There have been reports of RDRAND issues after resuming from suspend on
some AMD family 15h and family 16h systems. This issue stems from a BIOS
not performing the proper steps during resume to ensure RDRAND continues
to function properly.
RDRAND support is indicated by CPUID Fn00000001_ECX[30]. This bit can be
reset by clearing MSR C001_1004[62]. Any software that checks for RDRAND
support using CPUID, including the kernel, will believe that RDRAND is
not supported.
Update the CPU initialization to clear the RDRAND CPUID bit for any family
15h and 16h processor that supports RDRAND. If it is known that the family
15h or family 16h system does not have an RDRAND resume issue or that the
system will not be placed in suspend, the "rdrand=force" kernel parameter
can be used to stop the clearing of the RDRAND CPUID bit.
Additionally, update the suspend and resume path to save and restore the
MSR C001_1004 value to ensure that the RDRAND CPUID setting remains in
place after resuming from suspend.
Note, that clearing the RDRAND CPUID bit does not prevent a processor
that normally supports the RDRAND instruction from executing it. So any
code that determined the support based on family and model won't #UD.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chen Yu <yu.c.chen@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>
Cc: "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: <stable@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "x86@kernel.org" <x86@kernel.org>
Link: https://lkml.kernel.org/r/7543af91666f491547bd86cebb1e17c66824ab9f.1566229943.git.thomas.lendacky@amd.com
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Paolo Bonzini:
"Bugfixes, a pvspinlock optimization, and documentation moving"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: X86: Boost queue head vCPU to mitigate lock waiter preemption
Documentation: move Documentation/virtual to Documentation/virt
KVM: nVMX: Set cached_vmcs12 and cached_shadow_vmcs12 NULL after free
KVM: X86: Dynamically allocate user_fpu
KVM: X86: Fix fpu state crash in kvm guest
Revert "kvm: x86: Use task structs fpu field for user"
KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested
Renaming docs seems to be en vogue at the moment, so fix on of the
grossly misnamed directories. We usually never use "virtual" as
a shortcut for virtualization in the kernel, but always virt,
as seen in the virt/ top-level directory. Fix up the documentation
to match that.
Fixes: ed16648eb5 ("Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Merge tag 'for-linus-5.3a-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
"Fixes and features:
- A series to introduce a common command line parameter for disabling
paravirtual extensions when running as a guest in virtualized
environment
- A fix for int3 handling in Xen pv guests
- Removal of the Xen-specific tmem driver as support of tmem in Xen
has been dropped (and it was experimental only)
- A security fix for running as Xen dom0 (XSA-300)
- A fix for IRQ handling when offlining cpus in Xen guests
- Some small cleanups"
* tag 'for-linus-5.3a-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: let alloc_xenballooned_pages() fail if not enough memory free
xen/pv: Fix a boot up hang revealed by int3 self test
x86/xen: Add "nopv" support for HVM guest
x86/paravirt: Remove const mark from x86_hyper_xen_hvm variable
xen: Map "xen_nopv" parameter to "nopv" and mark it obsolete
x86: Add "nopv" parameter to disable PV extensions
x86/xen: Mark xen_hvm_need_lapic() and xen_x2apic_para_available() as __init
xen: remove tmem driver
Revert "x86/paravirt: Set up the virt_spin_lock_key after static keys get initialized"
xen/events: fix binding user event channels to cpus
- Add user space specific memory reading for kprobes
- Allow kprobes to be executed earlier in boot
The rest are mostly just various clean ups and small fixes.
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Merge tag 'trace-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The main changes in this release include:
- Add user space specific memory reading for kprobes
- Allow kprobes to be executed earlier in boot
The rest are mostly just various clean ups and small fixes"
* tag 'trace-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
tracing: Make trace_get_fields() global
tracing: Let filter_assign_type() detect FILTER_PTR_STRING
tracing: Pass type into tracing_generic_entry_update()
ftrace/selftest: Test if set_event/ftrace_pid exists before writing
ftrace/selftests: Return the skip code when tracing directory not configured in kernel
tracing/kprobe: Check registered state using kprobe
tracing/probe: Add trace_event_call accesses APIs
tracing/probe: Add probe event name and group name accesses APIs
tracing/probe: Add trace flag access APIs for trace_probe
tracing/probe: Add trace_event_file access APIs for trace_probe
tracing/probe: Add trace_event_call register API for trace_probe
tracing/probe: Add trace_probe init and free functions
tracing/uprobe: Set print format when parsing command
tracing/kprobe: Set print format right after parsed command
kprobes: Fix to init kprobes in subsys_initcall
tracepoint: Use struct_size() in kmalloc()
ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS
ftrace: Enable trampoline when rec count returns back to one
tracing/kprobe: Do not run kprobe boot tests if kprobe_event is on cmdline
tracing: Make a separate config for trace event self tests
...
Merge more updates from Andrew Morton:
"VM:
- z3fold fixes and enhancements by Henry Burns and Vitaly Wool
- more accurate reclaimed slab caches calculations by Yafang Shao
- fix MAP_UNINITIALIZED UAPI symbol to not depend on config, by
Christoph Hellwig
- !CONFIG_MMU fixes by Christoph Hellwig
- new novmcoredd parameter to omit device dumps from vmcore, by
Kairui Song
- new test_meminit module for testing heap and pagealloc
initialization, by Alexander Potapenko
- ioremap improvements for huge mappings, by Anshuman Khandual
- generalize kprobe page fault handling, by Anshuman Khandual
- device-dax hotplug fixes and improvements, by Pavel Tatashin
- enable synchronous DAX fault on powerpc, by Aneesh Kumar K.V
- add pte_devmap() support for arm64, by Robin Murphy
- unify locked_vm accounting with a helper, by Daniel Jordan
- several misc fixes
core/lib:
- new typeof_member() macro including some users, by Alexey Dobriyan
- make BIT() and GENMASK() available in asm, by Masahiro Yamada
- changed LIST_POISON2 on x86_64 to 0xdead000000000122 for better
code generation, by Alexey Dobriyan
- rbtree code size optimizations, by Michel Lespinasse
- convert struct pid count to refcount_t, by Joel Fernandes
get_maintainer.pl:
- add --no-moderated switch to skip moderated ML's, by Joe Perches
misc:
- ptrace PTRACE_GET_SYSCALL_INFO interface
- coda updates
- gdb scripts, various"
[ Using merge message suggestion from Vlastimil Babka, with some editing - Linus ]
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (100 commits)
fs/select.c: use struct_size() in kmalloc()
mm: add account_locked_vm utility function
arm64: mm: implement pte_devmap support
mm: introduce ARCH_HAS_PTE_DEVMAP
mm: clean up is_device_*_page() definitions
mm/mmap: move common defines to mman-common.h
mm: move MAP_SYNC to asm-generic/mman-common.h
device-dax: "Hotremove" persistent memory that is used like normal RAM
mm/hotplug: make remove_memory() interface usable
device-dax: fix memory and resource leak if hotplug fails
include/linux/lz4.h: fix spelling and copy-paste errors in documentation
ipc/mqueue.c: only perform resource calculation if user valid
include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures
scripts/gdb: add helpers to find and list devices
scripts/gdb: add lx-genpd-summary command
drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl
kernel/pid.c: convert struct pid count to refcount_t
drivers/rapidio/devices/rio_mport_cdev.c: NUL terminate some strings
select: shift restore_saved_sigmask_unless() into poll_select_copy_remaining()
select: change do_poll() to return -ERESTARTNOHAND rather than -EINTR
...
In virtualization environment, PV extensions (drivers, interrupts,
timers, etc) are enabled in the majority of use cases which is the
best option.
However, in some cases (kexec not fully working, benchmarking)
we want to disable PV extensions. We have "xen_nopv" for that purpose
but only for XEN. For a consistent admin experience a common command
line parameter "nopv" set across all PV guest implementations is a
better choice.
There are guest types which just won't work without PV extensions,
like Xen PV, Xen PVH and jailhouse. add a "ignore_nopv" member to
struct hypervisor_x86 set to true for those guest types and call
the detect functions only if nopv is false or ignore_nopv is true.
Suggested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
The Xen tmem (transcendent memory) driver can be removed, as the
related Xen hypervisor feature never made it past the "experimental"
state and will be removed in future Xen versions (>= 4.13).
The xen-selfballoon driver depends on tmem, so it can be removed, too.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Since commit 2724273e8f ("vmcore: add API to collect hardware dump in
second kernel"), drivers are allowed to add device related dump data to
vmcore as they want by using the device dump API. This has a potential
issue, the data is stored in memory, drivers may append too much data
and use too much memory. The vmcore is typically used in a kdump kernel
which runs in a pre-reserved small chunk of memory. So as a result it
will make kdump unusable at all due to OOM issues.
So introduce new 'novmcoredd' command line option. User can disable
device dump to reduce memory usage. This is helpful if device dump is
using too much memory, disabling device dump could make sure a regular
vmcore without device dump data is still available.
[akpm@linux-foundation.org: tweak documentation]
[akpm@linux-foundation.org: vmcore.c needs moduleparam.h]
Link: http://lkml.kernel.org/r/20190528111856.7276-1-kasong@redhat.com
Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Cc: "David S . Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull rst conversion of docs from Mauro Carvalho Chehab:
"As agreed with Jon, I'm sending this big series directly to you, c/c
him, as this series required a special care, in order to avoid
conflicts with other trees"
* tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (77 commits)
docs: kbuild: fix build with pdf and fix some minor issues
docs: block: fix pdf output
docs: arm: fix a breakage with pdf output
docs: don't use nested tables
docs: gpio: add sysfs interface to the admin-guide
docs: locking: add it to the main index
docs: add some directories to the main documentation index
docs: add SPDX tags to new index files
docs: add a memory-devices subdir to driver-api
docs: phy: place documentation under driver-api
docs: serial: move it to the driver-api
docs: driver-api: add remaining converted dirs to it
docs: driver-api: add xilinx driver API documentation
docs: driver-api: add a series of orphaned documents
docs: admin-guide: add a series of orphaned documents
docs: cgroup-v1: add it to the admin-guide book
docs: aoe: add it to the driver-api book
docs: add some documentation dirs to the driver-api book
docs: driver-model: move it to the driver-api book
docs: lp855x-driver.rst: add it to the driver-api book
...
There are lots of documents under Documentation/*.txt and a few other
orphan documents elsehwere that belong to the driver-API book.
Move them to their right place.
Reviewed-by: Cornelia Huck <cohuck@redhat.com> # vfio-related parts
Acked-by: Logan Gunthorpe <logang@deltatee.com> # switchtec
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
There are lots of documents that belong to the admin-guide but
are on random places (most under Documentation root dir).
Move them to the admin guide.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
The Kdump documentation describes procedures with admins use
in order to solve issues on their systems.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
The docs under Documentation/laptops contain users specific
information.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
The stuff under sysctl describes /sys interface from userspace
point of view. So, add it to the admin-guide and remove the
:orphan: from its index file.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Rename the block documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Rename the /proc/sys/ documentation files to ReST, using the
README file as a template for an index.rst, adding the other
files there via TOC markup.
Despite being written on different times with different
styles, try to make them somewhat coherent with a similar
look and feel, ensuring that they'll look nice as both
raw text file and as via the html output produced by the
Sphinx build system.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Rename the blockdev documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.
The drbd sub-directory contains some graphs and data flows.
Add those too to the documentation.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Rename the laptops documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Notable changes:
- Removal of the NPU DMA code, used by the out-of-tree Nvidia driver, as well
as some other functions only used by drivers that haven't (yet?) made it
upstream.
- A fix for a bug in our handling of hardware watchpoints (eg. perf record -e
mem: ...) which could lead to register corruption and kernel crashes.
- Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for vmalloc
when using the Radix MMU.
- A large but incremental rewrite of our exception handling code to use gas
macros rather than multiple levels of nested CPP macros.
And the usual small fixes, cleanups and improvements.
Thanks to:
Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab, Aneesh Kumar K.V, Anju
T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Cédric Le Goater,
Christian Lamparter, Christophe Leroy, Christophe Lombard, Christoph Hellwig,
Daniel Axtens, Denis Efremov, Enrico Weigelt, Frederic Barrat, Gautham R.
Shenoy, Geert Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg
Kurz, Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro
Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N. Rao,
Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi Bangoria,
Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher Boessenkool, Shaokun
Zhang, Shawn Anastasio, Stewart Smith, Suraj Jitindar Singh, Thiago Jung
Bauermann, YueHaibing.
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Merge tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Notable changes:
- Removal of the NPU DMA code, used by the out-of-tree Nvidia driver,
as well as some other functions only used by drivers that haven't
(yet?) made it upstream.
- A fix for a bug in our handling of hardware watchpoints (eg. perf
record -e mem: ...) which could lead to register corruption and
kernel crashes.
- Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for
vmalloc when using the Radix MMU.
- A large but incremental rewrite of our exception handling code to
use gas macros rather than multiple levels of nested CPP macros.
And the usual small fixes, cleanups and improvements.
Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab,
Aneesh Kumar K.V, Anju T Sudhakar, Anton Blanchard, Arnd Bergmann,
Athira Rajeev, Cédric Le Goater, Christian Lamparter, Christophe
Leroy, Christophe Lombard, Christoph Hellwig, Daniel Axtens, Denis
Efremov, Enrico Weigelt, Frederic Barrat, Gautham R. Shenoy, Geert
Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg Kurz,
Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro
Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N.
Rao, Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi
Bangoria, Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher
Boessenkool, Shaokun Zhang, Shawn Anastasio, Stewart Smith, Suraj
Jitindar Singh, Thiago Jung Bauermann, YueHaibing"
* tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (163 commits)
powerpc/powernv/idle: Fix restore of SPRN_LDBAR for POWER9 stop state.
powerpc/eeh: Handle hugepages in ioremap space
ocxl: Update for AFU descriptor template version 1.1
powerpc/boot: pass CONFIG options in a simpler and more robust way
powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h
powerpc/irq: Don't WARN continuously in arch_local_irq_restore()
powerpc/module64: Use symbolic instructions names.
powerpc/module32: Use symbolic instructions names.
powerpc: Move PPC_HA() PPC_HI() and PPC_LO() to ppc-opcode.h
powerpc/module64: Fix comment in R_PPC64_ENTRY handling
powerpc/boot: Add lzo support for uImage
powerpc/boot: Add lzma support for uImage
powerpc/boot: don't force gzipped uImage
powerpc/8xx: Add microcode patch to move SMC parameter RAM.
powerpc/8xx: Use IO accessors in microcode programming.
powerpc/8xx: replace #ifdefs by IS_ENABLED() in microcode.c
powerpc/8xx: refactor programming of microcode CPM params.
powerpc/8xx: refactor printing of microcode patch name.
powerpc/8xx: Refactor microcode write
powerpc/8xx: refactor writing of CPM microcode arrays
...
Patch series "add init_on_alloc/init_on_free boot options", v10.
Provide init_on_alloc and init_on_free boot options.
These are aimed at preventing possible information leaks and making the
control-flow bugs that depend on uninitialized values more deterministic.
Enabling either of the options guarantees that the memory returned by the
page allocator and SL[AU]B is initialized with zeroes. SLOB allocator
isn't supported at the moment, as its emulation of kmem caches complicates
handling of SLAB_TYPESAFE_BY_RCU caches correctly.
Enabling init_on_free also guarantees that pages and heap objects are
initialized right after they're freed, so it won't be possible to access
stale data by using a dangling pointer.
As suggested by Michal Hocko, right now we don't let the heap users to
disable initialization for certain allocations. There's not enough
evidence that doing so can speed up real-life cases, and introducing ways
to opt-out may result in things going out of control.
This patch (of 2):
The new options are needed to prevent possible information leaks and make
control-flow bugs that depend on uninitialized values more deterministic.
This is expected to be on-by-default on Android and Chrome OS. And it
gives the opportunity for anyone else to use it under distros too via the
boot args. (The init_on_free feature is regularly requested by folks
where memory forensics is included in their threat models.)
init_on_alloc=1 makes the kernel initialize newly allocated pages and heap
objects with zeroes. Initialization is done at allocation time at the
places where checks for __GFP_ZERO are performed.
init_on_free=1 makes the kernel initialize freed pages and heap objects
with zeroes upon their deletion. This helps to ensure sensitive data
doesn't leak via use-after-free accesses.
Both init_on_alloc=1 and init_on_free=1 guarantee that the allocator
returns zeroed memory. The two exceptions are slab caches with
constructors and SLAB_TYPESAFE_BY_RCU flag. Those are never
zero-initialized to preserve their semantics.
Both init_on_alloc and init_on_free default to zero, but those defaults
can be overridden with CONFIG_INIT_ON_ALLOC_DEFAULT_ON and
CONFIG_INIT_ON_FREE_DEFAULT_ON.
If either SLUB poisoning or page poisoning is enabled, those options take
precedence over init_on_alloc and init_on_free: initialization is only
applied to unpoisoned allocations.
Slowdown for the new features compared to init_on_free=0, init_on_alloc=0:
hackbench, init_on_free=1: +7.62% sys time (st.err 0.74%)
hackbench, init_on_alloc=1: +7.75% sys time (st.err 2.14%)
Linux build with -j12, init_on_free=1: +8.38% wall time (st.err 0.39%)
Linux build with -j12, init_on_free=1: +24.42% sys time (st.err 0.52%)
Linux build with -j12, init_on_alloc=1: -0.13% wall time (st.err 0.42%)
Linux build with -j12, init_on_alloc=1: +0.57% sys time (st.err 0.40%)
The slowdown for init_on_free=0, init_on_alloc=0 compared to the baseline
is within the standard error.
The new features are also going to pave the way for hardware memory
tagging (e.g. arm64's MTE), which will require both on_alloc and on_free
hooks to set the tags for heap objects. With MTE, tagging will have the
same cost as memory initialization.
Although init_on_free is rather costly, there are paranoid use-cases where
in-memory data lifetime is desired to be minimized. There are various
arguments for/against the realism of the associated threat models, but
given that we'll need the infrastructure for MTE anyway, and there are
people who want wipe-on-free behavior no matter what the performance cost,
it seems reasonable to include it in this series.
[glider@google.com: v8]
Link: http://lkml.kernel.org/r/20190626121943.131390-2-glider@google.com
[glider@google.com: v9]
Link: http://lkml.kernel.org/r/20190627130316.254309-2-glider@google.com
[glider@google.com: v10]
Link: http://lkml.kernel.org/r/20190628093131.199499-2-glider@google.com
Link: http://lkml.kernel.org/r/20190617151050.92663-2-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.cz> [page and dmapool parts
Acked-by: James Morris <jamorris@linux.microsoft.com>]
Cc: Christoph Lameter <cl@linux.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Sandeep Patil <sspatil@android.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Jann Horn <jannh@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When debug_pagealloc is enabled, we currently allocate the page_ext
array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now that
we have the page_type field in struct page, we can use that instead, as
guard pages are neither PageSlab nor mapped to userspace. This reduces
memory overhead when debug_pagealloc is enabled and there are no other
features requiring the page_ext array.
Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- A fair pile of RST conversions, many from Mauro. These create more
than the usual number of simple but annoying merge conflicts with other
trees, unfortunately. He has a lot more of these waiting on the wings
that, I think, will go to you directly later on.
- A new document on how to use merges and rebases in kernel repos, and one
on Spectre vulnerabilities.
- Various improvements to the build system, including automatic markup of
function() references because some people, for reasons I will never
understand, were of the opinion that :c:func:``function()`` is
unattractive and not fun to type.
- We now recommend using sphinx 1.7, but still support back to 1.4.
- Lots of smaller improvements, warning fixes, typo fixes, etc.
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Merge tag 'docs-5.3' of git://git.lwn.net/linux
Pull Documentation updates from Jonathan Corbet:
"It's been a relatively busy cycle for docs:
- A fair pile of RST conversions, many from Mauro. These create more
than the usual number of simple but annoying merge conflicts with
other trees, unfortunately. He has a lot more of these waiting on
the wings that, I think, will go to you directly later on.
- A new document on how to use merges and rebases in kernel repos,
and one on Spectre vulnerabilities.
- Various improvements to the build system, including automatic
markup of function() references because some people, for reasons I
will never understand, were of the opinion that
:c:func:``function()`` is unattractive and not fun to type.
- We now recommend using sphinx 1.7, but still support back to 1.4.
- Lots of smaller improvements, warning fixes, typo fixes, etc"
* tag 'docs-5.3' of git://git.lwn.net/linux: (129 commits)
docs: automarkup.py: ignore exceptions when seeking for xrefs
docs: Move binderfs to admin-guide
Disable Sphinx SmartyPants in HTML output
doc: RCU callback locks need only _bh, not necessarily _irq
docs: format kernel-parameters -- as code
Doc : doc-guide : Fix a typo
platform: x86: get rid of a non-existent document
Add the RCU docs to the core-api manual
Documentation: RCU: Add TOC tree hooks
Documentation: RCU: Rename txt files to rst
Documentation: RCU: Convert RCU UP systems to reST
Documentation: RCU: Convert RCU linked list to reST
Documentation: RCU: Convert RCU basic concepts to reST
docs: filesystems: Remove uneeded .rst extension on toctables
scripts/sphinx-pre-install: fix out-of-tree build
docs: zh_CN: submitting-drivers.rst: Remove a duplicated Documentation/
Documentation: PGP: update for newer HW devices
Documentation: Add section about CPU vulnerabilities for Spectre
Documentation: platform: Delete x86-laptop-drivers.txt
docs: Note that :c:func: should no longer be used
...
The previous commit added macro calls in the entry code which mitigate the
Spectre v1 swapgs issue if the X86_FEATURE_FENCE_SWAPGS_* features are
enabled. Enable those features where applicable.
The mitigations may be disabled with "nospectre_v1" or "mitigations=off".
There are different features which can affect the risk of attack:
- When FSGSBASE is enabled, unprivileged users are able to place any
value in GS, using the wrgsbase instruction. This means they can
write a GS value which points to any value in kernel space, which can
be useful with the following gadget in an interrupt/exception/NMI
handler:
if (coming from user space)
swapgs
mov %gs:<percpu_offset>, %reg1
// dependent load or store based on the value of %reg
// for example: mov %(reg1), %reg2
If an interrupt is coming from user space, and the entry code
speculatively skips the swapgs (due to user branch mistraining), it
may speculatively execute the GS-based load and a subsequent dependent
load or store, exposing the kernel data to an L1 side channel leak.
Note that, on Intel, a similar attack exists in the above gadget when
coming from kernel space, if the swapgs gets speculatively executed to
switch back to the user GS. On AMD, this variant isn't possible
because swapgs is serializing with respect to future GS-based
accesses.
NOTE: The FSGSBASE patch set hasn't been merged yet, so the above case
doesn't exist quite yet.
- When FSGSBASE is disabled, the issue is mitigated somewhat because
unprivileged users must use prctl(ARCH_SET_GS) to set GS, which
restricts GS values to user space addresses only. That means the
gadget would need an additional step, since the target kernel address
needs to be read from user space first. Something like:
if (coming from user space)
swapgs
mov %gs:<percpu_offset>, %reg1
mov (%reg1), %reg2
// dependent load or store based on the value of %reg2
// for example: mov %(reg2), %reg3
It's difficult to audit for this gadget in all the handlers, so while
there are no known instances of it, it's entirely possible that it
exists somewhere (or could be introduced in the future). Without
tooling to analyze all such code paths, consider it vulnerable.
Effects of SMAP on the !FSGSBASE case:
- If SMAP is enabled, and the CPU reports RDCL_NO (i.e., not
susceptible to Meltdown), the kernel is prevented from speculatively
reading user space memory, even L1 cached values. This effectively
disables the !FSGSBASE attack vector.
- If SMAP is enabled, but the CPU *is* susceptible to Meltdown, SMAP
still prevents the kernel from speculatively reading user space
memory. But it does *not* prevent the kernel from reading the
user value from L1, if it has already been cached. This is probably
only a small hurdle for an attacker to overcome.
Thanks to Dave Hansen for contributing the speculative_smap() function.
Thanks to Andrew Cooper for providing the inside scoop on whether swapgs
is serializing on AMD.
[ tglx: Fixed the USER fence decision and polished the comment as suggested
by Dave Hansen ]
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Pull cgroup updates from Tejun Heo:
"Documentation updates and the addition of cgroup_parse_float() which
will be used by new controllers including blk-iocost"
* 'for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
docs: cgroup-v1: convert docs to ReST and rename to *.rst
cgroup: Move cgroup_parse_float() implementation out of CONFIG_SYSFS
cgroup: add cgroup_parse_float()
Pull RCU updates from Ingo Molnar:
"The changes in this cycle are:
- RCU flavor consolidation cleanups and optmizations
- Documentation updates
- Miscellaneous fixes
- SRCU updates
- RCU-sync flavor consolidation
- Torture-test updates
- Linux-kernel memory-consistency-model updates, most notably the
addition of plain C-language accesses"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits)
tools/memory-model: Improve data-race detection
tools/memory-model: Change definition of rcu-fence
tools/memory-model: Expand definition of barrier
tools/memory-model: Do not use "herd" to refer to "herd7"
tools/memory-model: Fix comment in MP+poonceonces.litmus
Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic()
rcu: Don't return a value from rcu_assign_pointer()
rcu: Force inlining of rcu_read_lock()
rcu: Fix irritating whitespace error in rcu_assign_pointer()
rcu: Upgrade sync_exp_work_done() to smp_mb()
rcutorture: Upper case solves the case of the vanishing NULL pointer
torture: Suppress propagating trace_printk() warning
rcutorture: Dump trace buffer for callback pipe drain failures
torture: Add --trust-make to suppress "make clean"
torture: Make --cpus override idleness calculations
torture: Run kernel build in source directory
torture: Add function graph-tracing cheat sheet
torture: Capture qemu output
rcutorture: Tweak kvm options
rcutorture: Add trivial RCU implementation
...
Pull x86 vsyscall updates from Thomas Gleixner:
"Further hardening of the legacy vsyscall by providing support for
execute only mode and switching the default to it.
This prevents a certain class of attacks which rely on the vsyscall
page being accessible at a fixed address in the canonical kernel
address space"
* 'x86-entry-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
selftests/x86: Add a test for process_vm_readv() on the vsyscall page
x86/vsyscall: Add __ro_after_init to global variables
x86/vsyscall: Change the default vsyscall mode to xonly
selftests/x86/vsyscall: Verify that vsyscall=none blocks execution
x86/vsyscall: Document odd SIGSEGV error code for vsyscalls
x86/vsyscall: Show something useful on a read fault
x86/vsyscall: Add a new vsyscall=xonly mode
Documentation/admin: Remove the vsyscall=native documentation
commit 243e25112d ("powerpc/xive: Native exploitation of the XIVE
interrupt controller") added an option to turn off Linux native XIVE
usage via the xive=off kernel command line option.
This documents this option.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Stewart Smith <stewart@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
With vsyscall emulation on, a readable vsyscall page is still exposed that
contains syscall instructions that validly implement the vsyscalls.
This is required because certain dynamic binary instrumentation tools
attempt to read the call targets of call instructions in the instrumented
code. If the instrumented code uses vsyscalls, then the vsyscall page needs
to contain readable code.
Unfortunately, leaving readable memory at a deterministic address can be
used to help various ASLR bypasses, so some hardening value can be gained
by disallowing vsyscall reads.
Given how rarely the vsyscall page needs to be readable, add a mechanism to
make the vsyscall page be execute only.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/d17655777c21bc09a7af1bbcf74e6f2b69a51152.1561610354.git.luto@kernel.org
This sets the HAVE_ARCH_HUGE_VMAP option, and defines the required
page table functions.
This enables huge (2MB and 1GB) ioremap mappings. I don't have a
benchmark for this change, but huge vmap will be used by a later core
kernel change to enable huge vmalloc memory mappings. This improves
cached `git diff` performance by about 5% on a 2-node POWER9 with 32MB
size dentry cache hash.
Profiling git diff dTLB misses with a vanilla kernel:
81.75% git [kernel.vmlinux] [k] __d_lookup_rcu
7.21% git [kernel.vmlinux] [k] strncpy_from_user
1.77% git [kernel.vmlinux] [k] find_get_entry
1.59% git [kernel.vmlinux] [k] kmem_cache_free
40,168 dTLB-miss
0.100342754 seconds time elapsed
With powerpc huge vmalloc:
2,987 dTLB-miss
0.095933138 seconds time elapsed
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Convert the PM documents to ReST, in order to allow them to
build with Sphinx.
The conversion is actually:
- add blank lines and indentation in order to identify paragraphs;
- fix tables markups;
- add some lists markups;
- mark literal blocks;
- adjust title markups.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Sphinx need to know when a paragraph ends. So, do some adjustments
at the file for it to be properly parsed.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
that's said, I believe that this file should be moved to the
GPU/DRM documentation.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Convert those documents and prepare them to be part of the kernel
API book, as most of the stuff there are related to the
Kernel interfaces.
Still, in the future, it would make sense to split the docs,
as some of the stuff is clearly focused on sysadmin tasks.
The conversion is actually:
- add blank lines and identation in order to identify paragraphs;
- fix tables markups;
- add some lists markups;
- mark literal blocks;
- adjust title markups.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Convert the cgroup-v1 files to ReST format, in order to
allow a later addition to the admin-guide.
The conversion is actually:
- add blank lines and identation in order to identify paragraphs;
- fix tables markups;
- add some lists markups;
- mark literal blocks;
- adjust title markups.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Convert kdump documentation to ReST and add it to the
user faced manual, as the documents are mainly focused on
sysadmins that would be enabling kdump.
Note: the vmcoreinfo.rst has one very long title on one of its
sub-sections:
PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision|PG_head_mask|PAGE_BUDDY_MAPCOUNT_VALUE(~PG_buddy)|PAGE_OFFLINE_MAPCOUNT_VALUE(~PG_offline)
I opted to break this one, into two entries with the same content,
in order to make it easier to display after being parsed in html and PDF.
The conversion is actually:
- add blank lines and identation in order to identify paragraphs;
- fix tables markups;
- add some lists markups;
- mark literal blocks;
- adjust title markups.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The conversion is actually:
- add blank lines and identation in order to identify paragraphs;
- fix tables markups;
- add some lists markups;
- mark literal blocks;
- adjust title markups.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The conversion is actually:
- add blank lines and identation in order to identify paragraphs;
- fix tables markups;
- add some lists markups;
- mark literal blocks;
- adjust title markups.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Also, removed the Maintained by, as requested by Geert.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Convert all text files with s390 documentation to ReST format.
Tried to preserve as much as possible the original document
format. Still, some of the files required some work in order
for it to be visible on both plain text and after converted
to html.
The conversion is actually:
- add blank lines and identation in order to identify paragraphs;
- fix tables markups;
- add some lists markups;
- mark literal blocks;
- adjust title markups.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
The hisax driver got removed on 85993b8c97 ("isdn: remove hisax driver"),
but a left-over was kept at kernel-parameters.txt.
Fixes: 85993b8c97 ("isdn: remove hisax driver")
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Mostly due to x86 and acpi conversion, several documentation
links are still pointing to the old file. Fix them.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
Reviewed-by: Sven Van Asbroeck <TheSven73@gmail.com>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The default behavior of hardlockup depends on the config of
CONFIG_BOOTPARAM_HARDLOCKUP_PANIC.
Fix the description of nmi_watchdog to make it clear.
Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add kprobe_event= boot parameter to define kprobe events
at boot time.
The definition syntax is similar to tracefs/kprobe_events
interface, but use ',' and ';' instead of ' ' and '\n'
respectively. e.g.
kprobe_event=p,vfs_read,$arg1,$arg2
This puts a probe on vfs_read with argument1 and 2, and
enable the new event.
Link: http://lkml.kernel.org/r/155851395498.15728.830529496248543583.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Some workloads need to change kthread priority for RCU core processing
without affecting other softirq work. This commit therefore introduces
the rcutree.use_softirq kernel boot parameter, which moves the RCU core
work from softirq to a per-CPU SCHED_OTHER kthread named rcuc. Use of
SCHED_OTHER approach avoids the scalability problems that appeared
with the earlier attempt to move RCU core processing to from softirq
to kthreads. That said, kernels built with RCU_BOOST=y will run the
rcuc kthreads at the RCU-boosting priority.
Note that rcutree.use_softirq=0 must be specified to move RCU core
processing to the rcuc kthreads: rcutree.use_softirq=1 is the default.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[ paulmck: Adjust for invoke_rcu_callbacks() only ever being invoked
from RCU core processing, in contrast to softirq->rcuc transition
in old mainline RCU priority boosting. ]
[ paulmck: Avoid wakeups when scheduler might have invoked rcu_read_unlock()
while holding rq or pi locks, also possibly fixing a pre-existing latent
bug involving raise_softirq()-induced wakeups. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Currently on panic, kernel will lower the loglevel and print out pending
printk msg only with console_flush_on_panic().
Add an option for users to configure the "panic_print" to replay all
dmesg in buffer, some of which they may have never seen due to the
loglevel setting, which will help panic debugging .
[feng.tang@intel.com: keep the original console_flush_on_panic() inside panic()]
Link: http://lkml.kernel.org/r/1556199137-14163-1-git-send-email-feng.tang@intel.com
[feng.tang@intel.com: use logbuf lock to protect the console log index]
Link: http://lkml.kernel.org/r/1556269868-22654-1-git-send-email-feng.tang@intel.com
Link: http://lkml.kernel.org/r/1556095872-36838-1-git-send-email-feng.tang@intel.com
Signed-off-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
