Commit Graph

1351128 Commits

Author SHA1 Message Date
Mark Rutland
8738288a08 arm64/fpsimd: Factor out {sve,sme}_state_size() helpers
In subsequent patches we'll need to determine the SVE/SME state size for
a given SVE VL and SME VL regardless of whether a task is currently
configured with those VLs. Split the sizing logic out of
sve_state_size() and sme_state_size() so that we don't need to open-code
this logic elsewhere.

At the same time, apply minor cleanups:

* Move sve_state_size() into fpsimd.h, matching the placement of
  sme_state_size().

* Remove the feature checks from sve_state_size(). We only call
  sve_state_size() when at least one of SVE and SME are supported, and
  when either of the two is not supported, the task's corresponding
  SVE/SME vector length will be zero.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250508132644.1395904-8-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
2025-05-08 15:29:09 +01:00
Mark Rutland
b255be4269 arm64/fpsimd: Clarify sve_sync_*() functions
The sve_sync_{to,from}_fpsimd*() functions are intended to
extract/insert the currently effective FPSIMD state of a task regardless
of whether the task's state is saved in FPSIMD format or SVE format.
Historically they were only used by ptrace, but sve_sync_to_fpsimd() is
now used more widely, and sve_sync_from_fpsimd_zeropad() may be used
more widely in future.

When FPSIMD/SVE state tracking was changed across commits:

  baa8515281 ("arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE")
  a0136be443 (arm64/fpsimd: Load FP state based on recorded data type")
  bbc6172eef ("arm64/fpsimd: SME no longer requires SVE register state")
  8c845e2731 ("arm64/sve: Leave SVE enabled on syscall if we don't context switch")

... sve_sync_to_fpsimd() was updated to consider task->thread.fp_type
rather than the task's TIF_SVE and PSTATE.SM, but (apparently due to an
oversight) sve_sync_from_fpsimd_zeropad() was left as-is, leaving the
two inconsistent.

Due to this, sve_sync_from_fpsimd_zeropad() may copy state from
task->thread.uw.fpsimd_state into task->thread.sve_state when
task->thread.fp_type == FP_STATE_FPSIMD. This is redundant (but benign)
as task->thread.uw.fpsimd_state is the effective state that will be
restored, and task->thread.sve_state will not be consumed. For
consistency, and to avoid the redundant work, it better for
sve_sync_from_fpsimd_zeropad() to consider task->thread.fp_type alone,
matching sve_sync_to_fpsimd().

The naming of both functions is somehat unfortunate, as it is unclear
when and why they copy state. It would be better to describe them in
terms of the effective state.

Considering all of the above, clean this up:

* Adjust sve_sync_from_fpsimd_zeropad() to consider
  task->thread.fp_type.

* Update comments to clarify the intended semantics/usage. I've removed
  the description that task->thread.sve_state must have been allocated,
  as this is only necessary when task->thread.fp_type == FP_STATE_SVE,
  which itself implies that task->thread.sve_state must have been
  allocated.

* Rename the functions to more clearly indicate when/why they copy
  state:

  - sve_sync_to_fpsimd() => fpsimd_sync_from_effective_state()

  - sve_sync_from_fpsimd_zeropad => fpsimd_sync_to_effective_state_zeropad()

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250508132644.1395904-7-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
2025-05-08 15:29:09 +01:00
Mark Rutland
316283f276 arm64/fpsimd: ptrace: Consistently handle partial writes to NT_ARM_(S)SVE
Partial writes to the NT_ARM_SVE and NT_ARM_SSVE regsets using an
payload are handled inconsistently and non-deterministically. A comment
within sve_set_common() indicates that we intended that a partial write
would preserve any effective FPSIMD/SVE state which was not overwritten,
but this has never worked consistently, and during syscalls the FPSIMD
vector state may be non-deterministically preserved and may be
erroneously migrated between streaming and non-streaming SVE modes.

The simplest fix is to handle a partial write by consistently zeroing
the remaining state. As detailed below I do not believe this will
adversely affect any real usage.

Neither GDB nor LLDB attempt partial writes to these regsets, and the
documentation (in Documentation/arch/arm64/sve.rst) has always indicated
that state preservation was not guaranteed, as is says:

| The effect of writing a partial, incomplete payload is unspecified.

When the logic was originally introduced in commit:

  43d4da2c45 ("arm64/sve: ptrace and ELF coredump support")

... there were two potential behaviours, depending on TIF_SVE:

* When TIF_SVE was clear, all SVE state would be zeroed, excluding the
  low 128 bits of vectors shared with FPSIMD, FPSR, and FPCR.

* When TIF_SVE was set, all SVE state would be zeroed, including the
  low 128 bits of vectors shared with FPSIMD, but excluding FPSR and
  FPCR.

Note that as writing to NT_ARM_SVE would set TIF_SVE, partial writes to
NT_ARM_SVE would not be idempotent, and if a first write preserved the
low 128 bits, a subsequent (potentially identical) partial write would
discard the low 128 bits.

When support for the NT_ARM_SSVE regset was added in commit:

  e12310a0d3 ("arm64/sme: Implement ptrace support for streaming mode SVE registers")

... the above behaviour was retained for writes to the NT_ARM_SVE
regset, though writes to the NT_ARM_SSVE would always zero the SVE
registers and would not inherit FPSIMD register state. This happened as
fpsimd_sync_to_sve() only copied the FPSIMD regs when TIF_SVE was clear
and PSTATE.SM==0.

Subsequently, when FPSIMD/SVE state tracking was changed across commits:

  baa8515281 ("arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE")
  a0136be443 (arm64/fpsimd: Load FP state based on recorded data type")
  bbc6172eef ("arm64/fpsimd: SME no longer requires SVE register state")
  8c845e2731 ("arm64/sve: Leave SVE enabled on syscall if we don't context switch")

... there was no corresponding update to the ptrace code, nor to
fpsimd_sync_to_sve(), which stil considers TIF_SVE and PSTATE.SM rather
than the saved fp_type. The saved state can be in the FPSIMD format
regardless of whether TIF_SVE is set or clear, and the saved type can
change non-deterministically during syscalls. Consequently a subsequent
partial write to the NT_ARM_SVE or NT_ARM_SSVE regsets may
non-deterministically preserve the FPSIMD state, and may migrate this
state between streaming and non-streaming modes.

Clean this up by never attempting to preserve ANY state when writing an
SVE payload to the NT_ARM_SVE/NT_ARM_SSVE regsets, zeroing all relevant
state including FPSR and FPCR. This simplifies the code, makes the
behaviour deterministic, and avoids migrating state between streaming
and non-streaming modes. As above, I do not believe this should
adversely affect existing userspace applications.

At the same time, remove fpsimd_sync_to_sve(). It is no longer used,
doesn't do what its documentation implies, and gets in the way of other
cleanups and fixes.

Fixes: 43d4da2c45 ("arm64/sve: ptrace and ELF coredump support")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Spickett <david.spickett@arm.com>
Cc: Luis Machado <luis.machado@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250508132644.1395904-6-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
2025-05-08 15:29:08 +01:00
Mark Rutland
be625d803c arm64/fpsimd: signal: Consistently read FPSIMD context
For historical reasons, restore_sve_fpsimd_context() has an open-coded
copy of the logic from read_fpsimd_context(), which is used to either
restore an FPSIMD-only context, or to merge FPSIMD state into an
SVE state when restoring an SVE+FPSIMD context. The logic is *almost*
identical.

Refactor the logic to avoid duplication and make this clearer.

This comes with two functional changes that I do not believe will be
problematic in practice:

* The user_fpsimd_state::size field will be checked in all restore paths
  that consume it user_fpsimd_state. The kernel always populates this
  field when delivering a signal, and so this should contain the
  expected value unless it has been corrupted.

* If a read of user_fpsimd_state fails, we will return early without
  modifying TIF_SVE, the saved SVCR, or the save fp_type. This will
  leave the task in a consistent state, without potentially resurrecting
  stale FPSIMD state. A read of user_fpsimd_state should never fail
  unless the structure has been corrupted or the stack has been
  unmapped.

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250508132644.1395904-5-mark.rutland@arm.com
[will: Ensure read_fpsimd_context() returns negative error code or zero]
Signed-off-by: Will Deacon <will@kernel.org>
2025-05-08 15:28:27 +01:00
Mark Rutland
b465ace426 arm64/fpsimd: signal: Mandate SVE payload for streaming-mode state
Non-streaming SVE state may be preserved without an SVE payload, in
which case the SVE context only has a header with VL==0, and all state
can be restored from the FPSIMD context. Streaming SVE state is always
preserved with an SVE payload, where the SVE context header has VL!=0,
and the SVE_SIG_FLAG_SM flag is set.

The kernel never preserves an SVE context where SVE_SIG_FLAG_SM is set
without an SVE payload. However, restore_sve_fpsimd_context() doesn't
forbid restoring such a context, and will handle this case by clearing
PSTATE.SM and restoring the FPSIMD context into non-streaming mode,
which isn't consistent with the SVE_SIG_FLAG_SM flag.

Forbid this case, and mandate an SVE payload when the SVE_SIG_FLAG_SM
flag is set. This avoids an awkward ABI quirk and reduces the risk that
later rework to this code permits configuring a task with PSTATE.SM==1
and fp_type==FP_STATE_FPSIMD.

I've marked this as a fix given that we never intended to support this
case, and we don't want anyone to start relying upon the old behaviour
once we re-enable SME.

Fixes: 85ed24dad2 ("arm64/sme: Implement streaming SVE signal handling")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250508132644.1395904-4-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
2025-05-08 15:23:36 +01:00
Mark Rutland
1bf663a86a arm64/fpsimd: signal: Clear PSTATE.SM when restoring FPSIMD frame only
On systems with SVE and/or SME, the kernel will always create SVE and
FPSIMD signal frames when delivering a signal, but a user can manipulate
signal frames such that a signal return only observes an FPSIMD signal
frame. When this happens, restore_fpsimd_context() will restore state
such that fp_type==FP_STATE_FPSIMD, but will leave PSTATE.SM as-is.

It is possible for a user to set PSTATE.SM between syscall entry and
execution of the sigreturn logic (e.g. via ptrace), and consequently the
sigreturn may result in the task having PSTATE.SM==1 and
fp_type==FP_STATE_FPSIMD.

For various reasons it is not legitimate for a task to be in a state
where PSTATE.SM==1 and fp_type==FP_STATE_FPSIMD. Portions of the user
ABI are written with the requirement that streaming SVE state is always
presented in SVE format rather than FPSIMD format, and as there is no
mechanism to permit access to only the FPSIMD subset of streaming SVE
state, streaming SVE state must always be saved and restored in SVE
format.

Fix restore_fpsimd_context() to clear PSTATE.SM when restoring an FPSIMD
signal frame without an SVE signal frame. This matches the current
behaviour when an SVE signal frame is present, but the SVE signal frame
has no register payload (e.g. as is the case on SME-only systems which
lack SVE).

This change should have no effect for applications which do not alter
signal frames (i.e. almost all applications). I do not expect
non-{malicious,buggy} applications to hide the SVE signal frame, but
I've chosen to clear PSTATE.SM rather than mandating the presence of an
SVE signal frame in case there is some legacy (non-SME) usage that I am
not currently aware of.

For context, the SME handling was originally introduced in commit:

  85ed24dad2 ("arm64/sme: Implement streaming SVE signal handling")

... and subsequently updated/fixed to handle SME-only systems in commits:

  7dde62f068 ("arm64/signal: Always accept SVE signal frames on SME only systems")
  f26cd73721 ("arm64/signal: Always allocate SVE signal frames on SME only systems")

Fixes: 85ed24dad2 ("arm64/sme: Implement streaming SVE signal handling")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250508132644.1395904-3-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
2025-05-08 15:23:36 +01:00
Mark Rutland
398edaa12f arm64/fpsimd: Do not discard modified SVE state
Historically SVE state was discarded deterministically early in the
syscall entry path, before ptrace is notified of syscall entry. This
permitted ptrace to modify SVE state before and after the "real" syscall
logic was executed, with the modified state being retained.

This behaviour was changed by commit:

  8c845e2731 ("arm64/sve: Leave SVE enabled on syscall if we don't context switch")

That commit was intended to speed up workloads that used SVE by
opportunistically leaving SVE enabled when returning from a syscall.
The syscall entry logic was modified to truncate the SVE state without
disabling userspace access to SVE, and fpsimd_save_user_state() was
modified to discard userspace SVE state whenever
in_syscall(current_pt_regs()) is true, i.e. when
current_pt_regs()->syscallno != NO_SYSCALL.

Leaving SVE enabled opportunistically resulted in a couple of changes to
userspace visible behaviour which weren't described at the time, but are
logical consequences of opportunistically leaving SVE enabled:

* Signal handlers can observe the type of saved state in the signal's
  sve_context record. When the kernel only tracks FPSIMD state, the 'vq'
  field is 0 and there is no space allocated for register contents. When
  the kernel tracks SVE state, the 'vq' field is non-zero and the
  register contents are saved into the record.

  As a result of the above commit, 'vq' (and the presence of SVE
  register state) is non-deterministically zero or non-zero for a period
  of time after a syscall. The effective register state is still
  deterministic.

  Hopefully no-one relies on this being deterministic. In general,
  handlers for asynchronous events cannot expect a deterministic state.

* Similarly to signal handlers, ptrace requests can observe the type of
  saved state in the NT_ARM_SVE and NT_ARM_SSVE regsets, as this is
  exposed in the header flags. As a result of the above commit, this is
  now in a non-deterministic state after a syscall. The effective
  register state is still deterministic.

  Hopefully no-one relies on this being deterministic. In general,
  debuggers would have to handle this changing at arbitrary points
  during program flow.

Discarding the SVE state within fpsimd_save_user_state() resulted in
other changes to userspace visible behaviour which are not desirable:

* A ptrace tracer can modify (or create) a tracee's SVE state at syscall
  entry or syscall exit. As a result of the above commit, the tracee's
  SVE state can be discarded non-deterministically after modification,
  rather than being retained as it previously was.

  Note that for co-operative tracer/tracee pairs, the tracer may
  (re)initialise the tracee's state arbitrarily after the tracee sends
  itself an initial SIGSTOP via a syscall, so this affects realistic
  design patterns.

* The current_pt_regs()->syscallno field can be modified via ptrace, and
  can be altered even when the tracee is not really in a syscall,
  causing non-deterministic discarding to occur in situations where this
  was not previously possible.

Further, using current_pt_regs()->syscallno in this way is unsound:

* There are data races between readers and writers of the
  current_pt_regs()->syscallno field.

  The current_pt_regs()->syscallno field is written in interruptible
  task context using plain C accesses, and is read in irq/softirq
  context using plain C accesses. These accesses are subject to data
  races, with the usual concerns with tearing, etc.

* Writes to current_pt_regs()->syscallno are subject to compiler
  reordering.

  As current_pt_regs()->syscallno is written with plain C accesses,
  the compiler is free to move those writes arbitrarily relative to
  anything which doesn't access the same memory location.

  In theory this could break signal return, where prior to restoring the
  SVE state, restore_sigframe() calls forget_syscall(). If the write
  were hoisted after restore of some SVE state, that state could be
  discarded unexpectedly.

  In practice that reordering cannot happen in the absence of LTO (as
  cross compilation-unit function calls happen prevent this reordering),
  and that reordering appears to be unlikely in the presence of LTO.

Additionally, since commit:

  f130ac0ae4 ("arm64: syscall: unmask DAIF earlier for SVCs")

... DAIF is unmasked before el0_svc_common() sets regs->syscallno to the
real syscall number. Consequently state may be saved in SVE format prior
to this point.

Considering all of the above, current_pt_regs()->syscallno should not be
used to infer whether the SVE state can be discarded. Luckily we can
instead use cpu_fp_state::to_save to track when it is safe to discard
the SVE state:

* At syscall entry, after the live SVE register state is truncated, set
  cpu_fp_state::to_save to FP_STATE_FPSIMD to indicate that only the
  FPSIMD portion is live and needs to be saved.

* At syscall exit, once the task's state is guaranteed to be live, set
  cpu_fp_state::to_save to FP_STATE_CURRENT to indicate that TIF_SVE
  must be considered to determine which state needs to be saved.

* Whenever state is modified, it must be saved+flushed prior to
  manipulation. The state will be truncated if necessary when it is
  saved, and reloading the state will set fp_state::to_save to
  FP_STATE_CURRENT, preventing subsequent discarding.

This permits SVE state to be discarded *only* when it is known to have
been truncated (and the non-FPSIMD portions must be zero), and ensures
that SVE state is retained after it is explicitly modified.

For backporting, note that this fix depends on the following commits:

* b2482807fb ("arm64/sme: Optimise SME exit on syscall entry")
* f130ac0ae4 ("arm64: syscall: unmask DAIF earlier for SVCs")
* 929fa99b12 ("arm64/fpsimd: signal: Always save+flush state early")

Fixes: 8c845e2731 ("arm64/sve: Leave SVE enabled on syscall if we don't context switch")
Fixes: f130ac0ae4 ("arm64: syscall: unmask DAIF earlier for SVCs")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250508132644.1395904-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
2025-05-08 15:23:35 +01:00
Mark Rutland
f699c66691 arm64/fpsimd: Avoid warning when sve_to_fpsimd() is unused
Historically fpsimd_to_sve() and sve_to_fpsimd() were (conditionally)
called by functions which were defined regardless of CONFIG_ARM64_SVE.
Hence it was necessary that both fpsimd_to_sve() and sve_to_fpsimd()
were always defined and not guarded by ifdeffery.

As a result of the removal of fpsimd_signal_preserve_current_state() in
commit:

  929fa99b12 ("arm64/fpsimd: signal: Always save+flush state early")

... sve_to_fpsimd() has no callers when CONFIG_ARM64_SVE=n, resulting in
a build-time warnign that it is unused:

| arch/arm64/kernel/fpsimd.c:676:13: warning: unused function 'sve_to_fpsimd' [-Wunused-function]
|   676 | static void sve_to_fpsimd(struct task_struct *task)
|       |             ^~~~~~~~~~~~~
| 1 warning generated.

In contrast, fpsimd_to_sve() still has callers which are defined when
CONFIG_ARM64_SVE=n, and it would be awkward to hide this behind
ifdeffery and/or to use stub functions.

For now, suppress the warning by marking both fpsimd_to_sve() and
sve_to_fpsimd() as 'static inline', as we usually do for stub functions.
The compiler will no longer warn if either function is unused.

Aside from suppressing the warning, there should be no functional change
as a result of this patch.

Link: https://lore.kernel.org/linux-arm-kernel/20250429194600.GA26883@willie-the-truck/
Reported-by: Will Deacon <will@kernel.org>
Fixes: 929fa99b12 ("arm64/fpsimd: signal: Always save+flush state early")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250430173240.4023627-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-30 18:52:15 +01:00
Mark Rutland
b376108e1f arm64/fpsimd: signal: Clear TPIDR2 when delivering signals
Linux is intended to be compatible with userspace written to Arm's
AAPCS64 procedure call standard [1,2]. For the Scalable Matrix Extension
(SME), AAPCS64 was extended with a "ZA lazy saving scheme", where SME's
ZA tile is lazily callee-saved and caller-restored. In this scheme,
TPIDR2_EL0 indicates whether the ZA tile is live or has been saved by
pointing to a "TPIDR2 block" in memory, which has a "za_save_buffer"
pointer. This scheme has been implemented in GCC and LLVM, with
necessary runtime support implemented in glibc.

AAPCS64 does not specify how the ZA lazy saving scheme is expected to
interact with signal handling, and the behaviour that AAPCS64 currently
recommends for (sig)setjmp() and (sig)longjmp() does not always compose
safely with signal handling, as explained below.

When Linux delivers a signal, it creates signal frames which contain the
original values of PSTATE.ZA, the ZA tile, and TPIDR_EL2. Between saving
the original state and entering the signal handler, Linux clears
PSTATE.ZA, but leaves TPIDR2_EL0 unchanged. Consequently a signal
handler can be entered with PSTATE.ZA=0 (meaning accesses to ZA will
trap), while TPIDR_EL0 is non-null (which may indicate that ZA needs to
be lazily saved, depending on the contents of the TPIDR2 block). While
in this state, libc and/or compiler runtime code, such as longjmp(), may
attempt to save ZA. As PSTATE.ZA=0, these accesses will trap, causing
the kernel to inject a SIGILL. Note that by virtue of lazy saving
occurring in libc and/or C runtime code, this can be triggered by
application/library code which is unaware of SME.

To avoid the problem above, the kernel must ensure that signal handlers
are entered with PSTATE.ZA and TPIDR2_EL0 configured in a manner which
complies with the ZA lazy saving scheme. Practically speaking, the only
choice is to enter signal handlers with PSTATE.ZA=0 and TPIDR2_EL0=NULL.
This change should not impact SME code which does not follow the ZA lazy
saving scheme (and hence does not use TPIDR2_EL0).

An alternative approach that was considered is to have the signal
handler inherit the original values of both PSTATE.ZA and TPIDR2_EL0,
relying on lazy save/restore sequences being idempotent and capable of
racing safely. This is not safe as signal handlers must be assumed to
have a "private ZA" interface, and therefore cannot be entered with
PSTATE.ZA=1 and TPIDR2_EL0=NULL, but it is legitimate for signals to be
taken from this state.

With the kernel fixed to clear TPIDR2_EL0, there are a couple of
remaining issues (largely masked by the first issue) that must be fixed
in userspace:

(1) When a (sig)setjmp() + (sig)longjmp() pair cross a signal boundary,
    ZA state may be discarded when it needs to be preserved.

    Currently, the ZA lazy saving scheme recommends that setjmp() does
    not save ZA, and recommends that longjmp() is responsible for saving
    ZA. A call to longjmp() in a signal handler will not have visibility
    of ZA state that existed prior to entry to the signal, and when a
    longjmp() is used to bypass a usual signal return, unsaved ZA state
    will be discarded erroneously.

    To fix this, it is necessary for setjmp() to eagerly save ZA state,
    and for longjmp() to configure PSTATE.ZA=0 and TPIDR2_EL0=NULL. This
    works regardless of whether a signal boundary is crossed.

(2) When a C++ exception is thrown and crosses a signal boundary before
    it is caught, ZA state may be discarded when it needs to be
    preserved.

    AAPCS64 requires that exception handlers are entered with
    PSTATE.{SM,ZA}={0,0} and TPIDR2_EL0=NULL, with exception unwind code
    expected to perform any necessary save of ZA state.

    Where it is necessary to perform an exception unwind across an
    exception boundary, the unwind code must recover any necessary ZA
    state (along with TPIDR2) from signal frames.

Fix the kernel as described above, with setup_return() clearing
TPIDR2_EL0 when delivering a signal. Folk on CC are working on fixes for
the remaining userspace issues, including updates/fixes to the AAPCS64
specification and glibc.

[1] https://github.com/ARM-software/abi-aa/releases/download/2025Q1/aapcs64.pdf
[2] c51addc3dc/aapcs64/aapcs64.rst

Fixes: 39782210eb ("arm64/sme: Implement ZA signal handling")
Fixes: 39e5449928 ("arm64/signal: Include TPIDR2 in the signal context")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Kiss <daniel.kiss@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Richard Sandiford <richard.sandiford@arm.com>
Cc: Sander De Smalen <sander.desmalen@arm.com>
Cc: Tamas Petz <tamas.petz@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yury Khrustalev <yury.khrustalev@arm.com>
Link: https://lore.kernel.org/r/20250417190113.3778111-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-28 20:23:06 +01:00
Mark Rutland
2fe2b96c38 arm64/fpsimd: signal: Simplify preserve_tpidr2_context()
During a context-switch, tls_thread_switch() reads and writes a task's
thread_struct::tpidr2_el0 field. Other code shouldn't access this field
for an active task, as such accesses would form a data-race with a
concurrent context-switch.

The usage in preserve_tpidr2_context() is suspicious, but benign as any
race with a context switch will write the same value back to
current->thread.tpidr2_el0.

Make this clearer and match restore_tpidr2_context() by using a
temporary variable instead, avoiding the (benign) data-race.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-14-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:31 +01:00
Mark Rutland
929fa99b12 arm64/fpsimd: signal: Always save+flush state early
There are several issues with the way the native signal handling code
manipulates FPSIMD/SVE/SME state, described in detail below. These
issues largely result from races with preemption and inconsistent
handling of live state vs saved state.

Known issues with native FPSIMD/SVE/SME state management include:

* On systems with FPMR, the code to save/restore the FPMR accesses the
  register while it is not owned by the current task. Consequently, this
  may corrupt the FPMR of the current task and/or may corrupt the FPMR
  of an unrelated task. The FPMR save/restore has been broken since it
  was introduced in commit:

    8c46def444 ("arm64/signal: Add FPMR signal handling")

* On systems with SME, setup_return() modifies both the live register
  state and the saved state register state regardless of whether the
  task's state is live, and without holding the cpu fpsimd context.
  Consequently:

  - This may corrupt the state an unrelated task which has PSTATE.SM set
    and/or PSTATE.ZA set.

  - The task may enter the signal handler in streaming mode, and or with
    ZA storage enabled unexpectedly.

  - The task may enter the signal handler in non-streaming SVE mode with
    stale SVE register state, which may have been inherited from
    streaming SVE mode unexpectedly. Where the streaming and
    non-streaming vector lengths differ, this may be packed into
    registers arbitrarily.

  This logic has been broken since it was introduced in commit:

    40a8e87bb3 ("arm64/sme: Disable ZA and streaming mode when handling signals")

  Further incorrect manipulation of state was added in commits:

    ea64baacbc ("arm64/signal: Flush FPSIMD register state when disabling streaming mode")
    baa8515281 ("arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE")

* Several restoration functions use fpsimd_flush_task_state() to discard
  the live FPSIMD/SVE/SME while the in-memory copy is stale.

  When a subset of the FPSIMD/SVE/SME state is restored, the remainder
  may be non-deterministically reset to a stale snapshot from some
  arbitrary point in the past.

  This non-deterministic discarding was introduced in commit:

    8cd969d28f ("arm64/sve: Signal handling support")

  As of that commit, when TIF_SVE was initially clear, failure to
  restore the SVE signal frame could reset the FPSIMD registers to a
  stale snapshot.

  The pattern of discarding unsaved state was subsequently copied into
  restoration functions for some new state in commits:

    39782210eb ("arm64/sme: Implement ZA signal handling")
    ee072cf708 ("arm64/sme: Implement signal handling for ZT")

* On systems with SME/SME2, the entire FPSIMD/SVE/SME state may be
  loaded onto the CPU redundantly. Either restore_fpsimd_context() or
  restore_sve_fpsimd_context() will load the entire FPSIMD/SVE/SME state
  via fpsimd_update_current_state() before restore_za_context() and
  restore_zt_context() each discard the state via
  fpsimd_flush_task_state().

  This is purely redundant work, and not a functional bug.

To fix these issues, rework the native signal handling code to always
save+flush the current task's FPSIMD/SVE/SME state before manipulating
that state. This avoids races with preemption and ensures that state is
manipulated consistently regardless of whether it happened to be live
prior to manipulation. This largely involes:

* Using fpsimd_save_and_flush_current_state() to save+flush the state
  for both signal delivery and signal return, before the state is
  manipulated in any way.

* Removing fpsimd_signal_preserve_current_state() and updating
  preserve_fpsimd_context() to explicitly ensure that the FPSIMD state
  is up-to-date, as preserve_fpsimd_context() is the only consumer of
  the FPSIMD state during signal delivery.

* Modifying fpsimd_update_current_state() to not reload the FPSIMD state
  onto the CPU. Ideally we'd remove fpsimd_update_current_state()
  entirely, but I've left that for subsequent patches as there are a
  number of of other problems with the FPSIMD<->SVE conversion helpers
  that should be addressed at the same time. For now I've removed the
  misleading comment.

For setup_return(), we need to decide (for ABI reasons) whether signal
delivery should have all the side-effects of an SMSTOP. For now I've
left a TODO comment, as there are other questions in this area that I'll
address with subsequent patches.

Fixes: 8c46def444 ("arm64/signal: Add FPMR signal handling")
Fixes: 40a8e87bb3 ("arm64/sme: Disable ZA and streaming mode when handling signals")
Fixes: ea64baacbc ("arm64/signal: Flush FPSIMD register state when disabling streaming mode")
Fixes: baa8515281 ("arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE")
Fixes: 8cd969d28f ("arm64/sve: Signal handling support")
Fixes: 39782210eb ("arm64/sme: Implement ZA signal handling")
Fixes: ee072cf708 ("arm64/sme: Implement signal handling for ZT")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-13-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:31 +01:00
Mark Rutland
3aa4d74438 arm64/fpsimd: signal32: Always save+flush state early
There are several issues with the way the native signal handling code
manipulates FPSIMD/SVE/SME state. To fix those issues, subsequent
patches will rework the native signal handling code to always save+flush
the current task's FPSIMD/SVE/SME state before manipulating that state.

In preparation for those changes, rework the compat signal handling code
to save+flush the current task's FPSIMD state before manipulating it.

Subsequent patches will remove fpsimd_signal_preserve_current_state()
and fpsimd_update_current_state(). Compat tasks can only have FPSIMD
state, and cannot have any SVE or SME state. Thus, the SVE state
manipulation present in fpsimd_signal_preserve_current_state() and
fpsimd_update_current_state() is not necessary, and it is safe to
directly manipulate current->thread.uw.fpsimd_state once it has been
saved+flushed.

Use fpsimd_save_and_flush_current_state() to save+flush the state for
both signal delivery and signal return, before the state is manipulated
in any way. While it would be safe for compat_restore_vfp_context() to
use fpsimd_flush_task_state(current), there are several extant issues in
the native signal code resulting from incorrect use of
fpsimd_flush_task_state(), and for consistency it is preferable to use
fpsimd_save_and_flush_current_state().

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-12-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:31 +01:00
Mark Rutland
d3a181588d arm64/fpsimd: Add fpsimd_save_and_flush_current_state()
When the current task's FPSIMD/SVE/SME state may be live on *any* CPU in
the system, special care must be taken when manipulating that state, as
this manipulation can race with preemption and/or asynchronous usage of
FPSIMD/SVE/SME (e.g. kernel-mode NEON in softirq handlers).

Even when manipulation is is protected with get_cpu_fpsimd_context() and
get_cpu_fpsimd_context(), the logic necessary when the state is live on
the current CPU can be wildly different from the logic necessary when
the state is not live on the current CPU. A number of historical and
extant issues result from failing to handle these cases consistetntly
and/or correctly.

To make it easier to get such manipulation correct, add a new
fpsimd_save_and_flush_current_state() helper function, which ensures
that the current task's state has been saved to memory and any stale
state on any CPU has been "flushed" such that is not live on any CPU in
the system. This will allow code to safely manipulate the saved state
without risk of races.

Subsequent patches will use the new function.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-11-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:31 +01:00
Mark Rutland
c94f2f3261 arm64/fpsimd: Fix merging of FPSIMD state during signal return
For backwards compatibility reasons, when a signal return occurs which
restores SVE state, the effective lower 128 bits of each of the SVE
vector registers are restored from the corresponding FPSIMD vector
register in the FPSIMD signal frame, overriding the values in the SVE
signal frame. This is intended to be the case regardless of streaming
mode.

To make this happen, restore_sve_fpsimd_context() uses
fpsimd_update_current_state() to merge the lower 128 bits from the
FPSIMD signal frame into the SVE register state. Unfortunately,
fpsimd_update_current_state() performs this merging dependent upon
TIF_SVE, which is not always correct for streaming SVE register state:

* When restoring non-streaming SVE register state there is no observable
  problem, as the signal return code configures TIF_SVE and the saved
  fp_type to match before calling fpsimd_update_current_state(), which
  observes either:

  - TIF_SVE set    AND  fp_type == FP_STATE_SVE
  - TIF_SVE clear  AND  fp_type == FP_STATE_FPSIMD

* On systems which have SME but not SVE, TIF_SVE cannot be set. Thus the
  merging will never happen for the streaming SVE register state.

* On systems which have SVE and SME, TIF_SVE can be set and cleared
  independently of PSTATE.SM. Thus the merging may or may not happen for
  streaming SVE register state.

  As TIF_SVE can be cleared non-deterministically during syscalls
  (including at the start of sigreturn()), the merging may occur
  non-deterministically from the perspective of userspace.

This logic has been broken since its introduction in commit:

  85ed24dad2 ("arm64/sme: Implement streaming SVE signal handling")

... at which point both fpsimd_signal_preserve_current_state() and
fpsimd_update_current_state() only checked TIF SVE. When PSTATE.SM==1
and TIF_SVE was clear, signal delivery would place stale FPSIMD state
into the FPSIMD signal frame, and signal return would not merge this
into the restored register state.

Subsequently, signal delivery was fixed as part of commit:

  61da7c8e2a ("arm64/signal: Don't assume that TIF_SVE means we saved SVE state")

... but signal restore was not given a corresponding fix, and when
TIF_SVE was clear, signal restore would still fail to merge the FPSIMD
state into the restored SVE register state. The 'Fixes' tag did not
indicate that this had been broken since its introduction.

Fix this by merging the FPSIMD state dependent upon the saved fp_type,
matching what we (currently) do during signal delivery.

As described above, when backporting this commit, it will also be
necessary to backport commit:

  61da7c8e2a ("arm64/signal: Don't assume that TIF_SVE means we saved SVE state")

... and prior to commit:

  baa8515281 ("arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE")

... it will be necessary for fpsimd_signal_preserve_current_state() and
fpsimd_update_current_state() to consider both TIF_SVE and
thread_sm_enabled(&current->thread), in place of the saved fp_type.

Fixes: 85ed24dad2 ("arm64/sme: Implement streaming SVE signal handling")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-10-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:31 +01:00
Mark Rutland
a90878f297 arm64/fpsimd: Reset FPMR upon exec()
An exec() is expected to reset all FPSIMD/SVE/SME state, and barring
special handling of the vector lengths, the state is expected to reset
to zero. This reset is handled in fpsimd_flush_thread(), which the core
exec() code calls via flush_thread().

When support was added for FPMR, no logic was added to
fpsimd_flush_thread() to reset the FPMR value, and thus it is
erroneously inherited across an exec().

Add the missing reset of FPMR.

Fixes: 203f2b95a8 ("arm64/fpsimd: Support FEAT_FPMR")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-9-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:31 +01:00
Mark Rutland
01098d893f arm64/fpsimd: Avoid clobbering kernel FPSIMD state with SMSTOP
On system with SME, a thread's kernel FPSIMD state may be erroneously
clobbered during a context switch immediately after that state is
restored. Systems without SME are unaffected.

If the CPU happens to be in streaming SVE mode before a context switch
to a thread with kernel FPSIMD state, fpsimd_thread_switch() will
restore the kernel FPSIMD state using fpsimd_load_kernel_state() while
the CPU is still in streaming SVE mode. When fpsimd_thread_switch()
subsequently calls fpsimd_flush_cpu_state(), this will execute an
SMSTOP, causing an exit from streaming SVE mode. The exit from
streaming SVE mode will cause the hardware to reset a number of
FPSIMD/SVE/SME registers, clobbering the FPSIMD state.

Fix this by calling fpsimd_flush_cpu_state() before restoring the kernel
FPSIMD state.

Fixes: e92bee9f86 ("arm64/fpsimd: Avoid erroneous elide of user state reload")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-8-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:31 +01:00
Mark Brown
e5fa85fce0 arm64/fpsimd: Don't corrupt FPMR when streaming mode changes
When the effective value of PSTATE.SM is changed from 0 to 1 or from 1
to 0 by any method, an entry or exit to/from streaming SVE mode is
performed, and hardware automatically resets a number of registers. As
of ARM DDI 0487 L.a, this means:

* All implemented bits of the SVE vector registers are set to zero.

* All implemented bits of the SVE predicate registers are set to zero.

* All implemented bits of FFR are set to zero, if FFR is implemented in
  the new mode.

* FPSR is set to 0x0000_0000_0800_009f.

* FPMR is set to 0, if FPMR is implemented.

Currently task_fpsimd_load() restores FPMR before restoring SVCR (which
is an accessor for PSTATE.{SM,ZA}), and so the restored value of FPMR
may be clobbered if the restored value of PSTATE.SM happens to differ
from the initial value of PSTATE.SM.

Fix this by moving the restore of FPMR later.

Note: this was originally posted as [1].

Fixes: 203f2b95a8 ("arm64/fpsimd: Support FEAT_FPMR")
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/linux-arm-kernel/20241204-arm64-sme-reenable-v2-2-bae87728251d@kernel.org/
[ Rutland: rewrite commit message ]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20250409164010.3480271-7-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:30 +01:00
Mark Brown
d3eaab3c70 arm64/fpsimd: Discard stale CPU state when handling SME traps
The logic for handling SME traps manipulates saved FPSIMD/SVE/SME state
incorrectly, and a race with preemption can result in a task having
TIF_SME set and TIF_FOREIGN_FPSTATE clear even though the live CPU state
is stale (e.g. with SME traps enabled). This can result in warnings from
do_sme_acc() where SME traps are not expected while TIF_SME is set:

|        /* With TIF_SME userspace shouldn't generate any traps */
|        if (test_and_set_thread_flag(TIF_SME))
|                WARN_ON(1);

This is very similar to the SVE issue we fixed in commit:

  751ecf6afd ("arm64/sve: Discard stale CPU state when handling SVE traps")

The race can occur when the SME trap handler is preempted before and
after manipulating the saved FPSIMD/SVE/SME state, starting and ending on
the same CPU, e.g.

| void do_sme_acc(unsigned long esr, struct pt_regs *regs)
| {
|         // Trap on CPU 0 with TIF_SME clear, SME traps enabled
|         // task->fpsimd_cpu is 0.
|         // per_cpu_ptr(&fpsimd_last_state, 0) is task.
|
|         ...
|
|         // Preempted; migrated from CPU 0 to CPU 1.
|         // TIF_FOREIGN_FPSTATE is set.
|
|         get_cpu_fpsimd_context();
|
|         /* With TIF_SME userspace shouldn't generate any traps */
|         if (test_and_set_thread_flag(TIF_SME))
|                 WARN_ON(1);
|
|         if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {
|                 unsigned long vq_minus_one =
|                         sve_vq_from_vl(task_get_sme_vl(current)) - 1;
|                 sme_set_vq(vq_minus_one);
|
|                 fpsimd_bind_task_to_cpu();
|         }
|
|         put_cpu_fpsimd_context();
|
|         // Preempted; migrated from CPU 1 to CPU 0.
|         // task->fpsimd_cpu is still 0
|         // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then:
|         // - Stale HW state is reused (with SME traps enabled)
|         // - TIF_FOREIGN_FPSTATE is cleared
|         // - A return to userspace skips HW state restore
| }

Fix the case where the state is not live and TIF_FOREIGN_FPSTATE is set
by calling fpsimd_flush_task_state() to detach from the saved CPU
state. This ensures that a subsequent context switch will not reuse the
stale CPU state, and will instead set TIF_FOREIGN_FPSTATE, forcing the
new state to be reloaded from memory prior to a return to userspace.

Note: this was originallly posted as [1].

Fixes: 8bd7f91c03 ("arm64/sme: Implement traps and syscall handling for SME")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/linux-arm-kernel/20241204-arm64-sme-reenable-v2-1-bae87728251d@kernel.org/
[ Rutland: rewrite commit message ]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:30 +01:00
Mark Rutland
d7649a4a60 arm64/fpsimd: Remove opportunistic freeing of SME state
When a task's SVE vector length (NSVL) is changed, and the task happens
to have SVCR.{SM,ZA}=={0,0}, vec_set_vector_length() opportunistically
frees the task's sme_state and clears TIF_SME.

The opportunistic freeing was added with no rationale in commit:

  d4d5be94a8 ("arm64/fpsimd: Ensure SME storage is allocated after SVE VL changes")

That commit fixed an unrelated problem where the task's sve_state was
freed while it could be used to store streaming mode register state,
where the fix was to re-allocate the task's sve_state.

There is no need to free and/or reallocate the task's sme_state when the
SVE vector length changes, and there is no need to clear TIF_SME. Given
the SME vector length (SVL) doesn't change, the task's sme_state remains
correctly sized.

Remove the unnecessary opportunistic freeing of the task's sme_state
when the task's SVE vector length is changed. The task's sme_state is
still freed when the SME vector length is changed.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-5-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:30 +01:00
Mark Rutland
45fd86986b arm64/fpsimd: Remove redundant SVE trap manipulation
When task_fpsimd_load() loads the saved FPSIMD/SVE/SME state, it
configures EL0 SVE traps by calling sve_user_{enable,disable}(). This is
unnecessary, and this is suspicious/confusing as task_fpsimd_load() does
not configure EL0 SME traps.

All calls to task_fpsimd_load() are followed by a call to
fpsimd_bind_task_to_cpu(), where the latter configures traps for SVE and
SME dependent upon the current values of TIF_SVE and TIF_SME, overriding
any trap configuration performed by task_fpsimd_load().

The calls to sve_user_{enable,disable}() calls in task_fpsimd_load()
have been redundant (though benign) since they were introduced in
commit:

  a0136be443 ("arm64/fpsimd: Load FP state based on recorded data type")

Remove the unnecessary and confusing SVE trap manipulation.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:30 +01:00
Mark Rutland
61db0e0ba3 arm64/fpsimd: Remove unused fpsimd_force_sync_to_sve()
There have been no users of fpsimd_force_sync_to_sve() since commit:

  bbc6172eef ("arm64/fpsimd: SME no longer requires SVE register state")

Remove fpsimd_force_sync_to_sve().

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:30 +01:00
Mark Rutland
95507570fb arm64/fpsimd: Avoid RES0 bits in the SME trap handler
The SME trap handler consumes RES0 bits from the ESR when determining
the reason for the trap, and depends upon those bits reading as zero.
This may break in future when those RES0 bits are allocated a meaning
and stop reading as zero.

For SME traps taken with ESR_ELx.EC == 0b011101, the specific reason for
the trap is indicated by ESR_ELx.ISS.SMTC ("SME Trap Code"). This field
occupies bits [2:0] of ESR_ELx.ISS, and as of ARM DDI 0487 L.a, bits
[24:3] of ESR_ELx.ISS are RES0. ESR_ELx.ISS itself occupies bits [24:0]
of ESR_ELx.

Extract the SMTC field specifically, matching the way we handle ESR_ELx
fields elsewhere, and ensuring that the handler is future-proof.

Fixes: 8bd7f91c03 ("arm64/sme: Implement traps and syscall handling for SME")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-04-09 18:06:30 +01:00
Linus Torvalds
0af2f6be1b Linux 6.15-rc1 2025-04-06 13:11:33 -07:00
Thomas Weißschuh
0efdedb335 tools/include: make uapi/linux/types.h usable from assembly
The "real" linux/types.h UAPI header gracefully degrades to a NOOP when
included from assembly code.

Mirror this behaviour in the tools/ variant.

Test for __ASSEMBLER__ over __ASSEMBLY__ as the former is provided by the
toolchain automatically.

Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/lkml/af553c62-ca2f-4956-932c-dd6e3a126f58@sirena.org.uk/
Fixes: c9fbaa8795 ("selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers")
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20250321-uapi-consistency-v1-1-439070118dc0@linutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2025-04-06 12:55:31 -07:00
Linus Torvalds
710329254d Turbostat 2025.05.06
Support up to 8192 processors
 Add cpuidle governor debug telemetry, disabled by default
 Update default output to exclude cpuidle invocation counts
 Bug fixes
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Merge tag 'turbostat-2025.05.06' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux

Pull turbostat updates from Len Brown:

 - support up to 8192 processors

 - add cpuidle governor debug telemetry, disabled by default

 - update default output to exclude cpuidle invocation counts

 - bug fixes

* tag 'turbostat-2025.05.06' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
  tools/power turbostat: v2025.05.06
  tools/power turbostat: disable "cpuidle" invocation counters, by default
  tools/power turbostat: re-factor sysfs code
  tools/power turbostat: Restore GFX sysfs fflush() call
  tools/power turbostat: Document GNR UncMHz domain convention
  tools/power turbostat: report CoreThr per measurement interval
  tools/power turbostat: Increase CPU_SUBSET_MAXCPUS to 8192
  tools/power turbostat: Add idle governor statistics reporting
  tools/power turbostat: Fix names matching
  tools/power turbostat: Allow Zero return value for some RAPL registers
  tools/power turbostat: Clustered Uncore MHz counters should honor show/hide options
2025-04-06 12:32:43 -07:00
Linus Torvalds
59f392fa7c soundwire fix for 6.15-rc1
- Fix to add missing config symbol CONFIG_SND_HDA_EXT_CORE required for
    asoc driver CONFIG_SND_SOF_SOF_HDA_SDW_BPT
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Merge tag 'soundwire-6.15-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/soundwire

Pull soundwire fix from Vinod Koul:

 - add missing config symbol CONFIG_SND_HDA_EXT_CORE required for asoc
   driver CONFIG_SND_SOF_SOF_HDA_SDW_BPT

* tag 'soundwire-6.15-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/soundwire:
  ASoC: SOF: Intel: Let SND_SOF_SOF_HDA_SDW_BPT select SND_HDA_EXT_CORE
2025-04-06 12:04:53 -07:00
Len Brown
03e00e373c tools/power turbostat: v2025.05.06
Support up to 8192 processors
Add cpuidle governor debug telemetry, disabled by default
Update default output to exclude cpuidle invocation counts
Bug fixes

Signed-off-by: Len Brown <len.brown@intel.com>
2025-04-06 14:49:20 -04:00
Len Brown
ec4acd3166 tools/power turbostat: disable "cpuidle" invocation counters, by default
Create "pct_idle" counter group, the sofware notion of residency
so it can now be singled out, independent of other counter groups.

Create "cpuidle" group, the cpuidle invocation counts.
Disable "cpuidle", by default.

Create "swidle" = "cpuidle" + "pct_idle".
Undocument "sysfs", the old name for "swidle", but keep it working
for backwards compatibilty.

Create "hwidle", all the HW idle counters

Modify "idle", enabled by default
"idle" = "hwidle" + "pct_idle" (and now excludes "cpuidle")

Signed-off-by: Len Brown <len.brown@intel.com>
2025-04-06 14:29:57 -04:00
Linus Torvalds
dda8887894 Fix a perf events time accounting bug.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf event fix from Ingo Molnar:
 "Fix a perf events time accounting bug"

* tag 'perf-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix child_total_time_enabled accounting bug at task exit
2025-04-06 10:48:12 -07:00
Linus Torvalds
302deb109d Miscellaneous scheduler fixes/updates:
- Fix a nonsensical Kconfig combination
  - Remove an unnecessary rseq-notification
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:

 - Fix a nonsensical Kconfig combination

 - Remove an unnecessary rseq-notification

* tag 'sched-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rseq: Eliminate useless task_work on execve
  sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP
2025-04-06 10:44:58 -07:00
Linus Torvalds
6f110a5e4f Disable SLUB_TINY for build testing
... and don't error out so hard on missing module descriptions.

Before commit 6c6c1fc09d ("modpost: require a MODULE_DESCRIPTION()")
we used to warn about missing module descriptions, but only when
building with extra warnigns (ie 'W=1').

After that commit the warning became an unconditional hard error.

And it turns out not all modules have been converted despite the claims
to the contrary.  As reported by Damian Tometzki, the slub KUnit test
didn't have a module description, and apparently nobody ever really
noticed.

The reason nobody noticed seems to be that the slub KUnit tests get
disabled by SLUB_TINY, which also ends up disabling a lot of other code,
both in tests and in slub itself.  And so anybody doing full build tests
didn't actually see this failre.

So let's disable SLUB_TINY for build-only tests, since it clearly ends
up limiting build coverage.  Also turn the missing module descriptions
error back into a warning, but let's keep it around for non-'W=1'
builds.

Reported-by: Damian Tometzki <damian@riscv-rocks.de>
Link: https://lore.kernel.org/all/01070196099fd059-e8463438-7b1b-4ec8-816d-173874be9966-000000@eu-central-1.amazonses.com/
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
Fixes: 6c6c1fc09d ("modpost: require a MODULE_DESCRIPTION()")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2025-04-06 10:00:04 -07:00
Len Brown
994633894f tools/power turbostat: re-factor sysfs code
Probe cpuidle "sysfs" residency and counts separately,
since soon we will make one disabled on, and the
other disabled off.

Clarify that some BIC (build-in-counters) are actually "groups".
since we're about to re-name some of those groups.

no functional change.

Signed-off-by: Len Brown <len.brown@intel.com>
2025-04-06 12:53:18 -04:00
Zhang Rui
f8b136ef26 tools/power turbostat: Restore GFX sysfs fflush() call
Do fflush() to discard the buffered data, before each read of the
graphics sysfs knobs.

Fixes: ba99a4fc8c ("tools/power turbostat: Remove unnecessary fflush() call")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2025-04-06 12:36:03 -04:00
Len Brown
3ae8508663 tools/power turbostat: Document GNR UncMHz domain convention
Document that on Intel Granite Rapids Systems,
Uncore domains 0-2 are CPU domains, and
uncore domains 3-4 are IO domains.

Signed-off-by: Len Brown <len.brown@intel.com>
2025-04-06 12:31:59 -04:00
Len Brown
f729775f79 tools/power turbostat: report CoreThr per measurement interval
The CoreThr column displays total thermal throttling events
since boot time.

Change it to report events during the measurement interval.

This is more useful for showing a user the current conditions.
Total events since boot time are still available to the user via
/sys/devices/system/cpu/cpu*/thermal_throttle/*

Document CoreThr on turbostat.8

Fixes: eae97e053f ("turbostat: Support thermal throttle count print")
Reported-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Chen Yu <yu.c.chen@intel.com>
2025-04-06 12:21:25 -04:00
Justin Ernst
eb187540d1 tools/power turbostat: Increase CPU_SUBSET_MAXCPUS to 8192
On systems with >= 1024 cpus (in my case 1152), turbostat fails with the error output:
	"turbostat: /sys/fs/cgroup/cpuset.cpus.effective: cpu str malformat 0-1151"

A similar error appears with the use of turbostat --cpu when the inputted cpu
range contains a cpu number >= 1024:
	# turbostat -c 1100-1151
	"--cpu 1100-1151" malformed
	...

Both errors are caused by parse_cpu_str() reaching its limit of CPU_SUBSET_MAXCPUS.

It's a good idea to limit the maximum cpu number being parsed, but 1024 is too low.
For a small increase in compute and allocated memory, increasing CPU_SUBSET_MAXCPUS
brings support for parsing cpu numbers >= 1024.

Increase CPU_SUBSET_MAXCPUS to 8192, a common setting for CONFIG_NR_CPUS on x86_64.

Signed-off-by: Justin Ernst <justin.ernst@hpe.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2025-04-06 12:14:14 -04:00
Linus Torvalds
16cd1c2657 A set of final cleanups for the timer subsystem:
1) Convert all del_timer[_sync]() instances over to the new
      timer_delete[_sync]() API and remove the legacy wrappers.
 
      Conversion was done with coccinelle plus some manual fixups as
      coccinelle chokes on scoped_guard().
 
   2) The final cleanup of the hrtimer_init() to hrtimer_setup() conversion.
 
      This has been delayed to the end of the merge window, so that all
      patches which have been merged through other trees are in mainline and
      all new users are catched.
 
 Doing this right before rc1 ensures that new code which is merged post rc1
 is not introducing new instances of the original functionality.
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Merge tag 'timers-cleanups-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer cleanups from Thomas Gleixner:
 "A set of final cleanups for the timer subsystem:

   - Convert all del_timer[_sync]() instances over to the new
     timer_delete[_sync]() API and remove the legacy wrappers.

     Conversion was done with coccinelle plus some manual fixups as
     coccinelle chokes on scoped_guard().

   - The final cleanup of the hrtimer_init() to hrtimer_setup()
     conversion.

     This has been delayed to the end of the merge window, so that all
     patches which have been merged through other trees are in mainline
     and all new users are catched.

  Doing this right before rc1 ensures that new code which is merged post
  rc1 is not introducing new instances of the original functionality"

* tag 'timers-cleanups-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tracing/timers: Rename the hrtimer_init event to hrtimer_setup
  hrtimers: Rename debug_init_on_stack() to debug_setup_on_stack()
  hrtimers: Rename debug_init() to debug_setup()
  hrtimers: Rename __hrtimer_init_sleeper() to __hrtimer_setup_sleeper()
  hrtimers: Remove unnecessary NULL check in hrtimer_start_range_ns()
  hrtimers: Make callback function pointer private
  hrtimers: Merge __hrtimer_init() into __hrtimer_setup()
  hrtimers: Switch to use __htimer_setup()
  hrtimers: Delete hrtimer_init()
  treewide: Convert new and leftover hrtimer_init() users
  treewide: Switch/rename to timer_delete[_sync]()
2025-04-06 08:35:37 -07:00
Linus Torvalds
ff0c66685d A set of updates for the interrupt subsystem:
1) A treewide cleanup for the irq_domain code, which makes the naming
      consistent and gets rid of the original oddity of naming domains
      'host'.
 
      This is a trivial mechanical change and is done late to ensure that
      all instances have been catched and new code merged post rc1 wont
      reintroduce new instances.
 
   2) A trivial consistency fix in the migration code
 
      The recent introduction of irq_force_complete_move() in the core
      code, causes a problem for the nostalgia crowd who maintains ia64 out
      of tree.
 
      The code assumes that hierarchical interrupt domains are enabled and
      dereferences irq_data::parent_data unconditionally. That works in mainline
      because both architectures which enable that code have hierarchical domains
      enabled. Though it breaks the ia64 build, which enables the functionality,
      but does not have hierarchical domains.
 
      While it's not really a problem for mainline today, this
      unconditional dereference is inconsistent and trivially fixable by
      using the existing helper function irqd_get_parent_data(), which has
      the appropriate #ifdeffery in place.
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Merge tag 'irq-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull more irq updates from Thomas Gleixner:
 "A set of updates for the interrupt subsystem:

   - A treewide cleanup for the irq_domain code, which makes the naming
     consistent and gets rid of the original oddity of naming domains
     'host'.

     This is a trivial mechanical change and is done late to ensure that
     all instances have been catched and new code merged post rc1 wont
     reintroduce new instances.

   - A trivial consistency fix in the migration code

     The recent introduction of irq_force_complete_move() in the core
     code, causes a problem for the nostalgia crowd who maintains ia64
     out of tree.

     The code assumes that hierarchical interrupt domains are enabled
     and dereferences irq_data::parent_data unconditionally. That works
     in mainline because both architectures which enable that code have
     hierarchical domains enabled. Though it breaks the ia64 build,
     which enables the functionality, but does not have hierarchical
     domains.

     While it's not really a problem for mainline today, this
     unconditional dereference is inconsistent and trivially fixable by
     using the existing helper function irqd_get_parent_data(), which
     has the appropriate #ifdeffery in place"

* tag 'irq-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/migration: Use irqd_get_parent_data() in irq_force_complete_move()
  irqdomain: Stop using 'host' for domain
  irqdomain: Rename irq_get_default_host() to irq_get_default_domain()
  irqdomain: Rename irq_set_default_host() to irq_set_default_domain()
2025-04-06 08:17:43 -07:00
Linus Torvalds
a91c49517d A revert to fix a adjtimex() regression:
The recent change to prevent that time goes backwards for the coarse time
 getters due to immediate multiplier adjustments via adjtimex(), changed the
 way how the timekeeping core treats that.
 
 That change result in a regression on the adjtimex() side, which is user
 space visible:
 
  1) The forwarding of the base time moves the update out of the original
     period and establishes a new one. That's changing the behaviour of the
     [PF]LL control, which user space expects to be applied periodically.
 
  2) The clearing of the accumulated NTP error due to #1, changes the
     behaviour as well.
 
 It was tried to delay the multiplier/frequency update to the next tick, but
 that did not solve the problem as userspace expects that the multiplier or
 frequency updates are in effect, when the syscall returns.
 
 There is a different solution for the coarse time problem available, so
 revert the offending commit to restore the existing adjtimex() behaviour.
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Merge tag 'timers-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fix from Thomas Gleixner:
 "A revert to fix a adjtimex() regression:

  The recent change to prevent that time goes backwards for the coarse
  time getters due to immediate multiplier adjustments via adjtimex(),
  changed the way how the timekeeping core treats that.

  That change result in a regression on the adjtimex() side, which is
  user space visible:

   1) The forwarding of the base time moves the update out of the
      original period and establishes a new one. That's changing the
      behaviour of the [PF]LL control, which user space expects to be
      applied periodically.

   2) The clearing of the accumulated NTP error due to #1, changes the
      behaviour as well.

  An attempt to delay the multiplier/frequency update to the next tick
  did not solve the problem as userspace expects that the multiplier or
  frequency updates are in effect, when the syscall returns.

  There is a different solution for the coarse time problem available,
  so revert the offending commit to restore the existing adjtimex()
  behaviour"

* tag 'timers-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "timekeeping: Fix possible inconsistencies in _COARSE clockids"
2025-04-06 08:13:16 -07:00
Linus Torvalds
1f80fbac0b sh updates for v6.15
- sh: defconfig: Drop obsolete CONFIG_NET_CLS_TCINDEX
 - sh: Align .bss section padding to 8-byte boundary
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Merge tag 'sh-for-v6.15-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/glaubitz/sh-linux

Pull sh updates from John Paul Adrian Glaubitz:
 "One important fix and one small configuration update.

  The first patch by Artur Rojek fixes an issue with the J2 firmware
  loader not being able to find the location of the device tree blob due
  to insufficient alignment of the .bss section which rendered J2 boards
  unbootable.

  The second patch by Johan Korsnes updates the defconfigs on sh to drop
  the CONFIG_NET_CLS_TCINDEX configuration option which became obsolete
  after 8c710f7525 ("net/sched: Retire tcindex classifier").

  Summary:

   - sh: defconfig: Drop obsolete CONFIG_NET_CLS_TCINDEX

   - sh: Align .bss section padding to 8-byte boundary"

* tag 'sh-for-v6.15-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/glaubitz/sh-linux:
  sh: defconfig: Drop obsolete CONFIG_NET_CLS_TCINDEX
  sh: Align .bss section padding to 8-byte boundary
2025-04-06 08:10:45 -07:00
Linus Torvalds
f4d2ef4825 Kbuild updates for v6.15
- Improve performance in gendwarfksyms
 
  - Remove deprecated EXTRA_*FLAGS and KBUILD_ENABLE_EXTRA_GCC_CHECKS
 
  - Support CONFIG_HEADERS_INSTALL for ARCH=um
 
  - Use more relative paths to sources files for better reproducibility
 
  - Support the loong64 Debian architecture
 
  - Add Kbuild bash completion
 
  - Introduce intermediate vmlinux.unstripped for architectures that need
    static relocations to be stripped from the final vmlinux
 
  - Fix versioning in Debian packages for -rc releases
 
  - Treat missing MODULE_DESCRIPTION() as an error
 
  - Convert Nios2 Makefiles to use the generic rule for built-in DTB
 
  - Add debuginfo support to the RPM package
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Merge tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Improve performance in gendwarfksyms

 - Remove deprecated EXTRA_*FLAGS and KBUILD_ENABLE_EXTRA_GCC_CHECKS

 - Support CONFIG_HEADERS_INSTALL for ARCH=um

 - Use more relative paths to sources files for better reproducibility

 - Support the loong64 Debian architecture

 - Add Kbuild bash completion

 - Introduce intermediate vmlinux.unstripped for architectures that need
   static relocations to be stripped from the final vmlinux

 - Fix versioning in Debian packages for -rc releases

 - Treat missing MODULE_DESCRIPTION() as an error

 - Convert Nios2 Makefiles to use the generic rule for built-in DTB

 - Add debuginfo support to the RPM package

* tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (40 commits)
  kbuild: rpm-pkg: build a debuginfo RPM
  kconfig: merge_config: use an empty file as initfile
  nios2: migrate to the generic rule for built-in DTB
  rust: kbuild: skip `--remap-path-prefix` for `rustdoc`
  kbuild: pacman-pkg: hardcode module installation path
  kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally
  modpost: require a MODULE_DESCRIPTION()
  kbuild: make all file references relative to source root
  x86: drop unnecessary prefix map configuration
  kbuild: deb-pkg: add comment about future removal of KDEB_COMPRESS
  kbuild: Add a help message for "headers"
  kbuild: deb-pkg: remove "version" variable in mkdebian
  kbuild: deb-pkg: fix versioning for -rc releases
  Documentation/kbuild: Fix indentation in modules.rst example
  x86: Get rid of Makefile.postlink
  kbuild: Create intermediate vmlinux build with relocations preserved
  kbuild: Introduce Kconfig symbol for linking vmlinux with relocations
  kbuild: link-vmlinux.sh: Make output file name configurable
  kbuild: do not generate .tmp_vmlinux*.map when CONFIG_VMLINUX_MAP=y
  Revert "kheaders: Ignore silly-rename files"
  ...
2025-04-05 15:46:50 -07:00
Linus Torvalds
758e4c86a1 drm fixes for 6.15-rc1
bridge:
 - tda998x: Select CONFIG_DRM_KMS_HELPER
 
 amdgpu:
 - Guard against potential division by 0 in fan code
 - Zero RPM support for SMU 14.0.2
 - Properly handle SI and CIK support being disabled
 - PSR fixes
 - DML2 fixes
 - DP Link training fix
 - Vblank fixes
 - RAS fixes
 - Partitioning fix
 - SDMA fix
 - SMU 13.0.x fixes
 - Rom fetching fix
 - MES fixes
 - Queue reset fix
 
 xe:
 - Fix NULL pointer dereference on error path
 - Add missing HW workaround for BMG
 - Fix survivability mode not triggering
 - Fix build warning when DRM_FBDEV_EMULATION is not set
 
 i915:
 - Bounds check for scalers in DSC prefill latency computation
 - Fix build by adding a missing include
 
 adp:
 - Fix error handling in plane setup
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Merge tag 'drm-next-2025-04-05' of https://gitlab.freedesktop.org/drm/kernel

Pull drm fixes from Dave Airlie:
 "Weekly fixes, mostly from the end of last week, this week was very
  quiet, maybe you scared everyone away. It's mostly amdgpu, and xe,
  with some i915, adp and bridge bits, since I think this is overly
  quiet I'd expect rc2 to be a bit more lively.

  bridge:
   - tda998x: Select CONFIG_DRM_KMS_HELPER

  amdgpu:
   - Guard against potential division by 0 in fan code
   - Zero RPM support for SMU 14.0.2
   - Properly handle SI and CIK support being disabled
   - PSR fixes
   - DML2 fixes
   - DP Link training fix
   - Vblank fixes
   - RAS fixes
   - Partitioning fix
   - SDMA fix
   - SMU 13.0.x fixes
   - Rom fetching fix
   - MES fixes
   - Queue reset fix

  xe:
   - Fix NULL pointer dereference on error path
   - Add missing HW workaround for BMG
   - Fix survivability mode not triggering
   - Fix build warning when DRM_FBDEV_EMULATION is not set

  i915:
   - Bounds check for scalers in DSC prefill latency computation
   - Fix build by adding a missing include

  adp:
   - Fix error handling in plane setup"

  # -----BEGIN PGP SIGNATURE-----

* tag 'drm-next-2025-04-05' of https://gitlab.freedesktop.org/drm/kernel: (34 commits)
  drm/i2c: tda998x: select CONFIG_DRM_KMS_HELPER
  drm/amdgpu/gfx12: fix num_mec
  drm/amdgpu/gfx11: fix num_mec
  drm/amd/pm: Add gpu_metrics_v1_8
  drm/amdgpu: Prefer shadow rom when available
  drm/amd/pm: Update smu metrics table for smu_v13_0_6
  drm/amd/pm: Remove host limit metrics support
  Remove unnecessary firmware version check for gc v9_4_2
  drm/amdgpu: stop unmapping MQD for kernel queues v3
  Revert "drm/amdgpu/sdma_v4_4_2: update VM flush implementation for SDMA"
  drm/amdgpu: Parse all deferred errors with UMC aca handle
  drm/amdgpu: Update ta ras block
  drm/amdgpu: Add NPS2 to DPX compatible mode
  drm/amdgpu: Use correct gfx deferred error count
  drm/amd/display: Actually do immediate vblank disable
  drm/amd/display: prevent hang on link training fail
  Revert "drm/amd/display: dml2 soc dscclk use DPM table clk setting"
  drm/amd/display: Increase vblank offdelay for PSR panels
  drm/amd: Handle being compiled without SI or CIK support better
  drm/amd/pm: Add zero RPM enabled OD setting support for SMU14.0.2
  ...
2025-04-05 15:35:11 -07:00
Uday Shankar
a7c699d090 kbuild: rpm-pkg: build a debuginfo RPM
The rpm-pkg make target currently suffers from a few issues related to
debuginfo:
1. debuginfo for things built into the kernel (vmlinux) is not available
   in any RPM produced by make rpm-pkg. This makes using tools like
   systemtap against a make rpm-pkg kernel impossible.
2. debug source for the kernel is not available. This means that
   commands like 'disas /s' in gdb, which display source intermixed with
   assembly, can only print file names/line numbers which then must be
   painstakingly resolved to actual source in a separate editor.
3. debuginfo for modules is available, but it remains bundled with the
   .ko files that contain module code, in the main kernel RPM. This is a
   waste of space for users who do not need to debug the kernel (i.e.
   most users).

Address all of these issues by additionally building a debuginfo RPM
when the kernel configuration allows for it, in line with standard
patterns followed by RPM distributors. With these changes:
1. systemtap now works (when these changes are backported to 6.11, since
   systemtap lags a bit behind in compatibility), as verified by the
   following simple test script:

   # stap -e 'probe kernel.function("do_sys_open").call { printf("%s\n", $$parms); }'
   dfd=0xffffffffffffff9c filename=0x7fe18800b160 flags=0x88800 mode=0x0
   ...

2. disas /s works correctly in gdb, with source and disassembly
   interspersed:

   # gdb vmlinux --batch -ex 'disas /s blk_op_str'
   Dump of assembler code for function blk_op_str:
   block/blk-core.c:
   125     {
      0xffffffff814c8740 <+0>:     endbr64

   127
   128             if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
      0xffffffff814c8744 <+4>:     mov    $0xffffffff824a7378,%rax
      0xffffffff814c874b <+11>:    cmp    $0x23,%edi
      0xffffffff814c874e <+14>:    ja     0xffffffff814c8768 <blk_op_str+40>
      0xffffffff814c8750 <+16>:    mov    %edi,%edi

   126             const char *op_str = "UNKNOWN";
      0xffffffff814c8752 <+18>:    mov    $0xffffffff824a7378,%rdx

   127
   128             if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
      0xffffffff814c8759 <+25>:    mov    -0x7dfa0160(,%rdi,8),%rax

   126             const char *op_str = "UNKNOWN";
      0xffffffff814c8761 <+33>:    test   %rax,%rax
      0xffffffff814c8764 <+36>:    cmove  %rdx,%rax

   129                     op_str = blk_op_name[op];
   130
   131             return op_str;
   132     }
      0xffffffff814c8768 <+40>:    jmp    0xffffffff81d01360 <__x86_return_thunk>
   End of assembler dump.

3. The size of the main kernel package goes down substantially,
   especially if many modules are built (quite typical). Here is a
   comparison of installed size of the kernel package (configured with
   allmodconfig, dwarf4 debuginfo, and module compression turned off)
   before and after this patch:

   # rpm -qi kernel-6.13* | grep -E '^(Version|Size)'
   Version     : 6.13.0postpatch+
   Size        : 1382874089
   Version     : 6.13.0prepatch+
   Size        : 17870795887

   This is a ~92% size reduction.

Note that a debuginfo package can only be produced if the following
configs are set:
- CONFIG_DEBUG_INFO=y
- CONFIG_MODULE_COMPRESS=n
- CONFIG_DEBUG_INFO_SPLIT=n

The first of these is obvious - we can't produce debuginfo if the build
does not generate it. The second two requirements can in principle be
removed, but doing so is difficult with the current approach, which uses
a generic rpmbuild script find-debuginfo.sh that processes all packaged
executables. If we want to remove those requirements the best path
forward is likely to add some debuginfo extraction/installation logic to
the modules_install target (controllable by flags). That way, it's
easier to operate on modules before they're compressed, and the logic
can be reused by all packaging targets.

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-04-06 06:22:01 +09:00
Daniel Gomez
a26fe287ee kconfig: merge_config: use an empty file as initfile
The scripts/kconfig/merge_config.sh script requires an existing
$INITFILE (or the $1 argument) as a base file for merging Kconfig
fragments. However, an empty $INITFILE can serve as an initial starting
point, later referenced by the KCONFIG_ALLCONFIG Makefile variable
if -m is not used. This variable can point to any configuration file
containing preset config symbols (the merged output) as stated in
Documentation/kbuild/kconfig.rst. When -m is used $INITFILE will
contain just the merge output requiring the user to run make (i.e.
KCONFIG_ALLCONFIG=<$INITFILE> make <allnoconfig/alldefconfig> or make
olddefconfig).

Instead of failing when `$INITFILE` is missing, create an empty file and
use it as the starting point for merges.

Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-04-06 06:22:01 +09:00
Masahiro Yamada
3b8241f64c nios2: migrate to the generic rule for built-in DTB
Commit 654102df2a ("kbuild: add generic support for built-in boot
DTBs") introduced generic support for built-in DTBs.

Select GENERIC_BUILTIN_DTB when built-in DTB support is enabled.

To keep consistency across architectures, this commit also renames
CONFIG_NIOS2_DTB_SOURCE_BOOL to CONFIG_BUILTIN_DTB, and
CONFIG_NIOS2_DTB_SOURCE to CONFIG_BUILTIN_DTB_NAME.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-04-06 06:22:01 +09:00
Johan Korsnes
5f2efd67a1 sh: defconfig: Drop obsolete CONFIG_NET_CLS_TCINDEX
This option was removed from Kconfig in 8c710f7525 ("net/sched:
Retire tcindex classifier") but from the defconfigs.

Fixes: 8c710f7525 ("net/sched: Retire tcindex classifier")
Signed-off-by: Johan Korsnes <johan.korsnes@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
2025-04-05 19:46:38 +02:00
Artur Rojek
427011db47 sh: Align .bss section padding to 8-byte boundary
J2-based devices expect to find a device tree blob at the end of the
.bss section. As of a77725a9a3 ("scripts/dtc: Update to upstream
version v1.6.1-19-g0a3a9d3449c8"), libfdt enforces 8-byte alignment
for the DTB, causing J2 devices to fail early in sh_fdt_init().

As the J2 loader firmware calculates the DTB location based on the kernel
image .bss section size rather than the __bss_stop symbol offset, the
required alignment can't be enforced with BSS_SECTION(0, PAGE_SIZE, 8).

To fix this, inline a modified version of the above macro which grows
.bss by the required size. While this change affects all existing SH
boards, it should be benign on platforms which don't need this alignment.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Tested-by: Rob Landley <rob@landley.net>
Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
2025-04-05 19:46:34 +02:00
Linus Torvalds
56f944529e Input updates for v6.15-rc0
- a brand new driver for touchpads and touchbars in newer Apple devices
 
 - support for Berlin-A series in goodix-berlin touchscreen driver
 
 - improvements to matrix_keypad driver to better handle GPIOs toggling
 
 - assorted small cleanups in other input drivers.
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Merge tag 'input-for-v6.15-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

Pull input updates from Dmitry Torokhov:

 - a brand new driver for touchpads and touchbars in newer Apple devices

 - support for Berlin-A series in goodix-berlin touchscreen driver

 - improvements to matrix_keypad driver to better handle GPIOs toggling

 - assorted small cleanups in other input drivers

* tag 'input-for-v6.15-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: goodix_berlin - add support for Berlin-A series
  dt-bindings: input: goodix,gt9916: Document gt9897 compatible
  dt-bindings: input: matrix_keypad - add wakeup-source property
  dt-bindings: input: matrix_keypad - add missing property
  Input: pm8941-pwrkey - fix dev_dbg() output in pm8941_pwrkey_irq()
  Input: synaptics - hide unused smbus_pnp_ids[] array
  Input: apple_z2 - fix potential confusion in Kconfig
  Input: matrix_keypad - use fsleep for delays after activating columns
  Input: matrix_keypad - add settle time after enabling all columns
  dt-bindings: input: matrix_keypad: add settle time after enabling all columns
  dt-bindings: input: matrix_keypad: convert to YAML
  dt-bindings: input: Correct indentation and style in DTS example
  MAINTAINERS: Add entries for Apple Z2 touchscreen driver
  Input: apple_z2 - add a driver for Apple Z2 touchscreens
  dt-bindings: input: touchscreen: Add Z2 controller
  Input: Switch to use hrtimer_setup()
  Input: drop vb2_ops_wait_prepare/finish
2025-04-05 09:20:39 -07:00
Nam Cao
244132c4e5 tracing/timers: Rename the hrtimer_init event to hrtimer_setup
The function hrtimer_init() doesn't exist anymore. It was replaced by
hrtimer_setup().

Thus, rename the hrtimer_init trace event to hrtimer_setup to keep it
consistent.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/cba84c3d853c5258aa3a262363a6eac08e2c7afc.1738746927.git.namcao@linutronix.de
2025-04-05 10:30:17 +02:00
Nam Cao
59c9edafc0 hrtimers: Rename debug_init_on_stack() to debug_setup_on_stack()
All the hrtimer_init*() functions have been renamed to hrtimer_setup*().
Rename debug_init_on_stack() to debug_setup_on_stack() as well, to keep the
names consistent.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/073cf6162779a2f5b12624677d4c49ee7eccc1ed.1738746927.git.namcao@linutronix.de
2025-04-05 10:30:17 +02:00