The patch titled
Subject: ARM: remove Thumb2 __builtin_thread_pointer workaround for Clang
has been added to the -mm mm-nonmm-unstable branch. Its filename is
arm-remove-thumb2-__builtin_thread_pointer-workaround-for-clang.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/arm-remove-thumb2-__builtin_thread_pointer-workaround-for-clang.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Nathan Chancellor <nathan@xxxxxxxxxx>
Subject: ARM: remove Thumb2 __builtin_thread_pointer workaround for Clang
Date: Thu, 25 Jan 2024 15:55:10 -0700
Now that the minimum supported version of LLVM for building the kernel has
been bumped to 13.0.1, the conditional expression added to get_current()
by commit c1e42efacb9b ("ARM: 9151/1: Thumb2: avoid
__builtin_thread_pointer() on Clang") is always true, as the build will
fail during the configuration stage for older LLVM versions. Remove it,
effectively reverting the aforementioned change.
Link: https://lkml.kernel.org/r/20240125-bump-min-llvm-ver-to-13-0-1-v1-4-f5ff9bda41c5@xxxxxxxxxx
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@xxxxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Conor Dooley <conor@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Nicolas Schier <nicolas@xxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm/include/asm/current.h | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
--- a/arch/arm/include/asm/current.h~arm-remove-thumb2-__builtin_thread_pointer-workaround-for-clang
+++ a/arch/arm/include/asm/current.h
@@ -18,18 +18,12 @@ static __always_inline __attribute_const
{
struct task_struct *cur;
-#if __has_builtin(__builtin_thread_pointer) && \
- defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) && \
- !(defined(CONFIG_THUMB2_KERNEL) && \
- defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 130001)
+#if __has_builtin(__builtin_thread_pointer) && defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO)
/*
* Use the __builtin helper when available - this results in better
* code, especially when using GCC in combination with the per-task
* stack protector, as the compiler will recognize that it needs to
* load the TLS register only once in every function.
- *
- * Clang < 13.0.1 gets this wrong for Thumb2 builds:
- * https://github.com/ClangBuiltLinux/linux/issues/1485
*/
cur = __builtin_thread_pointer();
#elif defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)
_
Patches currently in -mm which might be from nathan@xxxxxxxxxx are
selftests-bpf-update-llvm-phabricator-links.patch
arch-and-include-update-llvm-phabricator-links.patch
treewide-update-llvm-bugzilla-links.patch
kbuild-raise-the-minimum-supported-version-of-llvm-to-1301.patch
makefile-drop-warn-stack-size-plugin-opt.patch
x86-drop-stack-alignment-plugin-opt.patch
arm-remove-thumb2-__builtin_thread_pointer-workaround-for-clang.patch
arm64-kconfig-clean-up-tautological-llvm-version-checks.patch
powerpc-kconfig-remove-tautology-in-config_compat.patch
riscv-remove-mcount_name-workaround.patch
riscv-kconfig-remove-version-dependency-from-config_clang_supports_dynamic_ftrace.patch
fortify-drop-clang-version-check-for-1201-or-newer.patch
lib-kconfigdebug-update-clang-version-check-in-config_kcov.patch
compiler-clangh-update-__diag_clang-macros-for-minimum-version-bump.patch
