From: Josh Poimboeuf <jpoimboe@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
linux-arm-kernel@lists.infradead.org,
live-patching@vger.kernel.org, Song Liu <song@kernel.org>,
Miroslav Benes <mbenes@suse.cz>, Petr Mladek <pmladek@suse.com>,
Joe Lawrence <joe.lawrence@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Mark Brown <broonie@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Kees Cook <kees@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
linux-toolchains@vger.kernel.org
Subject: [PATCH 11/12] arm64/bti: Force-enable BTI linker veneers
Date: Fri, 14 Aug 2026 21:45:28 -0700 [thread overview]
Message-ID: <edae8b52c1cba6eecd0bc75f709f6009816b80b8.1786768375.git.jpoimboe@kernel.org> (raw)
In-Reply-To: <cover.1786768375.git.jpoimboe@kernel.org>
The linker only emits the BTI veneers if *all* input objects have
GNU_PROPERTY_AARCH64_FEATURE_1_BTI. All the kernel's objects now
advertise it, but if some object stops doing so, BTI veneers silently
stop getting created on >128MB kernels, resulting in BTI exceptions at
runtime.
Force BTI veneers enabled with "-z force-bti" to prevent a single bad
object from ruining things. This also emits a warning (or error with
CONFIG_WERROR) if any objects are missing the bit.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
arch/arm64/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 4eee721c0b278..d0db9a6766a2f 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -25,6 +25,7 @@ endif
ifeq ($(CONFIG_ARM64_BTI_KERNEL),y)
KBUILD_AFLAGS += -include $(srctree)/arch/arm64/include/asm/bti-note.h
+LDFLAGS_vmlinux += $(call ld-option,-z force-bti)
endif
cc_has_k_constraint := $(call try-run,echo \
--
2.55.0
next prev parent reply other threads:[~2026-08-15 4:45 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-15 4:45 [PATCH 00/12] arm64/bti: Fix kernel BTI issues with livepatch, large kernels, toolchains Josh Poimboeuf
2026-08-15 4:45 ` [PATCH 01/12] arm64/bti: Add BTI landing pad to __sdei_asm_handler() Josh Poimboeuf
2026-08-15 5:01 ` sashiko-bot
2026-08-15 4:45 ` [PATCH 02/12] arm64/module: Fix BTI exceptions caused by omitted landing pads in Clang 21 Josh Poimboeuf
2026-08-15 5:00 ` sashiko-bot
2026-08-15 9:56 ` Ard Biesheuvel
2026-08-15 18:57 ` Josh Poimboeuf
2026-08-17 11:11 ` Ard Biesheuvel
2026-08-17 21:44 ` Josh Poimboeuf
2026-08-16 9:41 ` Will Deacon
2026-08-16 13:49 ` Ard Biesheuvel
2026-08-16 18:46 ` Josh Poimboeuf
2026-08-15 4:45 ` [PATCH 03/12] arm64/bti: Fix BTI linker failures with long branches into .idmap.text Josh Poimboeuf
2026-08-17 11:05 ` Ard Biesheuvel
2026-08-15 4:45 ` [PATCH 04/12] arm64/bti: Work around ld crash caused by linker script aliases Josh Poimboeuf
2026-08-15 4:45 ` [PATCH 05/12] arm64/bti: Add link error for large kernels with BTI and unsupported toolchains Josh Poimboeuf
2026-08-15 4:45 ` [PATCH 06/12] arm64/bti: Add link error for large kernels with BTI and livepatch Josh Poimboeuf
2026-08-15 4:45 ` [PATCH 07/12] arm64/bti: Advertise BTI in assembly objects Josh Poimboeuf
2026-08-15 5:03 ` sashiko-bot
2026-08-15 21:53 ` Mark Brown
2026-08-15 4:45 ` [PATCH 08/12] arm64/bti: Enable BTI in the pi/ startup code Josh Poimboeuf
2026-08-15 4:45 ` [PATCH 09/12] efi/libstub: Preserve the GNU property note Josh Poimboeuf
2026-08-15 4:45 ` [PATCH 10/12] efi/libstub: Remove obsolete .note.gnu.property workaround Josh Poimboeuf
2026-08-17 19:54 ` Nick Desaulniers
2026-08-18 14:15 ` Ard Biesheuvel
2026-08-15 4:45 ` Josh Poimboeuf [this message]
2026-08-15 5:00 ` [PATCH 11/12] arm64/bti: Force-enable BTI linker veneers sashiko-bot
2026-08-15 4:45 ` [PATCH 12/12] arm64/bti: Enable kernel BTI for GCC Josh Poimboeuf
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