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
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
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
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
When compiled with -ffunction-sections (e.g., for LTO, livepatch, dead
code elimination, AutoFDO, or Propeller), the startup() function gets
compiled into the .text.startup section (or in some cases
.text.startup.constprop.0 or .text.startup.isra.0).
However, the .text.startup and .text.startup.* sections are also used by
the compiler for __attribute__((constructor)) code.
This naming conflict causes the vmlinux linker script to wrongly place
startup() function code in .init.text, which gets freed during boot.
Some builds have a mix of objects, both with and without
-ffunctions-sections, so it's not possible for the linker script to
disambiguate with #ifdef CONFIG_FUNCTION_SECTIONS or similar. This
means that "startup" unfortunately needs to be prohibited as a function
name.
Rename startup() to startup_hw(). For consistency, also rename its
shutdown() counterpart to shutdown_hw().
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/f0ee750f35c878172cc09916a0724b74e62eadc2.1763669451.git.jpoimboe@kernel.org
When compiled with -ffunction-sections (e.g., for LTO, livepatch, dead
code elimination, AutoFDO, or Propeller), the startup() function gets
compiled into the .text.startup section (or in some cases
.text.startup.constprop.0 or .text.startup.isra.0).
However, the .text.startup and .text.startup.* sections are also used by
the compiler for __attribute__((constructor)) code.
This naming conflict causes the vmlinux linker script to wrongly place
startup() function code in .init.text, which gets freed during boot.
Some builds have a mix of objects, both with and without
-ffunctions-sections, so it's not possible for the linker script to
disambiguate with #ifdef CONFIG_FUNCTION_SECTIONS or similar. This
means that "startup" unfortunately needs to be prohibited as a function
name.
Rename startup() to rs_startup(). For consistency, also rename its
shutdown() counterpart to rs_shutdown().
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/9e56afff5268b0b12b99a8aa9bf244d6ebdcdf47.1763669451.git.jpoimboe@kernel.org
When compiled with -ffunction-sections (e.g., for LTO, livepatch, dead
code elimination, AutoFDO, or Propeller), the startup() function gets
compiled into the .text.startup section (or in some cases
.text.startup.constprop.0 or .text.startup.isra.0).
However, the .text.startup and .text.startup.* sections are also used by
the compiler for __attribute__((constructor)) code.
This naming conflict causes the vmlinux linker script to wrongly place
startup() function code in .init.text, which gets freed during boot.
Some builds have a mix of objects, both with and without
-ffunctions-sections, so it's not possible for the linker script to
disambiguate with #ifdef CONFIG_FUNCTION_SECTIONS or similar. This
means that "startup" unfortunately needs to be prohibited as a function
name.
Rename startup() to gc2235_startup().
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/d28103a6edf7beceb5e3c6fa24e49dbad1350389.1763669451.git.jpoimboe@kernel.org
When compiled with -ffunction-sections (e.g., for LTO, livepatch, dead
code elimination, AutoFDO, or Propeller), the startup() function gets
compiled into the .text.startup section (or in some cases
.text.startup.constprop.0 or .text.startup.isra.0).
However, the .text.startup and .text.startup.* sections are also used by
the compiler for __attribute__((constructor)) code.
This naming conflict causes the vmlinux linker script to wrongly place
startup() function code in .init.text, which gets freed during boot.
Some builds have a mix of objects, both with and without
-ffunctions-sections, so it's not possible for the linker script to
disambiguate with #ifdef CONFIG_FUNCTION_SECTIONS or similar. This
means that "startup" unfortunately needs to be prohibited as a function
name.
Rename startup() to icom_startup(). For consistency, also rename its
shutdown() counterpart to icom_shutdown().
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/1aee9ef69f9d40405676712b34f0c397706e7023.1763669451.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
The objtool .cold child/parent correlation is done in two phases: first
in elf_add_symbol() and later in add_jump_destinations().
The first phase is rather crude and can pick the wrong parent if there
are duplicates with the same name.
The second phase usually fixes that, but only if the parent has a direct
jump to the child. It does *not* work if the only branch from the
parent to the child is an alternative or jump table entry.
Make the first phase more robust by looking for the parent in the same
STT_FILE as the child.
Fixes the following objtool warnings in an AutoFDO build with a large
CLANG_AUTOFDO_PROFILE profile:
vmlinux.o: warning: objtool: rdev_add_key() falls through to next function rdev_add_key.cold()
vmlinux.o: warning: objtool: rdev_set_default_key() falls through to next function rdev_set_default_key.cold()
Fixes: 13810435b9 ("objtool: Support GCC 8's cold subfunctions")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/82c7b52e40efa75dd10e1c550cc75c1ce10ac2c9.1763671318.git.jpoimboe@kernel.org
AutoFDO enables -fsplit-machine-functions which can move the cold parts
of a function to a <func>.cold symbol in a .text.split.<func> section.
Unlike GCC, the Clang <func>.cold symbols are not marked STT_FUNC. This
confuses objtool in several ways, resulting in warnings like the
following:
vmlinux.o: warning: objtool: apply_retpolines.cold+0xfc: unsupported instruction in callable function
vmlinux.o: warning: objtool: machine_check_poll.cold+0x2e: unsupported instruction in callable function
vmlinux.o: warning: objtool: free_deferred_objects.cold+0x1f: relocation to !ENDBR: free_deferred_objects.cold+0x26
vmlinux.o: warning: objtool: rpm_idle.cold+0xe0: relocation to !ENDBR: rpm_idle.cold+0xe7
vmlinux.o: warning: objtool: tcp_rcv_state_process.cold+0x1c: relocation to !ENDBR: tcp_rcv_state_process.cold+0x23
Fix it by marking the .cold symbols as STT_FUNC.
Fixes: 2fd65f7afd ("AutoFDO: Enable machine function split optimization for AutoFDO")
Closes: https://lore.kernel.org/20251103215244.2080638-2-xur@google.com
Reported-by: Rong Xu <xur@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: xur@google.com
Tested-by: xur@google.com
Link: https://patch.msgid.link/20a67326f04b2a361c031b56d58e8a803b3c5893.1763671318.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
When compiling the kernel with -ffunction-sections enabled, the split()
function gets compiled into the .text.split section. In some cases it
can even be cloned into .text.split.constprop.0 or .text.split.isra.0.
However, .text.split.* is already reserved for use by the Clang
-fsplit-machine-functions flag, which is used by AutoFDO. That may
place part of a function's code in a .text.split.<func> section.
This naming conflict causes the vmlinux linker script to wrongly place
split() with other .text.split.* code, rather than where it belongs with
regular text.
Fix it by renaming split() to split_strings().
Fixes: 6568f14cb5 ("vmlinux.lds: Exclude .text.startup and .text.exit from TEXT_MAIN")
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: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://patch.msgid.link/92a194234a0f757765e275b288bb1a7236c2c35c.1762991150.git.jpoimboe@kernel.org
When compiling the kernel with -ffunction-sections (e.g., for LTO,
livepatch, dead code elimination, AutoFDO, or Propeller), the startup()
function gets compiled into the .text.startup section. In some cases it
can even be cloned into .text.startup.constprop.0 or
.text.startup.isra.0.
However, the .text.startup and .text.startup.* section names are already
reserved for use by the compiler for __attribute__((constructor)) code.
This naming conflict causes the vmlinux linker script to wrongly place
startup() function code in .init.text, which gets freed during boot.
Fix that by renaming startup() to ov2722_startup().
Fixes: 6568f14cb5 ("vmlinux.lds: Exclude .text.startup and .text.exit from TEXT_MAIN")
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: Hans de Goede <hansg@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://patch.msgid.link/bf8cd823a3f11f64cc82167913be5013c72afa57.1762991150.git.jpoimboe@kernel.org
Since:
6568f14cb5 ("vmlinux.lds: Exclude .text.startup and .text.exit from TEXT_MAIN")
the TEXT_MAIN macro uses a series of patterns to prevent the
.text.startup[.*] and .text.exit[.*] sections from getting
linked into the vmlinux runtime .text.
That commit is a tad too aggressive: it also inadvertently filters out
valid runtime text sections like .text.start and
.text.start.constprop.0, which can be generated for a function named
start() when -ffunction-sections is enabled.
As a result, those sections become orphans when building with
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION for arm:
arm-linux-gnueabi-ld: warning: orphan section `.text.start.constprop.0' from `drivers/usb/host/sl811-hcd.o' being placed in section `.text.start.constprop.0'
arm-linux-gnueabi-ld: warning: orphan section `.text.start.constprop.0' from `drivers/media/dvb-frontends/drxk_hard.o' being placed in section `.text.start.constprop.0'
arm-linux-gnueabi-ld: warning: orphan section `.text.start' from `drivers/media/dvb-frontends/stv0910.o' being placed in section `.text.start'
arm-linux-gnueabi-ld: warning: orphan section `.text.start.constprop.0' from `drivers/media/pci/ddbridge/ddbridge-sx8.o' being placed in section `.text.start.constprop.0'
Fix that by explicitly adding the partial "substring" sections (.text.s,
.text.st, .text.sta, etc) and their cloned derivatives.
While this unfortunately means that TEXT_MAIN continues to grow,
these changes are ultimately necessary for proper support of
-ffunction-sections.
Fixes: 6568f14cb5 ("vmlinux.lds: Exclude .text.startup and .text.exit from TEXT_MAIN")
Reported-by: kernel test robot <lkp@intel.com>
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/cd588144e63df901a656b06b566855019c4a931d.1762991150.git.jpoimboe@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202511040812.DFGedJiy-lkp@intel.com/
Pull i2c fix from Wolfram Sang:
"Two reverts merged into one commit to handle a regression caused by a
wrong cleanup because the underlying implications were unclear"
* tag 'i2c-for-6.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: muxes: pca954x: Fix broken reset-gpio usage
Pull Kbuild fixes from Nathan Chancellor:
- Strip trailing padding bytes from modules.builtin.modinfo to fix
error during modules_install with certain versions of kmod
- Drop unused static inline function warning in .c files with clang
from W=1 to W=2
- Ensure kernel-doc.py invocations use the PYTHON3 make variable to
ensure user's choice of Python interpreter is always respected
* tag 'kbuild-fixes-6.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
kbuild: Let kernel-doc.py use PYTHON3 override
compiler_types: Move unused static inline functions warning to W=2
kbuild: Strip trailing padding bytes from modules.builtin.modinfo
It is possible to force a specific version of python to be used when
building the kernel by passing PYTHON3= on the make command line.
However kernel-doc.py is currently called with python3 hard-coded and
thus ignores this setting.
Use $(PYTHON3) to run $(KERNELDOC) so that the desired version of
python is used.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://patch.msgid.link/20251107192933.2bfe9e57@endymion
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Pull drm fix from Dave Airlie:
"Brown paper bag, the dma mask fix which I applied and actually looked
through for bad things, actually broke newer GPUs, there might be some
latent part in the boot path that is assuming 32-bit still, but we
will figure that out elsewhere.
nouveau:
- revert DMA mask change"
* tag 'drm-fixes-2025-11-09' of https://gitlab.freedesktop.org/drm/kernel:
Revert "drm/nouveau: set DMA mask before creating the flush page"
