Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull spectre/meltdown updates from Thomas Gleixner:
 "The next round of updates related to melted spectrum:

   - The initial set of spectre V1 mitigations:

       - Array index speculation blocker and its usage for syscall,
         fdtable and the n180211 driver.

       - Speculation barrier and its usage in user access functions

   - Make indirect calls in KVM speculation safe

   - Blacklisting of known to be broken microcodes so IPBP/IBSR are not
     touched.

   - The initial IBPB support and its usage in context switch

   - The exposure of the new speculation MSRs to KVM guests.

   - A fix for a regression in x86/32 related to the cpu entry area

   - Proper whitelisting for known to be safe CPUs from the mitigations.

   - objtool fixes to deal proper with retpolines and alternatives

   - Exclude __init functions from retpolines which speeds up the boot
     process.

   - Removal of the syscall64 fast path and related cleanups and
     simplifications

   - Removal of the unpatched paravirt mode which is yet another source
     of indirect unproteced calls.

   - A new and undisputed version of the module mismatch warning

   - A couple of cleanup and correctness fixes all over the place

  Yet another step towards full mitigation. There are a few things still
  missing like the RBS underflow mitigation for Skylake and other small
  details, but that's being worked on.

  That said, I'm taking a belated christmas vacation for a week and hope
  that everything is magically solved when I'm back on Feb 12th"

* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
  KVM/SVM: Allow direct access to MSR_IA32_SPEC_CTRL
  KVM/VMX: Allow direct access to MSR_IA32_SPEC_CTRL
  KVM/VMX: Emulate MSR_IA32_ARCH_CAPABILITIES
  KVM/x86: Add IBPB support
  KVM/x86: Update the reverse_cpuid list to include CPUID_7_EDX
  x86/speculation: Fix typo IBRS_ATT, which should be IBRS_ALL
  x86/pti: Mark constant arrays as __initconst
  x86/spectre: Simplify spectre_v2 command line parsing
  x86/retpoline: Avoid retpolines for built-in __init functions
  x86/kvm: Update spectre-v1 mitigation
  KVM: VMX: make MSR bitmaps per-VCPU
  x86/paravirt: Remove 'noreplace-paravirt' cmdline option
  x86/speculation: Use Indirect Branch Prediction Barrier in context switch
  x86/cpuid: Fix up "virtual" IBRS/IBPB/STIBP feature bits on Intel
  x86/spectre: Fix spelling mistake: "vunerable"-> "vulnerable"
  x86/spectre: Report get_user mitigation for spectre_v1
  nl80211: Sanitize array index in parse_txq_params
  vfs, fdtable: Prevent bounds-check bypass via speculative execution
  x86/syscall: Sanitize syscall table de-references under speculation
  x86/get_user: Use pointer masking to limit speculation
  ...

1 files changed, 6 insertions, 3 deletions

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 1e3883e45687..74f6eee15179 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -21,6 +21,7 @@
 #include <linux/export.h>
 #include <linux/context_tracking.h>
 #include <linux/user-return-notifier.h>
+#include <linux/nospec.h>
 #include <linux/uprobes.h>
 #include <linux/livepatch.h>
 #include <linux/syscalls.h>
@@ -206,7 +207,7 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
 	 * special case only applies after poking regs and before the
 	 * very next return to user mode.
 	 */
-	current->thread.status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
+	ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
 #endif
 
 	user_enter_irqoff();
@@ -282,7 +283,8 @@ __visible void do_syscall_64(struct pt_regs *regs)
 	 * regs->orig_ax, which changes the behavior of some syscalls.
 	 */
 	if (likely((nr & __SYSCALL_MASK) < NR_syscalls)) {
-		regs->ax = sys_call_table[nr & __SYSCALL_MASK](
+		nr = array_index_nospec(nr & __SYSCALL_MASK, NR_syscalls);
+		regs->ax = sys_call_table[nr](
 			regs->di, regs->si, regs->dx,
 			regs->r10, regs->r8, regs->r9);
 	}
@@ -304,7 +306,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
 	unsigned int nr = (unsigned int)regs->orig_ax;
 
 #ifdef CONFIG_IA32_EMULATION
-	current->thread.status |= TS_COMPAT;
+	ti->status |= TS_COMPAT;
 #endif
 
 	if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) {
@@ -318,6 +320,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
 	}
 
 	if (likely(nr < IA32_NR_syscalls)) {
+		nr = array_index_nospec(nr, IA32_NR_syscalls);
 		/*
 		 * It's possible that a 32-bit syscall implementation
 		 * takes a 64-bit parameter but nonetheless assumes that