From: Julian Braha <julianbraha@gmail.com>
To: Josh Poimboeuf <jpoimboe@kernel.org>, x86@kernel.org
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Gary Guo <gary@garyguo.net>,
rust-for-linux@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
Miguel Ojeda <ojeda@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nicolas Schier <nsc@kernel.org>,
linux-kbuild@vger.kernel.org, Huacai Chen <chenhuacai@kernel.org>
Subject: Re: [PATCH v2 02/27] kbuild: Add CONFIG_OBJTOOL_DEFERRED
Date: Thu, 10 Sep 2026 20:22:37 +0100 [thread overview]
Message-ID: <1506b117-6e79-4740-8e31-ce0d7a9c0d1b@gmail.com> (raw)
In-Reply-To: <166ab4ef8f062db45d5e4ab928f940d08dc465d5.1788899473.git.jpoimboe@kernel.org>
Hi Josh,
On 9/8/26 21:33, Josh Poimboeuf wrote:
> For LTO, IBT, and KLP builds, the running of objtool is deferred to
> vmlinux.o rather than individual translation units. In preparation for
> deferring it in more cases, add a new config option.
>
> No functional change.
>
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
> ---
> arch/x86/boot/startup/Makefile | 2 +-
> lib/Kconfig.debug | 7 +++++++
> scripts/Makefile.build | 4 ++--
> scripts/Makefile.lib | 4 +---
> scripts/Makefile.vmlinux_o | 13 +++++++------
> scripts/link-vmlinux.sh | 3 +--
> 6 files changed, 19 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/boot/startup/Makefile b/arch/x86/boot/startup/Makefile
> index 5e499cfb29b5c..ab6e9970d4f4e 100644
> --- a/arch/x86/boot/startup/Makefile
> +++ b/arch/x86/boot/startup/Makefile
> @@ -36,7 +36,7 @@ $(patsubst %.o,$(obj)/%.o,$(lib-y)): OBJECT_FILES_NON_STANDARD := y
> # relocations, even if other objtool actions are being deferred.
> #
> $(pi-objs): objtool-enabled = 1
> -$(pi-objs): objtool-args = $(if $(delay-objtool),--dry-run,$(objtool-args-y)) --noabs
> +$(pi-objs): objtool-args = $(if $(CONFIG_OBJTOOL_DEFERRED),--dry-run,$(objtool-args-y)) --noabs
>
> #
> # Confine the startup code by prefixing all symbols with __pi_ (for position
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 134b15a44625e..566e5be4c3f57 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -588,6 +588,13 @@ config NOINSTR_VALIDATION
> select OBJTOOL
> default y
>
> +# For when objtool defers its work to the linked image (vmlinux.o or module.o)
> +# rather than running on individual translation units.
> +config OBJTOOL_DEFERRED
> + def_bool y
> + depends on OBJTOOL
> + depends on LTO_CLANG || X86_KERNEL_IBT || KLP_BUILD
> +
Just commenting: if you move this option OBJTOOL_DEFERRED (and
OBJTOOL_CONTROL_FLOW in the next patch) a few entries up in this Kconfig
file, menuconfig will render them as part of the OBJTOOL submenu because
of the dependency on OBJTOOL.
E.g. this ordering:
OBJTOOL
OBJTOOL_WERROR
OBJTOOL_DEFERRED
OBJTOOL_CONTROL_FLOW
STACK_VALIDATION
NOINSTR_VALIDATION
would render better.
But this is minor, I don't think it necessitates a v3 on its own.
- Julian Braha
next prev parent reply other threads:[~2026-09-10 19:22 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-08 20:33 [PATCH v2 00/27] objtool: dynamically detect noreturns Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 01/27] objtool: Remove obsolete noreturns.h entries Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 02/27] kbuild: Add CONFIG_OBJTOOL_DEFERRED Josh Poimboeuf
2026-09-10 19:22 ` Julian Braha [this message]
2026-09-08 20:33 ` [PATCH v2 03/27] kbuild: Add CONFIG_OBJTOOL_CONTROL_FLOW Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 04/27] objtool: Fix dead end detection for sibling calls Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 05/27] objtool: Refactor the noreturn/dead-end detection Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 06/27] objtool: Ignore traps after noreturn calls in STT_CODE Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 07/27] objtool: Make .discard.stack_frame_non_standard non-allocatable Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 08/27] efi/libstub: Drop .discard.addressable from the stub objects Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 09/27] efi/loongarch: Mark loongarch efi_boot_kernel() non-standard for objtool Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 10/27] objtool: Add ANNOTATE_IGNORE_NORETURN() Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 11/27] LoongArch: Annotate reboot and kexec paths as returnable Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 12/27] kbuild: Defer running objtool to link time for all CFG features Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 13/27] rust: Annotate the intrinsic stubs as returnable Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 14/27] panic: Mark abort() __noreturn Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 15/27] x86/xen: Ignore noreturn status of weak mem_map_via_hcall() Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 16/27] objtool: Detect noreturns in weak functions Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 17/27] x86/entry: Make rewind_stack_and_make_dead() a real function Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 18/27] x86/xen: Make xen_cpu_bringup_again() " Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 19/27] x86/xen: Make xen_start_kernel() noreturn Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 20/27] x86/boot: Rework how pi startup symbols get exposed to vmlinux Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 21/27] objtool: Fix noreturn detection for non-sibling jumps to SYM_CODE Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 22/27] objtool: Add options to write/read exported noreturns to/from a file Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 23/27] kbuild: Do the per-module objtool pass right before linking Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 24/27] kbuild: Generate the noreturn list and validate modules against it Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 25/27] objtool: Add ANNOTATE_EXPORTED_NORETURN() Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 26/27] objtool: Annotate all module-exported noreturns and remove noreturns.h Josh Poimboeuf
2026-09-08 20:33 ` [PATCH v2 27/27] objtool: Warn about missing/stale ANNOTATE_EXPORTED_NORETURN() usage Josh Poimboeuf
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