As we're going to require to access per-cpu variables at EL2,
let's craft the minimum set of accessors required to implement
reading a per-cpu variable, relying on tpidr_el2 to contain the
per-cpu offset.
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
If running on a system that performs dynamic SSBD mitigation, allow
userspace to request the mitigation for itself. This is implemented
as a prctl call, allowing the mitigation to be enabled or disabled at
will for this particular thread.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In order to allow userspace to be mitigated on demand, let's
introduce a new thread flag that prevents the mitigation from
being turned off when exiting to userspace, and doesn't turn
it on on entry into the kernel (with the assumption that the
mitigation is always enabled in the kernel itself).
This will be used by a prctl interface introduced in a later
patch.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
On a system where firmware can dynamically change the state of the
mitigation, the CPU will always come up with the mitigation enabled,
including when coming back from suspend.
If the user has requested "no mitigation" via a command line option,
let's enforce it by calling into the firmware again to disable it.
Similarily, for a resume from hibernate, the mitigation could have
been disabled by the boot kernel. Let's ensure that it is set
back on in that case.
Acked-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In order to avoid checking arm64_ssbd_callback_required on each
kernel entry/exit even if no mitigation is required, let's
add yet another alternative that by default jumps over the mitigation,
and that gets nop'ed out if we're doing dynamic mitigation.
Think of it as a poor man's static key...
Reviewed-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We're about to need the mitigation state in various parts of the
kernel in order to do the right thing for userspace and guests.
Let's expose an accessor that will let other subsystems know
about the state.
Reviewed-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
On a system where the firmware implements ARCH_WORKAROUND_2,
it may be useful to either permanently enable or disable the
workaround for cases where the user decides that they'd rather
not get a trap overhead, and keep the mitigation permanently
on or off instead of switching it on exception entry/exit.
In any case, default to the mitigation being enabled.
Reviewed-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In order for the kernel to protect itself, let's call the SSBD mitigation
implemented by the higher exception level (either hypervisor or firmware)
on each transition between userspace and kernel.
We must take the PSCI conduit into account in order to target the
right exception level, hence the introduction of a runtime patching
callback.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
As of Skylake Server, there are a number of free running counters in
each IIO Box that collect counts of per-box IO clocks and per-port
Input/Output x BW/Utilization.
The free running counters cannot be part of the existing IIO BOX,
because, quoting from Peter Zijlstra:
"This will result in some (probably) unexpected scheduling artifacts.
Probably the only way to really cure that is to have the free running
counters in their own PMU and not share with the GP counters of this
box."
So let's add a new PMU for the free running counters, as suggested.
The free-running counter is read-only and always active. Counting will
be suspended only when the IIO Box is powered down.
There are three types of IIO free-running counters on Skylake server, IO
CLOCKS counter, BANDWIDTH counters and UTILIZATION counters.
IO CLOCKS counter is a clock of IIO box.
BANDWIDTH counters are to count inbound(PCIe->CPU)/outbound(CPU->PCIe)
bandwidth.
UTILIZATION counters are to count input/output utilization.
The bit width of the free-running counters is 36-bits.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1525371913-10597-6-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are a number of free running counters introduced for uncore, which
provide highly valuable information to a wide array of customers.
However, the generic uncore code doesn't support them yet.
The free running counters will be specially handled based on their
unique attributes:
- They are read-only. They cannot be enabled/disabled.
- The event and the counter are always 1:1 mapped. It doesn't need to
be assigned nor tracked by event_list.
- They are always active. It doesn't need to check the availability.
- They have different bit width.
Also, using inline helpers to replace the check for fixed counter and
free running counter.
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1525371913-10597-5-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are a number of free running counters introduced for uncore, which
provide highly valuable information to a wide array of customers.
For example, Skylake Server has IIO free running counters to collect
Input/Output x BW/Utilization.
There is NO event available on the general purpose counters, that is
exactly the same as the free running counters. The generic uncore code
needs to be enhanced to support the new counters.
In the uncore document, there is no event-code assigned to free running
counters. Some events need to be defined to indicate the free running
counters. The events are encoded as event-code + umask-code.
The event-code for all free running counters is 0xff, which is the same
as the fixed counters:
- It has not been decided what code will be used for common events on
future platforms. 0xff is the only one which will definitely not be
used as any common event-code.
- Cannot re-use current events on the general purpose counters. Because
there is NO event available, that is exactly the same as the free
running counters.
- Even in the existing codes, the fixed counters for core, that have the
same event-code, may count different things. Hence, it should not
surprise the users if the free running counters that share the same
event-code also count different things.
Umask will be used to distinguish the counters.
The umask-code is used to distinguish a fixed counter and a free running
counter, and different types of free running counters.
For fixed counters, the umask-code is 0x0X, where X indicates the index
of the fixed counter, which starts from 0.
- Compatible with the old event encoding.
- Currently, there is only one fixed counter. There are still 15
reserved spaces for extension.
For free running counters, the umask-code uses the rest of the space.
It would follow the format of 0xXY:
- X stands for the type of free running counters, which starts from 1.
- Y stands for the index of free running counters of same type, which
starts from 0.
- The free running counters do different thing. It can be categorized to
several types, according to the MSR location, bit width and
definition. E.g. there are three types of IIO free running counters on
Skylake server to monitor IO CLOCKS, BANDWIDTH and UTILIZATION on
different ports. It makes it easy to locate the free running counter
of a specific type.
- So far, there are at most 8 counters of each type. There are still 8
reserved spaces for extension.
Introducing a new index to indicate the free running counters. Only one
index is enough for all free running counters. Because the free running
counters are always active, and the event and free running counter are
always 1:1 mapped, it does not need extra index to indicate the assigned
counter.
Introducing a new data structure to store free running counters related
information for each type. It includes the number of counters, bit
width, base address, offset between counters and offset between boxes.
Introducing several inline helpers to check index for fixed counter and
free running counter, validate free running counter event, and retrieve
the free running counter information according to box and event.
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1525371913-10597-4-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are two free-running counters for client IMC uncore. The
customized event_init() function hard codes their index to
'UNCORE_PMC_IDX_FIXED' and 'UNCORE_PMC_IDX_FIXED + 1'.
To support the index 'UNCORE_PMC_IDX_FIXED + 1', the generic
uncore_perf_event_update is obscurely hacked.
The code quality issue will bring problems when a new counter index is
introduced into the generic code, for example, a new index for
free-running counter.
Introducing a customized event_read() function for client IMC uncore.
The customized function is copied from previous generic
uncore_pmu_event_read().
The index 'UNCORE_PMC_IDX_FIXED + 1' will be isolated for client IMC
uncore only.
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1525371913-10597-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The reference to camera_supply_gpiod_table was added in the wrong function,
as observed from this randconfig build failure:
arch/arm/mach-pxa/ezx.c: In function 'e680_init':
arch/arm/mach-pxa/ezx.c:905:26: error: 'camera_supply_gpiod_table' undeclared (first use in this function)
gpiod_add_lookup_table(&camera_supply_gpiod_table);
Fixes: 6059577cb2 ("regulator: fixed: Convert to use GPIO descriptor only")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
We want SMCCC_ARCH_WORKAROUND_1 to be fast. As fast as possible.
So let's intercept it as early as we can by testing for the
function call number as soon as we've identified a HVC call
coming from the guest.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
In order to avoid aliasing attacks against the branch predictor
on Cortex-A15, let's invalidate the BTB on guest exit, which can
only be done by invalidating the icache (with ACTLR[0] being set).
We use the same hack as for A12/A17 to perform the vector decoding.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
In order to avoid aliasing attacks against the branch predictor,
let's invalidate the BTB on guest exit. This is made complicated
by the fact that we cannot take a branch before invalidating the
BTB.
We only apply this to A12 and A17, which are the only two ARM
cores on which this useful.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Warn at error level if the context switching function is not what we
are expecting. This can happen with big.Little systems, which we
currently do not support.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
In order to prevent aliasing attacks on the branch predictor,
invalidate the BTB or instruction cache on CPUs that are known to be
affected when taking an abort on a address that is outside of a user
task limit:
Cortex A8, A9, A12, A17, A73, A75: flush BTB.
Cortex A15, Brahma B15: invalidate icache.
If the IBE bit is not set, then there is little point to enabling the
workaround.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
When the branch predictor hardening is enabled, firmware must have set
the IBE bit in the auxiliary control register. If this bit has not
been set, the Spectre workarounds will not be functional.
Add validation that this bit is set, and print a warning at alert level
if this is not the case.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Harden the branch predictor against Spectre v2 attacks on context
switches for ARMv7 and later CPUs. We do this by:
Cortex A9, A12, A17, A73, A75: invalidating the BTB.
Cortex A15, Brahma B15: invalidating the instruction cache.
Cortex A57 and Cortex A72 are not addressed in this patch.
Cortex R7 and Cortex R8 are also not addressed as we do not enforce
memory protection on these cores.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Add support for per-processor bug checking - each processor function
descriptor gains a function pointer for this check, which must not be
an __init function. If non-NULL, this will be called whenever a CPU
enters the kernel via which ever path (boot CPU, secondary CPU startup,
CPU resuming, etc.)
This allows processor specific bug checks to validate that workaround
bits are properly enabled by firmware via all entry paths to the kernel.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Check for CPU bugs when secondary processors are being brought online,
and also when CPUs are resuming from a low power mode. This gives an
opportunity to check that processor specific bug workarounds are
correctly enabled for all paths that a CPU re-enters the kernel.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
This avoids a WARNING splat when loading the macsonic or macmace driver.
Please see commit 205e1b7f51 ("dma-mapping: warn when there is no
coherent_dma_mask").
This implementation of arch_setup_pdev_archdata() differs from the
powerpc one, in that this one avoids clobbering a device dma mask
which has already been initialized.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
It is a simple patch just for moving kvmppc_save_tm/kvmppc_restore_tm()
functionalities to tm.S. There is no logic change. The reconstruct of
those APIs will be done in later patches to improve readability.
It is for preparation of reusing those APIs on both HV/PR PPC KVM.
Some slight change during move the functions includes:
- surrounds some HV KVM specific code with CONFIG_KVM_BOOK3S_HV_POSSIBLE
for compilation.
- use _GLOBAL() to define kvmppc_save_tm/kvmppc_restore_tm()
[paulus@ozlabs.org - rebased on top of 7b0e827c69 ("KVM: PPC: Book3S HV:
Factor fake-suspend handling out of kvmppc_save/restore_tm", 2018-05-30)]
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This merges in the ppc-kvm topic branch of the powerpc repository
to get some changes on which future patches will depend, in particular
some new exports and TEXASR bit definitions.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This splits out the handling of "fake suspend" mode, part of the
hypervisor TM assist code for POWER9, and puts almost all of it in
new kvmppc_save_tm_hv and kvmppc_restore_tm_hv functions. The new
functions branch to kvmppc_save/restore_tm if the CPU does not
require hypervisor TM assistance.
With this, it will be more straightforward to move kvmppc_save_tm and
kvmppc_restore_tm to another file and use them for transactional
memory support in PR KVM. Additionally, it also makes the code a
bit clearer and reduces the number of feature sections.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Currently, PR KVM does not implement the configure_mmu operation, and
so the KVM_PPC_CONFIGURE_V3_MMU ioctl always fails with an EINVAL
error. This causes recent kernels to fail to boot as a PR KVM guest
on POWER9, since recent kernels booted in HPT mode do the
H_REGISTER_PROC_TBL hypercall, which causes userspace (QEMU) to do
KVM_PPC_CONFIGURE_V3_MMU, which fails.
This implements a minimal configure_mmu operation for PR KVM. It
succeeds only if the MMU is being configured for HPT mode and no
process table is being registered. This is enough to get recent
kernels to boot as a PR KVM guest.
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The x86 assembly implementations of Salsa20 use the frame base pointer
register (%ebp or %rbp), which breaks frame pointer convention and
breaks stack traces when unwinding from an interrupt in the crypto code.
Recent (v4.10+) kernels will warn about this, e.g.
WARNING: kernel stack regs at 00000000a8291e69 in syzkaller047086:4677 has bad 'bp' value 000000001077994c
[...]
But after looking into it, I believe there's very little reason to still
retain the x86 Salsa20 code. First, these are *not* vectorized
(SSE2/SSSE3/AVX2) implementations, which would be needed to get anywhere
close to the best Salsa20 performance on any remotely modern x86
processor; they're just regular x86 assembly. Second, it's still
unclear that anyone is actually using the kernel's Salsa20 at all,
especially given that now ChaCha20 is supported too, and with much more
efficient SSSE3 and AVX2 implementations. Finally, in benchmarks I did
on both Intel and AMD processors with both gcc 8.1.0 and gcc 4.9.4, the
x86_64 salsa20-asm is actually slightly *slower* than salsa20-generic
(~3% slower on Skylake, ~10% slower on Zen), while the i686 salsa20-asm
is only slightly faster than salsa20-generic (~15% faster on Skylake,
~20% faster on Zen). The gcc version made little difference.
So, the x86_64 salsa20-asm is pretty clearly useless. That leaves just
the i686 salsa20-asm, which based on my tests provides a 15-20% speed
boost. But that's without updating the code to not use %ebp. And given
the maintenance cost, the small speed difference vs. salsa20-generic,
the fact that few people still use i686 kernels, the doubt that anyone
is even using the kernel's Salsa20 at all, and the fact that a SSE2
implementation would almost certainly be much faster on any remotely
modern x86 processor yet no one has cared enough to add one yet, I don't
think it's worthwhile to keep.
Thus, just remove both the x86_64 and i686 salsa20-asm implementations.
Reported-by: syzbot+ffa3a158337bbc01ff09@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Several source files have been taken from OpenSSL. In some of them a
comment that "permission to use under GPL terms is granted" was
included below a contradictory license statement. In several cases,
there was no indication that the license of the code was compatible
with the GPLv2.
This change clarifies the licensing for all of these files. I've
confirmed with the author (Andy Polyakov) that a) he has licensed the
files with the GPLv2 comment under that license and b) that he's also
happy to license the other files under GPLv2 too. In one case, the
file is already contained in his CRYPTOGAMS bundle, which has a GPLv2
option, and so no special measures are needed.
In all cases, the license status of code has been clarified by making
the GPLv2 license prominent.
The .S files have been regenerated from the updated .pl files.
This is a comment-only change. No code is changed.
Signed-off-by: Adam Langley <agl@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Commit 56e8e57fc3 ("crypto: morus - Add common SIMD glue code for
MORUS") accidetally consiedered the glue code to be usable by different
architectures, but it seems to be only usable on x86.
This patch moves it under arch/x86/crypto and adds 'depends on X86' to
the Kconfig options and also removes the prompt to hide these internal
options from the user.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Ondrej Mosnacek <omosnacek@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull s390 fixes from Martin Schwidefsky:
- a missing -msoft-float for the compile of the kexec purgatory
- a fix for the dasd driver to avoid the double use of a field in the
'struct request'
[ That latter one is being discussed, and Christoph asked for something
cleaner, but for now it's a fix ]
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/dasd: use blk_mq_rq_from_pdu for per request data
s390/purgatory: Fix endless interrupt loop
This reverts commit 3c6b38d45f "regulator: wm8994: Pass
descriptor instead of GPIO number" as it has problems with shared
GPIOs similar to that on s2mps11.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
The arch_get_random_seed_long() invocation done by the random device
driver is done in interrupt context and may be invoked very very
frequently. The existing s390 arch_get_random_seed*() implementation
uses the PRNO(TRNG) instruction which produces excellent high quality
entropy but is relatively slow and thus expensive.
This fix reworks the arch_get_random_seed* implementation. It
introduces a buffer concept to decouple the delivery of random data
via arch_get_random_seed*() from the generation of new random
bytes. The buffer of random data is filled asynchronously by a
workqueue thread.
If there are enough bytes in the buffer the s390_arch_random_generate()
just delivers these bytes. Otherwise false is returned until the worker
thread refills the buffer.
The worker fills the rng buffer by pulling fresh entropy from the
high quality (but slow) true hardware random generator. This entropy
is then spread over the buffer with an pseudo random generator.
As the arch_get_random_seed_long() fetches 8 bytes and the calling
function add_interrupt_randomness() counts this as 1 bit entropy the
distribution needs to make sure there is in fact 1 bit entropy
contained in 8 bytes of the buffer. The current values pull 32 byte
entropy and scatter this into a 2048 byte buffer. So 8 byte in the
buffer will contain 1 bit of entropy.
The worker thread is rescheduled based on the charge level of the
buffer but at least with 500 ms delay to avoid too much cpu consumption.
So the max. amount of rng data delivered via arch_get_random_seed is
limited to 4Kb per second.
Signed-off-by: Harald Freudenberger <freude@de.ibm.com>
Reviewed-by: Patrick Steuer <patrick.steuer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390 hardware supports the definition of a so-call Physical NETwork
IDentifier (short PNETID) per network device port. These PNETIDS
can be used to identify network devices that are attached to the same
physical network (broadcast domain).
This patch provides the interface to extract the PNETID of a port of
a device attached to the ccw-bus or pci-bus.
Parts of this patch are based on an initial implementation by
Thomas Richter.
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Pull RCU fix from Paul E. McKenney:
"This additional v4.18 pull request contains a single commit that fell
through the cracks:
Provide early rcu_cpu_starting() callback for the benefit of the
x86/mtrr code, which needs RCU to be available on incoming CPUs
earlier than has been the case in the past."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that the ARM CCI PMU driver can be built as a loadable module,
we get a link failure when MCPM is enabled:
ERROR: "mcpm_is_available" [drivers/perf/arm-cci.ko] undefined!
The simplest fix is to export that helper function.
Fixes: 8b0c93c20e ("perf/arm-cci: Allow building as a module")
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Geert Uytterhoeven <geert@linux-m68k.org> reported:
> HOSTLD scripts/mod/modpost
> CC arch/sh/kernel/traps_32.o
> arch/sh/kernel/traps_32.c: In function 'do_divide_error':
> arch/sh/kernel/traps_32.c:606:17: error: 'code' may be used uninitialized in this function [-Werror=uninitialized]
> cc1: all warnings being treated as errors
It is clear from inspection that do_divide_error is only called with
TRAP_DIVZERO_ERROR or TRAP_DIVOVF_ERROR, as that is the way
set_exception_table_vec is called. So let gcc know the other cases
should not be considered by returning in all other cases.
This removes the warning and let's the code continue to build.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Fixes: c65626c0cd ("signal/sh: Use force_sig_fault where appropriate")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
