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Add an early parameter that allows users to select the mode of operation
for KVM/arm64.
For now, the only supported value is "protected". By passing this flag
users opt into the hypervisor placing additional restrictions on the
host kernel. These allow the hypervisor to spawn guests whose state is
kept private from the host. Restrictions will include stage-2 address
translation to prevent host from accessing guest memory, filtering its
SMC calls, etc.
Without this parameter, the default behaviour remains selecting VHE/nVHE
based on hardware support and CONFIG_ARM64_VHE.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-2-dbrazdil@google.com
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Now that the PAN toggling has been removed, the only user of
__system_matches_cap() is has_generic_auth(), which is only built when
CONFIG_ARM64_PTR_AUTH is selected, and Qian reports that this results in
a build-time warning when CONFIG_ARM64_PTR_AUTH is not selected:
| arch/arm64/kernel/cpufeature.c:2649:13: warning: '__system_matches_cap' defined but not used [-Wunused-function]
| static bool __system_matches_cap(unsigned int n)
| ^~~~~~~~~~~~~~~~~~~~
It's tricky to restructure things to prevent this, so let's mark
__system_matches_cap() as __maybe_unused, as we used to do for the other
user of __system_matches_cap() which we just removed.
Reported-by: Qian Cai <qcai@redhat.com>
Suggested-by: Qian Cai <qcai@redhat.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20201203152403.26100-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Now that arm64 no longer uses UAO, remove the vestigal feature detection
code and Kconfig text.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-13-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Some code (e.g. futex) needs to make privileged accesses to userspace
memory, and uses uaccess_{enable,disable}_privileged() in order to
permit this. All other uaccess primitives use LDTR/STTR, and never need
to toggle PAN.
Remove the redundant PAN toggling.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-12-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Now that set_fs() is gone, addr_limit_user_check() is redundant. Remove
the checks and associated thread flag.
To ensure that _TIF_WORK_MASK can be used as an immediate value in an
AND instruction (as it is in `ret_to_user`), TIF_MTE_ASYNC_FAULT is
renumbered to keep the constituent bits of _TIF_WORK_MASK contiguous.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-11-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Now that the uaccess primitives dont take addr_limit into account, we
have no need to manipulate this via set_fs() and get_fs(). Remove
support for these, along with some infrastructure this renders
redundant.
We no longer need to flip UAO to access kernel memory under KERNEL_DS,
and head.S unconditionally clears UAO for all kernel configurations via
an ERET in init_kernel_el. Thus, we don't need to dynamically flip UAO,
nor do we need to context-switch it. However, we still need to adjust
PAN during SDEI entry.
Masking of __user pointers no longer needs to use the dynamic value of
addr_limit, and can use a constant derived from the maximum possible
userspace task size. A new TASK_SIZE_MAX constant is introduced for
this, which is also used by core code. In configurations supporting
52-bit VAs, this may include a region of unusable VA space above a
48-bit TTBR0 limit, but never includes any portion of TTBR1.
Note that TASK_SIZE_MAX is an exclusive limit, while USER_DS and
KERNEL_DS were inclusive limits, and is converted to a mask by
subtracting one.
As the SDEI entry code repurposes the otherwise unnecessary
pt_regs::orig_addr_limit field to store the TTBR1 of the interrupted
context, for now we rename that to pt_regs::sdei_ttbr1. In future we can
consider factoring that out.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: James Morse <james.morse@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-10-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Now the uaccess primitives use LDTR/STTR unconditionally, the
uao_{ldp,stp,user_alternative} asm macros are misnamed, and have a
redundant argument. Let's remove the redundant argument and rename these
to user_{ldp,stp,ldst} respectively to clean this up.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Robin Murohy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-9-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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This patch separates arm64's user and kernel memory access primitives
into distinct routines, adding new __{get,put}_kernel_nofault() helpers
to access kernel memory, upon which core code builds larger copy
routines.
The kernel access routines (using LDR/STR) are not affected by PAN (when
legitimately accessing kernel memory), nor are they affected by UAO.
Switching to KERNEL_DS may set UAO, but this does not adversely affect
the kernel access routines.
The user access routines (using LDTR/STTR) are not affected by PAN (when
legitimately accessing user memory), but are affected by UAO. As these
are only legitimate to use under USER_DS with UAO clear, this should not
be problematic.
Routines performing atomics to user memory (futex and deprecated
instruction emulation) still need to transiently clear PAN, and these
are left as-is. These are never used on kernel memory.
Subsequent patches will refactor the uaccess helpers to remove redundant
code, and will also remove the redundant PAN/UAO manipulation.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-8-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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As a step towards implementing __{get,put}_kernel_nofault(), this patch
splits most user-memory specific logic out of __{get,put}_user(), with
the memory access and fault handling in new __{raw_get,put}_mem()
helpers.
For now the LDR/LDTR patching is left within the *get_mem() helpers, and
will be removed in a subsequent patch.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-7-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently __copy_user_flushcache() open-codes raw_copy_from_user(), and
doesn't use uaccess_mask_ptr() on the user address. Let's have it call
raw_copy_from_user(), which is both a simplification and ensures that
user pointers are masked under speculation.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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We currently have many uaccess_*{enable,disable}*() variants, which
subsequent patches will cut down as part of removing set_fs() and
friends. Once this simplification is made, most uaccess routines will
only need to ensure that the user page tables are mapped in TTBR0, as is
currently dealt with by uaccess_ttbr0_{enable,disable}().
The existing uaccess_{enable,disable}() routines ensure that user page
tables are mapped in TTBR0, and also disable PAN protections, which is
necessary to be able to use atomics on user memory, but also permit
unrelated privileged accesses to access user memory.
As preparatory step, let's rename uaccess_{enable,disable}() to
uaccess_{enable,disable}_privileged(), highlighting this caveat and
discouraging wider misuse. Subsequent patches can reuse the
uaccess_{enable,disable}() naming for the common case of ensuring the
user page tables are mapped in TTBR0.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-5-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In preparation for removing addr_limit and set_fs() we must decouple the
SDEI PAN/UAO manipulation from the uaccess code, and explicitly
reinitialize these as required.
SDEI enters the kernel with a non-architectural exception, and prior to
the most recent revision of the specification (ARM DEN 0054B), PSTATE
bits (e.g. PAN, UAO) are not manipulated in the same way as for
architectural exceptions. Notably, older versions of the spec can be
read ambiguously as to whether PSTATE bits are inherited unchanged from
the interrupted context or whether they are generated from scratch, with
TF-A doing the latter.
We have three cases to consider:
1) The existing TF-A implementation of SDEI will clear PAN and clear UAO
(along with other bits in PSTATE) when delivering an SDEI exception.
2) In theory, implementations of SDEI prior to revision B could inherit
PAN and UAO (along with other bits in PSTATE) unchanged from the
interrupted context. However, in practice such implementations do not
exist.
3) Going forward, new implementations of SDEI must clear UAO, and
depending on SCTLR_ELx.SPAN must either inherit or set PAN.
As we can ignore (2) we can assume that upon SDEI entry, UAO is always
clear, though PAN may be clear, inherited, or set per SCTLR_ELx.SPAN.
Therefore, we must explicitly initialize PAN, but do not need to do
anything for UAO.
Considering what we need to do:
* When set_fs() is removed, force_uaccess_begin() will have no HW
side-effects. As this only clears UAO, which we can assume has already
been cleared upon entry, this is not a problem. We do not need to add
code to manipulate UAO explicitly.
* PAN may be cleared upon entry (in case 1 above), so where a kernel is
built to use PAN and this is supported by all CPUs, the kernel must
set PAN upon entry to ensure expected behaviour.
* PAN may be inherited from the interrupted context (in case 3 above),
and so where a kernel is not built to use PAN or where PAN support is
not uniform across CPUs, the kernel must clear PAN to ensure expected
behaviour.
This patch reworks the SDEI code accordingly, explicitly setting PAN to
the expected state in all cases. To cater for the cases where the kernel
does not use PAN or this is not uniformly supported by hardware we add a
new cpu_has_pan() helper which can be used regardless of whether the
kernel is built to use PAN.
The existing system_uses_ttbr0_pan() is redefined in terms of
system_uses_hw_pan() both for clarity and as a minor optimization when
HW PAN is not selected.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The SDEI support code is split across arch/arm64/ and drivers/firmware/,
largley this is split so that the arch-specific portions are under
arch/arm64, and the management logic is under drivers/firmware/.
However, exception entry fixups are currently under drivers/firmware.
Let's move the exception entry fixups under arch/arm64/. This
de-clutters the management logic, and puts all the arch-specific
portions in one place. Doing this also allows the fixups to be applied
earlier, so things like PAN and UAO will be in a known good state before
we run other logic. This will also make subsequent refactoring easier.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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As with SCTLR_ELx and other control registers, some PSTATE bits are
UNKNOWN out-of-reset, and we may not be able to rely on hardware or
firmware to initialize them to our liking prior to entry to the kernel,
e.g. in the primary/secondary boot paths and return from idle/suspend.
It would be more robust (and easier to reason about) if we consistently
initialized PSTATE to a default value, as we do with control registers.
This will ensure that the kernel is not adversely affected by bits it is
not aware of, e.g. when support for a feature such as PAN/UAO is
disabled.
This patch ensures that PSTATE is consistently initialized at boot time
via an ERET. This is not intended to relax the existing requirements
(e.g. DAIF bits must still be set prior to entering the kernel). For
features detected dynamically (which may require system-wide support),
it is still necessary to subsequently modify PSTATE.
As ERET is not always a Context Synchronization Event, an ISB is placed
before each exception return to ensure updates to control registers have
taken effect. This handles the kernel being entered with SCTLR_ELx.EOS
clear (or any future control bits being in an UNKNOWN state).
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201113124937.20574-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Let's make SCTLR_ELx initialization a bit clearer by using meaningful
names for the initialization values, following the same scheme for
SCTLR_EL1 and SCTLR_EL2.
These definitions will be used more widely in subsequent patches.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201113124937.20574-5-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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For a while now el2_setup has performed some basic initialization of EL1
even when the kernel is booted at EL1, so the name is a little
misleading. Further, some comments are stale as with VHE it doesn't drop
the CPU to EL1.
To clarify things, rename el2_setup to init_kernel_el, and update
comments to be clearer as to the function's purpose.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201113124937.20574-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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To make callsites easier to read, add trivial C wrappers for the
SET_PSTATE_*() helpers, and convert trivial uses over to these. The new
wrappers will be used further in subsequent patches.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201113124937.20574-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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For consistency, all tasks have a pt_regs reserved at the highest
portion of their task stack. Among other things, this ensures that a
task's SP is always pointing within its stack rather than pointing
immediately past the end.
While it is never legitimate to ERET from a kthread, we take pains to
initialize pt_regs for kthreads as if this were legitimate. As this is
never legitimate, the effects of an erroneous return are rarely tested.
Let's simplify things by initializing a kthread's pt_regs such that an
ERET is caught as an illegal exception return, and removing the explicit
initialization of other exception context. Note that as
spectre_v4_enable_task_mitigation() only manipulates the PSTATE within
the unused regs this is safe to remove.
As user tasks will have their exception context initialized via
start_thread() or start_compat_thread(), this should only impact cases
where something has gone very wrong and we'd like that to be clearly
indicated.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201113124937.20574-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Registers x0/x1 get repeateadly pushed and poped during a host
HVC call. Instead, leave the registers on the stack, trading
a store instruction on the fast path for an add on the slow path.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Move the setting of SSBS directly into the HVC handler, using
the C helpers rather than the inline asssembly code.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Directly using the kimage_voffset variable is fine for now, but
will become more problematic as we start distrusting EL1.
Instead, patch the kimage_voffset into the HYP text, ensuring
we don't have to load an untrusted value later on.
Signed-off-by: Marc Zyngier <maz@kernel.org>
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When building with LTO, there is an increased risk of the compiler
converting an address dependency headed by a READ_ONCE() invocation
into a control dependency and consequently allowing for harmful
reordering by the CPU.
Ensure that such transformations are harmless by overriding the generic
READ_ONCE() definition with one that provides acquire semantics when
building with LTO.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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In preparation for patching the internals of READ_ONCE() itself, replace
its usage on the alternatives patching patch with a volatile variable
instead.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Armv8.3 introduced the LDAPR instruction, which provides weaker memory
ordering semantics than LDARi (RCpc vs RCsc). Generally, we provide an
RCsc implementation when implementing the Linux memory model, but LDAPR
can be used as a useful alternative to dependency ordering, particularly
when the compiler is capable of breaking the dependencies.
Since LDAPR is not available on all CPUs, add a cpufeature to detect it at
runtime and allow the instruction to be used with alternative code
patching.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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asm/alternative.h contains both the macros needed to use alternatives,
as well the type definitions and function prototypes for applying them.
Split the header in two, so that alternatives can be used from core
header files such as linux/compiler.h without the risk of circular
includes
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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The uao_* alternative asm macros are only used by the uaccess assembly
routines in arch/arm64/lib/, where they are included indirectly via
asm-uaccess.h. Since they're specific to the uaccess assembly (and will
lose the alternatives in subsequent patches), let's move them into
asm-uaccess.h.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
[will: update #include in mte.S to pull in uao asm macros]
Signed-off-by: Will Deacon <will@kernel.org>
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Now that we can use function pointer, use a dispatch table to call
the individual HVC handlers, leading to more maintainable code.
Further improvements include helpers to declare the mapping of
local variables to values passed in the host context.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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KVM/arm64 is so far unable to deal with function pointers, as the compiler
will generate the kernel's runtime VA, and not the linear mapping address,
meaning that kern_hyp_va() will give the wrong result.
We so far have been able to use PC-relative addressing, but that's not
always easy to use, and prevents the implementation of things like
the mapping of an index to a pointer.
To allow this, provide a new helper that computes the required
translation from the kernel image to the HYP VA space.
Signed-off-by: Marc Zyngier <maz@kernel.org>
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current->group_leader->exit_signal may change during copy_process() if
current->real_parent exits.
Move the assignment inside tasklist_lock to avoid the race.
Signed-off-by: Eddy Wu <eddy_wu@trendmicro.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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It's buggy:
On Fri, Nov 06, 2020 at 10:30:08PM +0800, Minh Yuan wrote:
> We recently discovered a slab-out-of-bounds read in fbcon in the latest
> kernel ( v5.10-rc2 for now ). The root cause of this vulnerability is that
> "fbcon_do_set_font" did not handle "vc->vc_font.data" and
> "vc->vc_font.height" correctly, and the patch
> <https://lkml.org/lkml/2020/9/27/223> for VT_RESIZEX can't handle this
> issue.
>
> Specifically, we use KD_FONT_OP_SET to set a small font.data for tty6, and
> use KD_FONT_OP_SET again to set a large font.height for tty1. After that,
> we use KD_FONT_OP_COPY to assign tty6's vc_font.data to tty1's vc_font.data
> in "fbcon_do_set_font", while tty1 retains the original larger
> height. Obviously, this will cause an out-of-bounds read, because we can
> access a smaller vc_font.data with a larger vc_font.height.
Further there was only one user ever.
- Android's loadfont, busybox and console-tools only ever use OP_GET
and OP_SET
- fbset documentation only mentions the kernel cmdline font: option,
not anything else.
- systemd used OP_COPY before release 232 published in Nov 2016
Now unfortunately the crucial report seems to have gone down with
gmane, and the commit message doesn't say much. But the pull request
hints at OP_COPY being broken
https://github.com/systemd/systemd/pull/3651
So in other words, this never worked, and the only project which
foolishly every tried to use it, realized that rather quickly too.
Instead of trying to fix security issues here on dead code by adding
missing checks, fix the entire thing by removing the functionality.
Note that systemd code using the OP_COPY function ignored the return
value, so it doesn't matter what we're doing here really - just in
case a lone server somewhere happens to be extremely unlucky and
running an affected old version of systemd. The relevant code from
font_copy_to_all_vcs() in systemd was:
/* copy font from active VT, where the font was uploaded to */
cfo.op = KD_FONT_OP_COPY;
cfo.height = vcs.v_active-1; /* tty1 == index 0 */
(void) ioctl(vcfd, KDFONTOP, &cfo);
Note this just disables the ioctl, garbage collecting the now unused
callbacks is left for -next.
v2: Tetsuo found the old mail, which allowed me to find it on another
archive. Add the link too.
Acked-by: Peilin Ye <yepeilin.cs@gmail.com>
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
References: https://lists.freedesktop.org/archives/systemd-devel/2016-June/036935.html
References: https://github.com/systemd/systemd/pull/3651
Cc: Greg KH <greg@kroah.com>
Cc: Peilin Ye <yepeilin.cs@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://lore.kernel.org/r/20201108153806.3140315-1-daniel.vetter@ffwll.ch
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Gratian managed to trigger the BUG_ON(!newowner) in fixup_pi_state_owner().
This is one possible chain of events leading to this:
Task Prio Operation
T1 120 lock(F)
T2 120 lock(F) -> blocks (top waiter)
T3 50 (RT) lock(F) -> boosts T1 and blocks (new top waiter)
XX timeout/ -> wakes T2
signal
T1 50 unlock(F) -> wakes T3 (rtmutex->owner == NULL, waiter bit is set)
T2 120 cleanup -> try_to_take_mutex() fails because T3 is the top waiter
and the lower priority T2 cannot steal the lock.
-> fixup_pi_state_owner() sees newowner == NULL -> BUG_ON()
The comment states that this is invalid and rt_mutex_real_owner() must
return a non NULL owner when the trylock failed, but in case of a queued
and woken up waiter rt_mutex_real_owner() == NULL is a valid transient
state. The higher priority waiter has simply not yet managed to take over
the rtmutex.
The BUG_ON() is therefore wrong and this is just another retry condition in
fixup_pi_state_owner().
Drop the locks, so that T3 can make progress, and then try the fixup again.
Gratian provided a great analysis, traces and a reproducer. The analysis is
to the point, but it confused the hell out of that tglx dude who had to
page in all the futex horrors again. Condensed version is above.
[ tglx: Wrote comment and changelog ]
Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
Reported-by: Gratian Crisan <gratian.crisan@ni.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87a6w6x7bb.fsf@ni.com
Link: https://lore.kernel.org/r/87sg9pkvf7.fsf@nanos.tec.linutronix.de
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As shown through runtime testing, the "filename" allocation is not
always freed in perf_event_parse_addr_filter().
There are three possible ways that this could happen:
- It could be allocated twice on subsequent iterations through the loop,
- or leaked on the success path,
- or on the failure path.
Clean up the code flow to make it obvious that 'filename' is always
freed in the reallocation path and in the two return paths as well.
We rely on the fact that kfree(NULL) is NOP and filename is initialized
with NULL.
This fixes the leak. No other side effects expected.
[ Dan Carpenter: cleaned up the code flow & added a changelog. ]
[ Ingo Molnar: updated the changelog some more. ]
Fixes: 375637bc5249 ("perf/core: Introduce address range filtering")
Signed-off-by: "kiyin(尹亮)" <kiyin@tencent.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "Srivatsa S. Bhat" <srivatsa@csail.mit.edu>
Cc: Anthony Liguori <aliguori@amazon.com>
--
kernel/events/core.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
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Testing shows a problem in that UV5 hubless systems were not being
recognized. Add them to the list of OEM IDs checked.
Fixes: 6c7794423a998 ("Add UV5 direct references")
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201105222741.157029-4-mike.travis@hpe.com
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Testing shows that trailing spaces caused problems with the OEM_ID and
the OEM_TABLE_ID. One being that the OEM_ID would not string compare
correctly. Another the OEM_ID and OEM_TABLE_ID would be concatenated
in the printout. Remove any trailing spaces.
Fixes: 1e61f5a95f191 ("Add and decode Arch Type in UVsystab")
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201105222741.157029-3-mike.travis@hpe.com
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Testing shows a problem in that the OEM_TABLE_ID was missing for
hubless systems. This is used to determine the APIC type (legacy or
extended). Add the OEM_TABLE_ID to the early hubless processing.
Fixes: 1e61f5a95f191 ("Add and decode Arch Type in UVsystab")
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201105222741.157029-2-mike.travis@hpe.com
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Implement ->read_iter for all proc "seq files" so that splice works on
them.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Implement ->read_iter for all proc "single files" so that more bionic
tests cases can pass when they call splice() on other fun files like
/proc/version
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Implement ->read_iter so that splice can be used on this file.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Implement ->read_iter so that the Android bionic test suite can use
this random proc file for its splice test case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Wire up generic_file_splice_read for the iter based proxy ops, so
that splice reads from them work.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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iov_iter based variant for reading a seq_file. seq_read is
reimplemented on top of the iter variant.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Commit aa1c09cb65e2 ("null_blk: Fix locking in zoned mode") changed
zone locking to using the potentially sleeping wait_on_bit_io()
function. This is acceptable when memory backing is enabled as the
device queue is in that case marked as blocking, but this triggers a
scheduling while in atomic context with memory backing disabled.
Fix this by relying solely on the device zone spinlock for zone
information protection without temporarily releasing this lock around
null_process_cmd() execution in null_zone_write(). This is OK to do
since when memory backing is disabled, command processing does not
block and the memory backing lock nullb->lock is unused. This solution
avoids the overhead of having to mark a zoned null_blk device queue as
blocking when memory backing is unused.
This patch also adds comments to the zone locking code to explain the
unusual locking scheme.
Fixes: aa1c09cb65e2 ("null_blk: Fix locking in zoned mode")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Commit 2ae0b31e0face ("tty: don't crash in tty_init_dev when missing
tty_port") didn't fully prevent the crash as the cleanup path in
tty_init_dev() calls release_tty() which dereferences tty->port
without checking it for non-null.
Add tty->port checks to release_tty to avoid the kernel crash.
Fixes: 2ae0b31e0face ("tty: don't crash in tty_init_dev when missing tty_port")
Signed-off-by: Matthias Reichl <hias@horus.com>
Link: https://lore.kernel.org/r/20201105123432.4448-1-hias@horus.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add the missing platform_driver_unregister() before return
from serial_txx9_init in the error handling case when failed
to register serial_txx9_pci_driver with macro ENABLE_SERIAL_TXX9_PCI
defined.
Fixes: ab4382d27412 ("tty: move drivers/serial/ to drivers/tty/serial/")
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Link: https://lore.kernel.org/r/20201103084942.109076-1-miaoqinglang@huawei.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Since 699cc4dfd140 (tty: serial: imx: add imx earlycon driver), the earlycon
part of imx serial is a separate driver and isn't necessarily enabled anymore
when the console is enabled. This causes users to loose the earlycon
functionality when upgrading their kenrel configuration via oldconfig.
Enable earlycon by default when IMX_SERIAL_CONSOLE is enabled.
Fixes: 699cc4dfd140 (tty: serial: imx: add imx earlycon driver)
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Link: https://lore.kernel.org/r/20201105204026.1818219-1-l.stach@pengutronix.de
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Mediatek 8250 port supports speed higher than uartclk / 16. If the baud
rates in both the new and the old termios setting are higher than
uartclk / 16, the WARN_ON in uart_get_baud_rate() will be triggered.
Passing NULL as the old termios so uart_get_baud_rate() will use
uartclk / 16 - 1 as the new baud rate which will be replaced by the
original baud rate later by tty_termios_encode_baud_rate() in
mtk8250_set_termios().
Fixes: 551e553f0d4a ("serial: 8250_mtk: Fix high-speed baud rates clamping")
Signed-off-by: Claire Chang <tientzu@chromium.org>
Link: https://lore.kernel.org/r/20201102120749.374458-1-tientzu@chromium.org
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Mimic the pre-existing ACPI and Device Tree event log behavior by not
creating the binary_bios_measurements file when the EFI TPM event log is
empty.
This fixes the following NULL pointer dereference that can occur when
reading /sys/kernel/security/tpm0/binary_bios_measurements after the
kernel received an empty event log from the firmware:
BUG: kernel NULL pointer dereference, address: 000000000000002c
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 2 PID: 3932 Comm: fwupdtpmevlog Not tainted 5.9.0-00003-g629990edad62 #17
Hardware name: LENOVO 20LCS03L00/20LCS03L00, BIOS N27ET38W (1.24 ) 11/28/2019
RIP: 0010:tpm2_bios_measurements_start+0x3a/0x550
Code: 54 53 48 83 ec 68 48 8b 57 70 48 8b 1e 65 48 8b 04 25 28 00 00 00 48 89 45 d0 31 c0 48 8b 82 c0 06 00 00 48 8b 8a c8 06 00 00 <44> 8b 60 1c 48 89 4d a0 4c 89 e2 49 83 c4 20 48 83 fb 00 75 2a 49
RSP: 0018:ffffa9c901203db0 EFLAGS: 00010246
RAX: 0000000000000010 RBX: 0000000000000000 RCX: 0000000000000010
RDX: ffff8ba1eb99c000 RSI: ffff8ba1e4ce8280 RDI: ffff8ba1e4ce8258
RBP: ffffa9c901203e40 R08: ffffa9c901203dd8 R09: ffff8ba1ec443300
R10: ffffa9c901203e50 R11: 0000000000000000 R12: ffff8ba1e4ce8280
R13: ffffa9c901203ef0 R14: ffffa9c901203ef0 R15: ffff8ba1e4ce8258
FS: 00007f6595460880(0000) GS:ffff8ba1ef880000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000002c CR3: 00000007d8d18003 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
? __kmalloc_node+0x113/0x320
? kvmalloc_node+0x31/0x80
seq_read+0x94/0x420
vfs_read+0xa7/0x190
ksys_read+0xa7/0xe0
__x64_sys_read+0x1a/0x20
do_syscall_64+0x37/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
In this situation, the bios_event_log pointer in the tpm_bios_log struct
was not NULL but was equal to the ZERO_SIZE_PTR (0x10) value. This was
due to the following kmemdup() in tpm_read_log_efi():
int tpm_read_log_efi(struct tpm_chip *chip)
{
...
/* malloc EventLog space */
log->bios_event_log = kmemdup(log_tbl->log, log_size, GFP_KERNEL);
if (!log->bios_event_log) {
ret = -ENOMEM;
goto out;
}
...
}
When log_size is zero, due to an empty event log from firmware,
ZERO_SIZE_PTR is returned from kmemdup(). Upon a read of the
binary_bios_measurements file, the tpm2_bios_measurements_start()
function does not perform a ZERO_OR_NULL_PTR() check on the
bios_event_log pointer before dereferencing it.
Rather than add a ZERO_OR_NULL_PTR() check in functions that make use of
the bios_event_log pointer, simply avoid creating the
binary_bios_measurements_file as is done in other event log retrieval
backends.
Explicitly ignore all of the events in the final event log when the main
event log is empty. The list of events in the final event log cannot be
accurately parsed without referring to the first event in the main event
log (the event log header) so the final event log is useless in such a
situation.
Fixes: 58cc1e4faf10 ("tpm: parse TPM event logs based on EFI table")
Link: https://lore.kernel.org/linux-integrity/E1FDCCCB-CA51-4AEE-AC83-9CDE995EAE52@canonical.com/
Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reported-by: Kenneth R. Crudup <kenny@panix.com>
Reported-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: Thiébaud Weksteen <tweek@google.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
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There is a misconfiguration in the bios of the gpio pin used for the
interrupt in the T490s. When interrupts are enabled in the tpm_tis
driver code this results in an interrupt storm. This was initially
reported when we attempted to enable the interrupt code in the tpm_tis
driver, which previously wasn't setting a flag to enable it. Due to
the reports of the interrupt storm that code was reverted and we went back
to polling instead of using interrupts. Now that we know the T490s problem
is a firmware issue, add code to check if the system is a T490s and
disable interrupts if that is the case. This will allow us to enable
interrupts for everyone else. If the user has a fixed bios they can
force the enabling of interrupts with tpm_tis.interrupts=1 on the
kernel command line.
Cc: Peter Huewe <peterhuewe@gmx.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
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Sometimes we would get the following flow when doing an i2cset:
0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
I2C_SLAVE_WRITE_RECEIVED
0x1 STATUS SLAVE_ACTIVITY=0x0 : RAW_INTR_STAT=0x714 : INTR_STAT=0x204
I2C_SLAVE_WRITE_REQUESTED
I2C_SLAVE_WRITE_RECEIVED
Documentation/i2c/slave-interface.rst says that I2C_SLAVE_WRITE_REQUESTED,
which is mandatory, should be sent while the data did not arrive yet. It
means in a write-request I2C_SLAVE_WRITE_REQUESTED should be reported
before any I2C_SLAVE_WRITE_RECEIVED.
By the way, I2C_SLAVE_STOP didn't be reported in the above case because
DW_IC_INTR_STAT was not 0x200.
dev->status can be used to record the current state, especially Designware
I2C controller has no interrupts to identify a write-request. This patch
makes not only I2C_SLAVE_WRITE_REQUESTED been reported first when
IC_INTR_RX_FULL is rising and dev->status isn't STATUS_WRITE_IN_PROGRESS
but also I2C_SLAVE_STOP been reported when a STOP condition is received.
Signed-off-by: Michael Wu <michael.wu@vatics.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
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David Brazdil
Mark Rutland
Marc Zyngier
Will Deacon
Linus Torvalds
Eddy Wu
Daniel Vetter
Mike Galbraith
kiyin(尹亮)
Mike Travis
Christoph Hellwig
Greg Kroah-Hartman
Damien Le Moal
Matthias Reichl
Qinglang Miao
Lucas Stach
Claire Chang
Tyler Hicks
Jerry Snitselaar
Michael Wu