Pull ARM SoC fixes from Olof Johansson:
"Volume is a little higher than usual due to a set of gpio fixes for
Davinci platforms that's been around a while, still seemed appropriate
to not hold off until next merge window.
Besides that it's the usual mix of minor fixes, mostly corrections of
small stuff in device trees.
Major stability-related one is the removal of a regulator from DT on
Rock960, since DVFS caused undervoltage. I expect it'll be restored
once they figure out the underlying issue"
* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (28 commits)
MAINTAINERS: Remove unused Qualcomm SoC mailing list
ARM: davinci: dm644x: set the GPIO base to 0
ARM: davinci: da830: set the GPIO base to 0
ARM: davinci: dm355: set the GPIO base to 0
ARM: davinci: dm646x: set the GPIO base to 0
ARM: davinci: dm365: set the GPIO base to 0
ARM: davinci: da850: set the GPIO base to 0
gpio: davinci: restore a way to manually specify the GPIO base
ARM: davinci: dm644x: define gpio interrupts as separate resources
ARM: davinci: dm355: define gpio interrupts as separate resources
ARM: davinci: dm646x: define gpio interrupts as separate resources
ARM: davinci: dm365: define gpio interrupts as separate resources
ARM: davinci: da8xx: define gpio interrupts as separate resources
ARM: dts: at91: sama5d2: use the divided clock for SMC
ARM: dts: imx51-zii-rdu1: Remove EEPROM node
ARM: dts: rockchip: Remove @0 from the veyron memory node
arm64: dts: rockchip: Fix PCIe reset polarity for rk3399-puma-haikou.
arm64: dts: qcom: msm8998: Reserve gpio ranges on MTP
arm64: dts: sdm845-mtp: Reserve reserved gpios
arm64: dts: ti: k3-am654: Fix wakeup_uart reg address
...
Pull xen fixes from Juergen Gross:
- A revert of a previous commit as it is no longer necessary and has
shown to cause problems in some memory hotplug cases.
- Some small fixes and a minor cleanup.
- A patch for adding better diagnostic data in a very rare failure
case.
* tag 'for-linus-4.20a-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
pvcalls-front: fixes incorrect error handling
Revert "xen/balloon: Mark unallocated host memory as UNUSABLE"
xen: xlate_mmu: add missing header to fix 'W=1' warning
xen/x86: add diagnostic printout to xen_mc_flush() in case of error
x86/xen: cleanup includes in arch/x86/xen/spinlock.c
Pull STIBP fallout fixes from Thomas Gleixner:
"The performance destruction department finally got it's act together
and came up with a cure for the STIPB regression:
- Provide a command line option to control the spectre v2 user space
mitigations. Default is either seccomp or prctl (if seccomp is
disabled in Kconfig). prctl allows mitigation opt-in, seccomp
enables the migitation for sandboxed processes.
- Rework the code to handle the conditional STIBP/IBPB control and
remove the now unused ptrace_may_access_sched() optimization
attempt
- Disable STIBP automatically when SMT is disabled
- Optimize the switch_to() logic to avoid MSR writes and invocations
of __switch_to_xtra().
- Make the asynchronous speculation TIF updates synchronous to
prevent stale mitigation state.
As a general cleanup this also makes retpoline directly depend on
compiler support and removes the 'minimal retpoline' option which just
pretended to provide some form of security while providing none"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
x86/speculation: Provide IBPB always command line options
x86/speculation: Add seccomp Spectre v2 user space protection mode
x86/speculation: Enable prctl mode for spectre_v2_user
x86/speculation: Add prctl() control for indirect branch speculation
x86/speculation: Prepare arch_smt_update() for PRCTL mode
x86/speculation: Prevent stale SPEC_CTRL msr content
x86/speculation: Split out TIF update
ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS
x86/speculation: Prepare for conditional IBPB in switch_mm()
x86/speculation: Avoid __switch_to_xtra() calls
x86/process: Consolidate and simplify switch_to_xtra() code
x86/speculation: Prepare for per task indirect branch speculation control
x86/speculation: Add command line control for indirect branch speculation
x86/speculation: Unify conditional spectre v2 print functions
x86/speculataion: Mark command line parser data __initdata
x86/speculation: Mark string arrays const correctly
x86/speculation: Reorder the spec_v2 code
x86/l1tf: Show actual SMT state
x86/speculation: Rework SMT state change
sched/smt: Expose sched_smt_present static key
...
Pull few more MIPS fixes from Paul Burton:
- Fix mips_get_syscall_arg() to operate on the task specified when
detecting o32 tasks running on MIPS64 kernels.
- Fix some incorrect GPIO pin muxing for the MT7620 SoC.
- Update the linux-mips mailing list address.
* tag 'mips_fixes_4.20_4' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MAINTAINERS: Update linux-mips mailing list address
MIPS: ralink: Fix mt7620 nd_sd pinmux
mips: fix mips_get_syscall_arg o32 check
i.MX fixes for 4.20, round 2:
- Reomve non-existing EEPROM device from imx51-zii-rdu1 board.
It was added by mistake.
* tag 'imx-fixes-4.20-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
ARM: dts: imx51-zii-rdu1: Remove EEPROM node
Signed-off-by: Olof Johansson <olof@lixom.net>
Few minor fixes for omaps for v4.20-rc cycle
This set of fixes contains minor regression fixes for LogicPD dts files
for MMC pinctrl and interrupts. There is also one section annotation fix
that shows up with Clang, and a fix for an unitialized field for omap1.
* tag 'omap-for-v4.20/fixes-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
ARM: OMAP1: ams-delta: Fix possible use of uninitialized field
ARM: dts: am3517-som: Fix WL127x Wifi interrupt
ARM: dts: logicpd-somlv: Fix interrupt on mmc3_dat1
ARM: dts: LogicPD Torpedo: Fix mmc3_dat1 interrupt
ARM: dts: am3517: Fix pinmuxing for CD on MMC1
ARM: OMAP2+: prm44xx: Fix section annotation on omap44xx_prm_enable_io_wakeup
Signed-off-by: Olof Johansson <olof@lixom.net>
DaVinci: fix GPIO breakage after v4.19
This set of changes is needed to fix the broken GPIO support
for DaVinci boards in legacy mode after certain changes made to the
GPIO driver in 4.19, namely: commits 587f7a694f ("gpio: davinci: Use
dev name for label and automatic base selection") and eb3744a2dd
("gpio: davinci: Do not assume continuous IRQ numbering").
* tag 'davinci-fixes-for-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/nsekhar/linux-davinci:
ARM: davinci: dm644x: set the GPIO base to 0
ARM: davinci: da830: set the GPIO base to 0
ARM: davinci: dm355: set the GPIO base to 0
ARM: davinci: dm646x: set the GPIO base to 0
ARM: davinci: dm365: set the GPIO base to 0
ARM: davinci: da850: set the GPIO base to 0
gpio: davinci: restore a way to manually specify the GPIO base
ARM: davinci: dm644x: define gpio interrupts as separate resources
ARM: davinci: dm355: define gpio interrupts as separate resources
ARM: davinci: dm646x: define gpio interrupts as separate resources
ARM: davinci: dm365: define gpio interrupts as separate resources
ARM: davinci: da8xx: define gpio interrupts as separate resources
Signed-off-by: Olof Johansson <olof@lixom.net>
Removal of vdd_log regulator on rk960 to fix a stability issue
and fixup of the pcie reset polarity on puma-haikou.
* tag 'v4.20-rockchip-dts64fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip:
arm64: dts: rockchip: Fix PCIe reset polarity for rk3399-puma-haikou.
arm64: dts: rockchip: remove vdd_log from rock960 to fix a stability issues
Signed-off-by: Olof Johansson <olof@lixom.net>
Moving the veyron memory node from memory@0 back to memory, as the
firmware on these devices as issues identifying the formally correct
node.
* tag 'v4.20-rockchip-dts32fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip:
ARM: dts: rockchip: Remove @0 from the veyron memory node
Signed-off-by: Olof Johansson <olof@lixom.net>
AT91 fixes for 4.20
- Fix the SMC parent clock
* tag 'at91-4.20-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux:
ARM: dts: at91: sama5d2: use the divided clock for SMC
Signed-off-by: Olof Johansson <olof@lixom.net>
Pull x86 fixes from Ingo Molnar:
"Misc fixes:
- MCE related boot crash fix on certain AMD systems
- FPU exception handling fix
- FPU handling race fix
- revert+rewrite of the RSDP boot protocol extension, use boot_params
instead
- documentation fix"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/MCE/AMD: Fix the thresholding machinery initialization order
x86/fpu: Use the correct exception table macro in the XSTATE_OP wrapper
x86/fpu: Disable bottom halves while loading FPU registers
x86/acpi, x86/boot: Take RSDP address from boot params if available
x86/boot: Mostly revert commit ae7e1238e6 ("Add ACPI RSDP address to setup_header")
x86/ptrace: Fix documentation for tracehook_report_syscall_entry()
Pull tracing fixes from Steven Rostedt:
"While rewriting the function graph tracer, I discovered a design flaw
that was introduced by a patch that tried to fix one bug, but by doing
so created another bug.
As both bugs corrupt the output (but they do not crash the kernel), I
decided to fix the design such that it could have both bugs fixed. The
original fix, fixed time reporting of the function graph tracer when
doing a max_depth of one. This was code that can test how much the
kernel interferes with userspace. But in doing so, it could corrupt
the time keeping of the function profiler.
The issue is that the curr_ret_stack variable was being used for two
different meanings. One was to keep track of the stack pointer on the
ret_stack (shadow stack used by the function graph tracer), and the
other use case was the graph call depth. Although, the two may be
closely related, where they got updated was the issue that lead to the
two different bugs that required the two use cases to be updated
differently.
The big issue with this fix is that it requires changing each
architecture. The good news is, I was able to remove a lot of code
that was duplicated within the architectures and place it into a
single location. Then I could make the fix in one place.
I pushed this code into linux-next to let it settle over a week, and
before doing so, I cross compiled all the affected architectures to
make sure that they built fine.
In the mean time, I also pulled in a patch that fixes the sched_switch
previous tasks state output, that was not actually correct"
* tag 'trace-v4.20-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
sched, trace: Fix prev_state output in sched_switch tracepoint
function_graph: Have profiler use curr_ret_stack and not depth
function_graph: Reverse the order of pushing the ret_stack and the callback
function_graph: Move return callback before update of curr_ret_stack
function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack
function_graph: Make ftrace_push_return_trace() static
sparc/function_graph: Simplify with function_graph_enter()
sh/function_graph: Simplify with function_graph_enter()
s390/function_graph: Simplify with function_graph_enter()
riscv/function_graph: Simplify with function_graph_enter()
powerpc/function_graph: Simplify with function_graph_enter()
parisc: function_graph: Simplify with function_graph_enter()
nds32: function_graph: Simplify with function_graph_enter()
MIPS: function_graph: Simplify with function_graph_enter()
microblaze: function_graph: Simplify with function_graph_enter()
arm64: function_graph: Simplify with function_graph_enter()
ARM: function_graph: Simplify with function_graph_enter()
x86/function_graph: Simplify with function_graph_enter()
function_graph: Create function_graph_enter() to consolidate architecture code
Pull s390 updates from Martin Schwidefsky:
- Add two missing kfree calls on error paths in the vfio-ccw code
- Make sure that all data structures of a mediated vfio-ccw device are
initialized before registering it
- Fix a sparse warning in vfio-ccw
- A followup patch for the pgtable_bytes accounting, the page table
downgrade for compat processes missed a mm_dec_nr_pmds()
- Reject sampling requests in the PMU init function of the CPU
measurement counter facility
- With the vfio AP driver an AP queue needs to be reset on every device
probe as the alternative driver could have modified the device state
* tag 's390-4.20-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/mm: correct pgtable_bytes on page table downgrade
s390/zcrypt: reinit ap queue state machine during device probe
s390/cpum_cf: Reject request for sampling in event initialization
s390/cio: Fix cleanup when unsupported IDA format is used
s390/cio: Fix cleanup of pfn_array alloc failure
vfio: ccw: Register mediated device once all structures are initialized
s390/cio: make vfio_ccw_io_region static
This reverts commit b3cf8528bb.
That commit unintentionally broke Xen balloon memory hotplug with
"hotplug_unpopulated" set to 1. As long as "System RAM" resource
got assigned under a new "Unusable memory" resource in IO/Mem tree
any attempt to online this memory would fail due to general kernel
restrictions on having "System RAM" resources as 1st level only.
The original issue that commit has tried to workaround fa564ad963
("x86/PCI: Enable a 64bit BAR on AMD Family 15h (Models 00-1f, 30-3f,
60-7f)") also got amended by the following 03a551734 ("x86/PCI: Move
and shrink AMD 64-bit window to avoid conflict") which made the
original fix to Xen ballooning unnecessary.
Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Failure of an element of a Xen multicall is signalled via a WARN()
only if the kernel is compiled with MC_DEBUG. It is impossible to
know which element failed and why it did so.
Change that by printing the related information even without MC_DEBUG,
even if maybe in some limited form (e.g. without information which
caller produced the failing element).
Move the printing out of the switch statement in order to have the
same information for a single call.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Since commit 4378a7d4be ("arm64: implement syscall wrappers")
introduced "__arm64_" prefix to all syscall wrapper symbols in
sys_call_table, syscall tracer can not find corresponding
metadata from syscall name. In the result, we have no syscall
ftrace events on arm64 kernel, and some bpf testcases are failed
on arm64.
To fix this issue, this introduces custom
arch_syscall_match_sym_name() which skips first 8 bytes when
comparing the syscall and symbol names.
Fixes: 4378a7d4be ("arm64: implement syscall wrappers")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual address
for a cacheable mapping of a location is being accessed by a core while
another core is remapping the virtual address to a new physical page
using the recommended break-before-make sequence, then under very rare
circumstances TLBI+DSB completes before a read using the translation
being invalidated has been observed by other observers. The workaround
repeats the TLBI+DSB operation and is shared with the Qualcomm Falkor
erratum 1009
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Pull networking fixes from David Miller:
1) ARM64 JIT fixes for subprog handling from Daniel Borkmann.
2) Various sparc64 JIT bug fixes (fused branch convergance, frame
pointer usage detection logic, PSEODU call argument handling).
3) Fix to use BH locking in nf_conncount, from Taehee Yoo.
4) Fix race of TX skb freeing in ipheth driver, from Bernd Eckstein.
5) Handle return value of TX NAPI completion properly in lan743x
driver, from Bryan Whitehead.
6) MAC filter deletion in i40e driver clears wrong state bit, from
Lihong Yang.
7) Fix use after free in rionet driver, from Pan Bian.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (53 commits)
s390/qeth: fix length check in SNMP processing
net: hisilicon: remove unexpected free_netdev
rapidio/rionet: do not free skb before reading its length
i40e: fix kerneldoc for xsk methods
ixgbe: recognize 1000BaseLX SFP modules as 1Gbps
i40e: Fix deletion of MAC filters
igb: fix uninitialized variables
netfilter: nf_tables: deactivate expressions in rule replecement routine
lan743x: Enable driver to work with LAN7431
tipc: fix lockdep warning during node delete
lan743x: fix return value for lan743x_tx_napi_poll
net: via: via-velocity: fix spelling mistake "alignement" -> "alignment"
qed: fix spelling mistake "attnetion" -> "attention"
net: thunderx: fix NULL pointer dereference in nic_remove
sctp: increase sk_wmem_alloc when head->truesize is increased
firestream: fix spelling mistake: "Inititing" -> "Initializing"
net: phy: add workaround for issue where PHY driver doesn't bind to the device
usbnet: ipheth: fix potential recvmsg bug and recvmsg bug 2
sparc: Adjust bpf JIT prologue for PSEUDO calls.
bpf, doc: add entries of who looks over which jits
...
Pull Xtensa fixes from Max Filippov:
- fix kernel exception on userspace access to a currently disabled
coprocessor
- fix coprocessor data saving/restoring in configurations with multiple
coprocessors
- fix ptrace access to coprocessor data on configurations with multiple
coprocessors with high alignment requirements
* tag 'xtensa-20181128' of git://github.com/jcmvbkbc/linux-xtensa:
xtensa: fix coprocessor part of ptrace_{get,set}xregs
xtensa: fix coprocessor context offset definitions
xtensa: enable coprocessors that are being flushed
Pull kvm fixes from Paolo Bonzini:
"Bugfixes, many of them reported by syzkaller and mostly predating the
merge window"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
kvm: svm: Ensure an IBPB on all affected CPUs when freeing a vmcb
kvm: mmu: Fix race in emulated page table writes
KVM: nVMX: vmcs12 revision_id is always VMCS12_REVISION even when copied from eVMCS
KVM: nVMX: Verify eVMCS revision id match supported eVMCS version on eVMCS VMPTRLD
KVM: nVMX/nSVM: Fix bug which sets vcpu->arch.tsc_offset to L1 tsc_offset
x86/kvm/vmx: fix old-style function declaration
KVM: x86: fix empty-body warnings
KVM: VMX: Update shared MSRs to be saved/restored on MSR_EFER.LMA changes
KVM: x86: Fix kernel info-leak in KVM_HC_CLOCK_PAIRING hypercall
KVM: nVMX: Fix kernel info-leak when enabling KVM_CAP_HYPERV_ENLIGHTENED_VMCS more than once
svm: Add mutex_lock to protect apic_access_page_done on AMD systems
KVM: X86: Fix scan ioapic use-before-initialization
KVM: LAPIC: Fix pv ipis use-before-initialization
KVM: VMX: re-add ple_gap module parameter
KVM: PPC: Book3S HV: Fix handling for interrupted H_ENTER_NESTED
If 'prctl' mode of user space protection from spectre v2 is selected
on the kernel command-line, STIBP and IBPB are applied on tasks which
restrict their indirect branch speculation via prctl.
SECCOMP enables the SSBD mitigation for sandboxed tasks already, so it
makes sense to prevent spectre v2 user space to user space attacks as
well.
The Intel mitigation guide documents how STIPB works:
Setting bit 1 (STIBP) of the IA32_SPEC_CTRL MSR on a logical processor
prevents the predicted targets of indirect branches on any logical
processor of that core from being controlled by software that executes
(or executed previously) on another logical processor of the same core.
Ergo setting STIBP protects the task itself from being attacked from a task
running on a different hyper-thread and protects the tasks running on
different hyper-threads from being attacked.
While the document suggests that the branch predictors are shielded between
the logical processors, the observed performance regressions suggest that
STIBP simply disables the branch predictor more or less completely. Of
course the document wording is vague, but the fact that there is also no
requirement for issuing IBPB when STIBP is used points clearly in that
direction. The kernel still issues IBPB even when STIBP is used until Intel
clarifies the whole mechanism.
IBPB is issued when the task switches out, so malicious sandbox code cannot
mistrain the branch predictor for the next user space task on the same
logical processor.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Casey Schaufler <casey.schaufler@intel.com>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Waiman Long <longman9394@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Dave Stewart <david.c.stewart@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181125185006.051663132@linutronix.de
The seccomp speculation control operates on all tasks of a process, but
only the current task of a process can update the MSR immediately. For the
other threads the update is deferred to the next context switch.
This creates the following situation with Process A and B:
Process A task 2 and Process B task 1 are pinned on CPU1. Process A task 2
does not have the speculation control TIF bit set. Process B task 1 has the
speculation control TIF bit set.
CPU0 CPU1
MSR bit is set
ProcB.T1 schedules out
ProcA.T2 schedules in
MSR bit is cleared
ProcA.T1
seccomp_update()
set TIF bit on ProcA.T2
ProcB.T1 schedules in
MSR is not updated <-- FAIL
This happens because the context switch code tries to avoid the MSR update
if the speculation control TIF bits of the incoming and the outgoing task
are the same. In the worst case ProcB.T1 and ProcA.T2 are the only tasks
scheduling back and forth on CPU1, which keeps the MSR stale forever.
In theory this could be remedied by IPIs, but chasing the remote task which
could be migrated is complex and full of races.
The straight forward solution is to avoid the asychronous update of the TIF
bit and defer it to the next context switch. The speculation control state
is stored in task_struct::atomic_flags by the prctl and seccomp updates
already.
Add a new TIF_SPEC_FORCE_UPDATE bit and set this after updating the
atomic_flags. Check the bit on context switch and force a synchronous
update of the speculation control if set. Use the same mechanism for
updating the current task.
Reported-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Casey Schaufler <casey.schaufler@intel.com>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Waiman Long <longman9394@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Dave Stewart <david.c.stewart@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1811272247140.1875@nanos.tec.linutronix.de
The IBPB speculation barrier is issued from switch_mm() when the kernel
switches to a user space task with a different mm than the user space task
which ran last on the same CPU.
An additional optimization is to avoid IBPB when the incoming task can be
ptraced by the outgoing task. This optimization only works when switching
directly between two user space tasks. When switching from a kernel task to
a user space task the optimization fails because the previous task cannot
be accessed anymore. So for quite some scenarios the optimization is just
adding overhead.
The upcoming conditional IBPB support will issue IBPB only for user space
tasks which have the TIF_SPEC_IB bit set. This requires to handle the
following cases:
1) Switch from a user space task (potential attacker) which has
TIF_SPEC_IB set to a user space task (potential victim) which has
TIF_SPEC_IB not set.
2) Switch from a user space task (potential attacker) which has
TIF_SPEC_IB not set to a user space task (potential victim) which has
TIF_SPEC_IB set.
This needs to be optimized for the case where the IBPB can be avoided when
only kernel threads ran in between user space tasks which belong to the
same process.
The current check whether two tasks belong to the same context is using the
tasks context id. While correct, it's simpler to use the mm pointer because
it allows to mangle the TIF_SPEC_IB bit into it. The context id based
mechanism requires extra storage, which creates worse code.
When a task is scheduled out its TIF_SPEC_IB bit is mangled as bit 0 into
the per CPU storage which is used to track the last user space mm which was
running on a CPU. This bit can be used together with the TIF_SPEC_IB bit of
the incoming task to make the decision whether IBPB needs to be issued or
not to cover the two cases above.
As conditional IBPB is going to be the default, remove the dubious ptrace
check for the IBPB always case and simply issue IBPB always when the
process changes.
Move the storage to a different place in the struct as the original one
created a hole.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Casey Schaufler <casey.schaufler@intel.com>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Waiman Long <longman9394@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Dave Stewart <david.c.stewart@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181125185005.466447057@linutronix.de
