Commit Graph
570 Commits
Author SHA1 Message Date
Linus Torvalds 764e77d868 Merge tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "Futex updates:

   - Optimize futex hash bucket access patterns (Peter Zijlstra)

   - Large series to address the robust futex unlock race for real, by
     Thomas Gleixner:

      "The robust futex unlock mechanism is racy in respect to the
       clearing of the robust_list_head::list_op_pending pointer because
       unlock and clearing the pointer are not atomic.

       The race window is between the unlock and clearing the pending op
       pointer. If the task is forced to exit in this window, exit will
       access a potentially invalid pending op pointer when cleaning up
       the robust list.

       That happens if another task manages to unmap the object
       containing the lock before the cleanup, which results in an UAF.

       In the worst case this UAF can lead to memory corruption when
       unrelated content has been mapped to the same address by the time
       the access happens.

       User space can't solve this problem without help from the kernel.
       This series provides the kernel side infrastructure to help it
       along:

        1) Combined unlock, pointer clearing, wake-up for the
           contended case

        2) VDSO based unlock and pointer clearing helpers with a
           fix-up function in the kernel when user space was interrupted
           within the critical section.

      ... with help by André Almeida:

        - Add a note about robust list race condition (André Almeida)
        - Add self-tests for robust release operations (André Almeida)

  Context analysis updates:

   - Implement context analysis for 'struct rt_mutex'. (Bart Van Assche)
   - Bump required Clang version to 23 (Marco Elver)

  Guard infrastructure updates:

   - Series to remove NULL check from unconditional guards (Dmitry
     Ilvokhin)

  Lockdep updates:

   - Restore self-test migrate_disable() and sched_rt_mutex state on
     PREEMPT_RT (Karl Mehltretter)

  Membarriers updates:

   - Use per-CPU mutexes for targeted commands (Aniket Gattani)
   - Modernize membarrier_global_expedited with cleanup guards (Aniket
     Gattani)
   - Add rseq stress test for CFS throttle interactions (Aniket Gattani)

  percpu-rwsems updates:

   - Extract __percpu_up_read() to optimize inlining overhead (Dmitry
     Ilvokhin)

  Seqlocks updates:

   - Allow UBSAN_ALIGNMENT to fail optimizing (Heiko Carstens)

  Lock tracing:

   - Add contended_release tracepoint to sleepable locks such as
     mutexes, percpu-rwsems, rtmutexes, rwsems and semaphores (Dmitry
     Ilvokhin)

  MAINTAINERS updates:

   - MAINTAINERS: Add RUST [SYNC] entry (Boqun Feng)

  Misc updates and fixes by Randy Dunlap, YE WEI-HONG, Fabricio Parra,
  Dmitry Ilvokhin and Peter Zijlstra"

* tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (36 commits)
  locking: Add contended_release tracepoint to sleepable locks
  locking/percpu-rwsem: Extract __percpu_up_read()
  tracing/lock: Remove unnecessary linux/sched.h include
  futex: Optimize futex hash bucket access patterns
  rust: sync: completion: Mark inline complete_all and wait_for_completion
  MAINTAINERS: Add RUST [SYNC] entry
  cleanup: Specify nonnull argument index
  selftests: futex: Add tests for robust release operations
  Documentation: futex: Add a note about robust list race condition
  x86/vdso: Implement __vdso_futex_robust_try_unlock()
  x86/vdso: Prepare for robust futex unlock support
  futex: Provide infrastructure to plug the non contended robust futex unlock race
  futex: Add robust futex unlock IP range
  futex: Add support for unlocking robust futexes
  futex: Cleanup UAPI defines
  x86: Select ARCH_MEMORY_ORDER_TSO
  uaccess: Provide unsafe_atomic_store_release_user()
  futex: Provide UABI defines for robust list entry modifiers
  futex: Move futex related mm_struct data into a struct
  futex: Make futex_mm_init() void
  ...
2026-06-15 14:21:14 +05:30
Rong Xu 2566fa7b2f kconfig: Remove the architecture specific config for Propeller
The CONFIG_PROPELLER_CLANG option currently depends on
ARCH_SUPPORTS_PROPELLER_CLANG, but this dependency seems unnecessary.

Remove ARCH_SUPPORTS_PROPELLER_CLANG and allow users to control
Propeller builds solely through CONFIG_PROPELLER_CLANG. This simplifies
the kconfig and avoids potential confusion.

Move the .llvm_bb_addr_map sections grouping to
include/asm-generic/vmlinux.lds.h.

The Propeller documentation has been updated to reflect the most
recent tool location and now includes instructions for arm64.

Contributor Acknowledgments:
  * SPE instructions: Daniel Hoekwater <hoekwater@google.com>

Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Will Deacon <will@kernel.org>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Yabin Cui <yabinc@google.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20260604195612.3757860-3-xur@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-06-05 21:12:08 -07:00
Rong Xu e88b2fe8b9 kconfig: Remove the architecture specific config for AutoFDO
The CONFIG_AUTOFDO_CLANG option currently depends on
ARCH_SUPPORTS_AUTOFDO_CLANG, but this dependency seems unnecessary.

Remove ARCH_SUPPORTS_AUTOFDO_CLANG and allow users to control AutoFDO
builds solely through CONFIG_AUTOFDO_CLANG. This simplifies the kconfig
and avoids potential confusion.

Expand the AutoFDO documentation to include instructions for arm64.

Contributor acknowledgments:
  * SPE instructions: Daniel Hoekwater <hoekwater@google.com>
  * ETM instructions: Yabin Cui <yabinc@google.com>

Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Will Deacon <will@kernel.org>
Tested-by: Yabin Cui <yabinc@google.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20260604195612.3757860-2-xur@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-06-05 21:12:08 -07:00
Thomas Gleixner 6149fc36c0 uaccess: Provide unsafe_atomic_store_release_user()
The upcoming support for unlocking robust futexes in the kernel requires
store release semantics. Syscalls do not imply memory ordering on all
architectures so the unlock operation requires a barrier.

This barrier can be avoided when stores imply release like on x86.

Provide a generic version with a smp_mb() before the unsafe_put_user(),
which can be overridden by architectures.

Provide also a ARCH_MEMORY_ORDER_TSO Kconfig option, which can be selected
by architectures with Total Store Order (TSO), where store implies release,
so that the smp_mb() in the generic implementation can be avoided.

If that is set a barrier() is used instead of smp_mb(), which is not
required for the use case at hand, but makes it future proof for other
usage to prevent the compiler from reordering.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://patch.msgid.link/20260602090535.513181528@kernel.org
2026-06-03 11:38:50 +02:00
Rong Xu 9f2aee8f7d kbuild: distributed build support for Clang ThinLTO
Add distributed ThinLTO build support for the Linux kernel.
This new mode offers several advantages: (1) Increased
flexibility in handling user-specified build options.
(2) Improved user-friendliness for developers. (3) Greater
convenience for integrating with objtool and livepatch.

Note that "distributed" in this context refers to a term
that differentiates in-process ThinLTO builds by invoking
backend compilation through the linker, not necessarily
building in distributed environments.

Distributed ThinLTO is enabled via the
`CONFIG_LTO_CLANG_THIN_DIST` Kconfig option. For example:
 > make LLVM=1 defconfig
 > scripts/config -e LTO_CLANG_THIN_DIST
 > make LLVM=1 oldconfig
 > make LLVM=1 vmlinux -j <..>

The build flow proceeds in four stages:
  1. Perform FE compilation, mirroring the in-process ThinLTO mode.
  2. Thin-link the generated IR files and object files.
  3. Find all IR files and perform BE compilation, using the flags
    stored in the .*.o.cmd files.
  4. Link the BE results to generate the final vmlinux.o.

NOTE: This patch currently implements the build for the main kernel
image (vmlinux) only. Kernel module support is planned for a
subsequent patch.

Tested on the following arch: x86, arm64, loongarch, and
riscv.

The earlier implementation details can be found here:
https://discourse.llvm.org/t/rfc-distributed-thinlto-build-for-kernel/85934

Signed-off-by: Rong Xu <xur@google.com>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Piotr Gorski <piotrgorski@cachyos.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260529185347.2418373-4-xur@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-05-29 13:44:29 -07:00
Nathan Chancellor de0bf1e138 arch/Kconfig: Remove tautological condition from AUTOFDO_CLANG
Now that the minimum supported version of LLVM for building the kernel
has been raised to 17.0.1, the clang version check in
CONFIG_AUTOFDO_CLANG can be removed because it is always true.

Reviewed-by: Rong Xu <xur@google.com>
Link: https://patch.msgid.link/20260517-bump-minimum-supported-llvm-version-to-17-v2-6-b3b8cda46bdd@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-05-27 15:20:04 -07:00
Nathan Chancellor 2189cb1a80 arch/Kconfig: Remove tautological conditions from HAS_LTO_CLANG
Now that the minimum supported version of LLVM for building the kernel
has been raised to 17.0.1, two dependency lines in CONFIG_HAS_LTO_CLANG
are always true because Clang will always be newer than 17.0.0, so they
can be removed.

Reviewed-by: Nicolas Schier <nsc@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patch.msgid.link/20260517-bump-minimum-supported-llvm-version-to-17-v2-5-b3b8cda46bdd@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-05-27 15:20:04 -07:00
Linus Torvalds eb5249b125 Merge tag 'parisc-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc architecture updates from Helge Deller:

 - A fix to make modules on 32-bit parisc architecture work again

 - Drop ip_fast_csum() inline assembly to avoid unaligned memory
   accesses

 - Allow to build kernel without 32-bit VDSO

 - Reference leak fix in error path in LED driver

* tag 'parisc-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: led: fix reference leak on failed device registration
  module.lds.S: Fix modules on 32-bit parisc architecture
  parisc: Allow to build without VDSO32
  parisc: Include 32-bit VDSO only when building for 32-bit or compat mode
  parisc: Allow to disable COMPAT mode on 64-bit kernel
  parisc: Fix default stack size when COMPAT=n
  parisc: Fix signal code to depend on CONFIG_COMPAT instead of CONFIG_64BIT
  parisc: is_compat_task() shall return false for COMPAT=n
  parisc: Avoid compat syscalls when COMPAT=n
  parisc: _llseek syscall is only available for 32-bit userspace
  parisc: Drop ip_fast_csum() inline assembly implementation
  parisc: update outdated comments for renamed ccio_alloc_consistent()
2026-04-18 11:37:36 -07:00
Linus Torvalds 9cdca33667 Merge tag 'integrity-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull integrity updates from Mimi Zohar:
 "There are two main changes, one feature removal, some code cleanup,
  and a number of bug fixes.

  Main changes:
   - Detecting secure boot mode was limited to IMA. Make detecting
     secure boot mode accessible to EVM and other LSMs
   - IMA sigv3 support was limited to fsverity. Add IMA sigv3 support
     for IMA regular file hashes and EVM portable signatures

  Remove:
   - Remove IMA support for asychronous hash calculation originally
     added for hardware acceleration

  Cleanup:
   - Remove unnecessary Kconfig CONFIG_MODULE_SIG and CONFIG_KEXEC_SIG
     tests
   - Add descriptions of the IMA atomic flags

  Bug fixes:
   - Like IMA, properly limit EVM "fix" mode
   - Define and call evm_fix_hmac() to update security.evm
   - Fallback to using i_version to detect file change for filesystems
     that do not support STATX_CHANGE_COOKIE
   - Address missing kernel support for configured (new) TPM hash
     algorithms
   - Add missing crypto_shash_final() return value"

* tag 'integrity-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  evm: Enforce signatures version 3 with new EVM policy 'bit 3'
  integrity: Allow sigv3 verification on EVM_XATTR_PORTABLE_DIGSIG
  ima: add support to require IMA sigv3 signatures
  ima: add regular file data hash signature version 3 support
  ima: Define asymmetric_verify_v3() to verify IMA sigv3 signatures
  ima: remove buggy support for asynchronous hashes
  integrity: Eliminate weak definition of arch_get_secureboot()
  ima: Add code comments to explain IMA iint cache atomic_flags
  ima_fs: Correctly create securityfs files for unsupported hash algos
  ima: check return value of crypto_shash_final() in boot aggregate
  ima: Define and use a digest_size field in the ima_algo_desc structure
  powerpc/ima: Drop unnecessary check for CONFIG_MODULE_SIG
  ima: efi: Drop unnecessary check for CONFIG_MODULE_SIG/CONFIG_KEXEC_SIG
  ima: fallback to using i_version to detect file change
  evm: fix security.evm for a file with IMA signature
  s390: Drop unnecessary CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT
  evm: Don't enable fix mode when secure boot is enabled
  integrity: Make arch_ima_get_secureboot integrity-wide
2026-04-17 15:42:01 -07:00
Helge Deller 1221365f55 module.lds.S: Fix modules on 32-bit parisc architecture
On the 32-bit parisc architecture, we always used the
-ffunction-sections compiler option to tell the compiler to put the
functions into seperate text sections. This is necessary, otherwise
"big" kernel modules like ext4 or ipv6 fail to load because some
branches won't be able to reach their stubs.

Commit 1ba9f89794 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related
macros") broke this for parisc because all text sections will get
unconditionally merged now.

Introduce the ARCH_WANTS_MODULES_TEXT_SECTIONS config option which
avoids the text section merge for modules, and fix this issue by
enabling this option by default for 32-bit parisc.

Fixes: 1ba9f89794 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros")
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: stable@vger.kernel.org # v6.19+
Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-04-17 15:46:46 +02:00
Linus Torvalds d568788baa Merge tag 'hardening-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening updates from Kees Cook:

 - randomize_kstack: Improve implementation across arches (Ryan Roberts)

 - lkdtm/fortify: Drop unneeded FORTIFY_STR_OBJECT test

 - refcount: Remove unused __signed_wrap function annotations

* tag 'hardening-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lkdtm/fortify: Drop unneeded FORTIFY_STR_OBJECT test
  refcount: Remove unused __signed_wrap function annotations
  randomize_kstack: Unify random source across arches
  randomize_kstack: Maintain kstack_offset per task
2026-04-13 17:52:29 -07:00
Miguel Ojeda b28711ac98 rust: simplify RUSTC_VERSION Kconfig conditions
With the Rust version bump in place, several Kconfig conditions based on
`RUSTC_VERSION` are always true.

Thus simplify them.

The minimum supported major LLVM version by our new Rust minimum version
is now LLVM 18, instead of LLVM 16. However, there are no possible
cleanups for `RUSTC_LLVM_VERSION`.

Reviewed-by: Tamir Duberstein <tamird@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260405235309.418950-9-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-04-07 10:00:23 +02:00
Ryan Roberts a96ef5848c randomize_kstack: Unify random source across arches
Previously different architectures were using random sources of
differing strength and cost to decide the random kstack offset. A number
of architectures (loongarch, powerpc, s390, x86) were using their
timestamp counter, at whatever the frequency happened to be. Other
arches (arm64, riscv) were using entropy from the crng via
get_random_u16().

There have been concerns that in some cases the timestamp counters may
be too weak, because they can be easily guessed or influenced by user
space. And get_random_u16() has been shown to be too costly for the
level of protection kstack offset randomization provides.

So let's use a common, architecture-agnostic source of entropy; a
per-cpu prng, seeded at boot-time from the crng. This has a few
benefits:

  - We can remove choose_random_kstack_offset(); That was only there to
    try to make the timestamp counter value a bit harder to influence
    from user space [*].

  - The architecture code is simplified. All it has to do now is call
    add_random_kstack_offset() in the syscall path.

  - The strength of the randomness can be reasoned about independently
    of the architecture.

  - Arches previously using get_random_u16() now have much faster
    syscall paths, see below results.

[*] Additionally, this gets rid of some redundant work on s390 and x86.
Before this patch, those architectures called
choose_random_kstack_offset() under arch_exit_to_user_mode_prepare(),
which is also called for exception returns to userspace which were *not*
syscalls (e.g. regular interrupts). Getting rid of
choose_random_kstack_offset() avoids a small amount of redundant work
for the non-syscall cases.

In some configurations, add_random_kstack_offset() will now call
instrumentable code, so for a couple of arches, I have moved the call a
bit later to the first point where instrumentation is allowed. This
doesn't impact the efficacy of the mechanism.

There have been some claims that a prng may be less strong than the
timestamp counter if not regularly reseeded. But the prng has a period
of about 2^113. So as long as the prng state remains secret, it should
not be possible to guess. If the prng state can be accessed, we have
bigger problems.

Additionally, we are only consuming 6 bits to randomize the stack, so
there are only 64 possible random offsets. I assert that it would be
trivial for an attacker to brute force by repeating their attack and
waiting for the random stack offset to be the desired one. The prng
approach seems entirely proportional to this level of protection.

Performance data are provided below. The baseline is v6.18 with rndstack
on for each respective arch. (I)/(R) indicate statistically significant
improvement/regression. arm64 platform is AWS Graviton3 (m7g.metal).
x86_64 platform is AWS Sapphire Rapids (m7i.24xlarge):

+-----------------+--------------+---------------+---------------+
| Benchmark       | Result Class |  per-cpu-prng |  per-cpu-prng |
|                 |              | arm64 (metal) |   x86_64 (VM) |
+=================+==============+===============+===============+
| syscall/getpid  | mean (ns)    |    (I) -9.50% |   (I) -17.65% |
|                 | p99 (ns)     |   (I) -59.24% |   (I) -24.41% |
|                 | p99.9 (ns)   |   (I) -59.52% |   (I) -28.52% |
+-----------------+--------------+---------------+---------------+
| syscall/getppid | mean (ns)    |    (I) -9.52% |   (I) -19.24% |
|                 | p99 (ns)     |   (I) -59.25% |   (I) -25.03% |
|                 | p99.9 (ns)   |   (I) -59.50% |   (I) -28.17% |
+-----------------+--------------+---------------+---------------+
| syscall/invalid | mean (ns)    |   (I) -10.31% |   (I) -18.56% |
|                 | p99 (ns)     |   (I) -60.79% |   (I) -20.06% |
|                 | p99.9 (ns)   |   (I) -61.04% |   (I) -25.04% |
+-----------------+--------------+---------------+---------------+

I tested an earlier version of this change on x86 bare metal and it
showed a smaller but still significant improvement. The bare metal
system wasn't available this time around so testing was done in a VM
instance. I'm guessing the cost of rdtsc is higher for VMs.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://patch.msgid.link/20260303150840.3789438-3-ryan.roberts@arm.com
Signed-off-by: Kees Cook <kees@kernel.org>
2026-03-24 21:12:03 -07:00
Nathan Chancellor 7caedbb5ad integrity: Eliminate weak definition of arch_get_secureboot()
security/integrity/secure_boot.c contains a single __weak function,
which breaks recordmcount when building with clang:

  $ make -skj"$(nproc)" ARCH=powerpc LLVM=1 ppc64_defconfig security/integrity/secure_boot.o
  Cannot find symbol for section 2: .text.
  security/integrity/secure_boot.o: failed

Introduce a Kconfig symbol, CONFIG_HAVE_ARCH_GET_SECUREBOOT, to indicate
that an architecture provides a definition of arch_get_secureboot().
Provide a static inline stub when this symbol is not defined to achieve
the same effect as the __weak function, allowing secure_boot.c to be
removed altogether. Move the s390 definition of arch_get_secureboot()
out of the CONFIG_KEXEC_FILE block to ensure it is always available, as
it does not actually depend on KEXEC_FILE.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 31a6a07eef ("integrity: Make arch_ima_get_secureboot integrity-wide")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2026-03-13 11:37:13 -04:00
Juergen Gross e6b2aa6d40 sched: Move clock related paravirt code to kernel/sched
Paravirt clock related functions are available in multiple archs.

In order to share the common parts, move the common static keys
to kernel/sched/ and remove them from the arch specific files.

Make a common paravirt_steal_clock() implementation available in
kernel/sched/cputime.c, guarding it with a new config option
CONFIG_HAVE_PV_STEAL_CLOCK_GEN, which can be selected by an arch
in case it wants to use that common variant.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260105110520.21356-7-jgross@suse.com
2026-01-12 15:39:14 +01:00
Lukas Bulwahn cd4eaccc00 treewide: drop outdated compiler version remarks in Kconfig help texts
As of writing, Documentation/Changes states the minimal versions of GNU C
being 8.1, Clang being 15.0.0 and binutils being 2.30.  A few Kconfig help
texts are pointing out that specific GCC and Clang versions are needed,
but by now, those pointers to versions, such later than 4.0, later than
4.4, or clang later than 5.0, are obsolete and unlikely to be found by
users configuring their kernel builds anyway.

Drop these outdated remarks in Kconfig help texts referring to older
compiler and binutils versions.  No functional change.

Link: https://lkml.kernel.org/r/20251010082138.185752-1-lukas.bulwahn@redhat.com
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Russel King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-12 10:00:14 -08:00
Nathan Chancellor 39c89ee6e9 compiler_types: Introduce __nocfi_generic
There are two different ways that LLVM can expand kCFI operand bundles
in LLVM IR: generically in the middle end or using an architecture
specific sequence when lowering LLVM IR to machine code in the backend.
The generic pass allows any architecture to take advantage of kCFI but
the expansion of these bundles in the middle end can mess with
optimizations that may turn indirect calls into direct calls when the
call target is known at compile time, such as after inlining.

Add __nocfi_generic, dependent on an architecture selecting
CONFIG_ARCH_USES_CFI_GENERIC_LLVM_PASS, to disable kCFI bundle
generation in functions where only the generic kCFI pass may cause
problems.

Link: https://github.com/ClangBuiltLinux/linux/issues/2124
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20251025-idpf-fix-arm-kcfi-build-error-v1-1-ec57221153ae@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
2025-10-29 20:04:55 -07:00
Conor Dooley 812258ff41 rust: cfi: only 64-bit arm and x86 support CFI_CLANG
The kernel uses the standard rustc targets for non-x86 targets, and out
of those only 64-bit arm's target has kcfi support enabled. For x86, the
custom 64-bit target enables kcfi.

The HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC config option that allows
CFI_CLANG to be used in combination with RUST does not check whether the
rustc target supports kcfi. This breaks the build on riscv (and
presumably 32-bit arm) when CFI_CLANG and RUST are enabled at the same
time.

Ordinarily, a rustc-option check would be used to detect target support
but unfortunately rustc-option filters out the target for reasons given
in commit 46e24a545c ("rust: kasan/kbuild: fix missing flags on first
build"). As a result, if the host supports kcfi but the target does not,
e.g. when building for riscv on x86_64, the build would remain broken.

Instead, make HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC depend on the only
two architectures where the target used supports it to fix the build.

CC: stable@vger.kernel.org
Fixes: ca627e6365 ("rust: cfi: add support for CFI_CLANG with Rust")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250908-distill-lint-1ae78bcf777c@spud
Signed-off-by: Paul Walmsley <pjw@kernel.org>
2025-10-09 19:36:45 -06:00
Linus Torvalds 7f70725741 Merge tag 'kbuild-6.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux
Pull Kbuild updates from Nathan Chancellor:

 - Extend modules.builtin.modinfo to include module aliases from
   MODULE_DEVICE_TABLE for builtin modules so that userspace tools (such
   as kmod) can verify that a particular module alias will be handled by
   a builtin module

 - Bump the minimum version of LLVM for building the kernel to 15.0.0

 - Upgrade several userspace API checks in headers_check.pl to errors

 - Unify and consolidate CONFIG_WERROR / W=e handling

 - Turn assembler and linker warnings into errors with CONFIG_WERROR /
   W=e

 - Respect CONFIG_WERROR / W=e when building userspace programs
   (userprogs)

 - Enable -Werror unconditionally when building host programs
   (hostprogs)

 - Support copy_file_range() and data segment alignment in gen_init_cpio
   to improve performance on filesystems that support reflinks such as
   btrfs and XFS

 - Miscellaneous small changes to scripts and configuration files

* tag 'kbuild-6.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (47 commits)
  modpost: Initialize builtin_modname to stop SIGSEGVs
  Documentation: kbuild: note CONFIG_DEBUG_EFI in reproducible builds
  kbuild: vmlinux.unstripped should always depend on .vmlinux.export.o
  modpost: Create modalias for builtin modules
  modpost: Add modname to mod_device_table alias
  scsi: Always define blogic_pci_tbl structure
  kbuild: extract modules.builtin.modinfo from vmlinux.unstripped
  kbuild: keep .modinfo section in vmlinux.unstripped
  kbuild: always create intermediate vmlinux.unstripped
  s390: vmlinux.lds.S: Reorder sections
  KMSAN: Remove tautological checks
  objtool: Drop noinstr hack for KCSAN_WEAK_MEMORY
  lib/Kconfig.debug: Drop CLANG_VERSION check from DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
  riscv: Remove ld.lld version checks from many TOOLCHAIN_HAS configs
  riscv: Unconditionally use linker relaxation
  riscv: Remove version check for LTO_CLANG selects
  powerpc: Drop unnecessary initializations in __copy_inst_from_kernel_nofault()
  mips: Unconditionally select ARCH_HAS_CURRENT_STACK_POINTER
  arm64: Remove tautological LLVM Kconfig conditions
  ARM: Clean up definition of ARM_HAS_GROUP_RELOCS
  ...
2025-10-01 20:58:51 -07:00
Linus Torvalds 4b81e2eb9e Merge tag 'timers-vdso-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull VDSO updates from Thomas Gleixner:

 - Further consolidation of the VDSO infrastructure and the common data
   store

 - Simplification of the related Kconfig logic

 - Improve the VDSO selftest suite

* tag 'timers-vdso-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  selftests: vDSO: Drop vdso_test_clock_getres
  selftests: vDSO: vdso_test_abi: Add tests for clock_gettime64()
  selftests: vDSO: vdso_test_abi: Test CPUTIME clocks
  selftests: vDSO: vdso_test_abi: Use explicit indices for name array
  selftests: vDSO: vdso_test_abi: Drop clock availability tests
  selftests: vDSO: vdso_test_abi: Use ksft_finished()
  selftests: vDSO: vdso_test_abi: Correctly skip whole test with missing vDSO
  selftests: vDSO: Fix -Wunitialized in powerpc VDSO_CALL() wrapper
  vdso: Add struct __kernel_old_timeval forward declaration to gettime.h
  vdso: Gate VDSO_GETRANDOM behind HAVE_GENERIC_VDSO
  vdso: Drop Kconfig GENERIC_VDSO_TIME_NS
  vdso: Drop Kconfig GENERIC_VDSO_DATA_STORE
  vdso: Drop kconfig GENERIC_COMPAT_VDSO
  vdso: Drop kconfig GENERIC_VDSO_32
  riscv: vdso: Untangle Kconfig logic
  time: Build generic update_vsyscall() only with generic time vDSO
  vdso/gettimeofday: Remove !CONFIG_TIME_NS stubs
  vdso: Move ENABLE_COMPAT_VDSO from core to arm64
  ARM: VDSO: Remove cntvct_ok global variable
  vdso/datastore: Gate time data behind CONFIG_GENERIC_GETTIMEOFDAY
2025-09-30 16:58:21 -07:00
Linus Torvalds 7601d18be0 Merge tag 'core-core-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull TIF bit unification updates from Thomas Gleixner:
 "A set of changes to consolidate the generic TIF (thread info flag)
  bits accross architectures.

  All architectures define the same set of generic TIF bits. This makes
  it pointlessly hard to add a new generic TIF bit or to change an
  existing one.

  Provide a generic variant and convert the architectures which utilize
  the generic entry code over to use it. The TIF space is divided into
  16 generic bits and 16 architecture specific bits, which turned out to
  provide enough space on both sides"

* tag 'core-core-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  LoongArch: Fix bitflag conflict for TIF_FIXADE
  riscv: Use generic TIF bits
  loongarch: Use generic TIF bits
  s390/entry: Remove unused TIF flags
  s390: Use generic TIF bits
  x86: Use generic TIF bits
  asm-generic: Provide generic TIF infrastructure
2025-09-30 14:36:20 -07:00
Linus Torvalds 6c7340a7a8 Merge tag 'sched-core-2025-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
 "Core scheduler changes:

   - Make migrate_{en,dis}able() inline, to improve performance
     (Menglong Dong)

   - Move STDL_INIT() functions out-of-line (Peter Zijlstra)

   - Unify the SCHED_{SMT,CLUSTER,MC} Kconfig (Peter Zijlstra)

  Fair scheduling:

   - Defer throttling to when tasks exit to user-space, to reduce the
     chance & impact of throttle-preemption with held locks and other
     resources (Aaron Lu, Valentin Schneider)

   - Get rid of sched_domains_curr_level hack for tl->cpumask(), as the
     warning was getting triggered on certain topologies (Peter
     Zijlstra)

  Misc cleanups & fixes:

   - Header cleanups (Menglong Dong)

   - Fix race in push_dl_task() (Harshit Agarwal)"

* tag 'sched-core-2025-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix some typos in include/linux/preempt.h
  sched: Make migrate_{en,dis}able() inline
  rcu: Replace preempt.h with sched.h in include/linux/rcupdate.h
  arch: Add the macro COMPILE_OFFSETS to all the asm-offsets.c
  sched/fair: Do not balance task to a throttled cfs_rq
  sched/fair: Do not special case tasks in throttled hierarchy
  sched/fair: update_cfs_group() for throttled cfs_rqs
  sched/fair: Propagate load for throttled cfs_rq
  sched/fair: Get rid of throttled_lb_pair()
  sched/fair: Task based throttle time accounting
  sched/fair: Switch to task based throttle model
  sched/fair: Implement throttle task work and related helpers
  sched/fair: Add related data structure for task based throttle
  sched: Unify the SCHED_{SMT,CLUSTER,MC} Kconfig
  sched: Move STDL_INIT() functions out-of-line
  sched/fair: Get rid of sched_domains_curr_level hack for tl->cpumask()
  sched/deadline: Fix race in push_dl_task()
2025-09-30 10:35:11 -07:00
Kees Cook 23ef9d4397 kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI
The kernel's CFI implementation uses the KCFI ABI specifically, and is
not strictly tied to a particular compiler. In preparation for GCC
supporting KCFI, rename CONFIG_CFI_CLANG to CONFIG_CFI (along with
associated options).

Use new "transitional" Kconfig option for old CONFIG_CFI_CLANG that will
enable CONFIG_CFI during olddefconfig.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250923213422.1105654-3-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
2025-09-24 14:29:14 -07:00
Thomas Gleixner 2958934348 asm-generic: Provide generic TIF infrastructure
Common TIF bits do not have to be defined by every architecture. They can
be defined in a generic header.

That allows adding generic TIF bits without chasing a gazillion of
architecture headers, which is again a unjustified burden on anyone who
works on generic infrastructure as it always needs a boat load of work to
keep existing architecture code working when adding new stuff.

While it is not as horrible as the ignorance of the generic entry
infrastructure, it is a welcome mechanism to make architecture people
rethink their approach of just leaching generic improvements into
architecture code and thereby making it accumulatingly harder to maintain
and improve generic code. It's about time that this changes.

Provide the infrastructure and split the TIF space in half, 16 generic and
16 architecture specific bits.

This could probably be extended by TIF_SINGLESTEP and BLOCKSTEP, but those
are only used in architecture specific code. So leave them alone for now.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2025-09-17 08:14:03 +02:00
Thomas Weißschuh 7b338f6d4e vdso: Drop Kconfig GENERIC_VDSO_DATA_STORE
All users of the generic vDSO library also use the generic vDSO datastore.

Remove the now unnecessary Kconfig symbol.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/all/20250826-vdso-cleanups-v1-9-d9b65750e49f@linutronix.de
2025-09-04 11:23:50 +02:00