Merge android-4.4.180 (71cb827) into msm-4.4

* refs/heads/tmp-71cb827
  Linux 4.4.180
  powerpc/lib: fix book3s/32 boot failure due to code patching
  powerpc/booke64: set RI in default MSR
  drivers/virt/fsl_hypervisor.c: prevent integer overflow in ioctl
  drivers/virt/fsl_hypervisor.c: dereferencing error pointers in ioctl
  bonding: fix arp_validate toggling in active-backup mode
  ipv4: Fix raw socket lookup for local traffic
  vrf: sit mtu should not be updated when vrf netdev is the link
  vlan: disable SIOCSHWTSTAMP in container
  packet: Fix error path in packet_init
  net: ucc_geth - fix Oops when changing number of buffers in the ring
  bridge: Fix error path for kobject_init_and_add()
  powerpc/64s: Include cpu header
  USB: serial: fix unthrottle races
  USB: serial: use variable for status
  x86/bugs: Change L1TF mitigation string to match upstream
  x86/speculation/mds: Fix documentation typo
  Documentation: Correct the possible MDS sysfs values
  x86/mds: Add MDSUM variant to the MDS documentation
  x86/speculation/mds: Add 'mitigations=' support for MDS
  x86/speculation: Support 'mitigations=' cmdline option
  cpu/speculation: Add 'mitigations=' cmdline option
  x86/speculation/mds: Print SMT vulnerable on MSBDS with mitigations off
  x86/speculation/mds: Fix comment
  x86/speculation/mds: Add SMT warning message
  x86/speculation: Move arch_smt_update() call to after mitigation decisions
  x86/cpu/bugs: Use __initconst for 'const' init data
  Documentation: Add MDS vulnerability documentation
  Documentation: Move L1TF to separate directory
  x86/speculation/mds: Add mitigation mode VMWERV
  x86/speculation/mds: Add sysfs reporting for MDS
  x86/speculation/l1tf: Document l1tf in sysfs
  x86/speculation/mds: Add mitigation control for MDS
  x86/speculation/mds: Conditionally clear CPU buffers on idle entry
  x86/speculation/mds: Clear CPU buffers on exit to user
  x86/speculation/mds: Add mds_clear_cpu_buffers()
  x86/kvm: Expose X86_FEATURE_MD_CLEAR to guests
  x86/speculation/mds: Add BUG_MSBDS_ONLY
  x86/speculation/mds: Add basic bug infrastructure for MDS
  x86/speculation: Consolidate CPU whitelists
  x86/msr-index: Cleanup bit defines
  kvm: x86: Report STIBP on GET_SUPPORTED_CPUID
  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: Prevent stale SPEC_CTRL msr content
  x86/speculation: Prepare arch_smt_update() for PRCTL mode
  x86/speculation: Split out TIF update
  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/speculation: Rework SMT state change
  sched: Add sched_smt_active()
  x86/Kconfig: Select SCHED_SMT if SMP enabled
  x86/speculation: Reorganize speculation control MSRs update
  x86/speculation: Rename SSBD update functions
  x86/speculation: Disable STIBP when enhanced IBRS is in use
  x86/speculation: Move STIPB/IBPB string conditionals out of cpu_show_common()
  x86/speculation: Remove unnecessary ret variable in cpu_show_common()
  x86/speculation: Clean up spectre_v2_parse_cmdline()
  x86/speculation: Update the TIF_SSBD comment
  x86/speculation: Propagate information about RSB filling mitigation to sysfs
  x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation
  x86/speculation: Apply IBPB more strictly to avoid cross-process data leak
  x86/mm: Use WRITE_ONCE() when setting PTEs
  KVM: x86: SVM: Call x86_spec_ctrl_set_guest/host() with interrupts disabled
  x86/cpu: Sanitize FAM6_ATOM naming
  x86/microcode: Update the new microcode revision unconditionally
  x86/microcode: Make sure boot_cpu_data.microcode is up-to-date
  x86/speculation: Remove SPECTRE_V2_IBRS in enum spectre_v2_mitigation
  x86/bugs: Fix the AMD SSBD usage of the SPEC_CTRL MSR
  locking/atomics, asm-generic: Move some macros from <linux/bitops.h> to a new <linux/bits.h> file
  x86/bugs: Switch the selection of mitigation from CPU vendor to CPU features
  x86/bugs: Add AMD's SPEC_CTRL MSR usage
  x86/bugs: Add AMD's variant of SSB_NO
  x86/speculation: Simplify the CPU bug detection logic
  x86/speculation: Support Enhanced IBRS on future CPUs
  x86/cpufeatures: Hide AMD-specific speculation flags
  x86/MCE: Save microcode revision in machine check records
  x86/microcode/intel: Check microcode revision before updating sibling threads
  bitops: avoid integer overflow in GENMASK(_ULL)
  x86: stop exporting msr-index.h to userland
  x86/microcode/intel: Add a helper which gives the microcode revision
  locking/static_keys: Provide DECLARE and well as DEFINE macros
  Don't jump to compute_result state from check_result state
  x86/vdso: Pass --eh-frame-hdr to the linker
  cw1200: fix missing unlock on error in cw1200_hw_scan()
  gpu: ipu-v3: dp: fix CSC handling
  selftests/net: correct the return value for run_netsocktests
  s390: ctcm: fix ctcm_new_device error return code
  ipvs: do not schedule icmp errors from tunnels
  init: initialize jump labels before command line option parsing
  tools lib traceevent: Fix missing equality check for strcmp
  KVM: x86: avoid misreporting level-triggered irqs as edge-triggered in tracing
  s390/3270: fix lockdep false positive on view->lock
  s390/dasd: Fix capacity calculation for large volumes
  libnvdimm/btt: Fix a kmemdup failure check
  HID: input: add mapping for keyboard Brightness Up/Down/Toggle keys
  HID: input: add mapping for Expose/Overview key
  iio: adc: xilinx: fix potential use-after-free on remove
  platform/x86: sony-laptop: Fix unintentional fall-through
  netfilter: compat: initialize all fields in xt_init
  timer/debug: Change /proc/timer_stats from 0644 to 0600
  ASoC: Intel: avoid Oops if DMA setup fails
  ipv6: fix a potential deadlock in do_ipv6_setsockopt()
  UAS: fix alignment of scatter/gather segments
  Bluetooth: Align minimum encryption key size for LE and BR/EDR connections
  Bluetooth: hidp: fix buffer overflow
  scsi: qla2xxx: Fix incorrect region-size setting in optrom SYSFS routines
  usb: dwc3: Fix default lpm_nyet_threshold value
  genirq: Prevent use-after-free and work list corruption
  iommu/amd: Set exclusion range correctly
  scsi: csiostor: fix missing data copy in csio_scsi_err_handler()
  perf/x86/intel: Fix handling of wakeup_events for multi-entry PEBS
  ASoC: tlv320aic32x4: Fix Common Pins
  ASoC: cs4270: Set auto-increment bit for register writes
  ASoC:soc-pcm:fix a codec fixup issue in TDM case
  scsi: libsas: fix a race condition when smp task timeout
  media: v4l2: i2c: ov7670: Fix PLL bypass register values
  x86/mce: Improve error message when kernel cannot recover, p2
  selinux: never allow relabeling on context mounts
  Input: snvs_pwrkey - initialize necessary driver data before enabling IRQ
  staging: iio: adt7316: fix the dac write calculation
  staging: iio: adt7316: fix the dac read calculation
  staging: iio: adt7316: allow adt751x to use internal vref for all dacs
  usb: usbip: fix isoc packet num validation in get_pipe
  ARM: iop: don't use using 64-bit DMA masks
  ARM: orion: don't use using 64-bit DMA masks
  xsysace: Fix error handling in ace_setup
  hugetlbfs: fix memory leak for resv_map
  net: hns: Fix WARNING when remove HNS driver with SMMU enabled
  net: hns: Use NAPI_POLL_WEIGHT for hns driver
  scsi: storvsc: Fix calculation of sub-channel count
  vfio/pci: use correct format characters
  rtc: da9063: set uie_unsupported when relevant
  debugfs: fix use-after-free on symlink traversal
  jffs2: fix use-after-free on symlink traversal
  bonding: show full hw address in sysfs for slave entries
  igb: Fix WARN_ONCE on runtime suspend
  rtc: sh: Fix invalid alarm warning for non-enabled alarm
  HID: debug: fix race condition with between rdesc_show() and device removal
  USB: core: Fix bug caused by duplicate interface PM usage counter
  USB: core: Fix unterminated string returned by usb_string()
  USB: w1 ds2490: Fix bug caused by improper use of altsetting array
  USB: yurex: Fix protection fault after device removal
  packet: validate msg_namelen in send directly
  bnxt_en: Improve multicast address setup logic.
  ipv6: invert flowlabel sharing check in process and user mode
  ipv6/flowlabel: wait rcu grace period before put_pid()
  ipv4: ip_do_fragment: Preserve skb_iif during fragmentation
  ALSA: line6: use dynamic buffers
  vfio/type1: Limit DMA mappings per container
  kconfig/[mn]conf: handle backspace (^H) key
  libata: fix using DMA buffers on stack
  scsi: zfcp: reduce flood of fcrscn1 trace records on multi-element RSCN
  ceph: fix use-after-free on symlink traversal
  usb: u132-hcd: fix resource leak
  scsi: qla4xxx: fix a potential NULL pointer dereference
  net: ethernet: ti: fix possible object reference leak
  net: ibm: fix possible object reference leak
  net: xilinx: fix possible object reference leak
  net: ks8851: Set initial carrier state to down
  net: ks8851: Delay requesting IRQ until opened
  net: ks8851: Reassert reset pin if chip ID check fails
  net: ks8851: Dequeue RX packets explicitly
  ARM: dts: pfla02: increase phy reset duration
  usb: gadget: net2272: Fix net2272_dequeue()
  usb: gadget: net2280: Fix net2280_dequeue()
  usb: gadget: net2280: Fix overrun of OUT messages
  sc16is7xx: missing unregister/delete driver on error in sc16is7xx_init()
  netfilter: bridge: set skb transport_header before entering NF_INET_PRE_ROUTING
  qlcnic: Avoid potential NULL pointer dereference
  usbnet: ipheth: fix potential null pointer dereference in ipheth_carrier_set
  usbnet: ipheth: prevent TX queue timeouts when device not ready
  Documentation: Add nospectre_v1 parameter
  powerpc/fsl: Add FSL_PPC_BOOK3E as supported arch for nospectre_v2 boot arg
  powerpc/fsl: Fixed warning: orphan section `__btb_flush_fixup'
  powerpc/fsl: Sanitize the syscall table for NXP PowerPC 32 bit platforms
  powerpc/fsl: Flush the branch predictor at each kernel entry (32 bit)
  powerpc/fsl: Emulate SPRN_BUCSR register
  powerpc/fsl: Flush branch predictor when entering KVM
  powerpc/fsl: Enable runtime patching if nospectre_v2 boot arg is used
  ipv4: set the tcp_min_rtt_wlen range from 0 to one day
  net: stmmac: move stmmac_check_ether_addr() to driver probe
  team: fix possible recursive locking when add slaves
  ipv4: add sanity checks in ipv4_link_failure()
  Revert "block/loop: Use global lock for ioctl() operation."
  bpf: reject wrong sized filters earlier
  tipc: check link name with right length in tipc_nl_compat_link_set
  tipc: check bearer name with right length in tipc_nl_compat_bearer_enable
  netfilter: ebtables: CONFIG_COMPAT: drop a bogus WARN_ON
  NFS: Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family.
  fs/proc/proc_sysctl.c: Fix a NULL pointer dereference
  intel_th: gth: Fix an off-by-one in output unassigning
  slip: make slhc_free() silently accept an error pointer
  tipc: handle the err returned from cmd header function
  powerpc/fsl: Fix the flush of branch predictor.
  powerpc/security: Fix spectre_v2 reporting
  powerpc/fsl: Update Spectre v2 reporting
  powerpc/fsl: Flush the branch predictor at each kernel entry (64bit)
  powerpc/fsl: Add nospectre_v2 command line argument
  powerpc/fsl: Fix spectre_v2 mitigations reporting
  powerpc/fsl: Add macro to flush the branch predictor
  powerpc/fsl: Add infrastructure to fixup branch predictor flush
  powerpc: Avoid code patching freed init sections
  powerpc/powernv: Query firmware for count cache flush settings
  powerpc/pseries: Query hypervisor for count cache flush settings
  powerpc/64s: Add support for software count cache flush
  powerpc/64s: Add new security feature flags for count cache flush
  powerpc/asm: Add a patch_site macro & helpers for patching instructions
  powerpc/fsl: Add barrier_nospec implementation for NXP PowerPC Book3E
  powerpc/64: Make meltdown reporting Book3S 64 specific
  powerpc/64: Call setup_barrier_nospec() from setup_arch()
  powerpc/64: Add CONFIG_PPC_BARRIER_NOSPEC
  powerpc/64: Make stf barrier PPC_BOOK3S_64 specific.
  powerpc/64: Disable the speculation barrier from the command line
  powerpc64s: Show ori31 availability in spectre_v1 sysfs file not v2
  powerpc/64s: Enhance the information in cpu_show_spectre_v1()
  powerpc: Use barrier_nospec in copy_from_user()
  powerpc/64: Use barrier_nospec in syscall entry
  powerpc/64s: Enable barrier_nospec based on firmware settings
  powerpc/64s: Patch barrier_nospec in modules
  powerpc/64s: Add support for ori barrier_nospec patching
  powerpc/64s: Add barrier_nospec
  powerpc/64s: Add support for a store forwarding barrier at kernel entry/exit
  powerpc/64s: Fix section mismatch warnings from setup_rfi_flush()
  powerpc/pseries: Restore default security feature flags on setup
  powerpc: Move default security feature flags
  powerpc/pseries: Fix clearing of security feature flags
  powerpc/64s: Wire up cpu_show_spectre_v2()
  powerpc/64s: Wire up cpu_show_spectre_v1()
  powerpc/pseries: Use the security flags in pseries_setup_rfi_flush()
  powerpc/powernv: Use the security flags in pnv_setup_rfi_flush()
  powerpc/64s: Enhance the information in cpu_show_meltdown()
  powerpc/64s: Move cpu_show_meltdown()
  powerpc/powernv: Set or clear security feature flags
  powerpc/pseries: Set or clear security feature flags
  powerpc: Add security feature flags for Spectre/Meltdown
  powerpc/rfi-flush: Call setup_rfi_flush() after LPM migration
  powerpc/pseries: Add new H_GET_CPU_CHARACTERISTICS flags
  powerpc/rfi-flush: Differentiate enabled and patched flush types
  powerpc/rfi-flush: Always enable fallback flush on pseries
  powerpc/rfi-flush: Make it possible to call setup_rfi_flush() again
  powerpc/rfi-flush: Move the logic to avoid a redo into the debugfs code
  powerpc/powernv: Support firmware disable of RFI flush
  powerpc/pseries: Support firmware disable of RFI flush
  powerpc/64s: Improve RFI L1-D cache flush fallback
  powerpc/xmon: Add RFI flush related fields to paca dump
  USB: Consolidate LPM checks to avoid enabling LPM twice
  USB: Add new USB LPM helpers
  sunrpc: don't mark uninitialised items as VALID.
  nfsd: Don't release the callback slot unless it was actually held
  ceph: fix ci->i_head_snapc leak
  ceph: ensure d_name stability in ceph_dentry_hash()
  sched/numa: Fix a possible divide-by-zero
  trace: Fix preempt_enable_no_resched() abuse
  MIPS: scall64-o32: Fix indirect syscall number load
  cifs: do not attempt cifs operation on smb2+ rename error
  KVM: fail KVM_SET_VCPU_EVENTS with invalid exception number
  kbuild: simplify ld-option implementation
  ANDROID: cuttlefish_defconfig: Disable DEVTMPFS
  ANDROID: Move from clang r349610 to r353983c.
  f2fs: fix to avoid accessing xattr across the boundary
  f2fs: fix to avoid potential race on sbi->unusable_block_count access/update
  f2fs: add tracepoint for f2fs_filemap_fault()
  f2fs: introduce DATA_GENERIC_ENHANCE
  f2fs: fix to handle error in f2fs_disable_checkpoint()
  f2fs: remove redundant check in f2fs_file_write_iter()
  f2fs: fix to be aware of readonly device in write_checkpoint()
  f2fs: fix to skip recovery on readonly device
  f2fs: fix to consider multiple device for readonly check
  f2fs: relocate chksum_offset for large_nat_bitmap feature
  f2fs: allow unfixed f2fs_checkpoint.checksum_offset
  f2fs: Replace spaces with tab
  f2fs: insert space before the open parenthesis '('
  f2fs: allow address pointer number of dnode aligning to specified size
  f2fs: introduce f2fs_read_single_page() for cleanup
  f2fs: mark is_extension_exist() inline
  f2fs: fix to set FI_UPDATE_WRITE correctly
  f2fs: fix to avoid panic in f2fs_inplace_write_data()
  f2fs: fix to do sanity check on valid block count of segment
  f2fs: fix to do sanity check on valid node/block count
  f2fs: fix to avoid panic in do_recover_data()
  f2fs: fix to do sanity check on free nid
  f2fs: fix to do checksum even if inode page is uptodate
  f2fs: fix to avoid panic in f2fs_remove_inode_page()
  f2fs: fix to clear dirty inode in error path of f2fs_iget()
  f2fs: remove new blank line of f2fs kernel message
  f2fs: fix wrong __is_meta_io() macro
  f2fs: fix to avoid panic in dec_valid_node_count()
  f2fs: fix to avoid panic in dec_valid_block_count()
  f2fs: fix to use inline space only if inline_xattr is enable
  f2fs: fix to retrieve inline xattr space
  f2fs: fix error path of recovery
  f2fs: fix to avoid deadloop in foreground GC
  f2fs: data: fix warning Using plain integer as NULL pointer
  f2fs: add tracepoint for f2fs_file_write_iter()
  f2fs: add comment for conditional compilation statement
  f2fs: fix potential recursive call when enabling data_flush
  f2fs: improve discard handling with multi-device volumes
  f2fs: Reduce zoned block device memory usage
  f2fs: Fix use of number of devices

Sleepable function handle_lmk_event() is called in atomic context,
so ignored the commit "ANDROID: Communicates LMK events to userland
where they can be logged"

Conflicts:
	arch/powerpc/include/asm/uaccess.h
	kernel/cpu.c
	kernel/irq/manage.c
	kernel/time/timer_stats.c
	net/ipv4/sysctl_net_ipv4.c

Change-Id: I3e5bd447057b44a28fc5000403198ae0fd644480
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>

1 files changed, 90 insertions, 24 deletions

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 6d683bbb3502..f3237e4cb18f 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -30,6 +30,12 @@
  *	Implement flush IPI by CALL_FUNCTION_VECTOR, Alex Shi
  */
 
+/*
+ * Use bit 0 to mangle the TIF_SPEC_IB state into the mm pointer which is
+ * stored in cpu_tlb_state.last_user_mm_ibpb.
+ */
+#define LAST_USER_MM_IBPB	0x1UL
+
 atomic64_t last_mm_ctx_id = ATOMIC64_INIT(1);
 
 struct flush_tlb_info {
@@ -101,41 +107,101 @@ void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 	local_irq_restore(flags);
 }
 
-void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
-			struct task_struct *tsk)
+static inline unsigned long mm_mangle_tif_spec_ib(struct task_struct *next)
 {
-	unsigned cpu = smp_processor_id();
+	unsigned long next_tif = task_thread_info(next)->flags;
+	unsigned long ibpb = (next_tif >> TIF_SPEC_IB) & LAST_USER_MM_IBPB;
 
-	if (likely(prev != next)) {
-		u64 last_ctx_id = this_cpu_read(cpu_tlbstate.last_ctx_id);
+	return (unsigned long)next->mm | ibpb;
+}
+
+static void cond_ibpb(struct task_struct *next)
+{
+	if (!next || !next->mm)
+		return;
+
+	/*
+	 * Both, the conditional and the always IBPB mode use the mm
+	 * pointer to avoid the IBPB when switching between tasks of the
+	 * same process. Using the mm pointer instead of mm->context.ctx_id
+	 * opens a hypothetical hole vs. mm_struct reuse, which is more or
+	 * less impossible to control by an attacker. Aside of that it
+	 * would only affect the first schedule so the theoretically
+	 * exposed data is not really interesting.
+	 */
+	if (static_branch_likely(&switch_mm_cond_ibpb)) {
+		unsigned long prev_mm, next_mm;
 
 		/*
-		 * Avoid user/user BTB poisoning by flushing the branch
-		 * predictor when switching between processes. This stops
-		 * one process from doing Spectre-v2 attacks on another.
+		 * This is a bit more complex than the always mode because
+		 * it has to handle two 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 could be done by unconditionally issuing IBPB when
+		 * a task which has TIF_SPEC_IB set is either scheduled in
+		 * or out. Though that results in two flushes when:
+		 *
+		 * - the same user space task is scheduled out and later
+		 *   scheduled in again and only a kernel thread ran in
+		 *   between.
+		 *
+		 * - a user space task belonging to the same process is
+		 *   scheduled in after a kernel thread ran in between
 		 *
-		 * As an optimization, flush indirect branches only when
-		 * switching into processes that disable dumping. This
-		 * protects high value processes like gpg, without having
-		 * too high performance overhead. IBPB is *expensive*!
+		 * - a user space task belonging to the same process is
+		 *   scheduled in immediately.
 		 *
-		 * This will not flush branches when switching into kernel
-		 * threads. It will also not flush if we switch to idle
-		 * thread and back to the same process. It will flush if we
-		 * switch to a different non-dumpable process.
+		 * Optimize this with reasonably small overhead for the
+		 * above cases. Mangle the TIF_SPEC_IB bit into the mm
+		 * pointer of the incoming task which is stored in
+		 * cpu_tlbstate.last_user_mm_ibpb for comparison.
 		 */
-		if (tsk && tsk->mm &&
-		    tsk->mm->context.ctx_id != last_ctx_id &&
-		    get_dumpable(tsk->mm) != SUID_DUMP_USER)
+		next_mm = mm_mangle_tif_spec_ib(next);
+		prev_mm = this_cpu_read(cpu_tlbstate.last_user_mm_ibpb);
+
+		/*
+		 * Issue IBPB only if the mm's are different and one or
+		 * both have the IBPB bit set.
+		 */
+		if (next_mm != prev_mm &&
+		    (next_mm | prev_mm) & LAST_USER_MM_IBPB)
 			indirect_branch_prediction_barrier();
 
+		this_cpu_write(cpu_tlbstate.last_user_mm_ibpb, next_mm);
+	}
+
+	if (static_branch_unlikely(&switch_mm_always_ibpb)) {
 		/*
-		 * Record last user mm's context id, so we can avoid
-		 * flushing branch buffer with IBPB if we switch back
-		 * to the same user.
+		 * Only flush when switching to a user space task with a
+		 * different context than the user space task which ran
+		 * last on this CPU.
+		 */
+		if (this_cpu_read(cpu_tlbstate.last_user_mm) != next->mm) {
+			indirect_branch_prediction_barrier();
+			this_cpu_write(cpu_tlbstate.last_user_mm, next->mm);
+		}
+	}
+}
+
+void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
+			struct task_struct *tsk)
+{
+	unsigned cpu = smp_processor_id();
+
+	if (likely(prev != next)) {
+		/*
+		 * Avoid user/user BTB poisoning by flushing the branch
+		 * predictor when switching between processes. This stops
+		 * one process from doing Spectre-v2 attacks on another.
 		 */
-		if (next != &init_mm)
-			this_cpu_write(cpu_tlbstate.last_ctx_id, next->context.ctx_id);
+		cond_ibpb(tsk);
 
 		this_cpu_write(cpu_tlbstate.state, TLBSTATE_OK);
 		this_cpu_write(cpu_tlbstate.active_mm, next);