomplete due to the
existence of alternatives and switch tables. Now that we have
sym->alias, the canonical alias fix can be done much simpler in the
first pass, making the second pass obsolete.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/bdab245a38000a5407f663a031f39e14c67a43d4.1763671318.git.jpoimboe@kernel.org
When compiled with -ffunction-sections, a function named startup() will
be placed in .text.startup. However, .text.startup is also used by the
compiler for functions with __attribute__((constructor)).
That creates an ambiguity for the vmlinux linker script, which needs to
differentiate those two cases.
Similar naming conflicts exist for functions named exit(), split(),
unlikely(), hot() and unknown().
One potential solution would be to use '#ifdef CC_USING_FUNCTION_SECTIONS'
to create two distinct implementations of the TEXT_MAIN macro. However,
-ffunction-sections can be (and is) enabled or disabled on a per-object
basis (for example via ccflags-y or AUTOFDO_PROFILE).
So the recently unified TEXT_MAIN macro (commit 1ba9f89794
("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros")) is
necessary. This means there's no way for the linker script to
disambiguate things.
Instead, use objtool to warn on any function names whose resulting
section names might create ambiguity when the kernel is compiled (in
whole or in part) with -ffunction-sections.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: live-patching@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://patch.msgid.link/65fedea974fe14be487c8867a0b8d0e4a294ce1e.1762991150.git.jpoimboe@kernel.org
If an insn->alt points to a STAC/CLAC instruction, skip_alt_group()
assumes it's part of an alternative ("alt group") as opposed to some
other kind of "alt" such as an exception fixup.
While that assumption may hold true in the current code base, Linus has
an out-of-tree patch which breaks that assumption by replacing the
STAC/CLAC alternatives with raw STAC/CLAC instructions.
Make skip_alt_group() more robust by making sure it's actually an alt
group before continuing.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: 2d12c6fb78 ("objtool: Remove ANNOTATE_IGNORE_ALTERNATIVE from CLAC/STAC")
Closes: https://lore.kernel.org/CAHk-=wi6goUT36sR8GE47_P-aVrd5g38=VTRHpktWARbyE-0ow@mail.gmail.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://patch.msgid.link/3d22415f7b8e06a64e0873b21f48389290eeaa49.1761767616.git.jpoimboe@kernel.org
Fix compilation failure when compiling the kernel with the x32 toolchain.
In file included from check.c:16:
check.c: In function ¡check_abs_references¢:
/usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:47:17: error: format ¡%lx¢ expects argument of type ¡long unsigned int¢, but argument 7 has type ¡u64¢ {aka ¡long
long unsigned int¢} [-Werror=format=]
47 | "%s%s%s: objtool" extra ": " format "\n", \
| ^~~~~~~~~~~~~~~~~
/usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:54:9: note: in expansion of macro ¡___WARN¢
54 | ___WARN(severity, "", format, ##__VA_ARGS__)
| ^~~~~~~
/usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:74:27: note: in expansion of macro ¡__WARN¢
74 | #define WARN(format, ...) __WARN(WARN_STR, format, ##__VA_ARGS__)
| ^~~~~~
check.c:4713:33: note: in expansion of macro ¡WARN¢
4713 | WARN("section %s has absolute relocation at offset 0x%lx",
| ^~~~
Fixes: 0d6e4563fc ("objtool: Add action to check for absence of absolute relocations")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://patch.msgid.link/1ac32fff-2e67-5155-f570-69aad5bf5412@redhat.com
Between Rust 1.79 and 1.86, under `CONFIG_RUST_KERNEL_DOCTESTS=y`,
`objtool` may report:
rust/doctests_kernel_generated.o: warning: objtool:
rust_doctest_kernel_alloc_kbox_rs_13() falls through to next
function rust_doctest_kernel_alloc_kvec_rs_0()
(as well as in rust_doctest_kernel_alloc_kvec_rs_0) due to calls to the
`noreturn` symbol:
core::option::expect_failed
from code added in commits 779db37373 ("rust: alloc: kvec: implement
AsPageIter for VVec") and 671618432f ("rust: alloc: kbox: implement
AsPageIter for VBox").
Thus add the mangled one to the list so that `objtool` knows it is
actually `noreturn`.
This can be reproduced as well in other versions by tweaking the code,
such as the latest stable Rust (1.90.0).
Stable does not have code that triggers this, but it could have it in
the future. Downstream forks could too. Thus tag it for backport.
See commit 56d680dd23 ("objtool/rust: list `noreturn` Rust functions")
for more details.
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Cc: stable@vger.kernel.org # Needed in 6.12.y and later.
Link: https://patch.msgid.link/20251020020714.2511718-1-ojeda@kernel.org
In preparation for klp-build, enable "classic" objtool to work on
livepatch modules:
- Avoid duplicate symbol/section warnings for prefix symbols and the
.static_call_sites and __mcount_loc sections which may have already
been extracted by klp diff.
- Add __klp_funcs to the IBT function pointer section whitelist.
- Prevent KLP symbols from getting incorrectly classified as cold
subfunctions.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
The prefix symbol creation code currently ignores all errors, presumably
because some functions don't have the leading NOPs.
Shuffle the code around a bit, improve the error handling and document
why some errors are ignored.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Add a new klp diff subcommand which performs a binary diff between two
object files and extracts changed functions into a new object which can
then be linked into a livepatch module.
This builds on concepts from the longstanding out-of-tree kpatch [1]
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
(coming in a later patch) which injects #line directives into the
source .patch to preserve the original line numbers at compile time.
Note the end result of this subcommand is not yet functionally complete.
Livepatch needs some ELF magic which linkers don't like:
- Two relocation sections (.rela*, .klp.rela*) for the same text
section.
- Use of SHN_LIVEPATCH to mark livepatch symbols.
Unfortunately linkers tend to mangle such things. To work around that,
klp diff generates a linker-compliant intermediate binary which encodes
the relevant KLP section/reloc/symbol metadata.
After module linking, a klp post-link step (coming soon) will clean up
the mess and convert the linked .ko into a fully compliant livepatch
module.
Note this subcommand requires the diffed binaries to have been compiled
with -ffunction-sections and -fdata-sections, and processed with
'objtool --checksum'. Those constraints will be handled by a klp-build
script introduced in a later patch.
Without '-ffunction-sections -fdata-sections', reliable object diffing
would be infeasible due to toolchain limitations:
- For intra-file+intra-section references, the compiler might
occasionally generated hard-coded instruction offsets instead of
relocations.
- Section-symbol-based references can be ambiguous:
- Overlapping or zero-length symbols create ambiguity as to which
symbol is being referenced.
- A reference to the end of a symbol (e.g., checking array bounds)
can be misinterpreted as a reference to the next symbol, or vice
versa.
A potential future alternative to '-ffunction-sections -fdata-sections'
would be to introduce a toolchain option that forces symbol-based
(non-section) relocations.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Add a --debug-checksum=<funcs> option to the check subcommand to print
the calculated checksum of each instruction in the given functions.
This is useful for determining where two versions of a function begin to
diverge.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
In preparation for the objtool klp diff subcommand, add a command-line
option to generate a unique checksum for each function. This will
enable detection of functions which have changed between two versions of
an object file.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
... for reading annotation types.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
The add_jump_destinations() logic is a bit weird and convoluted after
being incrementally tweaked over the years. Refactor it to hopefully be
more logical and straightforward.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
The --backup option was removed with the following commit:
aa8b3e64fd ("objtool: Create backup on error and print args")
... which tied the backup functionality to --verbose, and only for
warnings/errors.
It's a bit inelegant and out of scope to tie that to --verbose.
Bring back the old --backup option, but with the new behavior: only on
warnings/errors, and print the args to make it easier to recreate.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
When a to-be-created section already exists, there's no point in
emptying the various lists if their respective sections already exist.
In fact it's better to leave them intact as they might get used later.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Simplify the relocation offset calculation in unwind_read_hints(),
similar to other conversions which have already been done.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
In preparation for the objtool klp diff subcommand, introduce a flag to
identify __pfx_*() and __cfi_*() functions in advance so they don't need
to be manually identified every time a check is needed.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
When ignore_unreachable_insn() looks for weak function holes which jump
to their .cold functions, it assumes the parent function comes before
the corresponding .cold function in the symbol table. That's not
necessarily the case with -ffunction-sections.
Mark all the holes beforehand (including .cold functions) so the
ordering of the discovery doesn't matter.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Introduce a flag to identify .cold subfunctions so they can be detected
easier and faster.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Add some helper macros to improve readability.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
