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POR_EL0 is set to its most permissive value before setting up the
signal frame, to ensure that uaccess succeeds regardless of the
signal stack's pkey.
We are now tolerant to spurious POE faults. This means that we do
not strictly need to issue an ISB after updating POR_EL0, even when
followed by uaccess. The question is whether a fault is likely to
happen or not if the ISB is omitted; in this case the answer seems
to be no. If the regular stack is used, then it should already be
accessible. If the alternate signal stack is used, then a special
(inaccessible) pkey may be used - the assumption is that this
situation is very uncommon.
Remove the ISB to speed up the regular path - this should not have
any functional impact regardless of the scenario.
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Link: https://lore.kernel.org/r/20250619160042.2499290-3-kevin.brodsky@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Historically the behaviour of setup_return() was nondeterministic,
depending on whether the task's FSIMD/SVE/SME state happened to be live.
We fixed most of that in commit:
929fa99b1215 ("arm64/fpsimd: signal: Always save+flush state early")
... but we didn't decide on how clearing PSTATE.SM should behave, and left a
TODO comment to that effect.
Use the new task_smstop_sm() helper to make this behave as if an SMSTOP
instruction was used to exit streaming mode. This would have been the
most common behaviour prior to the commit above.
Fixes: 40a8e87bb328 ("arm64/sme: Disable ZA and streaming mode when handling signals")
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/20250508132644.1395904-10-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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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:
baa8515281b3 ("arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE")
a0136be443d5 (arm64/fpsimd: Load FP state based on recorded data type")
bbc6172eefdb ("arm64/fpsimd: SME no longer requires SVE register state")
8c845e273104 ("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>
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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>
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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: 85ed24dad290 ("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>
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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:
85ed24dad290 ("arm64/sme: Implement streaming SVE signal handling")
... and subsequently updated/fixed to handle SME-only systems in commits:
7dde62f0687c ("arm64/signal: Always accept SVE signal frames on SME only systems")
f26cd7372160 ("arm64/signal: Always allocate SVE signal frames on SME only systems")
Fixes: 85ed24dad290 ("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>
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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] https://github.com/ARM-software/abi-aa/blob/c51addc3dc03e73a016a1e4edf25440bcac76431/aapcs64/aapcs64.rst
Fixes: 39782210eb7e ("arm64/sme: Implement ZA signal handling")
Fixes: 39e54499280f ("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>
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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>
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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:
8c46def44409fc91 ("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:
40a8e87bb32855b3 ("arm64/sme: Disable ZA and streaming mode when handling signals")
Further incorrect manipulation of state was added in commits:
ea64baacbc36a0d5 ("arm64/signal: Flush FPSIMD register state when disabling streaming mode")
baa8515281b30861 ("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:
8cd969d28fd2848d ("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:
39782210eb7e8763 ("arm64/sme: Implement ZA signal handling")
ee072cf708048c0d ("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: 8c46def44409 ("arm64/signal: Add FPMR signal handling")
Fixes: 40a8e87bb328 ("arm64/sme: Disable ZA and streaming mode when handling signals")
Fixes: ea64baacbc36 ("arm64/signal: Flush FPSIMD register state when disabling streaming mode")
Fixes: baa8515281b3 ("arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE")
Fixes: 8cd969d28fd2 ("arm64/sve: Signal handling support")
Fixes: 39782210eb7e ("arm64/sme: Implement ZA signal handling")
Fixes: ee072cf70804 ("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>
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It is customary to list R, W, X permissions in that order. In fact
this is already the case for PIE constants (PIE_RWX). Rename POE_RXW
accordingly, as well as POE_XW (currently unused).
While at it also swap the W/X lines in
compute_s1_overlay_permissions() to follow the R, W, X order.
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Link: https://lore.kernel.org/r/20250219164029.2309119-3-kevin.brodsky@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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We currently have one helper to set a PIRx_ELx's permission field to
a given value, PIRx_ELx_PERM(), and another helper to extract a
permission field from POR_ELx, POR_ELx_IDX(). The naming is pretty
confusing - it isn't clear at all that "_PERM" corresponds to a
setter and "_IDX" to a getter.
This patch aims at improving the situation by using the same
suffixes as FIELD_PREP()/FIELD_GET(), which we have already adopted
for SYS_FIELD_{PREP,GET}():
* PIRx_ELx_PERM_PREP(), POR_ELx_PERM_PREP() create a register value
where the permission field for a given index is set to a given value.
* POR_ELx_PERM_GET() extracts the permission field from a given
register value for a given index.
These helpers are not implemented using FIELD_PREP()/FIELD_GET()
because the mask may not be constant, and they need to be usable in
assembly. They are all defined in asm/sysreg.h, as one would expect
for basic sysreg-related helpers.
Finally the new POR_ELx_PERM_* macros are used for existing
calculations in signal.c and mmu.c.
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Link: https://lore.kernel.org/r/20250219164029.2309119-2-kevin.brodsky@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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We are seeing a sparse warning in gcs_restore_signal():
arch/arm64/kernel/signal.c:1054:9: sparse: sparse: cast removes address space '__user' of expression
when storing the final GCSPR_EL0 value back into the register, caused by
the fact that write_sysreg_s() casts the value it writes to a u64 which
sparse sees as discarding the __userness of the pointer.
Avoid this by treating the address as an integer, casting to a pointer only
when using it to write to userspace.
While we're at it also inline gcs_signal_cap_valid() into it's one user
and make equivalent updates to gcs_signal_entry().
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202412082005.OBJ0BbWs-lkp@intel.com/
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241214-arm64-gcs-signal-sparse-v3-1-5e8d18fffc0c@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Commit eaf62ce1563b ("arm64/signal: Set up and restore the GCS
context for signal handlers") introduced a potential failure point
at the end of setup_return(). This is unfortunate as it is too late
to deliver a SIGSEGV: if that SIGSEGV is handled, the subsequent
sigreturn will end up returning to the original handler, which is
not the intention (since we failed to deliver that signal).
Make sure this does not happen by calling gcs_signal_entry()
at the very beginning of setup_return(), and add a comment just
after to discourage error cases being introduced from that point
onwards.
While at it, also take care of copy_siginfo_to_user(): since it may
fail, we shouldn't be calling it after setup_return() either. Call
it before setup_return() instead, and move the setting of X1/X2
inside setup_return() where it belongs (after the "point of no
failure").
Background: the first part of setup_rt_frame(), including
setup_sigframe(), has no impact on the execution of the interrupted
thread. The signal frame is written to the stack, but the stack
pointer remains unchanged. Failure at this stage can be recovered by
a SIGSEGV handler, and sigreturn will restore the original context,
at the point where the original signal occurred. On the other hand,
once setup_return() has updated registers including SP, the thread's
control flow has been modified and we must deliver the original
signal.
Fixes: eaf62ce1563b ("arm64/signal: Set up and restore the GCS context for signal handlers")
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241210160940.2031997-1-kevin.brodsky@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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* for-next/pkey-signal:
: Bring arm64 pkey signal delivery in line with the x86 behaviour
selftests/mm: Fix unused function warning for aarch64_write_signal_pkey()
selftests/mm: Define PKEY_UNRESTRICTED for pkey_sighandler_tests
selftests/mm: Enable pkey_sighandler_tests on arm64
selftests/mm: Use generic pkey register manipulation
arm64: signal: Remove unused macro
arm64: signal: Remove unnecessary check when saving POE state
arm64: signal: Improve POR_EL0 handling to avoid uaccess failures
firmware: arm_sdei: Fix the input parameter of cpuhp_remove_state()
Revert "kasan: Disable Software Tag-Based KASAN with GCC"
kasan: Fix Software Tag-Based KASAN with GCC
kasan: Disable Software Tag-Based KASAN with GCC
Documentation/protection-keys: add AArch64 to documentation
arm64: set POR_EL0 for kernel threads
# Conflicts:
# arch/arm64/kernel/signal.c
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'for-next/tlb', 'for-next/misc', 'for-next/mte', 'for-next/sysreg', 'for-next/stacktrace', 'for-next/hwcap3', 'for-next/kselftest', 'for-next/crc32', 'for-next/guest-cca', 'for-next/haft' and 'for-next/scs', remote-tracking branch 'arm64/for-next/perf' into for-next/core
* arm64/for-next/perf:
perf: Switch back to struct platform_driver::remove()
perf: arm_pmuv3: Add support for Samsung Mongoose PMU
dt-bindings: arm: pmu: Add Samsung Mongoose core compatible
perf/dwc_pcie: Fix typos in event names
perf/dwc_pcie: Add support for Ampere SoCs
ARM: pmuv3: Add missing write_pmuacr()
perf/marvell: Marvell PEM performance monitor support
perf/arm_pmuv3: Add PMUv3.9 per counter EL0 access control
perf/dwc_pcie: Convert the events with mixed case to lowercase
perf/cxlpmu: Support missing events in 3.1 spec
perf: imx_perf: add support for i.MX91 platform
dt-bindings: perf: fsl-imx-ddr: Add i.MX91 compatible
drivers perf: remove unused field pmu_node
* for-next/gcs: (42 commits)
: arm64 Guarded Control Stack user-space support
kselftest/arm64: Fix missing printf() argument in gcs/gcs-stress.c
arm64/gcs: Fix outdated ptrace documentation
kselftest/arm64: Ensure stable names for GCS stress test results
kselftest/arm64: Validate that GCS push and write permissions work
kselftest/arm64: Enable GCS for the FP stress tests
kselftest/arm64: Add a GCS stress test
kselftest/arm64: Add GCS signal tests
kselftest/arm64: Add test coverage for GCS mode locking
kselftest/arm64: Add a GCS test program built with the system libc
kselftest/arm64: Add very basic GCS test program
kselftest/arm64: Always run signals tests with GCS enabled
kselftest/arm64: Allow signals tests to specify an expected si_code
kselftest/arm64: Add framework support for GCS to signal handling tests
kselftest/arm64: Add GCS as a detected feature in the signal tests
kselftest/arm64: Verify the GCS hwcap
arm64: Add Kconfig for Guarded Control Stack (GCS)
arm64/ptrace: Expose GCS via ptrace and core files
arm64/signal: Expose GCS state in signal frames
arm64/signal: Set up and restore the GCS context for signal handlers
arm64/mm: Implement map_shadow_stack()
...
* for-next/probes:
: Various arm64 uprobes/kprobes cleanups
arm64: insn: Simulate nop instruction for better uprobe performance
arm64: probes: Remove probe_opcode_t
arm64: probes: Cleanup kprobes endianness conversions
arm64: probes: Move kprobes-specific fields
arm64: probes: Fix uprobes for big-endian kernels
arm64: probes: Fix simulate_ldr*_literal()
arm64: probes: Remove broken LDR (literal) uprobe support
* for-next/asm-offsets:
: arm64 asm-offsets.c cleanup (remove unused offsets)
arm64: asm-offsets: remove PREEMPT_DISABLE_OFFSET
arm64: asm-offsets: remove DMA_{TO,FROM}_DEVICE
arm64: asm-offsets: remove VM_EXEC and PAGE_SZ
arm64: asm-offsets: remove MM_CONTEXT_ID
arm64: asm-offsets: remove COMPAT_{RT_,SIGFRAME_REGS_OFFSET
arm64: asm-offsets: remove VMA_VM_*
arm64: asm-offsets: remove TSK_ACTIVE_MM
* for-next/tlb:
: TLB flushing optimisations
arm64: optimize flush tlb kernel range
arm64: tlbflush: add __flush_tlb_range_limit_excess()
* for-next/misc:
: Miscellaneous patches
arm64: tls: Fix context-switching of tpidrro_el0 when kpti is enabled
arm64/ptrace: Clarify documentation of VL configuration via ptrace
acpi/arm64: remove unnecessary cast
arm64/mm: Change protval as 'pteval_t' in map_range()
arm64: uprobes: Optimize cache flushes for xol slot
acpi/arm64: Adjust error handling procedure in gtdt_parse_timer_block()
arm64: fix .data.rel.ro size assertion when CONFIG_LTO_CLANG
arm64/ptdump: Test both PTE_TABLE_BIT and PTE_VALID for block mappings
arm64/mm: Sanity check PTE address before runtime P4D/PUD folding
arm64/mm: Drop setting PTE_TYPE_PAGE in pte_mkcont()
ACPI: GTDT: Tighten the check for the array of platform timer structures
arm64/fpsimd: Fix a typo
arm64: Expose ID_AA64ISAR1_EL1.XS to sanitised feature consumers
arm64: Return early when break handler is found on linked-list
arm64/mm: Re-organize arch_make_huge_pte()
arm64/mm: Drop _PROT_SECT_DEFAULT
arm64: Add command-line override for ID_AA64MMFR0_EL1.ECV
arm64: head: Drop SWAPPER_TABLE_SHIFT
arm64: cpufeature: add POE to cpucap_is_possible()
arm64/mm: Change pgattr_change_is_safe() arguments as pteval_t
* for-next/mte:
: Various MTE improvements
selftests: arm64: add hugetlb mte tests
hugetlb: arm64: add mte support
* for-next/sysreg:
: arm64 sysreg updates
arm64/sysreg: Update ID_AA64MMFR1_EL1 to DDI0601 2024-09
* for-next/stacktrace:
: arm64 stacktrace improvements
arm64: preserve pt_regs::stackframe during exec*()
arm64: stacktrace: unwind exception boundaries
arm64: stacktrace: split unwind_consume_stack()
arm64: stacktrace: report recovered PCs
arm64: stacktrace: report source of unwind data
arm64: stacktrace: move dump_backtrace() to kunwind_stack_walk()
arm64: use a common struct frame_record
arm64: pt_regs: swap 'unused' and 'pmr' fields
arm64: pt_regs: rename "pmr_save" -> "pmr"
arm64: pt_regs: remove stale big-endian layout
arm64: pt_regs: assert pt_regs is a multiple of 16 bytes
* for-next/hwcap3:
: Add AT_HWCAP3 support for arm64 (also wire up AT_HWCAP4)
arm64: Support AT_HWCAP3
binfmt_elf: Wire up AT_HWCAP3 at AT_HWCAP4
* for-next/kselftest: (30 commits)
: arm64 kselftest fixes/cleanups
kselftest/arm64: Try harder to generate different keys during PAC tests
kselftest/arm64: Don't leak pipe fds in pac.exec_sign_all()
kselftest/arm64: Corrupt P0 in the irritator when testing SSVE
kselftest/arm64: Add FPMR coverage to fp-ptrace
kselftest/arm64: Expand the set of ZA writes fp-ptrace does
kselftets/arm64: Use flag bits for features in fp-ptrace assembler code
kselftest/arm64: Enable build of PAC tests with LLVM=1
kselftest/arm64: Check that SVCR is 0 in signal handlers
kselftest/arm64: Fix printf() compiler warnings in the arm64 syscall-abi.c tests
kselftest/arm64: Fix printf() warning in the arm64 MTE prctl() test
kselftest/arm64: Fix printf() compiler warnings in the arm64 fp tests
kselftest/arm64: Fix build with stricter assemblers
kselftest/arm64: Test signal handler state modification in fp-stress
kselftest/arm64: Provide a SIGUSR1 handler in the kernel mode FP stress test
kselftest/arm64: Implement irritators for ZA and ZT
kselftest/arm64: Remove unused ADRs from irritator handlers
kselftest/arm64: Correct misleading comments on fp-stress irritators
kselftest/arm64: Poll less often while waiting for fp-stress children
kselftest/arm64: Increase frequency of signal delivery in fp-stress
kselftest/arm64: Fix encoding for SVE B16B16 test
...
* for-next/crc32:
: Optimise CRC32 using PMULL instructions
arm64/crc32: Implement 4-way interleave using PMULL
arm64/crc32: Reorganize bit/byte ordering macros
arm64/lib: Handle CRC-32 alternative in C code
* for-next/guest-cca:
: Support for running Linux as a guest in Arm CCA
arm64: Document Arm Confidential Compute
virt: arm-cca-guest: TSM_REPORT support for realms
arm64: Enable memory encrypt for Realms
arm64: mm: Avoid TLBI when marking pages as valid
arm64: Enforce bounce buffers for realm DMA
efi: arm64: Map Device with Prot Shared
arm64: rsi: Map unprotected MMIO as decrypted
arm64: rsi: Add support for checking whether an MMIO is protected
arm64: realm: Query IPA size from the RMM
arm64: Detect if in a realm and set RIPAS RAM
arm64: rsi: Add RSI definitions
* for-next/haft:
: Support for arm64 FEAT_HAFT
arm64: pgtable: Warn unexpected pmdp_test_and_clear_young()
arm64: Enable ARCH_HAS_NONLEAF_PMD_YOUNG
arm64: Add support for FEAT_HAFT
arm64: setup: name 'tcr2' register
arm64/sysreg: Update ID_AA64MMFR1_EL1 register
* for-next/scs:
: Dynamic shadow call stack fixes
arm64/scs: Drop unused prototype __pi_scs_patch_vmlinux()
arm64/scs: Deal with 64-bit relative offsets in FDE frames
arm64/scs: Fix handling of DWARF augmentation data in CIE/FDE frames
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Commit 33f082614c34 ("arm64: signal: Allow expansion of the signal
frame") introduced the BASE_SIGFRAME_SIZE macro but it has
apparently never been used; just remove it.
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Link: https://lore.kernel.org/r/20241029144539.111155-4-kevin.brodsky@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The POE frame record is allocated unconditionally if POE is
supported. If the allocation fails, a SIGSEGV is delivered before
setup_sigframe() can be reached. As a result there is no need to
consider poe_offset before saving POR_EL0; just remove that check.
This is in line with other frame records (FPMR, TPIDR2).
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Link: https://lore.kernel.org/r/20241029144539.111155-3-kevin.brodsky@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Reset POR_EL0 to "allow all" before writing the signal frame, preventing
spurious uaccess failures.
When POE is supported, the POR_EL0 register constrains memory
accesses based on the target page's POIndex (pkey). This raises the
question: what constraints should apply to a signal handler? The
current answer is that POR_EL0 is reset to POR_EL0_INIT when
invoking the handler, giving it full access to POIndex 0. This is in
line with x86's MPK support and remains unchanged.
This is only part of the story, though. POR_EL0 constrains all
unprivileged memory accesses, meaning that uaccess routines such as
put_user() are also impacted. As a result POR_EL0 may prevent the
signal frame from being written to the signal stack (ultimately
causing a SIGSEGV). This is especially concerning when an alternate
signal stack is used, because userspace may want to prevent access
to it outside of signal handlers. There is currently no provision
for that: POR_EL0 is reset after writing to the stack, and
POR_EL0_INIT only enables access to POIndex 0.
This patch ensures that POR_EL0 is reset to its most permissive
state before the signal stack is accessed. Once the signal frame has
been fully written, POR_EL0 is still set to POR_EL0_INIT - it is up
to the signal handler to enable access to additional pkeys if
needed. As to sigreturn(), it expects having access to the stack
like any other syscall; we only need to ensure that POR_EL0 is
restored from the signal frame after all uaccess calls. This
approach is in line with the recent x86/pkeys series [1].
Resetting POR_EL0 early introduces some complications, in that we
can no longer read the register directly in preserve_poe_context().
This is addressed by introducing a struct (user_access_state)
and helpers to manage any such register impacting user accesses
(uaccess and accesses in userspace). Things look like this on signal
delivery:
1. Save original POR_EL0 into struct [save_reset_user_access_state()]
2. Set POR_EL0 to "allow all" [save_reset_user_access_state()]
3. Create signal frame
4. Write saved POR_EL0 value to the signal frame [preserve_poe_context()]
5. Finalise signal frame
6. If all operations succeeded:
a. Set POR_EL0 to POR_EL0_INIT [set_handler_user_access_state()]
b. Else reset POR_EL0 to its original value [restore_user_access_state()]
If any step fails when setting up the signal frame, the process will
be sent a SIGSEGV, which it may be able to handle. Step 6.b ensures
that the original POR_EL0 is saved in the signal frame when
delivering that SIGSEGV (so that the original value is restored by
sigreturn).
The return path (sys_rt_sigreturn) doesn't strictly require any change
since restore_poe_context() is already called last. However, to
avoid uaccess calls being accidentally added after that point, we
use the same approach as in the delivery path, i.e. separating
uaccess from writing to the register:
1. Read saved POR_EL0 value from the signal frame [restore_poe_context()]
2. Set POR_EL0 to the saved value [restore_user_access_state()]
[1] https://lore.kernel.org/lkml/20240802061318.2140081-1-aruna.ramakrishna@oracle.com/
Fixes: 9160f7e909e1 ("arm64: add POE signal support")
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Link: https://lore.kernel.org/r/20241029144539.111155-2-kevin.brodsky@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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Currently the signal handling code has its own struct frame_record,
the definition of struct pt_regs open-codes a frame record as an array,
and the kernel unwinder hard-codes frame record offsets.
Move to a common struct frame_record that can be used throughout the
kernel.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Puranjay Mohan <puranjay12@gmail.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241017092538.1859841-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Add a context for the GCS state and include it in the signal context when
running on a system that supports GCS. We reuse the same flags that the
prctl() uses to specify which GCS features are enabled and also provide the
current GCS pointer.
We do not support enabling GCS via signal return, there is a conflict
between specifying GCSPR_EL0 and allocation of a new GCS and this is not
an ancticipated use case. We also enforce GCS configuration locking on
signal return.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Acked-by: Yury Khrustalev <yury.khrustalev@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241001-arm64-gcs-v13-26-222b78d87eee@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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When invoking a signal handler we use the GCS configuration and stack
for the current thread.
Since we implement signal return by calling the signal handler with a
return address set up pointing to a trampoline in the vDSO we need to
also configure any active GCS for this by pushing a frame for the
trampoline onto the GCS. If we do not do this then signal return will
generate a GCS protection fault.
In order to guard against attempts to bypass GCS protections via signal
return we only allow returning with GCSPR_EL0 pointing to an address
where it was previously preempted by a signal. We do this by pushing a
cap onto the GCS, this takes the form of an architectural GCS cap token
with the top bit set and token type of 0 which we add on signal entry
and validate and pop off on signal return. The combination of the top
bit being set and the token type mean that this can't be interpreted as
a valid token or address.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241001-arm64-gcs-v13-25-222b78d87eee@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Add PKEY support to signals, by saving and restoring POR_EL0 from the stackframe.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20240822151113.1479789-20-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
"The major features are support for LPA2 (52-bit VA/PA with 4K and 16K
pages), the dpISA extension and Rust enabled on arm64. The changes are
mostly contained within the usual arch/arm64/, drivers/perf, the arm64
Documentation and kselftests. The exception is the Rust support which
touches some generic build files.
Summary:
- Reorganise the arm64 kernel VA space and add support for LPA2 (at
stage 1, KVM stage 2 was merged earlier) - 52-bit VA/PA address
range with 4KB and 16KB pages
- Enable Rust on arm64
- Support for the 2023 dpISA extensions (data processing ISA), host
only
- arm64 perf updates:
- StarFive's StarLink (integrates one or more CPU cores with a
shared L3 memory system) PMU support
- Enable HiSilicon Erratum 162700402 quirk for HIP09
- Several updates for the HiSilicon PCIe PMU driver
- Arm CoreSight PMU support
- Convert all drivers under drivers/perf/ to use .remove_new()
- Miscellaneous:
- Don't enable workarounds for "rare" errata by default
- Clean up the DAIF flags handling for EL0 returns (in preparation
for NMI support)
- Kselftest update for ptrace()
- Update some of the sysreg field definitions
- Slight improvement in the code generation for inline asm I/O
accessors to permit offset addressing
- kretprobes: acquire regs via a BRK exception (previously done
via a trampoline handler)
- SVE/SME cleanups, comment updates
- Allow CALL_OPS+CC_OPTIMIZE_FOR_SIZE with clang (previously
disabled due to gcc silently ignoring -falign-functions=N)"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (134 commits)
Revert "mm: add arch hook to validate mmap() prot flags"
Revert "arm64: mm: add support for WXN memory translation attribute"
Revert "ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512"
ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512
kselftest/arm64: Add 2023 DPISA hwcap test coverage
kselftest/arm64: Add basic FPMR test
kselftest/arm64: Handle FPMR context in generic signal frame parser
arm64/hwcap: Define hwcaps for 2023 DPISA features
arm64/ptrace: Expose FPMR via ptrace
arm64/signal: Add FPMR signal handling
arm64/fpsimd: Support FEAT_FPMR
arm64/fpsimd: Enable host kernel access to FPMR
arm64/cpufeature: Hook new identification registers up to cpufeature
docs: perf: Fix build warning of hisi-pcie-pmu.rst
perf: starfive: Only allow COMPILE_TEST for 64-bit architectures
MAINTAINERS: Add entry for StarFive StarLink PMU
docs: perf: Add description for StarFive's StarLink PMU
dt-bindings: perf: starfive: Add JH8100 StarLink PMU
perf: starfive: Add StarLink PMU support
docs: perf: Update usage for target filter of hisi-pcie-pmu
...
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'for-next/misc', 'for-next/daif-cleanup', 'for-next/kselftest', 'for-next/documentation', 'for-next/sysreg' and 'for-next/dpisa', remote-tracking branch 'arm64/for-next/perf' into for-next/core
* arm64/for-next/perf: (39 commits)
docs: perf: Fix build warning of hisi-pcie-pmu.rst
perf: starfive: Only allow COMPILE_TEST for 64-bit architectures
MAINTAINERS: Add entry for StarFive StarLink PMU
docs: perf: Add description for StarFive's StarLink PMU
dt-bindings: perf: starfive: Add JH8100 StarLink PMU
perf: starfive: Add StarLink PMU support
docs: perf: Update usage for target filter of hisi-pcie-pmu
drivers/perf: hisi_pcie: Merge find_related_event() and get_event_idx()
drivers/perf: hisi_pcie: Relax the check on related events
drivers/perf: hisi_pcie: Check the target filter properly
drivers/perf: hisi_pcie: Add more events for counting TLP bandwidth
drivers/perf: hisi_pcie: Fix incorrect counting under metric mode
drivers/perf: hisi_pcie: Introduce hisi_pcie_pmu_get_event_ctrl_val()
drivers/perf: hisi_pcie: Rename hisi_pcie_pmu_{config,clear}_filter()
drivers/perf: hisi: Enable HiSilicon Erratum 162700402 quirk for HIP09
perf/arm_cspmu: Add devicetree support
dt-bindings/perf: Add Arm CoreSight PMU
perf/arm_cspmu: Simplify counter reset
perf/arm_cspmu: Simplify attribute groups
perf/arm_cspmu: Simplify initialisation
...
* for-next/reorg-va-space:
: Reorganise the arm64 kernel VA space in preparation for LPA2 support
: (52-bit VA/PA).
arm64: kaslr: Adjust randomization range dynamically
arm64: mm: Reclaim unused vmemmap region for vmalloc use
arm64: vmemmap: Avoid base2 order of struct page size to dimension region
arm64: ptdump: Discover start of vmemmap region at runtime
arm64: ptdump: Allow all region boundaries to be defined at boot time
arm64: mm: Move fixmap region above vmemmap region
arm64: mm: Move PCI I/O emulation region above the vmemmap region
* for-next/rust-for-arm64:
: Enable Rust support for arm64
arm64: rust: Enable Rust support for AArch64
rust: Refactor the build target to allow the use of builtin targets
* for-next/misc:
: Miscellaneous arm64 patches
ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512
arm64: Remove enable_daif macro
arm64/hw_breakpoint: Directly use ESR_ELx_WNR for an watchpoint exception
arm64: cpufeatures: Clean up temporary variable to simplify code
arm64: Update setup_arch() comment on interrupt masking
arm64: remove unnecessary ifdefs around is_compat_task()
arm64: ftrace: Don't forbid CALL_OPS+CC_OPTIMIZE_FOR_SIZE with Clang
arm64/sme: Ensure that all fields in SMCR_EL1 are set to known values
arm64/sve: Ensure that all fields in ZCR_EL1 are set to known values
arm64/sve: Document that __SVE_VQ_MAX is much larger than needed
arm64: make member of struct pt_regs and it's offset macro in the same order
arm64: remove unneeded BUILD_BUG_ON assertion
arm64: kretprobes: acquire the regs via a BRK exception
arm64: io: permit offset addressing
arm64: errata: Don't enable workarounds for "rare" errata by default
* for-next/daif-cleanup:
: Clean up DAIF handling for EL0 returns
arm64: Unmask Debug + SError in do_notify_resume()
arm64: Move do_notify_resume() to entry-common.c
arm64: Simplify do_notify_resume() DAIF masking
* for-next/kselftest:
: Miscellaneous arm64 kselftest patches
kselftest/arm64: Test that ptrace takes effect in the target process
* for-next/documentation:
: arm64 documentation patches
arm64/sme: Remove spurious 'is' in SME documentation
arm64/fp: Clarify effect of setting an unsupported system VL
arm64/sme: Fix cut'n'paste in ABI document
arm64/sve: Remove bitrotted comment about syscall behaviour
* for-next/sysreg:
: sysreg updates
arm64/sysreg: Update ID_AA64DFR0_EL1 register
arm64/sysreg: Update ID_DFR0_EL1 register fields
arm64/sysreg: Add register fields for ID_AA64DFR1_EL1
* for-next/dpisa:
: Support for 2023 dpISA extensions
kselftest/arm64: Add 2023 DPISA hwcap test coverage
kselftest/arm64: Add basic FPMR test
kselftest/arm64: Handle FPMR context in generic signal frame parser
arm64/hwcap: Define hwcaps for 2023 DPISA features
arm64/ptrace: Expose FPMR via ptrace
arm64/signal: Add FPMR signal handling
arm64/fpsimd: Support FEAT_FPMR
arm64/fpsimd: Enable host kernel access to FPMR
arm64/cpufeature: Hook new identification registers up to cpufeature
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Expose FPMR in the signal context on systems where it is supported. The
kernel validates the exact size of the FPSIMD registers so we can't readily
add it to fpsimd_context without disruption.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240306-arm64-2023-dpisa-v5-4-c568edc8ed7f@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently do_notify_resume() lives in arch/arm64/kernel/signal.c, but it would
make more sense for it to live in entry-common.c as it handles more than
signals, and is coupled with the rest of the return-to-userspace sequence (e.g.
with unusual DAIF masking that matches the exception return requirements).
Move do_notify_resume() to entry-common.c.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
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/20240206123848.1696480-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Itaru Kitayama <itaru.kitayama@linux.dev>
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In do_notify_resume, we handle _TIF_NEED_RESCHED differently from all
other flags, leaving IRQ+FIQ masked when calling into schedule(). This
masking is a historical artifact, and it is not currently necessary
to mask IRQ+FIQ when calling into schedule (as evidenced by the generic
exit_to_user_mode_loop(), which unmasks IRQs before checking
_TIF_NEED_RESCHED and calling schedule()).
This patch removes the special case for _TIF_NEED_RESCHED, moving this
check into the main loop such that schedule() will be called from a
regular process context with IRQ+FIQ unmasked. This is a minor
simplification to do_notify_resume() and brings it into line with the
generic exit_to_user_mode_loop() logic. This will also aid subsequent
rework of DAIF management.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
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/20240206123848.1696480-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Itaru Kitayama <itaru.kitayama@linux.dev>
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When we are in a syscall we will only save the FPSIMD subset even though
the task still has access to the full register set, and on context switch
we will only remove TIF_SVE when loading the register state. This means
that the signal handling code should not assume that TIF_SVE means that
the register state is stored in SVE format, it should instead check the
format that was recorded during save.
Fixes: 8c845e273104 ("arm64/sve: Leave SVE enabled on syscall if we don't context switch")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240130-arm64-sve-signal-regs-v2-1-9fc6f9502782@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 shadow stack support from Dave Hansen:
"This is the long awaited x86 shadow stack support, part of Intel's
Control-flow Enforcement Technology (CET).
CET consists of two related security features: shadow stacks and
indirect branch tracking. This series implements just the shadow stack
part of this feature, and just for userspace.
The main use case for shadow stack is providing protection against
return oriented programming attacks. It works by maintaining a
secondary (shadow) stack using a special memory type that has
protections against modification. When executing a CALL instruction,
the processor pushes the return address to both the normal stack and
to the special permission shadow stack. Upon RET, the processor pops
the shadow stack copy and compares it to the normal stack copy.
For more information, refer to the links below for the earlier
versions of this patch set"
Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/
Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/
* tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
x86/shstk: Change order of __user in type
x86/ibt: Convert IBT selftest to asm
x86/shstk: Don't retry vm_munmap() on -EINTR
x86/kbuild: Fix Documentation/ reference
x86/shstk: Move arch detail comment out of core mm
x86/shstk: Add ARCH_SHSTK_STATUS
x86/shstk: Add ARCH_SHSTK_UNLOCK
x86: Add PTRACE interface for shadow stack
selftests/x86: Add shadow stack test
x86/cpufeatures: Enable CET CR4 bit for shadow stack
x86/shstk: Wire in shadow stack interface
x86: Expose thread features in /proc/$PID/status
x86/shstk: Support WRSS for userspace
x86/shstk: Introduce map_shadow_stack syscall
x86/shstk: Check that signal frame is shadow stack mem
x86/shstk: Check that SSP is aligned on sigreturn
x86/shstk: Handle signals for shadow stack
x86/shstk: Introduce routines modifying shstk
x86/shstk: Handle thread shadow stack
x86/shstk: Add user-mode shadow stack support
...
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When we use NT_ARM_SSVE to either enable streaming mode or change the
vector length for a process we do not currently do anything to ensure that
there is storage allocated for the SME specific register state. If the
task had not previously used SME or we changed the vector length then
the task will not have had TIF_SME set or backing storage for ZA/ZT
allocated, resulting in inconsistent register sizes when saving state
and spurious traps which flush the newly set register state.
We should set TIF_SME to disable traps and ensure that storage is
allocated for ZA and ZT if it is not already allocated. This requires
modifying sme_alloc() to make the flush of any existing register state
optional so we don't disturb existing state for ZA and ZT.
Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Reported-by: David Spickett <David.Spickett@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: <stable@vger.kernel.org> # 5.19.x
Link: https://lore.kernel.org/r/20230810-arm64-fix-ptrace-race-v1-1-a5361fad2bd6@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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A control-protection fault is triggered when a control-flow transfer
attempt violates Shadow Stack or Indirect Branch Tracking constraints.
For example, the return address for a RET instruction differs from the copy
on the shadow stack.
There already exists a control-protection fault handler for handling kernel
IBT faults. Refactor this fault handler into separate user and kernel
handlers, like the page fault handler. Add a control-protection handler
for usermode. To avoid ifdeffery, put them both in a new file cet.c, which
is compiled in the case of either of the two CET features supported in the
kernel: kernel IBT or user mode shadow stack. Move some static inline
functions from traps.c into a header so they can be used in cet.c.
Opportunistically fix a comment in the kernel IBT part of the fault
handler that is on the end of the line instead of preceding it.
Keep the same behavior for the kernel side of the fault handler, except for
converting a BUG to a WARN in the case of a #CP happening when the feature
is missing. This unifies the behavior with the new shadow stack code, and
also prevents the kernel from crashing under this situation which is
potentially recoverable.
The control-protection fault handler works in a similar way as the general
protection fault handler. It provides the si_code SEGV_CPERR to the signal
handler.
Co-developed-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Tested-by: John Allen <john.allen@amd.com>
Tested-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/all/20230613001108.3040476-28-rick.p.edgecombe%40intel.com
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'for-next/iss2-decode', 'for-next/kselftest', 'for-next/misc', 'for-next/feat_mops', 'for-next/module-alloc', 'for-next/sysreg', 'for-next/cpucap', 'for-next/acpi', 'for-next/kdump', 'for-next/acpi-doc', 'for-next/doc' and 'for-next/tpidr2-fix', remote-tracking branch 'arm64/for-next/perf' into for-next/core
* arm64/for-next/perf:
docs: perf: Fix warning from 'make htmldocs' in hisi-pmu.rst
docs: perf: Add new description for HiSilicon UC PMU
drivers/perf: hisi: Add support for HiSilicon UC PMU driver
drivers/perf: hisi: Add support for HiSilicon H60PA and PAv3 PMU driver
perf: arm_cspmu: Add missing MODULE_DEVICE_TABLE
perf/arm-cmn: Add sysfs identifier
perf/arm-cmn: Revamp model detection
perf/arm_dmc620: Add cpumask
dt-bindings: perf: fsl-imx-ddr: Add i.MX93 compatible
drivers/perf: imx_ddr: Add support for NXP i.MX9 SoC DDRC PMU driver
perf/arm_cspmu: Decouple APMT dependency
perf/arm_cspmu: Clean up ACPI dependency
ACPI/APMT: Don't register invalid resource
perf/arm_cspmu: Fix event attribute type
perf: arm_cspmu: Set irq affinitiy only if overflow interrupt is used
drivers/perf: hisi: Don't migrate perf to the CPU going to teardown
drivers/perf: apple_m1: Force 63bit counters for M2 CPUs
perf/arm-cmn: Fix DTC reset
perf: qcom_l2_pmu: Make l2_cache_pmu_probe_cluster() more robust
perf/arm-cci: Slightly optimize cci_pmu_sync_counters()
* for-next/kpti:
: Simplify KPTI trampoline exit code
arm64: entry: Simplify tramp_alias macro and tramp_exit routine
arm64: entry: Preserve/restore X29 even for compat tasks
* for-next/missing-proto-warn:
: Address -Wmissing-prototype warnings
arm64: add alt_cb_patch_nops prototype
arm64: move early_brk64 prototype to header
arm64: signal: include asm/exception.h
arm64: kaslr: add kaslr_early_init() declaration
arm64: flush: include linux/libnvdimm.h
arm64: module-plts: inline linux/moduleloader.h
arm64: hide unused is_valid_bugaddr()
arm64: efi: add efi_handle_corrupted_x18 prototype
arm64: cpuidle: fix #ifdef for acpi functions
arm64: kvm: add prototypes for functions called in asm
arm64: spectre: provide prototypes for internal functions
arm64: move cpu_suspend_set_dbg_restorer() prototype to header
arm64: avoid prototype warnings for syscalls
arm64: add scs_patch_vmlinux prototype
arm64: xor-neon: mark xor_arm64_neon_*() static
* for-next/iss2-decode:
: Add decode of ISS2 to data abort reports
arm64/esr: Add decode of ISS2 to data abort reporting
arm64/esr: Use GENMASK() for the ISS mask
* for-next/kselftest:
: Various arm64 kselftest improvements
kselftest/arm64: Log signal code and address for unexpected signals
kselftest/arm64: Add a smoke test for ptracing hardware break/watch points
* for-next/misc:
: Miscellaneous patches
arm64: alternatives: make clean_dcache_range_nopatch() noinstr-safe
arm64: hibernate: remove WARN_ON in save_processor_state
arm64/fpsimd: Exit streaming mode when flushing tasks
arm64: mm: fix VA-range sanity check
arm64/mm: remove now-superfluous ISBs from TTBR writes
arm64: consolidate rox page protection logic
arm64: set __exception_irq_entry with __irq_entry as a default
arm64: syscall: unmask DAIF for tracing status
arm64: lockdep: enable checks for held locks when returning to userspace
arm64/cpucaps: increase string width to properly format cpucaps.h
arm64/cpufeature: Use helper for ECV CNTPOFF cpufeature
* for-next/feat_mops:
: Support for ARMv8.8 memcpy instructions in userspace
kselftest/arm64: add MOPS to hwcap test
arm64: mops: allow disabling MOPS from the kernel command line
arm64: mops: detect and enable FEAT_MOPS
arm64: mops: handle single stepping after MOPS exception
arm64: mops: handle MOPS exceptions
KVM: arm64: hide MOPS from guests
arm64: mops: don't disable host MOPS instructions from EL2
arm64: mops: document boot requirements for MOPS
KVM: arm64: switch HCRX_EL2 between host and guest
arm64: cpufeature: detect FEAT_HCX
KVM: arm64: initialize HCRX_EL2
* for-next/module-alloc:
: Make the arm64 module allocation code more robust (clean-up, VA range expansion)
arm64: module: rework module VA range selection
arm64: module: mandate MODULE_PLTS
arm64: module: move module randomization to module.c
arm64: kaslr: split kaslr/module initialization
arm64: kasan: remove !KASAN_VMALLOC remnants
arm64: module: remove old !KASAN_VMALLOC logic
* for-next/sysreg: (21 commits)
: More sysreg conversions to automatic generation
arm64/sysreg: Convert TRBIDR_EL1 register to automatic generation
arm64/sysreg: Convert TRBTRG_EL1 register to automatic generation
arm64/sysreg: Convert TRBMAR_EL1 register to automatic generation
arm64/sysreg: Convert TRBSR_EL1 register to automatic generation
arm64/sysreg: Convert TRBBASER_EL1 register to automatic generation
arm64/sysreg: Convert TRBPTR_EL1 register to automatic generation
arm64/sysreg: Convert TRBLIMITR_EL1 register to automatic generation
arm64/sysreg: Rename TRBIDR_EL1 fields per auto-gen tools format
arm64/sysreg: Rename TRBTRG_EL1 fields per auto-gen tools format
arm64/sysreg: Rename TRBMAR_EL1 fields per auto-gen tools format
arm64/sysreg: Rename TRBSR_EL1 fields per auto-gen tools format
arm64/sysreg: Rename TRBBASER_EL1 fields per auto-gen tools format
arm64/sysreg: Rename TRBPTR_EL1 fields per auto-gen tools format
arm64/sysreg: Rename TRBLIMITR_EL1 fields per auto-gen tools format
arm64/sysreg: Convert OSECCR_EL1 to automatic generation
arm64/sysreg: Convert OSDTRTX_EL1 to automatic generation
arm64/sysreg: Convert OSDTRRX_EL1 to automatic generation
arm64/sysreg: Convert OSLAR_EL1 to automatic generation
arm64/sysreg: Standardise naming of bitfield constants in OSL[AS]R_EL1
arm64/sysreg: Convert MDSCR_EL1 to automatic register generation
...
* for-next/cpucap:
: arm64 cpucap clean-up
arm64: cpufeature: fold cpus_set_cap() into update_cpu_capabilities()
arm64: cpufeature: use cpucap naming
arm64: alternatives: use cpucap naming
arm64: standardise cpucap bitmap names
* for-next/acpi:
: Various arm64-related ACPI patches
ACPI: bus: Consolidate all arm specific initialisation into acpi_arm_init()
* for-next/kdump:
: Simplify the crashkernel reservation behaviour of crashkernel=X,high on arm64
arm64: add kdump.rst into index.rst
Documentation: add kdump.rst to present crashkernel reservation on arm64
arm64: kdump: simplify the reservation behaviour of crashkernel=,high
* for-next/acpi-doc:
: Update ACPI documentation for Arm systems
Documentation/arm64: Update ACPI tables from BBR
Documentation/arm64: Update references in arm-acpi
Documentation/arm64: Update ARM and arch reference
* for-next/doc:
: arm64 documentation updates
Documentation/arm64: Add ptdump documentation
* for-next/tpidr2-fix:
: Fix the TPIDR2_EL0 register restoring on sigreturn
kselftest/arm64: Add a test case for TPIDR2 restore
arm64/signal: Restore TPIDR2 register rather than memory state
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Currently when restoring the TPIDR2 signal context we set the new value
from the signal frame in the thread data structure but not the register,
following the pattern for the rest of the data we are restoring. This does
not work in the case of TPIDR2, the register always has the value for the
current task. This means that either we return to userspace and ignore the
new value or we context switch and save the register value on top of the
newly restored value.
Load the value from the signal context into the register instead.
Fixes: 39e54499280f ("arm64/signal: Include TPIDR2 in the signal context")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: <stable@vger.kernel.org> # 6.3.x
Link: https://lore.kernel.org/r/20230621-arm64-fix-tpidr2-signal-restore-v2-1-c8e8fcc10302@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The do_notify_resume() is in a header that is not included
for the definition, which causes a W=1 warning:
arch/arm64/kernel/signal.c:1280:6: error: no previous prototype for 'do_notify_resume' [-Werror=missing-prototypes]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230516160642.523862-14-arnd@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Move tpidr2 sigframe allocation from under the checking of
system_supports_sme() to the checking of system_supports_tpidr2().
Signed-off-by: Dongxu Sun <sundongxu3@huawei.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230317124915.1263-3-sundongxu3@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
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Since commit a9d6915859501("arm64/sme: Implement support
for TPIDR2"), We introduced system_supports_tpidr2() for
TPIDR2 handling. Let's use the specific check instead.
No functional changes.
Signed-off-by: Dongxu Sun <sundongxu3@huawei.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230317124915.1263-2-sundongxu3@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- Support for arm64 SME 2 and 2.1. SME2 introduces a new 512-bit
architectural register (ZT0, for the look-up table feature) that
Linux needs to save/restore
- Include TPIDR2 in the signal context and add the corresponding
kselftests
- Perf updates: Arm SPEv1.2 support, HiSilicon uncore PMU updates, ACPI
support to the Marvell DDR and TAD PMU drivers, reset DTM_PMU_CONFIG
(ARM CMN) at probe time
- Support for DYNAMIC_FTRACE_WITH_CALL_OPS on arm64
- Permit EFI boot with MMU and caches on. Instead of cleaning the
entire loaded kernel image to the PoC and disabling the MMU and
caches before branching to the kernel bare metal entry point, leave
the MMU and caches enabled and rely on EFI's cacheable 1:1 mapping of
all of system RAM to populate the initial page tables
- Expose the AArch32 (compat) ELF_HWCAP features to user in an arm64
kernel (the arm32 kernel only defines the values)
- Harden the arm64 shadow call stack pointer handling: stash the shadow
stack pointer in the task struct on interrupt, load it directly from
this structure
- Signal handling cleanups to remove redundant validation of size
information and avoid reading the same data from userspace twice
- Refactor the hwcap macros to make use of the automatically generated
ID registers. It should make new hwcaps writing less error prone
- Further arm64 sysreg conversion and some fixes
- arm64 kselftest fixes and improvements
- Pointer authentication cleanups: don't sign leaf functions, unify
asm-arch manipulation
- Pseudo-NMI code generation optimisations
- Minor fixes for SME and TPIDR2 handling
- Miscellaneous updates: ARCH_FORCE_MAX_ORDER is now selectable,
replace strtobool() to kstrtobool() in the cpufeature.c code, apply
dynamic shadow call stack in two passes, intercept pfn changes in
set_pte_at() without the required break-before-make sequence, attempt
to dump all instructions on unhandled kernel faults
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (130 commits)
arm64: fix .idmap.text assertion for large kernels
kselftest/arm64: Don't require FA64 for streaming SVE+ZA tests
kselftest/arm64: Copy whole EXTRA context
arm64: kprobes: Drop ID map text from kprobes blacklist
perf: arm_spe: Print the version of SPE detected
perf: arm_spe: Add support for SPEv1.2 inverted event filtering
perf: Add perf_event_attr::config3
arm64/sme: Fix __finalise_el2 SMEver check
drivers/perf: fsl_imx8_ddr_perf: Remove set-but-not-used variable
arm64/signal: Only read new data when parsing the ZT context
arm64/signal: Only read new data when parsing the ZA context
arm64/signal: Only read new data when parsing the SVE context
arm64/signal: Avoid rereading context frame sizes
arm64/signal: Make interface for restore_fpsimd_context() consistent
arm64/signal: Remove redundant size validation from parse_user_sigframe()
arm64/signal: Don't redundantly verify FPSIMD magic
arm64/cpufeature: Use helper macros to specify hwcaps
arm64/cpufeature: Always use symbolic name for feature value in hwcaps
arm64/sysreg: Initial unsigned annotations for ID registers
arm64/sysreg: Initial annotation of signed ID registers
...
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When we parse the ZT signal context we read the entire context from
userspace, including the generic signal context header which was already
read by parse_user_sigframe() and padding bytes that we ignore. Avoid the
possibility of relying on the second read of the data read twice by only
reading the data which we are actually going to use.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-7-4545c94b20ff@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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When we parse the ZA signal context we read the entire context from
userspace, including the generic signal context header which was already
read by parse_user_sigframe() and padding bytes that we ignore. Avoid the
possibility of relying on the second read of the data read twice by only
reading the data which we are actually going to use.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-6-4545c94b20ff@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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When we parse the SVE signal context we read the entire context from
userspace, including the generic signal context header which was already
read by parse_user_sigframe() and padding bytes that we ignore. Avoid the
possibility of relying on the second read of the data read twice by only
reading the data which we are actually going to use.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-5-4545c94b20ff@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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We need to read the sizes of the signal context frames as part of parsing
the overall signal context in parse_user_sigframe(). In the cases where we
defer frame specific parsing to other functions those functions (other
than the recently added TPIDR2 parser) reread the size and validate the
version they read, opening the possibility that the value may change.
Avoid this possibility by passing the size read in parse_user_sigframe()
through user_ctxs and referring to that.
For consistency we move the size check for the TPIDR2 context into the
TPIDR2 parsing function.
Note that for SVE, ZA and ZT contexts we still read the size again but
after this change we no longer use the value, further changes will avoid
the read.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-4-4545c94b20ff@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Instead of taking a pointer to struct user_ctxs like the other two
restore_blah_context() functions the FPSIMD function takes a pointer to the
user struct it should read. Change it to be consistent with the rest, both
for consistency and to prepare for changes which avoid rereading data that
has already been read by the core parsing code.
There should be no functional change from this patch.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-3-4545c94b20ff@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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There is some minimal size validation in parse_user_sigframe() however
all of the individual parsing functions perform frame specific validation
of the sizing information, remove the frame specific size checks in the
core so that there isn't any confusion about what we validate for size.
Since the checks in the SVE and ZA parsing are after we have read the
relevant context and since they won't report an error if the frame is
undersized they are adjusted to check for this before doing anything else.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-2-4545c94b20ff@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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We validate that the magic in the struct fpsimd_context is correct in
restore_fpsimd_context() but this is redundant since parse_user_sigframe()
uses this magic to decide to call the function in the first place. Remove
the extra validation.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-1-4545c94b20ff@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Patches on this branch depend on the branches merged above.
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Add a new signal frame record for TPIDR2 using the same format as we
already use for ESR with different magic, a header with the value from the
register appended as the only data. If SME is supported then this record is
always included.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Link: https://lore.kernel.org/r/20221208-arm64-tpidr2-sig-v3-2-c77c6c8775f4@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Add a new signal context type for ZT which is present in the signal frame
when ZA is enabled and ZT is supported by the system. In order to account
for the possible addition of further ZT registers in the future we make the
number of registers variable in the ABI, though currently the only possible
number is 1. We could just use a bare list head for the context since the
number of registers can be inferred from the size of the context but for
usability and future extensibility we define a header with the number of
registers and some reserved fields in it.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221208-arm64-sme2-v4-11-f2fa0aef982f@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In preparation for adding support for storage for ZT0 to the thread_struct
rename za_state to sme_state. Since ZT0 is accessible when PSTATE.ZA is
set just like ZA itself we will extend the allocation done for ZA to
cover it, avoiding the need to further expand task_struct for non-SME
tasks.
No functional changes.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221208-arm64-sme2-v4-1-f2fa0aef982f@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently we only allocate space for SVE signal frames on systems that
support SVE, meaning that SME only systems do not allocate a signal frame
for streaming mode SVE state. Change the check so space is allocated if
either feature is supported.
Fixes: 85ed24dad290 ("arm64/sme: Implement streaming SVE signal handling")
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221223-arm64-fix-sme-only-v1-3-938d663f69e5@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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Currently we reject an attempt to restore a SVE signal frame on a system
with SME but not SVE supported. This means that it is not possible to
disable streaming mode via signal return as this is configured via the
flags in the SVE signal context. Instead accept the signal frame, we will
require it to have a vector length of 0 specified and no payload since the
task will have no SVE vector length configured.
Fixes: 85ed24dad290 ("arm64/sme: Implement streaming SVE signal handling")
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221223-arm64-fix-sme-only-v1-2-938d663f69e5@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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