[ Upstream commit a3fecb9160482367365cc384c59dd220b162b066 ] While tracking down a problem where constant expressions used by BUILD_BUG_ON() suddenly stopped working[1], we found that an added static initializer was convincing the compiler that it couldn't track the state of the prior statically initialized value. Tracing this down found that ffs() was used in the initializer macro, but since it wasn't marked with __attribute__const__, the compiler had to assume the function might change variable states as a side-effect (which is not true for ffs(), which provides deterministic math results). For arc architecture with CONFIG_ISA_ARCV2=y, the __fls() function uses __builtin_arc_fls() which lacks GCC's const attribute, preventing compile-time constant folding, and KUnit testing of ffs/fls fails on arc[3]. A patch[2] to GCC to solve this has been sent. Add a fix for this by handling compile-time constants with the standard __builtin_clzl() builtin (which has const attribute) while preserving the optimized arc-specific builtin for runtime cases. This has the added benefit of skipping runtime calculation of compile-time constant values. Even with the GCC bug fixed (which is about "attribute const") this is a good change to avoid needless runtime costs, and should be done regardless of the state of GCC's bug. Build tested ARCH=arc allyesconfig with GCC arc-linux 15.2.0. Link: https://github.com/KSPP/linux/issues/364 [1] Link: https://gcc.gnu.org/pipermail/gcc-patches/2025-August/693273.html Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202508031025.doWxtzzc-lkp@intel.com/ [3] Signed-off-by: Kees Cook <kees@kernel.org> Acked-by: Vineet Gupta <vgupta@kernel.org> Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 35561bab768977c9e05f1f1a9bc00134c85f3e28 ] The include/generated/asm-offsets.h is generated in Kbuild during compiling from arch/SRCARCH/kernel/asm-offsets.c. When we want to generate another similar offset header file, circular dependency can happen. For example, we want to generate a offset file include/generated/test.h, which is included in include/sched/sched.h. If we generate asm-offsets.h first, it will fail, as include/sched/sched.h is included in asm-offsets.c and include/generated/test.h doesn't exist; If we generate test.h first, it can't success neither, as include/generated/asm-offsets.h is included by it. In x86_64, the macro COMPILE_OFFSETS is used to avoid such circular dependency. We can generate asm-offsets.h first, and if the COMPILE_OFFSETS is defined, we don't include the "generated/test.h". And we define the macro COMPILE_OFFSETS for all the asm-offsets.c for this purpose. Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit bbc46b23af5bb934cd1cf066ef4342cee457a24e ]
With the introduction of clone3 in commit 7f192e3cd316 ("fork: add
clone3") the effective bit width of clone_flags on all architectures was
increased from 32-bit to 64-bit, with a new type of u64 for the flags.
However, for most consumers of clone_flags the interface was not
changed from the previous type of unsigned long.
While this works fine as long as none of the new 64-bit flag bits
(CLONE_CLEAR_SIGHAND and CLONE_INTO_CGROUP) are evaluated, this is still
undesirable in terms of the principle of least surprise.
Thus, this commit fixes all relevant interfaces of the copy_thread
function that is called from copy_process to consistently pass
clone_flags as u64, so that no truncation to 32-bit integers occurs on
32-bit architectures.
Signed-off-by: Simon Schuster <schuster.simon@siemens-energy.com>
Link: https://lore.kernel.org/20250901-nios2-implement-clone3-v2-3-53fcf5577d57@siemens-energy.com
Fixes: c5febea0956fd387 ("fork: Pass struct kernel_clone_args into copy_thread")
Acked-by: Guo Ren (Alibaba Damo Academy) <guoren@kernel.org>
Acked-by: Andreas Larsson <andreas@gaisler.com> # sparc
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Instead of having the core code guess the note name for each regset, use USER_REGSET_NOTE_TYPE() to pick the correct name from elf.h. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kees Cook <kees@kernel.org> Cc: Akihiko Odaki <akihiko.odaki@daynix.com> Cc: linux-snps-arc@lists.infradead.org Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp> Link: https://lore.kernel.org/r/20250701135616.29630-5-Dave.Martin@arm.com Signed-off-by: Kees Cook <kees@kernel.org>
Pull ARC fixes from Vineet Gupta: - arch_atomic64_cmpxchg relaxed variant [Jason] - use of inbuilt swap in stack unwinder [Yu-Chun Lin] - use of __ASSEMBLER__ in kernel headers [Thomas Huth] * tag 'arc-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: ARC: Replace __ASSEMBLY__ with __ASSEMBLER__ in the non-uapi headers ARC: Replace __ASSEMBLY__ with __ASSEMBLER__ in uapi headers ARC: unwind: Use built-in sort swap to reduce code size and improve performance ARC: atomics: Implement arch_atomic64_cmpxchg using _relaxed
Make pte_swp_exclusive return bool instead of int. This will better reflect how pte_swp_exclusive is actually used in the code. This fixes swap/swapoff problems on Alpha due pte_swp_exclusive not returning correct values when _PAGE_SWP_EXCLUSIVE bit resides in upper 32-bits of PTE (like on alpha). Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Magnus Lindholm <linmag7@gmail.com> Cc: Sam James <sam@gentoo.org> Link: https://lore.kernel.org/lkml/20250218175735.19882-2-linmag7@gmail.com/ Link: https://lore.kernel.org/lkml/20250602041118.GA2675383@ZenIV/ [ Applied as the 'sed' script Al suggested - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While the GCC and Clang compilers already define __ASSEMBLER__ automatically when compiling assembly code, __ASSEMBLY__ is a macro that only gets defined by the Makefiles in the kernel. This can be very confusing when switching between userspace and kernelspace coding, or when dealing with uapi headers that rather should use __ASSEMBLER__ instead. So let's standardize on the __ASSEMBLER__ macro that is provided by the compilers now. This is a completely mechanical patch (done with a simple "sed -i" statement). Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Vineet Gupta <vgupta@kernel.org>
__ASSEMBLY__ is only defined by the Makefile of the kernel, so this is not really useful for uapi headers (unless the userspace Makefile defines it, too). Let's switch to __ASSEMBLER__ which gets set automatically by the compiler when compiling assembly code. Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Vineet Gupta <vgupta@kernel.org>
The custom swap function used in sort() was identical to the default built-in sort swap. Remove the custom swap function and passes NULL to sort(), allowing it to use the default swap function. This change reduces code size and improves performance, particularly when CONFIG_MITIGATION_RETPOLINE is enabled. With RETPOLINE mitigation, indirect function calls incur significant overhead, and using the default swap function avoids this cost. $ ./scripts/bloat-o-meter ./unwind.o.old ./unwind.o.new add/remove: 0/1 grow/shrink: 0/1 up/down: 0/-22 (-22) Function old new delta init_unwind_hdr.constprop 544 540 -4 swap_eh_frame_hdr_table_entries 18 - -18 Total: Before=4410, After=4388, chg -0.50% Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com> Signed-off-by: Vineet Gupta <vgupta@kernel.org>
The core atomic code has a number of macros where it elaborates architecture primitives into more functions. ARC uses arch_atomic64_cmpxchg() as it's architecture primitive which disable alot of the additional functions. Instead provide arch_cmpxchg64_relaxed() as the primitive and rely on the core macros to create arch_cmpxchg64(). The macros will also provide other functions, for instance, try_cmpxchg64_release(), giving a more complete implementation. Suggested-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/Z0747n5bSep4_1VX@J2N7QTR9R3 Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Vineet Gupta <vgupta@kernel.org>