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snprintf() returns the number of bytes that would be written,
which may be greater than the the actual length to be written.
show() methods should return the number of bytes printed into the
buffer. This is the return value of scnprintf().
Link: https://lkml.kernel.org/r/20200509085608.41061-3-chenzhou10@huawei.com
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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snprintf() returns the number of bytes that would be written,
which may be greater than the the actual length to be written.
show() methods should return the number of bytes printed into the
buffer. This is the return value of scnprintf().
Link: https://lkml.kernel.org/r/20200509085608.41061-2-chenzhou10@huawei.com
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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When strace wants to update the syscall number, it sets GPR2
to the desired number and updates the GPR via PTRACE_SETREGSET.
It doesn't update regs->int_code which would cause the old syscall
executed on syscall restart. As we cannot change the ptrace ABI and
don't have a field for the interruption code, check whether the tracee
is in a syscall and the last instruction was svc. In that case assume
that the tracer wants to update the syscall number and copy the GPR2
value to regs->int_code.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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tracing expects to see invalid syscalls, so pass it through.
The syscall path in entry.S checks the syscall number before
looking up the handler, so it is still safe.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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The current code returns the syscall number which an invalid
syscall number is supplied and tracing is enabled. This makes
the strace testsuite fail.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Use __secure_computing() and pass the register data via
seccomp_data so secure computing doesn't have to fetch it
again.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].
[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
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The CTR register reload in the KVM interrupt path used the wrong save
area for SLB (and NMI) interrupts.
Fixes: 9600f261acaa ("powerpc/64s/exception: Move KVM test to common code")
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200615061247.1310763-1-npiggin@gmail.com
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This patch implements support for PDSM request 'PAPR_PDSM_HEALTH'
that returns a newly introduced 'struct nd_papr_pdsm_health' instance
containing dimm health information back to user space in response to
ND_CMD_CALL. This functionality is implemented in newly introduced
papr_pdsm_health() that queries the nvdimm health information and
then copies this information to the package payload whose layout is
defined by 'struct nd_papr_pdsm_health'.
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200615124407.32596-7-vaibhav@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Introduce support for PAPR NVDIMM Specific Methods (PDSM) in papr_scm
module and add the command family NVDIMM_FAMILY_PAPR to the white list
of NVDIMM command sets. Also advertise support for ND_CMD_CALL for the
nvdimm command mask and implement necessary scaffolding in the module
to handle ND_CMD_CALL ioctl and PDSM requests that we receive.
The layout of the PDSM request as we expect from libnvdimm/libndctl is
described in newly introduced uapi header 'papr_pdsm.h' which
defines a 'struct nd_pkg_pdsm' and a maximal union named
'nd_pdsm_payload'. These new structs together with 'struct nd_cmd_pkg'
for a pdsm envelop thats sent by libndctl to libnvdimm and serviced by
papr_scm in 'papr_scm_service_pdsm()'. The PDSM request is
communicated by member 'struct nd_cmd_pkg.nd_command' together with
other information on the pdsm payload (size-in, size-out).
The patch also introduces 'struct pdsm_cmd_desc' instances of which
are stored in an array __pdsm_cmd_descriptors[] indexed with PDSM cmd
and corresponding access function pdsm_cmd_desc() is
introduced. 'struct pdsm_cdm_desc' holds the service function for a
given PDSM and corresponding payload in/out sizes.
A new function papr_scm_service_pdsm() is introduced and is called from
papr_scm_ndctl() in case of a PDSM request is received via ND_CMD_CALL
command from libnvdimm. The function performs validation on the PDSM
payload based on info present in corresponding PDSM descriptor and if
valid calls the 'struct pdcm_cmd_desc.service' function to service the
PDSM.
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200615124407.32596-6-vaibhav@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Since papr_scm_ndctl() can be called from outside papr_scm, its
exposed to the possibility of receiving NULL as value of 'cmd_rc'
argument. This patch updates papr_scm_ndctl() to protect against such
possibility by assigning it pointer to a local variable in case cmd_rc
== NULL.
Finally the patch also updates the 'default' add a debug log unknown
'cmd' values.
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200615124407.32596-5-vaibhav@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Implement support for fetching nvdimm health information via
H_SCM_HEALTH hcall as documented in Ref[1]. The hcall returns a pair
of 64-bit bitmap, bitwise-and of which is then stored in
'struct papr_scm_priv' and subsequently partially exposed to
user-space via newly introduced dimm specific attribute
'papr/flags'. Since the hcall is costly, the health information is
cached and only re-queried, 60s after the previous successful hcall.
The patch also adds a documentation text describing flags reported by
the the new sysfs attribute 'papr/flags' is also introduced at
Documentation/ABI/testing/sysfs-bus-papr-pmem.
[1] commit 58b278f568f0 ("powerpc: Provide initial documentation for
PAPR hcalls")
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200615124407.32596-4-vaibhav@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Add is_intr_type() and is_intr_type_n() to consolidate the boilerplate
code for querying a specific type of interrupt given an encoded value
from VMCS.VM_{ENTER,EXIT}_INTR_INFO, with and without an associated
vector respectively.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200609014518.26756-1-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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KASAN sw tagging sets a random tag of 8 bits in the top byte of the pointer
returned by the memory allocating functions. So for the functions unaware
of this change, the top 8 bits of the address must be reset which is done
by the function arch_kasan_reset_tag().
Signed-off-by: Shyam Thombre <sthombre@codeaurora.org>
Link: https://lore.kernel.org/r/1591787384-5823-1-git-send-email-sthombre@codeaurora.org
Signed-off-by: Will Deacon <will@kernel.org>
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When panicing due to an unknown/unhandled exception at EL1, dump the
registers of the faulting context so that it's easier to figure out
what went wrong. In particular, this makes it a lot easier to debug
in-kernel BTI failures since it pretty-prints PSTATE.BTYPE in the crash
log.
Cc: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200615113458.2884-1-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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sve_default_vl can be modified via the /proc/sys/abi/sve_default_vl
sysctl concurrently with use, and modified concurrently by multiple
threads.
Adding a lock for this seems overkill, and I don't want to think any
more than necessary, so just define wrappers using READ_ONCE()/
WRITE_ONCE().
This will avoid the possibility of torn accesses and repeated loads
and stores.
There's no evidence yet that this is going wrong in practice: this
is just hygiene. For generic sysctl users, it would be better to
build this kind of thing into the sysctl common code somehow.
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/1591808590-20210-3-git-send-email-Dave.Martin@arm.com
[will: move set_sve_default_vl() inside #ifdef to squash allnoconfig warning]
Signed-off-by: Will Deacon <will@kernel.org>
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For some reasons, running a simple qemu-kvm command with KCSAN will
reset AMD hosts. It turns out svm_vcpu_run() could not be instrumented.
Disable it for now.
# /usr/libexec/qemu-kvm -name ubuntu-18.04-server-cloudimg -cpu host
-smp 2 -m 2G -hda ubuntu-18.04-server-cloudimg.qcow2
=== console output ===
Kernel 5.6.0-next-20200408+ on an x86_64
hp-dl385g10-05 login:
<...host reset...>
HPE ProLiant System BIOS A40 v1.20 (03/09/2018)
(C) Copyright 1982-2018 Hewlett Packard Enterprise Development LP
Early system initialization, please wait...
Signed-off-by: Qian Cai <cai@lca.pw>
Message-Id: <20200415153709.1559-1-cai@lca.pw>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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With CONFIG_DEBUG_VIRTUAL=y, we can hit a BUG() if we take a hard
lockup watchdog interrupt when in OPAL mode.
This happens in show_instructions() if the kernel takes the watchdog
NMI IPI, or any other interrupt, with MSR_IR == 0. show_instructions()
updates the variable pc in the loop and the second iteration will
result in BUG().
We hit the BUG_ON due the below check in __va()
#define __va(x)
({
VIRTUAL_BUG_ON((unsigned long)(x) >= PAGE_OFFSET);
(void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET);
})
Fix it by moving the check out of the loop. Also update nip so that
the nip == pc check still matches.
Fixes: 4dd7554a6456 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va and __pa addresses")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Use IS_ENABLED(), massage change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200524093822.423487-1-aneesh.kumar@linux.ibm.com
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TEXT_OFFSET was recently changed to 0x0, in preparation for its removal
at a later stage, and a warning is emitted into the kernel log when the
bootloader appears to have failed to take the TEXT_OFFSET image header
value into account.
Ironically, this warning itself fails to take TEXT_OFFSET into account,
and compares the kernel image's alignment modulo 2M against a hardcoded
value of 0x0, and so the warning will trigger spuriously when TEXT_OFFSET
randomization is enabled.
Given the intent to get rid of TEXT_OFFSET entirely, let's fix this
oversight by just removing support for TEXT_OFFSET randomization.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200615101939.634391-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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During the KVM merging progress, a CONFIG_CPU_LOONGSON64 guard in commit
7f2a83f1c2a941ebfee53 ("KVM: MIPS: Add CPUCFG emulation for Loongson-3")
is missing by accident. So add it to avoid building error.
Fixes: 7f2a83f1c2a941ebfee53 ("KVM: MIPS: Add CPUCFG emulation for Loongson-3")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Message-Id: <1592204215-28704-1-git-send-email-chenhc@lemote.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull more Kbuild updates from Masahiro Yamada:
- fix build rules in binderfs sample
- fix build errors when Kbuild recurses to the top Makefile
- covert '---help---' in Kconfig to 'help'
* tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
treewide: replace '---help---' in Kconfig files with 'help'
kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables
samples: binderfs: really compile this sample and fix build issues
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fix from Michael Ellerman:
"One fix for a recent change which broke nested KVM guests on Power9.
Thanks to Alexey Kardashevskiy"
* tag 'powerpc-5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
KVM: PPC: Fix nested guest RC bits update
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Pull ARM fixes from Russell King:
- fix for "hex" Kconfig default to use 0x0 rather than 0 to allow these
to be removed from defconfigs
- fix from Ard Biesheuvel for EFI HYP mode booting
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8985/1: efi/decompressor: deal with HYP mode boot gracefully
ARM: 8984/1: Kconfig: set default ZBOOT_ROM_TEXT/BSS value to 0x0
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Pull OpenRISC update from Stafford Horne:
"One patch found wile I was getting the glibc port ready: fix issue
with clone TLS arg getting overwritten"
* tag 'for-linus' of git://github.com/openrisc/linux:
openrisc: Fix issue with argument clobbering for clone/fork
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git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha
Pull alpha updates from Matt Turner:
"A few changes for alpha. They're mostly small janitorial fixes but
there's also a build fix and most notably a patch from Mikulas that
fixes a hang on boot on the Avanti platform, which required quite a
bit of work and review"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha:
alpha: Fix build around srm_sysrq_reboot_op
alpha: c_next should increase position index
alpha: Replace sg++ with sg = sg_next(sg)
alpha: fix memory barriers so that they conform to the specification
alpha: remove unneeded semicolon in sys_eiger.c
alpha: remove unneeded semicolon in osf_sys.c
alpha: Replace strncmp with str_has_prefix
alpha: fix rtc port ranges
alpha: Kconfig: pedantic formatting
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 RAS updates from Thomas Gleixner:
"RAS updates from Borislav Petkov:
- Unmap a whole guest page if an MCE is encountered in it to avoid
follow-on MCEs leading to the guest crashing, by Tony Luck.
This change collided with the entry changes and the merge
resolution would have been rather unpleasant. To avoid that the
entry branch was merged in before applying this. The resulting code
did not change over the rebase.
- AMD MCE error thresholding machinery cleanup and hotplug
sanitization, by Thomas Gleixner.
- Change the MCE notifiers to denote whether they have handled the
error and not break the chain early by returning NOTIFY_STOP, thus
giving the opportunity for the later handlers in the chain to see
it. By Tony Luck.
- Add AMD family 0x17, models 0x60-6f support, by Alexander Monakov.
- Last but not least, the usual round of fixes and improvements"
* tag 'ras-core-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
x86/mce/dev-mcelog: Fix -Wstringop-truncation warning about strncpy()
x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned
EDAC/amd64: Add AMD family 17h model 60h PCI IDs
hwmon: (k10temp) Add AMD family 17h model 60h PCI match
x86/amd_nb: Add AMD family 17h model 60h PCI IDs
x86/mcelog: Add compat_ioctl for 32-bit mcelog support
x86/mce: Drop bogus comment about mce.kflags
x86/mce: Fixup exception only for the correct MCEs
EDAC: Drop the EDAC report status checks
x86/mce: Add mce=print_all option
x86/mce: Change default MCE logger to check mce->kflags
x86/mce: Fix all mce notifiers to update the mce->kflags bitmask
x86/mce: Add a struct mce.kflags field
x86/mce: Convert the CEC to use the MCE notifier
x86/mce: Rename "first" function as "early"
x86/mce/amd, edac: Remove report_gart_errors
x86/mce/amd: Make threshold bank setting hotplug robust
x86/mce/amd: Cleanup threshold device remove path
x86/mce/amd: Straighten CPU hotplug path
x86/mce/amd: Sanitize thresholding device creation hotplug path
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 entry updates from Thomas Gleixner:
"The x86 entry, exception and interrupt code rework
This all started about 6 month ago with the attempt to move the Posix
CPU timer heavy lifting out of the timer interrupt code and just have
lockless quick checks in that code path. Trivial 5 patches.
This unearthed an inconsistency in the KVM handling of task work and
the review requested to move all of this into generic code so other
architectures can share.
Valid request and solved with another 25 patches but those unearthed
inconsistencies vs. RCU and instrumentation.
Digging into this made it obvious that there are quite some
inconsistencies vs. instrumentation in general. The int3 text poke
handling in particular was completely unprotected and with the batched
update of trace events even more likely to expose to endless int3
recursion.
In parallel the RCU implications of instrumenting fragile entry code
came up in several discussions.
The conclusion of the x86 maintainer team was to go all the way and
make the protection against any form of instrumentation of fragile and
dangerous code pathes enforcable and verifiable by tooling.
A first batch of preparatory work hit mainline with commit
d5f744f9a2ac ("Pull x86 entry code updates from Thomas Gleixner")
That (almost) full solution introduced a new code section
'.noinstr.text' into which all code which needs to be protected from
instrumentation of all sorts goes into. Any call into instrumentable
code out of this section has to be annotated. objtool has support to
validate this.
Kprobes now excludes this section fully which also prevents BPF from
fiddling with it and all 'noinstr' annotated functions also keep
ftrace off. The section, kprobes and objtool changes are already
merged.
The major changes coming with this are:
- Preparatory cleanups
- Annotating of relevant functions to move them into the
noinstr.text section or enforcing inlining by marking them
__always_inline so the compiler cannot misplace or instrument
them.
- Splitting and simplifying the idtentry macro maze so that it is
now clearly separated into simple exception entries and the more
interesting ones which use interrupt stacks and have the paranoid
handling vs. CR3 and GS.
- Move quite some of the low level ASM functionality into C code:
- enter_from and exit to user space handling. The ASM code now
calls into C after doing the really necessary ASM handling and
the return path goes back out without bells and whistels in
ASM.
- exception entry/exit got the equivivalent treatment
- move all IRQ tracepoints from ASM to C so they can be placed as
appropriate which is especially important for the int3
recursion issue.
- Consolidate the declaration and definition of entry points between
32 and 64 bit. They share a common header and macros now.
- Remove the extra device interrupt entry maze and just use the
regular exception entry code.
- All ASM entry points except NMI are now generated from the shared
header file and the corresponding macros in the 32 and 64 bit
entry ASM.
- The C code entry points are consolidated as well with the help of
DEFINE_IDTENTRY*() macros. This allows to ensure at one central
point that all corresponding entry points share the same
semantics. The actual function body for most entry points is in an
instrumentable and sane state.
There are special macros for the more sensitive entry points, e.g.
INT3 and of course the nasty paranoid #NMI, #MCE, #DB and #DF.
They allow to put the whole entry instrumentation and RCU handling
into safe places instead of the previous pray that it is correct
approach.
- The INT3 text poke handling is now completely isolated and the
recursion issue banned. Aside of the entry rework this required
other isolation work, e.g. the ability to force inline bsearch.
- Prevent #DB on fragile entry code, entry relevant memory and
disable it on NMI, #MC entry, which allowed to get rid of the
nested #DB IST stack shifting hackery.
- A few other cleanups and enhancements which have been made
possible through this and already merged changes, e.g.
consolidating and further restricting the IDT code so the IDT
table becomes RO after init which removes yet another popular
attack vector
- About 680 lines of ASM maze are gone.
There are a few open issues:
- An escape out of the noinstr section in the MCE handler which needs
some more thought but under the aspect that MCE is a complete
trainwreck by design and the propability to survive it is low, this
was not high on the priority list.
- Paravirtualization
When PV is enabled then objtool complains about a bunch of indirect
calls out of the noinstr section. There are a few straight forward
ways to fix this, but the other issues vs. general correctness were
more pressing than parawitz.
- KVM
KVM is inconsistent as well. Patches have been posted, but they
have not yet been commented on or picked up by the KVM folks.
- IDLE
Pretty much the same problems can be found in the low level idle
code especially the parts where RCU stopped watching. This was
beyond the scope of the more obvious and exposable problems and is
on the todo list.
The lesson learned from this brain melting exercise to morph the
evolved code base into something which can be validated and understood
is that once again the violation of the most important engineering
principle "correctness first" has caused quite a few people to spend
valuable time on problems which could have been avoided in the first
place. The "features first" tinkering mindset really has to stop.
With that I want to say thanks to everyone involved in contributing to
this effort. Special thanks go to the following people (alphabetical
order): Alexandre Chartre, Andy Lutomirski, Borislav Petkov, Brian
Gerst, Frederic Weisbecker, Josh Poimboeuf, Juergen Gross, Lai
Jiangshan, Macro Elver, Paolo Bonzin,i Paul McKenney, Peter Zijlstra,
Vitaly Kuznetsov, and Will Deacon"
* tag 'x86-entry-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (142 commits)
x86/entry: Force rcu_irq_enter() when in idle task
x86/entry: Make NMI use IDTENTRY_RAW
x86/entry: Treat BUG/WARN as NMI-like entries
x86/entry: Unbreak __irqentry_text_start/end magic
x86/entry: __always_inline CR2 for noinstr
lockdep: __always_inline more for noinstr
x86/entry: Re-order #DB handler to avoid *SAN instrumentation
x86/entry: __always_inline arch_atomic_* for noinstr
x86/entry: __always_inline irqflags for noinstr
x86/entry: __always_inline debugreg for noinstr
x86/idt: Consolidate idt functionality
x86/idt: Cleanup trap_init()
x86/idt: Use proper constants for table size
x86/idt: Add comments about early #PF handling
x86/idt: Mark init only functions __init
x86/entry: Rename trace_hardirqs_off_prepare()
x86/entry: Clarify irq_{enter,exit}_rcu()
x86/entry: Remove DBn stacks
x86/entry: Remove debug IDT frobbing
x86/entry: Optimize local_db_save() for virt
...
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Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.
This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.
There are a variety of indentation styles found.
a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'
In order to convert all of them to 1 tab + 'help', I ran the
following commend:
$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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EFI on ARM only supports short descriptors, and given that it mandates
that the MMU and caches are on, it is implied that booting in HYP mode
is not supported.
However, implementations of EFI exist (i.e., U-Boot) that ignore this
requirement, which is not entirely unreasonable, given that it makes
HYP mode inaccessible to the operating system.
So let's make sure that we can deal with this condition gracefully.
We already tolerate booting the EFI stub with the caches off (even
though this violates the EFI spec as well), and so we should deal
with HYP mode boot with MMU and caches either on or off.
- When the MMU and caches are on, we can ignore the HYP stub altogether,
since we can carry on executing at HYP. We do need to ensure that we
disable the MMU at HYP before entering the kernel proper.
- When the MMU and caches are off, we have to drop to SVC mode so that
we can set up the page tables using short descriptors. In this case,
we need to install the HYP stub as usual, so that we can return to HYP
mode before handing over to the kernel proper.
Tested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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ZBOOT_ROM_TEXT and ZBOOT_ROM_BSS are defined as 'hex' but had a default
of "0". Kconfig will helpfully expand a text entry of 0 to 0x0 but
because this is not the same as the default value it was treated as
being explicitly set when running 'make savedefconfig' so most arm
defconfigs have CONFIG_ZBOOT_ROM_TEXT=0x0 and CONFIG_ZBOOT_ROM_BSS=0x0.
Change the default to 0x0 which will mean next time the defconfigs are
re-generated the spurious config entries will be removed.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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The patch introducing the struct was probably never compile tested,
because it sets a handler with a wrong function signature. Wrap the
handler into a functions with the correct signature to fix the build.
Fixes: 0f1c9688a194 ("tty/sysrq: alpha: export and use __sysrq_get_key_op()")
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Matt Turner <mattst88@gmail.com>
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Signed-off-by: Matt Turner <mattst88@gmail.com>
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Replace sg++ with sg = sg_next(sg).
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Matt Turner <mattst88@gmail.com>
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The commits cd0e00c10672 and 92d7223a7423 broke boot on the Alpha Avanti
platform. The patches move memory barriers after a write before the write.
The result is that if there's iowrite followed by ioread, there is no
barrier between them.
The Alpha architecture allows reordering of the accesses to the I/O space,
and the missing barrier between write and read causes hang with serial
port and real time clock.
This patch makes barriers confiorm to the specification.
1. We add mb() before readX_relaxed and writeX_relaxed -
memory-barriers.txt claims that these functions must be ordered w.r.t.
each other. Alpha doesn't order them, so we need an explicit barrier.
2. We add mb() before reads from the I/O space - so that if there's a
write followed by a read, there should be a barrier between them.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: cd0e00c10672 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering")
Fixes: 92d7223a7423 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering #2")
Cc: stable@vger.kernel.org # v4.17+
Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Reviewed-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Matt Turner <mattst88@gmail.com>
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Fix the following coccicheck warning:
arch/alpha/kernel/sys_eiger.c:179:2-3: Unneeded semicolon
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>
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Fix the following coccicheck warning:
arch/alpha/kernel/osf_sys.c:680:2-3: Unneeded semicolon
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>
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In commit b6b2735514bc
("tracing: Use str_has_prefix() instead of using fixed sizes")
the newly introduced str_has_prefix() was used
to replace error-prone strncmp(str, const, len).
Here fix codes with the same pattern.
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>
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Alpha incorrectly reports "0070-0080 : rtc" in /proc/ioports.
Fix this, so that it is "0070-007f".
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>
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Formatting of Kconfig files doesn't look so pretty, so let the
Great White Handkerchief come around and clean it up.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Signed-off-by: Matt Turner <mattst88@gmail.com>
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The idea of conditionally calling into rcu_irq_enter() only when RCU is
not watching turned out to be not completely thought through.
Paul noticed occasional premature end of grace periods in RCU torture
testing. Bisection led to the commit which made the invocation of
rcu_irq_enter() conditional on !rcu_is_watching().
It turned out that this conditional breaks RCU assumptions about the idle
task when the scheduler tick happens to be a nested interrupt. Nested
interrupts can happen when the first interrupt invokes softirq processing
on return which enables interrupts.
If that nested tick interrupt does not invoke rcu_irq_enter() then the
RCU's irq-nesting checks will believe that this interrupt came directly
from idle, which will cause RCU to report a quiescent state. Because this
interrupt instead came from a softirq handler which might have been
executing an RCU read-side critical section, this can cause the grace
period to end prematurely.
Change the condition from !rcu_is_watching() to is_idle_task(current) which
enforces that interrupts in the idle task unconditionally invoke
rcu_irq_enter() independent of the RCU state.
This is also correct vs. user mode entries in NOHZ full scenarios because
user mode entries bring RCU out of EQS and force the RCU irq nesting state
accounting to nested. As only the first interrupt can enter from user mode
a nested tick interrupt will enter from kernel mode and as the nesting
state accounting is forced to nesting it will not do anything stupid even
if rcu_irq_enter() has not been invoked.
Fixes: 3eeec3858488 ("x86/entry: Provide idtentry_entry/exit_cond_rcu()")
Reported-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: "Paul E. McKenney" <paulmck@kernel.org>
Reviewed-by: "Paul E. McKenney" <paulmck@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/87wo4cxubv.fsf@nanos.tec.linutronix.de
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The argument passed to cmpxchg is not guaranteed to be sign
extended, but lr.w sign extends on RV64I. This makes cmpxchg
fail on clang built kernels when __old is negative.
To fix this, we just cast __old to long which sign extends on
RV64I. With this fix, clang built RISC-V kernels now boot.
Link: https://github.com/ClangBuiltLinux/linux/issues/867
Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/lftan/nios2
Pull nios2 update from Ley Foon Tan:
"Mark expected switch fall-through in signal handling"
* tag 'nios2-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/lftan/nios2:
nios2: signal: Mark expected switch fall-through
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Pull more KVM updates from Paolo Bonzini:
"The guest side of the asynchronous page fault work has been delayed to
5.9 in order to sync with Thomas's interrupt entry rework, but here's
the rest of the KVM updates for this merge window.
MIPS:
- Loongson port
PPC:
- Fixes
ARM:
- Fixes
x86:
- KVM_SET_USER_MEMORY_REGION optimizations
- Fixes
- Selftest fixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (62 commits)
KVM: x86: do not pass poisoned hva to __kvm_set_memory_region
KVM: selftests: fix sync_with_host() in smm_test
KVM: async_pf: Inject 'page ready' event only if 'page not present' was previously injected
KVM: async_pf: Cleanup kvm_setup_async_pf()
kvm: i8254: remove redundant assignment to pointer s
KVM: x86: respect singlestep when emulating instruction
KVM: selftests: Don't probe KVM_CAP_HYPERV_ENLIGHTENED_VMCS when nested VMX is unsupported
KVM: selftests: do not substitute SVM/VMX check with KVM_CAP_NESTED_STATE check
KVM: nVMX: Consult only the "basic" exit reason when routing nested exit
KVM: arm64: Move hyp_symbol_addr() to kvm_asm.h
KVM: arm64: Synchronize sysreg state on injecting an AArch32 exception
KVM: arm64: Make vcpu_cp1x() work on Big Endian hosts
KVM: arm64: Remove host_cpu_context member from vcpu structure
KVM: arm64: Stop sparse from moaning at __hyp_this_cpu_ptr
KVM: arm64: Handle PtrAuth traps early
KVM: x86: Unexport x86_fpu_cache and make it static
KVM: selftests: Ignore KVM 5-level paging support for VM_MODE_PXXV48_4K
KVM: arm64: Save the host's PtrAuth keys in non-preemptible context
KVM: arm64: Stop save/restoring ACTLR_EL1
KVM: arm64: Add emulation for 32bit guests accessing ACTLR2
...
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For no reason other than beginning brainmelt, IDTENTRY_NMI was mapped to
IDTENTRY_IST.
This is not a problem on 64bit because the IST default entry point maps to
IDTENTRY_RAW which does not any entry handling. The surplus function
declaration for the noist C entry point is unused and as there is no ASM
code emitted for NMI this went unnoticed.
On 32bit IDTENTRY_IST maps to a regular IDTENTRY which does the normal
entry handling. That is clearly the wrong thing to do for NMI.
Map it to IDTENTRY_RAW to unbreak it. The IDTENTRY_NMI mapping needs to
stay to avoid emitting ASM code.
Fixes: 6271fef00b34 ("x86/entry: Convert NMI to IDTENTRY_NMI")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Debugged-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/CA+G9fYvF3cyrY+-iw_SZtpN-i2qA2BruHg4M=QYECU2-dNdsMw@mail.gmail.com
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BUG/WARN are cleverly optimized using UD2 to handle the BUG/WARN out of
line in an exception fixup.
But if BUG or WARN is issued in a funny RCU context, then the
idtentry_enter...() path might helpfully WARN that the RCU context is
invalid, which results in infinite recursion.
Split the BUG/WARN handling into an nmi_enter()/nmi_exit() path in
exc_invalid_op() to increase the chance to survive the experience.
[ tglx: Make the declaration match the implementation ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/f8fe40e0088749734b4435b554f73eee53dcf7a8.1591932307.git.luto@kernel.org
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Before commit 6cdf30375f82 ("powerpc/kvm/book3s: Use kvm helpers
to walk shadow or secondary table") we called __find_linux_pte() with
a page table pointer from a kvm_nested_guest struct but
now we rely on kvmhv_find_nested() which takes an L1 LPID and returns
a kvm_nested_guest pointer, however we pass a L0 LPID there and
the L2 guest hangs.
This fixes the LPID passed to kvmppc_hv_handle_set_rc().
Fixes: 6cdf30375f82 ("powerpc/kvm/book3s: Use kvm helpers to walk shadow or secondary table")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611030559.75257-1-aik@ozlabs.ru
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Mark switch cases where we are expecting to fall through.
Fix the following warning through the use of the new the new
pseudo-keyword fallthrough;
arch/nios2/kernel/signal.c:254:12: warning: this statement may fall through [-Wimplicit-fallthrough=]
254 | restart = -2;
| ~~~~~~~~^~~~
arch/nios2/kernel/signal.c:255:3: note: here
255 | case ERESTARTNOHAND:
| ^~~~
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull the Kernel Concurrency Sanitizer from Thomas Gleixner:
"The Kernel Concurrency Sanitizer (KCSAN) is a dynamic race detector,
which relies on compile-time instrumentation, and uses a
watchpoint-based sampling approach to detect races.
The feature was under development for quite some time and has already
found legitimate bugs.
Unfortunately it comes with a limitation, which was only understood
late in the development cycle:
It requires an up to date CLANG-11 compiler
CLANG-11 is not yet released (scheduled for June), but it's the only
compiler today which handles the kernel requirements and especially
the annotations of functions to exclude them from KCSAN
instrumentation correctly.
These annotations really need to work so that low level entry code and
especially int3 text poke handling can be completely isolated.
A detailed discussion of the requirements and compiler issues can be
found here:
https://lore.kernel.org/lkml/CANpmjNMTsY_8241bS7=XAfqvZHFLrVEkv_uM4aDUWE_kh3Rvbw@mail.gmail.com/
We came to the conclusion that trying to work around compiler
limitations and bugs again would end up in a major trainwreck, so
requiring a working compiler seemed to be the best choice.
For Continous Integration purposes the compiler restriction is
manageable and that's where most xxSAN reports come from.
For a change this limitation might make GCC people actually look at
their bugs. Some issues with CSAN in GCC are 7 years old and one has
been 'fixed' 3 years ago with a half baken solution which 'solved' the
reported issue but not the underlying problem.
The KCSAN developers also ponder to use a GCC plugin to become
independent, but that's not something which will show up in a few
days.
Blocking KCSAN until wide spread compiler support is available is not
a really good alternative because the continuous growth of lockless
optimizations in the kernel demands proper tooling support"
* tag 'locking-kcsan-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (76 commits)
compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining
compiler.h: Move function attributes to compiler_types.h
compiler.h: Avoid nested statement expression in data_race()
compiler.h: Remove data_race() and unnecessary checks from {READ,WRITE}_ONCE()
kcsan: Update Documentation to change supported compilers
kcsan: Remove 'noinline' from __no_kcsan_or_inline
kcsan: Pass option tsan-instrument-read-before-write to Clang
kcsan: Support distinguishing volatile accesses
kcsan: Restrict supported compilers
kcsan: Avoid inserting __tsan_func_entry/exit if possible
ubsan, kcsan: Don't combine sanitizer with kcov on clang
objtool, kcsan: Add kcsan_disable_current() and kcsan_enable_current_nowarn()
kcsan: Add __kcsan_{enable,disable}_current() variants
checkpatch: Warn about data_race() without comment
kcsan: Use GFP_ATOMIC under spin lock
Improve KCSAN documentation a bit
kcsan: Make reporting aware of KCSAN tests
kcsan: Fix function matching in report
kcsan: Change data_race() to no longer require marking racing accesses
kcsan: Move kcsan_{disable,enable}_current() to kcsan-checks.h
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull atomics rework from Thomas Gleixner:
"Peter Zijlstras rework of atomics and fallbacks. This solves two
problems:
1) Compilers uninline small atomic_* static inline functions which
can expose them to instrumentation.
2) The instrumentation of atomic primitives was done at the
architecture level while composites or fallbacks were provided at
the generic level. As a result there are no uninstrumented
variants of the fallbacks.
Both issues were in the way of fully isolating fragile entry code
pathes and especially the text poke int3 handler which is prone to an
endless recursion problem when anything in that code path is about to
be instrumented. This was always a problem, but got elevated due to
the new batch mode updates of tracing.
The solution is to mark the functions __always_inline and to flip the
fallback and instrumentation so the non-instrumented variants are at
the architecture level and the instrumentation is done in generic
code.
The latter introduces another fallback variant which will go away once
all architectures have been moved over to arch_atomic_*"
* tag 'locking-urgent-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/atomics: Flip fallbacks and instrumentation
asm-generic/atomic: Use __always_inline for fallback wrappers
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull more x86 updates from Thomas Gleixner:
"A set of fixes and updates for x86:
- Unbreak paravirt VDSO clocks.
While the VDSO code was moved into lib for sharing a subtle check
for the validity of paravirt clocks got replaced. While the
replacement works perfectly fine for bare metal as the update of
the VDSO clock mode is synchronous, it fails for paravirt clocks
because the hypervisor can invalidate them asynchronously.
Bring it back as an optional function so it does not inflict this
on architectures which are free of PV damage.
- Fix the jiffies to jiffies64 mapping on 64bit so it does not
trigger an ODR violation on newer compilers
- Three fixes for the SSBD and *IB* speculation mitigation maze to
ensure consistency, not disabling of some *IB* variants wrongly and
to prevent a rogue cross process shutdown of SSBD. All marked for
stable.
- Add yet more CPU models to the splitlock detection capable list
!@#%$!
- Bring the pr_info() back which tells that TSC deadline timer is
enabled.
- Reboot quirk for MacBook6,1"
* tag 'x86-urgent-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Unbreak paravirt VDSO clocks
lib/vdso: Provide sanity check for cycles (again)
clocksource: Remove obsolete ifdef
x86_64: Fix jiffies ODR violation
x86/speculation: PR_SPEC_FORCE_DISABLE enforcement for indirect branches.
x86/speculation: Prevent rogue cross-process SSBD shutdown
x86/speculation: Avoid force-disabling IBPB based on STIBP and enhanced IBRS.
x86/cpu: Add Sapphire Rapids CPU model number
x86/split_lock: Add Icelake microserver and Tigerlake CPU models
x86/apic: Make TSC deadline timer detection message visible
x86/reboot/quirks: Add MacBook6,1 reboot quirk
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