Commit graph

192,584 commits

Author SHA1 Message Date
Sean Christopherson
fd4c14c7b7 KVM: nSVM: Clear exit_code_hi in VMCB when synthesizing nested VM-Exits
commit da01f64e74 upstream.

Explicitly clear exit_code_hi in the VMCB when synthesizing "normal"
nested VM-Exits, as the full exit code is a 64-bit value (spoiler alert),
and all exit codes for non-failing VMRUN use only bits 31:0.

Cc: Jim Mattson <jmattson@google.com>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Cc: stable@vger.kernel.org
Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20251113225621.1688428-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-19 13:09:53 +01:00
Sean Christopherson
d8c44d5661 KVM: nSVM: Set exit_code_hi to -1 when synthesizing SVM_EXIT_ERR (failed VMRUN)
commit f402ecd7a8 upstream.

Set exit_code_hi to -1u as a temporary band-aid to fix a long-standing
(effectively since KVM's inception) bug where KVM treats the exit code as
a 32-bit value, when in reality it's a 64-bit value.  Per the APM, offset
0x70 is a single 64-bit value:

  070h 63:0 EXITCODE

And a sane reading of the error values defined in "Table C-1. SVM Intercept
Codes" is that negative values use the full 64 bits:

  –1 VMEXIT_INVALID Invalid guest state in VMCB.
  –2 VMEXIT_BUSYBUSY bit was set in the VMSA
  –3 VMEXIT_IDLE_REQUIREDThe sibling thread is not in an idle state
  -4 VMEXIT_INVALID_PMC Invalid PMC state

And that interpretation is confirmed by testing on Milan and Turin (by
setting bits in CR0[63:32] to generate VMEXIT_INVALID on VMRUN).

Furthermore, Xen has treated exitcode as a 64-bit value since HVM support
was adding in 2006 (see Xen commit d1bd157fbc ("Big merge the HVM
full-virtualisation abstractions.")).

Cc: Jim Mattson <jmattson@google.com>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Cc: stable@vger.kernel.org
Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20251113225621.1688428-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-19 13:09:53 +01:00
Yosry Ahmed
30c71d9b4d KVM: nSVM: Propagate SVM_EXIT_CR0_SEL_WRITE correctly for LMSW emulation
commit 5674a76db0 upstream.

When emulating L2 instructions, svm_check_intercept() checks whether a
write to CR0 should trigger a synthesized #VMEXIT with
SVM_EXIT_CR0_SEL_WRITE. For MOV-to-CR0, SVM_EXIT_CR0_SEL_WRITE is only
triggered if any bit other than CR0.MP and CR0.TS is updated. However,
according to the APM (24593—Rev.  3.42—March 2024, Table 15-7):

  The LMSW instruction treats the selective CR0-write
  intercept as a non-selective intercept (i.e., it intercepts
  regardless of the value being written).

Skip checking the changed bits for x86_intercept_lmsw and always inject
SVM_EXIT_CR0_SEL_WRITE.

Fixes: cfec82cb7d ("KVM: SVM: Add intercept check for emulated cr accesses")
Cc: stable@vger.kernel.org
Reported-by: Matteo Rizzo <matteorizzo@google.com>
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20251024192918.3191141-3-yosry.ahmed@linux.dev
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-19 13:09:53 +01:00
fuqiang wang
d2da0df7bb KVM: x86: Fix VM hard lockup after prolonged inactivity with periodic HV timer
commit 18ab3fc8e8 upstream.

When advancing the target expiration for the guest's APIC timer in periodic
mode, set the expiration to "now" if the target expiration is in the past
(similar to what is done in update_target_expiration()).  Blindly adding
the period to the previous target expiration can result in KVM generating
a practically unbounded number of hrtimer IRQs due to programming an
expired timer over and over.  In extreme scenarios, e.g. if userspace
pauses/suspends a VM for an extended duration, this can even cause hard
lockups in the host.

Currently, the bug only affects Intel CPUs when using the hypervisor timer
(HV timer), a.k.a. the VMX preemption timer.  Unlike the software timer,
a.k.a. hrtimer, which KVM keeps running even on exits to userspace, the
HV timer only runs while the guest is active.  As a result, if the vCPU
does not run for an extended duration, there will be a huge gap between
the target expiration and the current time the vCPU resumes running.
Because the target expiration is incremented by only one period on each
timer expiration, this leads to a series of timer expirations occurring
rapidly after the vCPU/VM resumes.

More critically, when the vCPU first triggers a periodic HV timer
expiration after resuming, advancing the expiration by only one period
will result in a target expiration in the past.  As a result, the delta
may be calculated as a negative value.  When the delta is converted into
an absolute value (tscdeadline is an unsigned u64), the resulting value
can overflow what the HV timer is capable of programming.  I.e. the large
value will exceed the VMX Preemption Timer's maximum bit width of
cpu_preemption_timer_multi + 32, and thus cause KVM to switch from the
HV timer to the software timer (hrtimers).

After switching to the software timer, periodic timer expiration callbacks
may be executed consecutively within a single clock interrupt handler,
because hrtimers honors KVM's request for an expiration in the past and
immediately re-invokes KVM's callback after reprogramming.  And because
the interrupt handler runs with IRQs disabled, restarting KVM's hrtimer
over and over until the target expiration is advanced to "now" can result
in a hard lockup.

E.g. the following hard lockup was triggered in the host when running a
Windows VM (only relevant because it used the APIC timer in periodic mode)
after resuming the VM from a long suspend (in the host).

  NMI watchdog: Watchdog detected hard LOCKUP on cpu 45
  ...
  RIP: 0010:advance_periodic_target_expiration+0x4d/0x80 [kvm]
  ...
  RSP: 0018:ff4f88f5d98d8ef0 EFLAGS: 00000046
  RAX: fff0103f91be678e RBX: fff0103f91be678e RCX: 00843a7d9e127bcc
  RDX: 0000000000000002 RSI: 0052ca4003697505 RDI: ff440d5bfbdbd500
  RBP: ff440d5956f99200 R08: ff2ff2a42deb6a84 R09: 000000000002a6c0
  R10: 0122d794016332b3 R11: 0000000000000000 R12: ff440db1af39cfc0
  R13: ff440db1af39cfc0 R14: ffffffffc0d4a560 R15: ff440db1af39d0f8
  FS:  00007f04a6ffd700(0000) GS:ff440db1af380000(0000) knlGS:000000e38a3b8000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 000000d5651feff8 CR3: 000000684e038002 CR4: 0000000000773ee0
  PKRU: 55555554
  Call Trace:
   <IRQ>
   apic_timer_fn+0x31/0x50 [kvm]
   __hrtimer_run_queues+0x100/0x280
   hrtimer_interrupt+0x100/0x210
   ? ttwu_do_wakeup+0x19/0x160
   smp_apic_timer_interrupt+0x6a/0x130
   apic_timer_interrupt+0xf/0x20
   </IRQ>

Moreover, if the suspend duration of the virtual machine is not long enough
to trigger a hard lockup in this scenario, since commit 98c25ead5e
("KVM: VMX: Move preemption timer <=> hrtimer dance to common x86"), KVM
will continue using the software timer until the guest reprograms the APIC
timer in some way.  Since the periodic timer does not require frequent APIC
timer register programming, the guest may continue to use the software
timer in perpetuity.

Fixes: d8f2f498d9 ("x86/kvm: fix LAPIC timer drift when guest uses periodic mode")
Cc: stable@vger.kernel.org
Signed-off-by: fuqiang wang <fuqiang.wng@gmail.com>
[sean: massage comments and changelog]
Link: https://patch.msgid.link/20251113205114.1647493-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-19 13:09:53 +01:00
fuqiang wang
6ae727f72b KVM: x86: Explicitly set new periodic hrtimer expiration in apic_timer_fn()
commit 9633f180ce upstream.

When restarting an hrtimer to emulate a the guest's APIC timer in periodic
mode, explicitly set the expiration using the target expiration computed
by advance_periodic_target_expiration() instead of adding the period to
the existing timer.  This will allow making adjustments to the expiration,
e.g. to deal with expirations far in the past, without having to implement
the same logic in both advance_periodic_target_expiration() and
apic_timer_fn().

Cc: stable@vger.kernel.org
Signed-off-by: fuqiang wang <fuqiang.wng@gmail.com>
[sean: split to separate patch, write changelog]
Link: https://patch.msgid.link/20251113205114.1647493-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-19 13:09:53 +01:00
Sean Christopherson
fa0c3fbc4b KVM: x86: WARN if hrtimer callback for periodic APIC timer fires with period=0
commit 0ea9494be9 upstream.

WARN and don't restart the hrtimer if KVM's callback runs with the guest's
APIC timer in periodic mode but with a period of '0', as not advancing the
hrtimer's deadline would put the CPU into an infinite loop of hrtimer
events.  Observing a period of '0' should be impossible, even when the
hrtimer is running on a different CPU than the vCPU, as KVM is supposed to
cancel the hrtimer before changing (or zeroing) the period, e.g. when
switching from periodic to one-shot.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251113205114.1647493-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-19 13:09:52 +01:00
Eric Biggers
3c35608d65 lib/crypto: x86/blake2s: Fix 32-bit arg treated as 64-bit
commit 2f22115709 upstream.

In the C code, the 'inc' argument to the assembly functions
blake2s_compress_ssse3() and blake2s_compress_avx512() is declared with
type u32, matching blake2s_compress().  The assembly code then reads it
from the 64-bit %rcx.  However, the ABI doesn't guarantee zero-extension
to 64 bits, nor do gcc or clang guarantee it.  Therefore, fix these
functions to read this argument from the 32-bit %ecx.

In theory, this bug could have caused the wrong 'inc' value to be used,
causing incorrect BLAKE2s hashes.  In practice, probably not: I've fixed
essentially this same bug in many other assembly files too, but there's
never been a real report of it having caused a problem.  In x86_64, all
writes to 32-bit registers are zero-extended to 64 bits.  That results
in zero-extension in nearly all situations.  I've only been able to
demonstrate a lack of zero-extension with a somewhat contrived example
involving truncation, e.g. when the C code has a u64 variable holding
0x1234567800000040 and passes it as a u32 expecting it to be truncated
to 0x40 (64).  But that's not what the real code does, of course.

Fixes: ed0356eda1 ("crypto: blake2s - x86_64 SIMD implementation")
Cc: stable@vger.kernel.org
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251102234209.62133-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-19 13:09:49 +01:00
Ben Collins
46778b34e0 powerpc/addnote: Fix overflow on 32-bit builds
[ Upstream commit 825ce89a3e ]

The PUT_64[LB]E() macros need to cast the value to unsigned long long
like the GET_64[LB]E() macros. Caused lots of warnings when compiled
on 32-bit, and clobbered addresses (36-bit P4080).

Signed-off-by: Ben Collins <bcollins@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/2025042122-mustard-wrasse-694572@boujee-and-buff
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:47 +01:00
Peter Zijlstra
0144d18dd9 x86/ptrace: Always inline trivial accessors
[ Upstream commit 1fe4002cf7 ]

A KASAN build bloats these single load/store helpers such that
it fails to inline them:

  vmlinux.o: error: objtool: irqentry_exit+0x5e8: call to instruction_pointer_set() with UACCESS enabled

Make sure the compiler isn't allowed to do stupid.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://patch.msgid.link/20251031105435.GU4068168@noisy.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:41 +01:00
Ondrej Mosnacek
b3f937e891 bpf, arm64: Do not audit capability check in do_jit()
[ Upstream commit 189e5deb94 ]

Analogically to the x86 commit 881a9c9cb7 ("bpf: Do not audit
capability check in do_jit()"), change the capable() call to
ns_capable_noaudit() in order to avoid spurious SELinux denials in audit
log.

The commit log from that commit applies here as well:
"""
The failure of this check only results in a security mitigation being
applied, slightly affecting performance of the compiled BPF program. It
doesn't result in a failed syscall, an thus auditing a failed LSM
permission check for it is unwanted. For example with SELinux, it causes
a denial to be reported for confined processes running as root, which
tends to be flagged as a problem to be fixed in the policy. Yet
dontauditing or allowing CAP_SYS_ADMIN to the domain may not be
desirable, as it would allow/silence also other checks - either going
against the principle of least privilege or making debugging potentially
harder.

Fix it by changing it from capable() to ns_capable_noaudit(), which
instructs the LSMs to not audit the resulting denials.
"""

Fixes: f300769ead ("arm64: bpf: Only mitigate cBPF programs loaded by unprivileged users")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Link: https://lore.kernel.org/r/20251204125916.441021-1-omosnace@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:41 +01:00
Liyuan Pang
a9bfe4eb01 ARM: 9464/1: fix input-only operand modification in load_unaligned_zeropad()
[ Upstream commit edb924a721 ]

In the inline assembly inside load_unaligned_zeropad(), the "addr" is
constrained as input-only operand. The compiler assumes that on exit
from the asm statement these operands contain the same values as they
had before executing the statement, but when kernel page fault happened, the assembly fixup code "bic %2 %2, #0x3" modify the value of "addr", which may lead to an unexpected behavior.

Use a temporary variable "tmp" to handle it, instead of modifying the
input-only operand, just like what arm64's load_unaligned_zeropad()
does.

Fixes: b9a50f7490 ("ARM: 7450/1: dcache: select DCACHE_WORD_ACCESS for little-endian ARMv6+ CPUs")
Co-developed-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Liyuan Pang <pangliyuan1@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:39 +01:00
Ritesh Harjani (IBM)
e0a6dcbb8c powerpc/64s/ptdump: Fix kernel_hash_pagetable dump for ISA v3.00 HPTE format
[ Upstream commit eae40a6da6 ]

HPTE format was changed since Power9 (ISA 3.0) onwards. While dumping
kernel hash page tables, nothing gets printed on powernv P9+. This patch
utilizes the helpers added in the patch tagged as fixes, to convert new
format to old format and dump the hptes. This fix is only needed for
native_find() (powernv), since pseries continues to work fine with the
old format.

Fixes: 6b243fcfb5 ("powerpc/64: Simplify adaptation to new ISA v3.00 HPTE format")
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/4c2bb9e5b3cfbc0dd80b61b67cdd3ccfc632684c.1761834163.git.ritesh.list@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:30 +01:00
Christophe Leroy
3061b299fc powerpc/32: Fix unpaired stwcx. on interrupt exit
[ Upstream commit 10e1c77c36 ]

Commit b96bae3ae2 ("powerpc/32: Replace ASM exception exit by C
exception exit from ppc64") erroneouly copied to powerpc/32 the logic
from powerpc/64 based on feature CPU_FTR_STCX_CHECKS_ADDRESS which is
always 0 on powerpc/32.

Re-instate the logic implemented by commit b64f87c16f ("[POWERPC]
Avoid unpaired stwcx. on some processors") which is based on
CPU_FTR_NEED_PAIRED_STWCX feature.

Fixes: b96bae3ae2 ("powerpc/32: Replace ASM exception exit by C exception exit from ppc64")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/6040b5dbcf5cdaa1cd919fcf0790f12974ea6e5a.1757666244.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:27 +01:00
Dapeng Mi
c0763fe31c perf/x86/intel: Correct large PEBS flag check
[ Upstream commit 5e4e355ae7 ]

current large PEBS flag check only checks if sample_regs_user contains
unsupported GPRs but doesn't check if sample_regs_intr contains
unsupported GPRs.

Of course, currently PEBS HW supports to sample all perf supported GPRs,
the missed check doesn't cause real issue. But it won't be true any more
after the subsequent patches support to sample SSP register. SSP
sampling is not supported by adaptive PEBS HW and it would be supported
until arch-PEBS HW. So correct this issue.

Fixes: a47ba4d77e ("perf/x86: Enable free running PEBS for REGS_USER/INTR")
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251029102136.61364-5-dapeng1.mi@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:26 +01:00
Tengda Wu
9ff4cea267 x86/dumpstack: Prevent KASAN false positive warnings in __show_regs()
[ Upstream commit ced37e9cea ]

When triggering a stack dump via sysrq (echo t > /proc/sysrq-trigger),
KASAN may report false-positive out-of-bounds access:

  BUG: KASAN: out-of-bounds in __show_regs+0x4b/0x340
  Call Trace:
    dump_stack_lvl
    print_address_description.constprop.0
    print_report
    __show_regs
    show_trace_log_lvl
    sched_show_task
    show_state_filter
    sysrq_handle_showstate
    __handle_sysrq
    write_sysrq_trigger
    proc_reg_write
    vfs_write
    ksys_write
    do_syscall_64
    entry_SYSCALL_64_after_hwframe

The issue occurs as follows:

  Task A (walk other tasks' stacks)           Task B (running)
  1. echo t > /proc/sysrq-trigger
  show_trace_log_lvl
    regs = unwind_get_entry_regs()
    show_regs_if_on_stack(regs)
                                              2. The stack value pointed by
                                                 `regs` keeps changing, and
                                                 so are the tags in its
                                                 KASAN shadow region.
      __show_regs(regs)
        regs->ax, regs->bx, ...
          3. hit KASAN redzones, OOB

When task A walks task B's stack without suspending it, the continuous changes
in task B's stack (and corresponding KASAN shadow tags) may cause task A to
hit KASAN redzones when accessing obsolete values on the stack, resulting in
false positive reports.

Simply stopping the task before unwinding is not a viable fix, as it would
alter the state intended to inspect. This is especially true for diagnosing
misbehaving tasks (e.g., in a hard lockup), where stopping might fail or hide
the root cause by changing the call stack.

Therefore, fix this by disabling KASAN checks during asynchronous stack
unwinding, which is identified when the unwinding task does not match the
current task (task != current).

  [ bp: Align arguments on function's opening brace. ]

Fixes: 3b3fa11bc7 ("x86/dumpstack: Print any pt_regs found on the stack")
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/all/20251023090632.269121-1-wutengda@huaweicloud.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:25 +01:00
Alexander Potapenko
898581813a x86: kmsan: don't instrument stack walking functions
[ Upstream commit 37ad4ee836 ]

Upon function exit, KMSAN marks local variables as uninitialized.  Further
function calls may result in the compiler creating the stack frame where
these local variables resided.  This results in frame pointers being
marked as uninitialized data, which is normally correct, because they are
not stack-allocated.

However stack unwinding functions are supposed to read and dereference the
frame pointers, in which case KMSAN might be reporting uses of
uninitialized values.

To work around that, we mark update_stack_state(), unwind_next_frame() and
show_trace_log_lvl() with __no_kmsan_checks, preventing all KMSAN reports
inside those functions and making them return initialized values.

Link: https://lkml.kernel.org/r/20220915150417.722975-40-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: ced37e9cea ("x86/dumpstack: Prevent KASAN false positive warnings in __show_regs()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:25 +01:00
Heiko Carstens
fc09726c92 s390/smp: Fix fallback CPU detection
[ Upstream commit 07a75d08cf ]

In case SCLP CPU detection does not work a fallback mechanism using SIGP is
in place. Since a cleanup this does not work correctly anymore: new CPUs
are only considered if their type matches the boot CPU.

Before the cleanup the information if a CPU type should be considered was
also part of a structure generated by the fallback mechanism and indicated
that a CPU type should not be considered when adding CPUs.

Since the rework a global SCLP state is used instead. If the global SCLP
state indicates that the CPU type should be considered and the fallback
mechanism is used, there may be a mismatch with CPU types if CPUs are
added. This can lead to a system with only a single CPU even tough there
are many more CPUs.

Address this by simply copying the boot cpu type into the generated data
structure from the fallback mechanism.

Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Fixes: d08d94306e ("s390/smp: cleanup core vs. cpu in the SCLP interface")
Reviewed-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:24 +01:00
Tim Harvey
d27289e628 arm64: dts: imx8mm-venice-gw72xx: remove unused sdhc1 pinctrl
[ Upstream commit d949b8d12d ]

The SDHC1 interface is not used on the imx8mm-venice-gw72xx. Remove the
unused pinctrl_usdhc1 iomux node.

Fixes: 6f30b27c5e ("arm64: dts: imx8mm: Add Gateworks i.MX 8M Mini Development Kits")
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19 13:09:23 +01:00
Maciej W. Rozycki
19f3ace949 MIPS: mm: Prevent a TLB shutdown on initial uniquification
commit 9f048fa487 upstream.

Depending on the particular CPU implementation a TLB shutdown may occur
if multiple matching entries are detected upon the execution of a TLBP
or the TLBWI/TLBWR instructions.  Given that we don't know what entries
we have been handed we need to be very careful with the initial TLB
setup and avoid all these instructions.

Therefore read all the TLB entries one by one with the TLBR instruction,
bypassing the content addressing logic, and truncate any large pages in
place so as to avoid a case in the second step where an incoming entry
for a large page at a lower address overlaps with a replacement entry
chosen at another index.  Then preinitialize the TLB using addresses
outside our usual unique range and avoiding clashes with any entries
received, before making the usual call to local_flush_tlb_all().

This fixes (at least) R4x00 cores if TLBP hits multiple matching TLB
entries (SGI IP22 PROM for examples sets up all TLBs to the same virtual
address).

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: 35ad7e1815 ("MIPS: mm: tlb-r4k: Uniquify TLB entries on init")
Cc: stable@vger.kernel.org
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com> # Boston I6400, M5150 sim
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07 06:09:34 +09:00
Jiri Olsa
5b9790d200 Revert "perf/x86: Always store regs->ip in perf_callchain_kernel()"
commit 6d08340d1e upstream.

This reverts commit 83f44ae0f8.

Currently we store initial stacktrace entry twice for non-HW ot_regs, which
means callers that fail perf_hw_regs(regs) condition in perf_callchain_kernel.

It's easy to reproduce this bpftrace:

  # bpftrace -e 'tracepoint:sched:sched_process_exec { print(kstack()); }'
  Attaching 1 probe...

        bprm_execve+1767
        bprm_execve+1767
        do_execveat_common.isra.0+425
        __x64_sys_execve+56
        do_syscall_64+133
        entry_SYSCALL_64_after_hwframe+118

When perf_callchain_kernel calls unwind_start with first_frame, AFAICS
we do not skip regs->ip, but it's added as part of the unwind process.
Hence reverting the extra perf_callchain_store for non-hw regs leg.

I was not able to bisect this, so I'm not really sure why this was needed
in v5.2 and why it's not working anymore, but I could see double entries
as far as v5.10.

I did the test for both ORC and framepointer unwind with and without the
this fix and except for the initial entry the stacktraces are the same.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20251104215405.168643-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07 06:09:34 +09:00
Nick Desaulniers
707d49dd44 Makefile.compiler: replace cc-ifversion with compiler-specific macros
commit 88b61e3bff upstream.

cc-ifversion is GCC specific. Replace it with compiler specific
variants. Update the users of cc-ifversion to use these new macros.

Link: https://github.com/ClangBuiltLinux/linux/issues/350
Link: https://lore.kernel.org/llvm/CAGG=3QWSAUakO42kubrCap8fp-gm1ERJJAYXTnP1iHk_wrH=BQ@mail.gmail.com/
Suggested-by: Bill Wendling <morbo@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
[nathan: Backport to 5.15 and eliminate instances of cc-ifversion that
         did not exist upstream when this change was original created]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07 06:09:32 +09:00
Maciej W. Rozycki
7536472a45 MIPS: Malta: Fix !EVA SOC-it PCI MMIO
commit ebd729fef3 upstream.

Fix a regression that has caused accesses to the PCI MMIO window to
complete unclaimed in non-EVA configurations with the SOC-it family of
system controllers, preventing PCI devices from working that use MMIO.

In the non-EVA case PHYS_OFFSET is set to 0, meaning that PCI_BAR0 is
set with an empty mask (and PCI_HEAD4 matches addresses starting from 0
accordingly).  Consequently all addresses are matched for incoming DMA
accesses from PCI.  This seems to confuse the system controller's logic
and outgoing bus cycles targeting the PCI MMIO window seem not to make
it to the intended devices.

This happens as well when a wider mask is used with PCI_BAR0, such as
0x80000000 or 0xe0000000, that makes addresses match that overlap with
the PCI MMIO window, which starts at 0x10000000 in our configuration.

Set the mask in PCI_BAR0 to 0xf0000000 for non-EVA then, covering the
non-EVA maximum 256 MiB of RAM, which is what YAMON does and which used
to work correctly up to the offending commit.  Set PCI_P2SCMSKL to match
PCI_BAR0 as required by the system controller's specification, and match
PCI_P2SCMAPL to PCI_HEAD4 for identity mapping.

Verified with:

Core board type/revision =      0x0d (Core74K) / 0x01
System controller/revision =    MIPS SOC-it 101 OCP / 1.3   SDR-FW-4:1
Processor Company ID/options =  0x01 (MIPS Technologies, Inc.) / 0x1c
Processor ID/revision =         0x97 (MIPS 74Kf) / 0x4c

for non-EVA and with:

Core board type/revision =      0x0c (CoreFPGA-5) / 0x00
System controller/revision =    MIPS ROC-it2 / 0.0   FW-1:1 (CLK_unknown) GIC
Processor Company ID/options =  0x01 (MIPS Technologies, Inc.) / 0x00
Processor ID/revision =         0xa0 (MIPS interAptiv UP) / 0x20

for EVA/non-EVA, fixing:

defxx 0000:00:12.0: assign IRQ: got 10
defxx: v1.12 2021/03/10  Lawrence V. Stefani and others
0000:00:12.0: Could not read adapter factory MAC address!

vs:

defxx 0000:00:12.0: assign IRQ: got 10
defxx: v1.12 2021/03/10  Lawrence V. Stefani and others
0000:00:12.0: DEFPA at MMIO addr = 0x10142000, IRQ = 10, Hardware addr = 00-00-f8-xx-xx-xx
0000:00:12.0: registered as fddi0

for non-EVA and causing no change for EVA.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: 422dd25664 ("MIPS: Malta: Allow PCI devices DMA to lower 2GB physical")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07 06:09:31 +09:00
Eric Biggers
20067f737d lib/crypto: arm/curve25519: Disable on CPU_BIG_ENDIAN
commit 44e8241c51 upstream.

On big endian arm kernels, the arm optimized Curve25519 code produces
incorrect outputs and fails the Curve25519 test.  This has been true
ever since this code was added.

It seems that hardly anyone (or even no one?) actually uses big endian
arm kernels.  But as long as they're ostensibly supported, we should
disable this code on them so that it's not accidentally used.

Note: for future-proofing, use !CPU_BIG_ENDIAN instead of
CPU_LITTLE_ENDIAN.  Both of these are arch-specific options that could
get removed in the future if big endian support gets dropped.

Fixes: d8f1308a02 ("crypto: arm/curve25519 - wire up NEON implementation")
Cc: stable@vger.kernel.org
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251104054906.716914-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:29 +09:00
Danil Skrebenkov
e5d5b4228e RISC-V: clear hot-unplugged cores from all task mm_cpumasks to avoid rfence errors
[ Upstream commit ae9e9f3d67 ]

openSBI v1.7 adds harts checks for ipi operations. Especially it
adds comparison between hmask passed as an argument from linux
and mask of online harts (from openSBI side). If they don't
fit each other the error occurs.

When cpu is offline, cpu_online_mask is explicitly cleared in
__cpu_disable. However, there is no explicit clearing of
mm_cpumask. mm_cpumask is used for rfence operations that
call openSBI RFENCE extension which uses ipi to remote harts.
If hart is offline there may be error if mask of linux is not
as mask of online harts in openSBI.

this patch adds explicit clearing of mm_cpumask for offline hart.

Signed-off-by: Danil Skrebenkov <danil.skrebenkov@cloudbear.ru>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20250919132849.31676-1-danil.skrebenkov@cloudbear.ru
[pjw@kernel.org: rewrote subject line for clarity]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:27 +09:00
Josephine Pfeiffer
f8d974a0e8 riscv: ptdump: use seq_puts() in pt_dump_seq_puts() macro
[ Upstream commit a74f038fa5 ]

The pt_dump_seq_puts() macro incorrectly uses seq_printf() instead of
seq_puts(). This is both a performance issue and conceptually wrong,
as the macro name suggests plain string output (puts) but the
implementation uses formatted output (printf).

The macro is used in ptdump.c:301 to output a newline character. Using
seq_printf() adds unnecessary overhead for format string parsing when
outputting this constant string.

This bug was introduced in commit 59c4da8640 ("riscv: Add support to
dump the kernel page tables") in 2020, which copied the implementation
pattern from other architectures that had the same bug.

Fixes: 59c4da8640 ("riscv: Add support to dump the kernel page tables")
Signed-off-by: Josephine Pfeiffer <hi@josie.lol>
Link: https://lore.kernel.org/r/20251018170451.3355496-1-hi@josie.lol
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:25 +09:00
Nicolas Ferre
e7322da6c5 ARM: at91: pm: save and restore ACR during PLL disable/enable
[ Upstream commit 0c01fe4965 ]

Add a new word in assembly to store ACR value during the calls
to at91_plla_disable/at91_plla_enable macros and use it.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
[cristian.birsan@microchip.com: remove ACR_DEFAULT_PLLA loading]
Signed-off-by: Cristian Birsan <cristian.birsan@microchip.com>
Link: https://lore.kernel.org/r/20250827145427.46819-4-nicolas.ferre@microchip.com
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:24 +09:00
Tiwei Bie
cebc9f5ee3 um: Fix help message for ssl-non-raw
[ Upstream commit 725e9d8186 ]

Add the missing option name in the help message. Additionally,
switch to __uml_help(), because this is a global option rather
than a per-channel option.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:24 +09:00
Koakuma
e500663366 sparc/module: Add R_SPARC_UA64 relocation handling
[ Upstream commit 05457d9617 ]

This is needed so that the kernel can handle R_SPARC_UA64 relocations,
which is emitted by LLVM's IAS.

Signed-off-by: Koakuma <koachan@protonmail.com>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:23 +09:00
Li RongQing
b16a010338 x86/kvm: Prefer native qspinlock for dedicated vCPUs irrespective of PV_UNHALT
[ Upstream commit 9605505039 ]

The commit b2798ba0b8 ("KVM: X86: Choose qspinlock when dedicated
physical CPUs are available") states that when PV_DEDICATED=1
(vCPU has dedicated pCPU), qspinlock should be preferred regardless of
PV_UNHALT.  However, the current implementation doesn't reflect this: when
PV_UNHALT=0, we still use virt_spin_lock() even with dedicated pCPUs.

This is suboptimal because:
1. Native qspinlocks should outperform virt_spin_lock() for dedicated
   vCPUs irrespective of HALT exiting
2. virt_spin_lock() should only be preferred when vCPUs may be preempted
   (non-dedicated case)

So reorder the PV spinlock checks to:
1. First handle dedicated pCPU case (disable virt_spin_lock_key)
2. Second check single CPU, and nopvspin configuration
3. Only then check PV_UNHALT support

This ensures we always use native qspinlock for dedicated vCPUs, delivering
pretty performance gains at high contention levels.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Tested-by: Wangyang Guo <wangyang.guo@intel.com>
Link: https://lore.kernel.org/r/20250722110005.4988-1-lirongqing@baidu.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:21 +09:00
Aleksander Jan Bajkowski
7ce10ef9a9 mips: lantiq: xway: sysctrl: rename stp clock
[ Upstream commit b0d04fe6a6 ]

Bindig requires a node name matching ‘^gpio@[0-9a-f]+$’. This patch
changes the clock name from “stp” to “gpio”.

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:20 +09:00
Aleksander Jan Bajkowski
e1f79a12bd mips: lantiq: danube: add missing device_type in pci node
[ Upstream commit d66949a187 ]

This fixes the following warning:
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: pci@e105400 (lantiq,pci-xway): 'device_type' is a required property
	from schema $id: http://devicetree.org/schemas/pci/pci-bus-common.yaml#

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:20 +09:00
Aleksander Jan Bajkowski
a39c88bedb mips: lantiq: danube: add missing properties to cpu node
[ Upstream commit e8dee66c37 ]

This fixes the following warnings:
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: cpus: '#address-cells' is a required property
	from schema $id: http://devicetree.org/schemas/cpus.yaml#
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: cpus: '#size-cells' is a required property
	from schema $id: http://devicetree.org/schemas/cpus.yaml#
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: cpu@0 (mips,mips24Kc): 'reg' is a required property
	from schema $id: http://devicetree.org/schemas/mips/cpus.yaml#

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:20 +09:00
Niklas Schnelle
a65cbffb0e powerpc/eeh: Use result of error_detected() in uevent
[ Upstream commit 704e5dd1c0 ]

Ever since uevent support was added for AER and EEH with commit
856e1eb9bd ("PCI/AER: Add uevents in AER and EEH error/resume"), it
reported PCI_ERS_RESULT_NONE as uevent when recovery begins.

Commit 7b42d97e99 ("PCI/ERR: Always report current recovery status for
udev") subsequently amended AER to report the actual return value of
error_detected().

Make the same change to EEH to align it with AER and s390.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/linux-pci/aIp6LiKJor9KLVpv@wunner.de/
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Link: https://patch.msgid.link/20250807-add_err_uevents-v5-3-adf85b0620b0@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:19 +09:00
Kirill A. Shutemov
d178723da2 x86/vsyscall: Do not require X86_PF_INSTR to emulate vsyscall
[ Upstream commit 8ba38a7a9a ]

emulate_vsyscall() expects to see X86_PF_INSTR in PFEC on a vsyscall
page fault, but the CPU does not report X86_PF_INSTR if neither
X86_FEATURE_NX nor X86_FEATURE_SMEP are enabled.

X86_FEATURE_NX should be enabled on nearly all 64-bit CPUs, except for
early P4 processors that did not support this feature.

Instead of explicitly checking for X86_PF_INSTR, compare the fault
address to RIP.

On machines with X86_FEATURE_NX enabled, issue a warning if RIP is equal
to fault address but X86_PF_INSTR is absent.

[ dhansen: flesh out code comments ]

Originally-by: Dave Hansen <dave.hansen@intel.com>
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Link: https://lore.kernel.org/all/bd81a98b-f8d4-4304-ac55-d4151a1a77ab@intel.com
Link: https://lore.kernel.org/all/20250624145918.2720487-1-kirill.shutemov%40linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:18 +09:00
Kees Cook
1ba13dde6a arc: Fix __fls() const-foldability via __builtin_clzl()
[ Upstream commit a3fecb9160 ]

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>
2025-12-07 06:09:16 +09:00
Matthieu Baerts (NGI0)
518eadd15f arch: back to -std=gnu89 in < v5.18
Recent fixes have been backported to < v5.18 to fix build issues with
GCC 5.15. They all force -std=gnu11 in the CFLAGS, "because [the kernel]
requests the gnu11 standard via '-std=' in the main Makefile".

This is true for >= 5.18 versions, but not before. This switch to
-std=gnu11 has been done in commit e8c07082a8 ("Kbuild: move to
-std=gnu11").

For a question of uniformity, force -std=gnu89, similar to what is done
in the main Makefile.

Note: the fixes tags below refers to upstream commits, but this fix is
only for kernels not having commit e8c07082a8 ("Kbuild: move to
-std=gnu11").

Fixes: 7cbb015e2d ("parisc: fix building with gcc-15")
Fixes: 3b8b80e993 ("s390: Add '-std=gnu11' to decompressor and purgatory CFLAGS")
Fixes: b3bee1e7c3 ("x86/boot: Compile boot code with -std=gnu11 too")
Fixes: ee2ab467bd ("x86/boot: Use '-std=gnu11' to fix build with GCC 15")
Fixes: 8ba14d9f49 ("efi: libstub: Use '-std=gnu11' to fix build with GCC 15")
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07 06:09:15 +09:00
Alexey Dobriyan
f28b14d235 x86/boot: Compile boot code with -std=gnu11 too
commit b3bee1e7c3 upstream.

Use -std=gnu11 for consistency with main kernel code.

It doesn't seem to change anything in vmlinux.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Link: https://lore.kernel.org/r/2058761e-12a4-4b2f-9690-3c3c1c9902a5@p183
[ This kernel version doesn't build with GCC 15:
    In file included from include/uapi/linux/posix_types.h:5,
                     from include/uapi/linux/types.h:14,
                     from include/linux/types.h:6,
                     from arch/x86/realmode/rm/wakeup.h:11,
                     from arch/x86/realmode/rm/wakemain.c:2:
    include/linux/stddef.h:11:9: error: cannot use keyword 'false' as enumeration constant
       11 |         false   = 0,
          |         ^~~~~
    include/linux/stddef.h:11:9: note: 'false' is a keyword with '-std=c23' onwards
    include/linux/types.h:30:33: error: 'bool' cannot be defined via 'typedef'
       30 | typedef _Bool                   bool;
          |                                 ^~~~
    include/linux/types.h:30:33: note: 'bool' is a keyword with '-std=c23' onwards
    include/linux/types.h:30:1: warning: useless type name in empty declaration
       30 | typedef _Bool                   bool;
          | ^~~~~~~

  The fix is similar to commit ee2ab467bd ("x86/boot: Use '-std=gnu11'
  to fix build with GCC 15") which has been backported to this kernel.

  Note: In < 5.18 version, -std=gnu89 is used instead of -std=gnu11, see
  commit e8c07082a8 ("Kbuild: move to -std=gnu11"). I suggest not to
  modify that in this commit here as all the other similar fixes to
  support GCC 15 set -std=gnu11. This can be done in a dedicated commit
  if needed. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07 06:09:15 +09:00
Babu Moger
42ccfa662c x86/resctrl: Fix miscount of bandwidth event when reactivating previously unavailable RMID
[ Upstream commit 15292f1b4c ]

Users can create as many monitoring groups as the number of RMIDs supported
by the hardware. However, on AMD systems, only a limited number of RMIDs
are guaranteed to be actively tracked by the hardware. RMIDs that exceed
this limit are placed in an "Unavailable" state.

When a bandwidth counter is read for such an RMID, the hardware sets
MSR_IA32_QM_CTR.Unavailable (bit 62). When such an RMID starts being tracked
again the hardware counter is reset to zero. MSR_IA32_QM_CTR.Unavailable
remains set on first read after tracking re-starts and is clear on all
subsequent reads as long as the RMID is tracked.

resctrl miscounts the bandwidth events after an RMID transitions from the
"Unavailable" state back to being tracked. This happens because when the
hardware starts counting again after resetting the counter to zero, resctrl
in turn compares the new count against the counter value stored from the
previous time the RMID was tracked.

This results in resctrl computing an event value that is either undercounting
(when new counter is more than stored counter) or a mistaken overflow (when
new counter is less than stored counter).

Reset the stored value (arch_mbm_state::prev_msr) of MSR_IA32_QM_CTR to
zero whenever the RMID is in the "Unavailable" state to ensure accurate
counting after the RMID resets to zero when it starts to be tracked again.

Example scenario that results in mistaken overflow
==================================================
1. The resctrl filesystem is mounted, and a task is assigned to a
   monitoring group.

   $mount -t resctrl resctrl /sys/fs/resctrl
   $mkdir /sys/fs/resctrl/mon_groups/test1/
   $echo 1234 > /sys/fs/resctrl/mon_groups/test1/tasks

   $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
   21323            <- Total bytes on domain 0
   "Unavailable"    <- Total bytes on domain 1

   Task is running on domain 0. Counter on domain 1 is "Unavailable".

2. The task runs on domain 0 for a while and then moves to domain 1. The
   counter starts incrementing on domain 1.

   $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
   7345357          <- Total bytes on domain 0
   4545             <- Total bytes on domain 1

3. At some point, the RMID in domain 0 transitions to the "Unavailable"
   state because the task is no longer executing in that domain.

   $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
   "Unavailable"    <- Total bytes on domain 0
   434341           <- Total bytes on domain 1

4.  Since the task continues to migrate between domains, it may eventually
    return to domain 0.

    $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
    17592178699059  <- Overflow on domain 0
    3232332         <- Total bytes on domain 1

In this case, the RMID on domain 0 transitions from "Unavailable" state to
active state. The hardware sets MSR_IA32_QM_CTR.Unavailable (bit 62) when
the counter is read and begins tracking the RMID counting from 0.

Subsequent reads succeed but return a value smaller than the previously
saved MSR value (7345357). Consequently, the resctrl's overflow logic is
triggered, it compares the previous value (7345357) with the new, smaller
value and incorrectly interprets this as a counter overflow, adding a large
delta.

In reality, this is a false positive: the counter did not overflow but was
simply reset when the RMID transitioned from "Unavailable" back to active
state.

Here is the text from APM [1] available from [2].

"In PQOS Version 2.0 or higher, the MBM hardware will set the U bit on the
first QM_CTR read when it begins tracking an RMID that it was not
previously tracking. The U bit will be zero for all subsequent reads from
that RMID while it is still tracked by the hardware. Therefore, a QM_CTR
read with the U bit set when that RMID is in use by a processor can be
considered 0 when calculating the difference with a subsequent read."

[1] AMD64 Architecture Programmer's Manual Volume 2: System Programming
    Publication # 24593 Revision 3.41 section 19.3.3 Monitoring L3 Memory
    Bandwidth (MBM).

  [ bp: Split commit message into smaller paragraph chunks for better
    consumption. ]

Fixes: 4d05bf71f1 ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: stable@vger.kernel.org # needs adjustments for <= v6.17
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 # [2]
(cherry picked from commit 15292f1b4c)
[babu.moger@amd.com: Fix conflict in monitor.c for v5.15 stable]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07 06:09:15 +09:00
Ondrej Mosnacek
9450d2fe01 bpf: Do not audit capability check in do_jit()
[ Upstream commit 881a9c9cb7 ]

The failure of this check only results in a security mitigation being
applied, slightly affecting performance of the compiled BPF program. It
doesn't result in a failed syscall, an thus auditing a failed LSM
permission check for it is unwanted. For example with SELinux, it causes
a denial to be reported for confined processes running as root, which
tends to be flagged as a problem to be fixed in the policy. Yet
dontauditing or allowing CAP_SYS_ADMIN to the domain may not be
desirable, as it would allow/silence also other checks - either going
against the principle of least privilege or making debugging potentially
harder.

Fix it by changing it from capable() to ns_capable_noaudit(), which
instructs the LSMs to not audit the resulting denials.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=2369326
Fixes: d4e89d212d ("x86/bpf: Call branch history clearing sequence on exit")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20251021122758.2659513-1-omosnace@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:13 +09:00
David Kaplan
a740e71c23 x86/bugs: Fix reporting of LFENCE retpoline
[ Upstream commit d1cc1baef6 ]

The LFENCE retpoline mitigation is not secure but the kernel prints
inconsistent messages about this fact.  The dmesg log says 'Mitigation:
LFENCE', implying the system is mitigated.  But sysfs reports 'Vulnerable:
LFENCE' implying the system (correctly) is not mitigated.

Fix this by printing a consistent 'Vulnerable: LFENCE' string everywhere
when this mitigation is selected.

Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250915134706.3201818-1-david.kaplan@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07 06:09:12 +09:00
Mark Rutland
dc9f91f849 arm64: errata: Apply workarounds for Neoverse-V3AE
commit 0c33aa1804 upstream.

Neoverse-V3AE is also affected by erratum #3312417, as described in its
Software Developer Errata Notice (SDEN) document:

  Neoverse V3AE (MP172) SDEN v9.0, erratum 3312417
  https://developer.arm.com/documentation/SDEN-2615521/9-0/

Enable the workaround for Neoverse-V3AE, and document this.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
[ Ryan: Trivial backport ]
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-29 14:03:13 +01:00
Mark Rutland
a6ef05314d arm64: cputype: Add Neoverse-V3AE definitions
commit 3bbf004c48 upstream.

Add cputype definitions for Neoverse-V3AE. These will be used for errata
detection in subsequent patches.

These values can be found in the Neoverse-V3AE TRM:

  https://developer.arm.com/documentation/SDEN-2615521/9-0/

... in section A.6.1 ("MIDR_EL1, Main ID Register").

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
[ Ryan: Trivial backport ]
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-29 14:03:13 +01:00
Maciej W. Rozycki
f2ef52fbdc MIPS: Malta: Fix keyboard resource preventing i8042 driver from registering
commit bf5570590a upstream.

MIPS Malta platform code registers the PCI southbridge legacy port I/O
PS/2 keyboard range as a standard resource marked as busy.  It prevents
the i8042 driver from registering as it fails to claim the resource in
a call to i8042_platform_init().  Consequently PS/2 keyboard and mouse
devices cannot be used with this platform.

Fix the issue by removing the busy marker from the standard reservation,
making the driver register successfully:

  serio: i8042 KBD port at 0x60,0x64 irq 1
  serio: i8042 AUX port at 0x60,0x64 irq 12

and the resource show up as expected among the legacy devices:

  00000000-00ffffff : MSC PCI I/O
    00000000-0000001f : dma1
    00000020-00000021 : pic1
    00000040-0000005f : timer
    00000060-0000006f : keyboard
      00000060-0000006f : i8042
    00000070-00000077 : rtc0
    00000080-0000008f : dma page reg
    000000a0-000000a1 : pic2
    000000c0-000000df : dma2
    [...]

If the i8042 driver has not been configured, then the standard resource
will remain there preventing any conflicting dynamic assignment of this
PCI port I/O address range.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/alpine.DEB.2.21.2510211919240.8377@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-29 14:03:11 +01:00
Huang Ying
8a2375b0e9 arm64, mm: avoid always making PTE dirty in pte_mkwrite()
[ Upstream commit 143937ca51 ]

Current pte_mkwrite_novma() makes PTE dirty unconditionally.  This may
mark some pages that are never written dirty wrongly.  For example,
do_swap_page() may map the exclusive pages with writable and clean PTEs
if the VMA is writable and the page fault is for read access.
However, current pte_mkwrite_novma() implementation always dirties the
PTE.  This may cause unnecessary disk writing if the pages are
never written before being reclaimed.

So, change pte_mkwrite_novma() to clear the PTE_RDONLY bit only if the
PTE_DIRTY bit is set to make it possible to make the PTE writable and
clean.

The current behavior was introduced in commit 73e86cb03c ("arm64:
Move PTE_RDONLY bit handling out of set_pte_at()").  Before that,
pte_mkwrite() only sets the PTE_WRITE bit, while set_pte_at() only
clears the PTE_RDONLY bit if both the PTE_WRITE and the PTE_DIRTY bits
are set.

To test the performance impact of the patch, on an arm64 server
machine, run 16 redis-server processes on socket 1 and 16
memtier_benchmark processes on socket 0 with mostly get
transactions (that is, redis-server will mostly read memory only).
The memory footprint of redis-server is larger than the available
memory, so swap out/in will be triggered.  Test results show that the
patch can avoid most swapping out because the pages are mostly clean.
And the benchmark throughput improves ~23.9% in the test.

Fixes: 73e86cb03c ("arm64: Move PTE_RDONLY bit handling out of set_pte_at()")
Signed-off-by: Huang Ying <ying.huang@linux.alibaba.com>
Cc: Will Deacon <will@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-10-29 14:03:11 +01:00
Geert Uytterhoeven
a6c202c341 m68k: bitops: Fix find_*_bit() signatures
[ Upstream commit 6d56740905 ]

The function signatures of the m68k-optimized implementations of the
find_{first,next}_{,zero_}bit() helpers do not match the generic
variants.

Fix this by changing all non-pointer inputs and outputs to "unsigned
long", and updating a few local variables.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202509092305.ncd9mzaZ-lkp@intel.com/
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: "Yury Norov (NVIDIA)" <yury.norov@gmail.com>
Link: https://patch.msgid.link/de6919554fbb4cd1427155c6bafbac8a9df822c8.1757517135.git.geert@linux-m68k.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-10-29 14:03:10 +01:00
Simon Schuster
25f09699ed nios2: ensure that memblock.current_limit is set when setting pfn limits
[ Upstream commit a20b83cf45 ]

On nios2, with CONFIG_FLATMEM set, the kernel relies on
memblock_get_current_limit() to determine the limits of mem_map, in
particular for max_low_pfn.
Unfortunately, memblock.current_limit is only default initialized to
MEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading
to situations where max_low_pfn can erroneously exceed the value of
max_pfn and, thus, the valid range of available DRAM.

This can in turn cause kernel-level paging failures, e.g.:

[   76.900000] Unable to handle kernel paging request at virtual address 20303000
[   76.900000] ea = c0080890, ra = c000462c, cause = 14
[   76.900000] Kernel panic - not syncing: Oops
[   76.900000] ---[ end Kernel panic - not syncing: Oops ]---

This patch fixes this by pre-calculating memblock.current_limit
based on the upper limits of the available memory ranges via
adjust_lowmem_bounds, a simplified version of the equivalent
implementation within the arm architecture.

Signed-off-by: Simon Schuster <schuster.simon@siemens-energy.com>
Signed-off-by: Andreas Oetken <andreas.oetken@siemens-energy.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-10-29 14:03:10 +01:00
Fabian Vogt
d38aec7cd3 riscv: kprobes: Fix probe address validation
[ Upstream commit 9e68bd803f ]

When adding a kprobe such as "p:probe/tcp_sendmsg _text+15392192",
arch_check_kprobe would start iterating all instructions starting from
_text until the probed address. Not only is this very inefficient, but
literal values in there (e.g. left by function patching) are
misinterpreted in a way that causes a desync.

Fix this by doing it like x86: start the iteration at the closest
preceding symbol instead of the given starting point.

Fixes: 87f48c7ccc ("riscv: kprobe: Fixup kernel panic when probing an illegal position")
Signed-off-by: Fabian Vogt <fvogt@suse.de>
Signed-off-by: Marvin Friedrich <marvin.friedrich@suse.com>
Acked-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/6191817.lOV4Wx5bFT@fvogt-thinkpad
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-10-29 14:03:09 +01:00
Catalin Marinas
55a954a54f arm64: mte: Do not flag the zero page as PG_mte_tagged
[ Upstream commit f620d66af3 ]

Commit 68d54ceeec ("arm64: mte: Allow PTRACE_PEEKMTETAGS access to the
zero page") attempted to fix ptrace() reading of tags from the zero page
by marking it as PG_mte_tagged during cpu_enable_mte(). The same commit
also changed the ptrace() tag access permission check to the VM_MTE vma
flag while turning the page flag test into a WARN_ON_ONCE().

Attempting to set the PG_mte_tagged flag early with
CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled may either hang (after commit
d77e59a8fc "arm64: mte: Lock a page for MTE tag initialisation") or
have the flags cleared later during page_alloc_init_late(). In addition,
pages_identical() -> memcmp_pages() will reject any comparison with the
zero page as it is marked as tagged.

Partially revert the above commit to avoid setting PG_mte_tagged on the
zero page. Update the __access_remote_tags() warning on untagged pages
to ignore the zero page since it is known to have the tags initialised.

Note that all user mapping of the zero page are marked as pte_special().
The arm64 set_pte_at() will not call mte_sync_tags() on such pages, so
PG_mte_tagged will remain cleared.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fixes: 68d54ceeec ("arm64: mte: Allow PTRACE_PEEKMTETAGS access to the zero page")
Reported-by: Gergely Kovacs <Gergely.Kovacs2@arm.com>
Cc: stable@vger.kernel.org # 5.10.x
Cc: Will Deacon <will@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lance Yang <lance.yang@linux.dev>
Acked-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Lance Yang <lance.yang@linux.dev>
Signed-off-by: Will Deacon <will@kernel.org>
[ replaced page_mte_tagged() and is_zero_page() with test_bit() and is_zero_pfn() ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-19 16:21:55 +02:00
Linus Torvalds
e035ca130f minmax: make generic MIN() and MAX() macros available everywhere
[ Upstream commit 1a251f52cf ]

This just standardizes the use of MIN() and MAX() macros, with the very
traditional semantics.  The goal is to use these for C constant
expressions and for top-level / static initializers, and so be able to
simplify the min()/max() macros.

These macro names were used by various kernel code - they are very
traditional, after all - and all such users have been fixed up, with a
few different approaches:

 - trivial duplicated macro definitions have been removed

   Note that 'trivial' here means that it's obviously kernel code that
   already included all the major kernel headers, and thus gets the new
   generic MIN/MAX macros automatically.

 - non-trivial duplicated macro definitions are guarded with #ifndef

   This is the "yes, they define their own versions, but no, the include
   situation is not entirely obvious, and maybe they don't get the
   generic version automatically" case.

 - strange use case #1

   A couple of drivers decided that the way they want to describe their
   versioning is with

	#define MAJ 1
	#define MIN 2
	#define DRV_VERSION __stringify(MAJ) "." __stringify(MIN)

   which adds zero value and I just did my Alexander the Great
   impersonation, and rewrote that pointless Gordian knot as

	#define DRV_VERSION "1.2"

   instead.

 - strange use case #2

   A couple of drivers thought that it's a good idea to have a random
   'MIN' or 'MAX' define for a value or index into a table, rather than
   the traditional macro that takes arguments.

   These values were re-written as C enum's instead. The new
   function-line macros only expand when followed by an open
   parenthesis, and thus don't clash with enum use.

Happily, there weren't really all that many of these cases, and a lot of
users already had the pattern of using '#ifndef' guarding (or in one
case just using '#undef MIN') before defining their own private version
that does the same thing. I left such cases alone.

Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-19 16:21:52 +02:00
Linus Torvalds
3d1169785a minmax: add a few more MIN_T/MAX_T users
[ Upstream commit 4477b39c32 ]

Commit 3a7e02c040 ("minmax: avoid overly complicated constant
expressions in VM code") added the simpler MIN_T/MAX_T macros in order
to avoid some excessive expansion from the rather complicated regular
min/max macros.

The complexity of those macros stems from two issues:

 (a) trying to use them in situations that require a C constant
     expression (in static initializers and for array sizes)

 (b) the type sanity checking

and MIN_T/MAX_T avoids both of these issues.

Now, in the whole (long) discussion about all this, it was pointed out
that the whole type sanity checking is entirely unnecessary for
min_t/max_t which get a fixed type that the comparison is done in.

But that still leaves min_t/max_t unnecessarily complicated due to
worries about the C constant expression case.

However, it turns out that there really aren't very many cases that use
min_t/max_t for this, and we can just force-convert those.

This does exactly that.

Which in turn will then allow for much simpler implementations of
min_t()/max_t().  All the usual "macros in all upper case will evaluate
the arguments multiple times" rules apply.

We should do all the same things for the regular min/max() vs MIN/MAX()
cases, but that has the added complexity of various drivers defining
their own local versions of MIN/MAX, so that needs another level of
fixes first.

Link: https://lore.kernel.org/all/b47fad1d0cf8449886ad148f8c013dae@AcuMS.aculab.com/
Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-19 16:21:52 +02:00