commit a7a248c593 upstream.
Add the documenation for TSX Async Abort. Include the description of
the issue, how to check the mitigation state, control the mitigation,
guidance for system administrators.
[ bp: Add proper SPDX tags, touch ups by Josh and me. ]
Co-developed-by: Antonio Gomez Iglesias <antonio.gomez.iglesias@intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Antonio Gomez Iglesias <antonio.gomez.iglesias@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mark Gross <mgross@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9d8d0294e7 upstream.
On x86_64, all returns to usermode go through
prepare_exit_to_usermode(), with the sole exception of do_nmi().
This even includes machine checks -- this was added several years
ago to support MCE recovery. Update the documentation.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jon Masters <jcm@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: 04dcbdb805 ("x86/speculation/mds: Clear CPU buffers on exit to user")
Link: http://lkml.kernel.org/r/999fa9e126ba6a48e9d214d2f18dbde5c62ac55c.1557865329.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 88640e1dcd upstream.
The double fault ESPFIX path doesn't return to user mode at all --
it returns back to the kernel by simulating a #GP fault.
prepare_exit_to_usermode() will run on the way out of
general_protection before running user code.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jon Masters <jcm@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: 04dcbdb805 ("x86/speculation/mds: Clear CPU buffers on exit to user")
Link: http://lkml.kernel.org/r/ac97612445c0a44ee10374f6ea79c222fe22a5c4.1557865329.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 95310e348a upstream
Fix a minor typo in the MDS documentation: "eanbled" -> "enabled".
Reported-by: Jeff Bastian <jbastian@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e672f8bf71 upstream
Updated the documentation for a new CVE-2019-11091 Microarchitectural Data
Sampling Uncacheable Memory (MDSUM) which is a variant of
Microarchitectural Data Sampling (MDS). MDS is a family of side channel
attacks on internal buffers in Intel CPUs.
MDSUM is a special case of MSBDS, MFBDS and MLPDS. An uncacheable load from
memory that takes a fault or assist can leave data in a microarchitectural
structure that may later be observed using one of the same methods used by
MSBDS, MFBDS or MLPDS. There are no new code changes expected for MDSUM.
The existing mitigation for MDS applies to MDSUM as well.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 22dd836508 upstream
In virtualized environments it can happen that the host has the microcode
update which utilizes the VERW instruction to clear CPU buffers, but the
hypervisor is not yet updated to expose the X86_FEATURE_MD_CLEAR CPUID bit
to guests.
Introduce an internal mitigation mode VMWERV which enables the invocation
of the CPU buffer clearing even if X86_FEATURE_MD_CLEAR is not set. If the
system has no updated microcode this results in a pointless execution of
the VERW instruction wasting a few CPU cycles. If the microcode is updated,
but not exposed to a guest then the CPU buffers will be cleared.
That said: Virtual Machines Will Eventually Receive Vaccine
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 07f07f55a2 upstream
Add a static key which controls the invocation of the CPU buffer clear
mechanism on idle entry. This is independent of other MDS mitigations
because the idle entry invocation to mitigate the potential leakage due to
store buffer repartitioning is only necessary on SMT systems.
Add the actual invocations to the different halt/mwait variants which
covers all usage sites. mwaitx is not patched as it's not available on
Intel CPUs.
The buffer clear is only invoked before entering the C-State to prevent
that stale data from the idling CPU is spilled to the Hyper-Thread sibling
after the Store buffer got repartitioned and all entries are available to
the non idle sibling.
When coming out of idle the store buffer is partitioned again so each
sibling has half of it available. Now CPU which returned from idle could be
speculatively exposed to contents of the sibling, but the buffers are
flushed either on exit to user space or on VMENTER.
When later on conditional buffer clearing is implemented on top of this,
then there is no action required either because before returning to user
space the context switch will set the condition flag which causes a flush
on the return to user path.
Note, that the buffer clearing on idle is only sensible on CPUs which are
solely affected by MSBDS and not any other variant of MDS because the other
MDS variants cannot be mitigated when SMT is enabled, so the buffer
clearing on idle would be a window dressing exercise.
This intentionally does not handle the case in the acpi/processor_idle
driver which uses the legacy IO port interface for C-State transitions for
two reasons:
- The acpi/processor_idle driver was replaced by the intel_idle driver
almost a decade ago. Anything Nehalem upwards supports it and defaults
to that new driver.
- The legacy IO port interface is likely to be used on older and therefore
unaffected CPUs or on systems which do not receive microcode updates
anymore, so there is no point in adding that.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 04dcbdb805 upstream
Add a static key which controls the invocation of the CPU buffer clear
mechanism on exit to user space and add the call into
prepare_exit_to_usermode() and do_nmi() right before actually returning.
Add documentation which kernel to user space transition this covers and
explain why some corner cases are not mitigated.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6a9e529272 upstream
The Microarchitectural Data Sampling (MDS) vulernabilities are mitigated by
clearing the affected CPU buffers. The mechanism for clearing the buffers
uses the unused and obsolete VERW instruction in combination with a
microcode update which triggers a CPU buffer clear when VERW is executed.
Provide a inline function with the assembly magic. The argument of the VERW
instruction must be a memory operand as documented:
"MD_CLEAR enumerates that the memory-operand variant of VERW (for
example, VERW m16) has been extended to also overwrite buffers affected
by MDS. This buffer overwriting functionality is not guaranteed for the
register operand variant of VERW."
Documentation also recommends to use a writable data segment selector:
"The buffer overwriting occurs regardless of the result of the VERW
permission check, as well as when the selector is null or causes a
descriptor load segment violation. However, for lowest latency we
recommend using a selector that indicates a valid writable data
segment."
Add x86 specific documentation about MDS and the internal workings of the
mitigation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d52888aa27 upstream
On 5-level paging the LDT remap area is placed in the middle of the KASLR
randomization region and it can overlap with the direct mapping, the
vmalloc or the vmap area.
The LDT mapping is per mm, so it cannot be moved into the P4D page table
next to the CPU_ENTRY_AREA without complicating PGD table allocation for
5-level paging.
The 4 PGD slot gap just before the direct mapping is reserved for
hypervisors, so it cannot be used.
Move the direct mapping one slot deeper and use the resulting gap for the
LDT remap area. The resulting layout is the same for 4 and 5 level paging.
[ tglx: Massaged changelog ]
Fixes: f55f0501cb ("x86/pti: Put the LDT in its own PGD if PTI is on")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: bp@alien8.de
Cc: hpa@zytor.com
Cc: dave.hansen@linux.intel.com
Cc: peterz@infradead.org
Cc: boris.ostrovsky@oracle.com
Cc: jgross@suse.com
Cc: bhe@redhat.com
Cc: willy@infradead.org
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181026122856.66224-2-kirill.shutemov@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Fix a few issues in Documentation/x86/earlyprintk.txt:
- correct typos, punctuation, missing word, wrong word
- change product name from Netchip to NetChip
- expand where to add "earlyprintk=dbg"
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Link: http://lkml.kernel.org/r/d0c40ac3-7659-6374-dbda-23d3d2577f30@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 timer updates from Thomas Gleixner:
"Early TSC based time stamping to allow better boot time analysis.
This comes with a general cleanup of the TSC calibration code which
grew warts and duct taping over the years and removes 250 lines of
code. Initiated and mostly implemented by Pavel with help from various
folks"
* 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
x86/kvmclock: Mark kvm_get_preset_lpj() as __init
x86/tsc: Consolidate init code
sched/clock: Disable interrupts when calling generic_sched_clock_init()
timekeeping: Prevent false warning when persistent clock is not available
sched/clock: Close a hole in sched_clock_init()
x86/tsc: Make use of tsc_calibrate_cpu_early()
x86/tsc: Split native_calibrate_cpu() into early and late parts
sched/clock: Use static key for sched_clock_running
sched/clock: Enable sched clock early
sched/clock: Move sched clock initialization and merge with generic clock
x86/tsc: Use TSC as sched clock early
x86/tsc: Initialize cyc2ns when tsc frequency is determined
x86/tsc: Calibrate tsc only once
ARM/time: Remove read_boot_clock64()
s390/time: Remove read_boot_clock64()
timekeeping: Default boot time offset to local_clock()
timekeeping: Replace read_boot_clock64() with read_persistent_wall_and_boot_offset()
s390/time: Add read_persistent_wall_and_boot_offset()
x86/xen/time: Output xen sched_clock time from 0
x86/xen/time: Initialize pv xen time in init_hypervisor_platform()
...
Pull x86 cache QoS (RDT/CAR) updates from Thomas Gleixner:
"Add support for pseudo-locked cache regions.
Cache Allocation Technology (CAT) allows on certain CPUs to isolate a
region of cache and 'lock' it. Cache pseudo-locking builds on the fact
that a CPU can still read and write data pre-allocated outside its
current allocated area on cache hit. With cache pseudo-locking data
can be preloaded into a reserved portion of cache that no application
can fill, and from that point on will only serve cache hits. The cache
pseudo-locked memory is made accessible to user space where an
application can map it into its virtual address space and thus have a
region of memory with reduced average read latency.
The locking is not perfect and gets totally screwed by WBINDV and
similar mechanisms, but it provides a reasonable enhancement for
certain types of latency sensitive applications.
The implementation extends the current CAT mechanism and provides a
generally useful exclusive CAT mode on which it builds the extra
pseude-locked regions"
* 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits)
x86/intel_rdt: Disable PMU access
x86/intel_rdt: Fix possible circular lock dependency
x86/intel_rdt: Make CPU information accessible for pseudo-locked regions
x86/intel_rdt: Support restoration of subset of permissions
x86/intel_rdt: Fix cleanup of plr structure on error
x86/intel_rdt: Move pseudo_lock_region_clear()
x86/intel_rdt: Limit C-states dynamically when pseudo-locking active
x86/intel_rdt: Support L3 cache performance event of Broadwell
x86/intel_rdt: More precise L2 hit/miss measurements
x86/intel_rdt: Create character device exposing pseudo-locked region
x86/intel_rdt: Create debugfs files for pseudo-locking testing
x86/intel_rdt: Create resctrl debug area
x86/intel_rdt: Ensure RDT cleanup on exit
x86/intel_rdt: Resctrl files reflect pseudo-locked information
x86/intel_rdt: Support creation/removal of pseudo-locked region
x86/intel_rdt: Pseudo-lock region creation/removal core
x86/intel_rdt: Discover supported platforms via prefetch disable bits
x86/intel_rdt: Add utilities to test pseudo-locked region possibility
x86/intel_rdt: Split resource group removal in two
x86/intel_rdt: Enable entering of pseudo-locksetup mode
...
When a resource group enters pseudo-locksetup mode it reflects that the
platform supports cache pseudo-locking and the resource group is unused,
ready to be used for a pseudo-locked region. Until it is set up as a
pseudo-locked region the resource group is "locked down" such that no new
tasks or cpus can be assigned to it. This is accomplished in a user visible
way by making the cpus, cpus_list, and tasks resctrl files inaccassible
(user cannot read from or write to these files).
When the resource group changes to pseudo-locked mode it represents a cache
pseudo-locked region. While not appropriate to make any changes to the cpus
assigned to this region it is useful to make it easy for the user to see
which cpus are associated with the pseudo-locked region.
Modify the permissions of the cpus/cpus_list file when the resource group
changes to pseudo-locked mode to support reading (not writing). The
information presented to the user when reading the file are the cpus
associated with the pseudo-locked region.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/12756b7963b6abc1bffe8fb560b87b75da827bd1.1530421961.git.reinette.chatre@intel.com
By default resource groups allow sharing of their cache allocations. There
is nothing that prevents a resource group from configuring a cache
allocation that overlaps with that of an existing resource group.
To enable resource groups to specify that their cache allocations cannot be
shared a resource group "mode" is introduced to support two possible modes:
"shareable" and "exclusive". A "shareable" resource group allows sharing of
its cache allocations, an "exclusive" resource group does not. A new
resctrl file "mode" associated with each resource group is used to
communicate its (the associated resource group's) mode setting and allow
the mode to be changed. The new "mode" file as well as two other resctrl
files, "bit_usage" and "size", are introduced in this series.
Add documentation for the three new resctrl files as well as one example
demonstrating their use.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/f03a3059ec40ae719be6f3fba9f446bb055e0064.1529706536.git.reinette.chatre@intel.com
Pull x86 cache resource controller updates from Thomas Gleixner:
"An update for the Intel Resource Director Technolgy (RDT) which adds a
feedback driven software controller to runtime adjust the bandwidth
allocation MSRs.
This makes the allocations more accurate and allows to use bandwidth
values in understandable units (MB/s) instead of using percentage
based allocations as the original, still available, interface.
The software controller can be enabled with a new mount option for the
resctrl filesystem"
* 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/intel_rdt/mba_sc: Feedback loop to dynamically update mem bandwidth
x86/intel_rdt/mba_sc: Prepare for feedback loop
x86/intel_rdt/mba_sc: Add schemata support
x86/intel_rdt/mba_sc: Add initialization support
x86/intel_rdt/mba_sc: Enable/disable MBA software controller
x86/intel_rdt/mba_sc: Documentation for MBA software controller(mba_sc)
This is something drivers should decide (modulo chipset quirks like
for VIA), which as far as I can tell is how things have been handled
for the last 15 years.
Note that we keep the usedac option for now, as it is used in the wild
to override the too generic VIA quirk.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Limiting the dma mask to avoid PCI (pre-PCIe) DAC cycles while paying
the huge overhead of an IOMMU is rather pointless, and this seriously
gets in the way of dma mapping work.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
This is just the minimal workaround. The file is mostly either stale
and/or duplicative of Documentation/admin-guide/kernel-parameters.txt,
but that is much more work than I'm willing to do right now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Pull x86 fixes from Thomas Gleixner:
"A set of fixes and updates for x86:
- Address a swiotlb regression which was caused by the recent DMA
rework and made driver fail because dma_direct_supported() returned
false
- Fix a signedness bug in the APIC ID validation which caused invalid
APIC IDs to be detected as valid thereby bloating the CPU possible
space.
- Fix inconsisten config dependcy/select magic for the MFD_CS5535
driver.
- Fix a corruption of the physical address space bits when encryption
has reduced the address space and late cpuinfo updates overwrite
the reduced bit information with the original value.
- Dominiks syscall rework which consolidates the architecture
specific syscall functions so all syscalls can be wrapped with the
same macros. This allows to switch x86/64 to struct pt_regs based
syscalls. Extend the clearing of user space controlled registers in
the entry patch to the lower registers"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/apic: Fix signedness bug in APIC ID validity checks
x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption
x86/olpc: Fix inconsistent MFD_CS5535 configuration
swiotlb: Use dma_direct_supported() for swiotlb_ops
syscalls/x86: Adapt syscall_wrapper.h to the new syscall stub naming convention
syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()
syscalls/core, syscalls/x86: Clean up compat syscall stub naming convention
syscalls/core, syscalls/x86: Clean up syscall stub naming convention
syscalls/x86: Extend register clearing on syscall entry to lower registers
syscalls/x86: Unconditionally enable 'struct pt_regs' based syscalls on x86_64
syscalls/x86: Use 'struct pt_regs' based syscall calling for IA32_EMULATION and x32
syscalls/core: Prepare CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y for compat syscalls
syscalls/x86: Use 'struct pt_regs' based syscall calling convention for 64-bit syscalls
syscalls/core: Introduce CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y
x86/syscalls: Don't pointlessly reload the system call number
x86/mm: Fix documentation of module mapping range with 4-level paging
x86/cpuid: Switch to 'static const' specifier
Pull trivial tree updates from Jiri Kosina.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
kfifo: fix inaccurate comment
tools/thermal: tmon: fix for segfault
net: Spelling s/stucture/structure/
edd: don't spam log if no EDD information is present
Documentation: Fix early-microcode.txt references after file rename
tracing: Block comments should align the * on each line
treewide: Fix typos in printk
GenWQE: Fix a typo in two comments
treewide: Align function definition open/close braces
Commit:
f5a40711fa ("x86/mm: Set MODULES_END to 0xffffffffff000000")
changed MODULES_END back to a fixed value, but didn't update the documentation
of memory layout for 4-level paging.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: f5a40711fa ("x86/mm: Set MODULES_END to 0xffffffffff000000")
Link: http://lkml.kernel.org/r/20180402121025.10244-1-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The file Documentation/x86/early-microcode.txt was renamed to
Documentation/x86/microcode.txt in 0e3258753f, but it was still
referenced by its old name in a three places:
* Documentation/x86/00-INDEX
* arch/x86/Kconfig
* arch/x86/kernel/cpu/microcode/amd.c
This commit updates these references accordingly.
Fixes: 0e3258753f ("x86/microcode: Document the three loading methods")
Signed-off-by: Jaak Ristioja <jaak@ristioja.ee>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
All pieces of the puzzle are in place and we can now allow to boot with
CONFIG_X86_5LEVEL=y on a machine without LA57 support.
Kernel will detect that LA57 is missing and fold p4d at runtime.
Update the documentation and the Kconfig option description to reflect the
change.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180214182542.69302-10-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Here is the set of "big" driver core patches for 4.16-rc1.
The majority of the work here is in the firmware subsystem, with reworks
to try to attempt to make the code easier to handle in the long run, but
no functional change. There's also some tree-wide sysfs attribute
fixups with lots of acks from the various subsystem maintainers, as well
as a handful of other normal fixes and changes.
And finally, some license cleanups for the driver core and sysfs code.
All have been in linux-next for a while with no reported issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-----BEGIN PGP SIGNATURE-----
iG0EABECAC0WIQT0tgzFv3jCIUoxPcsxR9QN2y37KQUCWnLvPw8cZ3JlZ0Brcm9h
aC5jb20ACgkQMUfUDdst+ynNzACgkzjPoBytJWbpWFt6SR6L33/u4kEAnRFvVCGL
s6ygQPQhZIjKk2Lxa2hC
=Zihy
-----END PGP SIGNATURE-----
Merge tag 'driver-core-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the set of "big" driver core patches for 4.16-rc1.
The majority of the work here is in the firmware subsystem, with
reworks to try to attempt to make the code easier to handle in the
long run, but no functional change. There's also some tree-wide sysfs
attribute fixups with lots of acks from the various subsystem
maintainers, as well as a handful of other normal fixes and changes.
And finally, some license cleanups for the driver core and sysfs code.
All have been in linux-next for a while with no reported issues"
* tag 'driver-core-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (48 commits)
device property: Define type of PROPERTY_ENRTY_*() macros
device property: Reuse property_entry_free_data()
device property: Move property_entry_free_data() upper
firmware: Fix up docs referring to FIRMWARE_IN_KERNEL
firmware: Drop FIRMWARE_IN_KERNEL Kconfig option
USB: serial: keyspan: Drop firmware Kconfig options
sysfs: remove DEBUG defines
sysfs: use SPDX identifiers
drivers: base: add coredump driver ops
sysfs: add attribute specification for /sysfs/devices/.../coredump
test_firmware: fix missing unlock on error in config_num_requests_store()
test_firmware: make local symbol test_fw_config static
sysfs: turn WARN() into pr_warn()
firmware: Fix a typo in fallback-mechanisms.rst
treewide: Use DEVICE_ATTR_WO
treewide: Use DEVICE_ATTR_RO
treewide: Use DEVICE_ATTR_RW
sysfs.h: Use octal permissions
component: add debugfs support
bus: simple-pm-bus: convert bool SIMPLE_PM_BUS to tristate
...
Pull x86/cache updates from Thomas Gleixner:
"A set of patches which add support for L2 cache partitioning to the
Intel RDT facility"
* 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/intel_rdt: Add command line parameter to control L2_CDP
x86/intel_rdt: Enable L2 CDP in MSR IA32_L2_QOS_CFG
x86/intel_rdt: Add two new resources for L2 Code and Data Prioritization (CDP)
x86/intel_rdt: Enumerate L2 Code and Data Prioritization (CDP) feature
x86/intel_rdt: Add L2CDP support in documentation
x86/intel_rdt: Update documentation
We've removed the option, so stop talking about it.
Signed-off-by: Benjamin Gilbert <benjamin.gilbert@coreos.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull x86 pti fixes from Thomas Gleixner:
"A small set of fixes for the meltdown/spectre mitigations:
- Make kprobes aware of retpolines to prevent probes in the retpoline
thunks.
- Make the machine check exception speculation protected. MCE used to
issue an indirect call directly from the ASM entry code. Convert
that to a direct call into a C-function and issue the indirect call
from there so the compiler can add the retpoline protection,
- Make the vmexit_fill_RSB() assembly less stupid
- Fix a typo in the PTI documentation"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/retpoline: Optimize inline assembler for vmexit_fill_RSB
x86/pti: Document fix wrong index
kprobes/x86: Disable optimizing on the function jumps to indirect thunk
kprobes/x86: Blacklist indirect thunk functions for kprobes
retpoline: Introduce start/end markers of indirect thunk
x86/mce: Make machine check speculation protected
L2 and L3 Code and Data Prioritization (CDP) can be enabled separately.
The existing mount parameter "cdp" is only for enabling L3 CDP and will be
kept for backwards compability.
Add a new mount parameter 'cdpl2' for L2 CDP.
[ tglx: Made changelog readable ]
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: Vikas" <vikas.shivappa@intel.com>
Cc: Sai Praneeth" <sai.praneeth.prakhya@intel.com>
Cc: Reinette" <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1513810644-78015-3-git-send-email-fenghua.yu@intel.com
With more flag bits in /proc/cpuinfo for RDT, it's better to classify the
bits for readability.
Some previously missing bits are added as well.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: Vikas" <vikas.shivappa@intel.com>
Cc: Sai Praneeth" <sai.praneeth.prakhya@intel.com>
Cc: Reinette" <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1513810644-78015-2-git-send-email-fenghua.yu@intel.com
Pull x86 pti updates from Thomas Gleixner:
"This contains:
- a PTI bugfix to avoid setting reserved CR3 bits when PCID is
disabled. This seems to cause issues on a virtual machine at least
and is incorrect according to the AMD manual.
- a PTI bugfix which disables the perf BTS facility if PTI is
enabled. The BTS AUX buffer is not globally visible and causes the
CPU to fault when the mapping disappears on switching CR3 to user
space. A full fix which restores BTS on PTI is non trivial and will
be worked on.
- PTI bugfixes for EFI and trusted boot which make sure that the user
space visible page table entries have the NX bit cleared
- removal of dead code in the PTI pagetable setup functions
- add PTI documentation
- add a selftest for vsyscall to verify that the kernel actually
implements what it advertises.
- a sysfs interface to expose vulnerability and mitigation
information so there is a coherent way for users to retrieve the
status.
- the initial spectre_v2 mitigations, aka retpoline:
+ The necessary ASM thunk and compiler support
+ The ASM variants of retpoline and the conversion of affected ASM
code
+ Make LFENCE serializing on AMD so it can be used as speculation
trap
+ The RSB fill after vmexit
- initial objtool support for retpoline
As I said in the status mail this is the most of the set of patches
which should go into 4.15 except two straight forward patches still on
hold:
- the retpoline add on of LFENCE which waits for ACKs
- the RSB fill after context switch
Both should be ready to go early next week and with that we'll have
covered the major holes of spectre_v2 and go back to normality"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits)
x86,perf: Disable intel_bts when PTI
security/Kconfig: Correct the Documentation reference for PTI
x86/pti: Fix !PCID and sanitize defines
selftests/x86: Add test_vsyscall
x86/retpoline: Fill return stack buffer on vmexit
x86/retpoline/irq32: Convert assembler indirect jumps
x86/retpoline/checksum32: Convert assembler indirect jumps
x86/retpoline/xen: Convert Xen hypercall indirect jumps
x86/retpoline/hyperv: Convert assembler indirect jumps
x86/retpoline/ftrace: Convert ftrace assembler indirect jumps
x86/retpoline/entry: Convert entry assembler indirect jumps
x86/retpoline/crypto: Convert crypto assembler indirect jumps
x86/spectre: Add boot time option to select Spectre v2 mitigation
x86/retpoline: Add initial retpoline support
objtool: Allow alternatives to be ignored
objtool: Detect jumps to retpoline thunks
x86/pti: Make unpoison of pgd for trusted boot work for real
x86/alternatives: Fix optimize_nops() checking
sysfs/cpu: Fix typos in vulnerability documentation
x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC
...
Add some details about how PTI works, what some of the downsides
are, and how to debug it when things go wrong.
Also document the kernel parameter: 'pti/nopti'.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Moritz Lipp <moritz.lipp@iaik.tugraz.at>
Cc: Daniel Gruss <daniel.gruss@iaik.tugraz.at>
Cc: Michael Schwarz <michael.schwarz@iaik.tugraz.at>
Cc: Richard Fellner <richard.fellner@student.tugraz.at>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andi Lutomirsky <luto@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180105174436.1BC6FA2B@viggo.jf.intel.com
Pull more x86 pti fixes from Thomas Gleixner:
"Another small stash of fixes for fallout from the PTI work:
- Fix the modules vs. KASAN breakage which was caused by making
MODULES_END depend of the fixmap size. That was done when the cpu
entry area moved into the fixmap, but now that we have a separate
map space for that this is causing more issues than it solves.
- Use the proper cache flush methods for the debugstore buffers as
they are mapped/unmapped during runtime and not statically mapped
at boot time like the rest of the cpu entry area.
- Make the map layout of the cpu_entry_area consistent for 4 and 5
level paging and fix the KASLR vaddr_end wreckage.
- Use PER_CPU_EXPORT for per cpu variable and while at it unbreak
nvidia gfx drivers by dropping the GPL export. The subject line of
the commit tells it the other way around, but I noticed that too
late.
- Fix the ASM alternative macros so they can be used in the middle of
an inline asm block.
- Rename the BUG_CPU_INSECURE flag to BUG_CPU_MELTDOWN so the attack
vector is properly identified. The Spectre mitigations will come
with their own bug bits later"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/pti: Rename BUG_CPU_INSECURE to BUG_CPU_MELTDOWN
x86/alternatives: Add missing '\n' at end of ALTERNATIVE inline asm
x86/tlb: Drop the _GPL from the cpu_tlbstate export
x86/events/intel/ds: Use the proper cache flush method for mapping ds buffers
x86/kaslr: Fix the vaddr_end mess
x86/mm: Map cpu_entry_area at the same place on 4/5 level
x86/mm: Set MODULES_END to 0xffffffffff000000
vaddr_end for KASLR is only documented in the KASLR code itself and is
adjusted depending on config options. So it's not surprising that a change
of the memory layout causes KASLR to have the wrong vaddr_end. This can map
arbitrary stuff into other areas causing hard to understand problems.
Remove the whole ifdef magic and define the start of the cpu_entry_area to
be the end of the KASLR vaddr range.
Add documentation to that effect.
Fixes: 92a0f81d89 ("x86/cpu_entry_area: Move it out of the fixmap")
Reported-by: Benjamin Gilbert <benjamin.gilbert@coreos.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Benjamin Gilbert <benjamin.gilbert@coreos.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>,
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801041320360.1771@nanos
There is no reason for 4 and 5 level pagetables to have a different
layout. It just makes determining vaddr_end for KASLR harder than
necessary.
Fixes: 92a0f81d89 ("x86/cpu_entry_area: Move it out of the fixmap")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Gilbert <benjamin.gilbert@coreos.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>,
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801041320360.1771@nanos
Since f06bdd4001 ("x86/mm: Adapt MODULES_END based on fixmap section size")
kasan_mem_to_shadow(MODULES_END) could be not aligned to a page boundary.
So passing page unaligned address to kasan_populate_zero_shadow() have two
possible effects:
1) It may leave one page hole in supposed to be populated area. After commit
21506525fb ("x86/kasan/64: Teach KASAN about the cpu_entry_area") that
hole happens to be in the shadow covering fixmap area and leads to crash:
BUG: unable to handle kernel paging request at fffffbffffe8ee04
RIP: 0010:check_memory_region+0x5c/0x190
Call Trace:
<NMI>
memcpy+0x1f/0x50
ghes_copy_tofrom_phys+0xab/0x180
ghes_read_estatus+0xfb/0x280
ghes_notify_nmi+0x2b2/0x410
nmi_handle+0x115/0x2c0
default_do_nmi+0x57/0x110
do_nmi+0xf8/0x150
end_repeat_nmi+0x1a/0x1e
Note, the crash likely disappeared after commit 92a0f81d89, which
changed kasan_populate_zero_shadow() call the way it was before
commit 21506525fb.
2) Attempt to load module near MODULES_END will fail, because
__vmalloc_node_range() called from kasan_module_alloc() will hit the
WARN_ON(!pte_none(*pte)) in the vmap_pte_range() and bail out with error.
To fix this we need to make kasan_mem_to_shadow(MODULES_END) page aligned
which means that MODULES_END should be 8*PAGE_SIZE aligned.
The whole point of commit f06bdd4001 was to move MODULES_END down if
NR_CPUS is big, so the cpu_entry_area takes a lot of space.
But since 92a0f81d89 ("x86/cpu_entry_area: Move it out of the fixmap")
the cpu_entry_area is no longer in fixmap, so we could just set
MODULES_END to a fixed 8*PAGE_SIZE aligned address.
Fixes: f06bdd4001 ("x86/mm: Adapt MODULES_END based on fixmap section size")
Reported-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Garnier <thgarnie@google.com>
Link: https://lkml.kernel.org/r/20171228160620.23818-1-aryabinin@virtuozzo.com
Pull x86 page table isolation updates from Thomas Gleixner:
"This is the final set of enabling page table isolation on x86:
- Infrastructure patches for handling the extra page tables.
- Patches which map the various bits and pieces which are required to
get in and out of user space into the user space visible page
tables.
- The required changes to have CR3 switching in the entry/exit code.
- Optimizations for the CR3 switching along with documentation how
the ASID/PCID mechanism works.
- Updates to dump pagetables to cover the user space page tables for
W+X scans and extra debugfs files to analyze both the kernel and
the user space visible page tables
The whole functionality is compile time controlled via a config switch
and can be turned on/off on the command line as well"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
x86/ldt: Make the LDT mapping RO
x86/mm/dump_pagetables: Allow dumping current pagetables
x86/mm/dump_pagetables: Check user space page table for WX pages
x86/mm/dump_pagetables: Add page table directory to the debugfs VFS hierarchy
x86/mm/pti: Add Kconfig
x86/dumpstack: Indicate in Oops whether PTI is configured and enabled
x86/mm: Clarify the whole ASID/kernel PCID/user PCID naming
x86/mm: Use INVPCID for __native_flush_tlb_single()
x86/mm: Optimize RESTORE_CR3
x86/mm: Use/Fix PCID to optimize user/kernel switches
x86/mm: Abstract switching CR3
x86/mm: Allow flushing for future ASID switches
x86/pti: Map the vsyscall page if needed
x86/pti: Put the LDT in its own PGD if PTI is on
x86/mm/64: Make a full PGD-entry size hole in the memory map
x86/events/intel/ds: Map debug buffers in cpu_entry_area
x86/cpu_entry_area: Add debugstore entries to cpu_entry_area
x86/mm/pti: Map ESPFIX into user space
x86/mm/pti: Share entry text PMD
x86/entry: Align entry text section to PMD boundary
...
With PTI enabled, the LDT must be mapped in the usermode tables somewhere.
The LDT is per process, i.e. per mm.
An earlier approach mapped the LDT on context switch into a fixmap area,
but that's a big overhead and exhausted the fixmap space when NR_CPUS got
big.
Take advantage of the fact that there is an address space hole which
provides a completely unused pgd. Use this pgd to manage per-mm LDT
mappings.
This has a down side: the LDT isn't (currently) randomized, and an attack
that can write the LDT is instant root due to call gates (thanks, AMD, for
leaving call gates in AMD64 but designing them wrong so they're only useful
for exploits). This can be mitigated by making the LDT read-only or
randomizing the mapping, either of which is strightforward on top of this
patch.
This will significantly slow down LDT users, but that shouldn't matter for
important workloads -- the LDT is only used by DOSEMU(2), Wine, and very
old libc implementations.
[ tglx: Cleaned it up. ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Shrink vmalloc space from 16384TiB to 12800TiB to enlarge the hole starting
at 0xff90000000000000 to be a full PGD entry.
A subsequent patch will use this hole for the pagetable isolation LDT
alias.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
