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

Pull x86 asm changes from Ingo Molnar:
 "The biggest changes in this cycle were:

   - Revamp, simplify (and in some cases fix) Time Stamp Counter (TSC)
     primitives.  (Andy Lutomirski)

   - Add new, comprehensible entry and exit handlers written in C.
     (Andy Lutomirski)

   - vm86 mode cleanups and fixes.  (Brian Gerst)

   - 32-bit compat code cleanups.  (Brian Gerst)

  The amount of simplification in low level assembly code is already
  palpable:

     arch/x86/entry/entry_32.S                          | 130 +----
     arch/x86/entry/entry_64.S                          | 197 ++-----

  but more simplifications are planned.

  There's also the usual laudry mix of low level changes - see the
  changelog for details"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (83 commits)
  x86/asm: Drop repeated macro of X86_EFLAGS_AC definition
  x86/asm/msr: Make wrmsrl() a function
  x86/asm/delay: Introduce an MWAITX-based delay with a configurable timer
  x86/asm: Add MONITORX/MWAITX instruction support
  x86/traps: Weaken context tracking entry assertions
  x86/asm/tsc: Add rdtscll() merge helper
  selftests/x86: Add syscall_nt selftest
  selftests/x86: Disable sigreturn_64
  x86/vdso: Emit a GNU hash
  x86/entry: Remove do_notify_resume(), syscall_trace_leave(), and their TIF masks
  x86/entry/32: Migrate to C exit path
  x86/entry/32: Remove 32-bit syscall audit optimizations
  x86/vm86: Rename vm86->v86flags and v86mask
  x86/vm86: Rename vm86->vm86_info to user_vm86
  x86/vm86: Clean up vm86.h includes
  x86/vm86: Move the vm86 IRQ definitions to vm86.h
  x86/vm86: Use the normal pt_regs area for vm86
  x86/vm86: Eliminate 'struct kernel_vm86_struct'
  x86/vm86: Move fields from 'struct kernel_vm86_struct' to 'struct vm86'
  x86/vm86: Move vm86 fields out of 'thread_struct'
  ...

diff --cc arch/x86/Kconfig
Simple merge

diff --cc arch/x86/Makefile
Simple merge

diff --cc arch/x86/include/asm/tsc.h
Simple merge

diff --cc arch/x86/kernel/apic/apic.c
Simple merge

diff --cc arch/x86/kernel/cpu/mcheck/mce.c
Simple merge

diff --cc arch/x86/kernel/cpu/perf_event.c
Simple merge

diff --cc arch/x86/kernel/irq.c
index c7dfe1b,d596eba..4616672
--- 1/arch/x86/kernel/irq.c
--- 2/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@@ -216,8 -216,23 +216,23 @@@ __visible unsigned int __irq_entry do_I
        unsigned vector = ~regs->orig_ax;
        unsigned irq;
  
+       /*
+        * NB: Unlike exception entries, IRQ entries do not reliably
+        * handle context tracking in the low-level entry code.  This is
+        * because syscall entries execute briefly with IRQs on before
+        * updating context tracking state, so we can take an IRQ from
+        * kernel mode with CONTEXT_USER.  The low-level entry code only
+        * updates the context if we came from user mode, so we won't
+        * switch to CONTEXT_KERNEL.  We'll fix that once the syscall
+        * code is cleaned up enough that we can cleanly defer enabling
+        * IRQs.
+        */
+ 
        entering_irq();
  
 -      rcu_lockdep_assert(rcu_is_watching(), "IRQ failed to wake up RCU");
+       /* entering_irq() tells RCU that we're not quiescent.  Check it. */
++      RCU_LOCKDEP_WARN(!rcu_is_watching(), "IRQ failed to wake up RCU");
+ 
        irq = __this_cpu_read(vector_irq[vector]);
  
        if (!handle_irq(irq, regs)) {

diff --cc arch/x86/kernel/process.c
index d83740a,2199d9b..6d0e62a
--- 1/arch/x86/kernel/process.c
--- 2/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@@ -29,7 -29,7 +29,8 @@@
  #include <asm/debugreg.h>
  #include <asm/nmi.h>
  #include <asm/tlbflush.h>
 +#include <asm/mce.h>
+ #include <asm/vm86.h>
  
  /*
   * per-CPU TSS segments. Threads are completely 'soft' on Linux,

diff --cc arch/x86/kernel/traps.c
index c5a5231,45e8d98..346eec7
--- 1/arch/x86/kernel/traps.c
--- 2/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@@ -108,13 -109,10 +109,10 @@@ static inline void preempt_conditional_
        preempt_count_dec();
  }
  
- enum ctx_state ist_enter(struct pt_regs *regs)
+ void ist_enter(struct pt_regs *regs)
  {
-       enum ctx_state prev_state;
- 
        if (user_mode(regs)) {
-               /* Other than that, we're just an exception. */
-               prev_state = exception_enter();
 -              rcu_lockdep_assert(rcu_is_watching(), "entry code didn't wake RCU");
++              RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
        } else {
                /*
                 * We might have interrupted pretty much anything.  In
@@@ -136,19 -132,14 +132,14 @@@
        preempt_count_add(HARDIRQ_OFFSET);
  
        /* This code is a bit fragile.  Test it. */
 -      rcu_lockdep_assert(rcu_is_watching(), "ist_enter didn't work");
 +      RCU_LOCKDEP_WARN(!rcu_is_watching(), "ist_enter didn't work");
- 
-       return prev_state;
  }
  
- void ist_exit(struct pt_regs *regs, enum ctx_state prev_state)
+ void ist_exit(struct pt_regs *regs)
  {
-       /* Must be before exception_exit. */
        preempt_count_sub(HARDIRQ_OFFSET);
  
-       if (user_mode(regs))
-               return exception_exit(prev_state);
-       else
+       if (!user_mode(regs))
                rcu_nmi_exit();
  }
  
@@@ -289,9 -280,10 +280,10 @@@ NOKPROBE_SYMBOL(do_trap)
  static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
                          unsigned long trapnr, int signr)
  {
-       enum ctx_state prev_state = exception_enter();
        siginfo_t info;
  
 -      rcu_lockdep_assert(rcu_is_watching(), "entry code didn't wake RCU");
++      RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
+ 
        if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
                        NOTIFY_STOP) {
                conditional_sti(regs);
@@@ -374,11 -364,10 +364,10 @@@ dotraplinkage void do_bounds(struct pt_
        const struct bndcsr *bndcsr;
        siginfo_t *info;
  
-       prev_state = exception_enter();
 -      rcu_lockdep_assert(rcu_is_watching(), "entry code didn't wake RCU");
++      RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
        if (notify_die(DIE_TRAP, "bounds", regs, error_code,
                        X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP)
-               goto exit;
+               return;
        conditional_sti(regs);
  
        if (!user_mode(regs))
@@@ -454,9 -441,8 +441,8 @@@ dotraplinkage voi
  do_general_protection(struct pt_regs *regs, long error_code)
  {
        struct task_struct *tsk;
-       enum ctx_state prev_state;
  
-       prev_state = exception_enter();
 -      rcu_lockdep_assert(rcu_is_watching(), "entry code didn't wake RCU");
++      RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
        conditional_sti(regs);
  
        if (v8086_mode(regs)) {
@@@ -513,7 -495,8 +495,8 @@@ dotraplinkage void notrace do_int3(stru
        if (poke_int3_handler(regs))
                return;
  
-       prev_state = ist_enter(regs);
+       ist_enter(regs);
 -      rcu_lockdep_assert(rcu_is_watching(), "entry code didn't wake RCU");
++      RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
  #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
        if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
                                SIGTRAP) == NOTIFY_STOP)
@@@ -747,21 -729,15 +729,15 @@@ static void math_error(struct pt_regs *
  
  dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
  {
-       enum ctx_state prev_state;
- 
-       prev_state = exception_enter();
 -      rcu_lockdep_assert(rcu_is_watching(), "entry code didn't wake RCU");
++      RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
        math_error(regs, error_code, X86_TRAP_MF);
-       exception_exit(prev_state);
  }
  
  dotraplinkage void
  do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
  {
-       enum ctx_state prev_state;
- 
-       prev_state = exception_enter();
 -      rcu_lockdep_assert(rcu_is_watching(), "entry code didn't wake RCU");
++      RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
        math_error(regs, error_code, X86_TRAP_XF);
-       exception_exit(prev_state);
  }
  
  dotraplinkage void
@@@ -773,9 -749,7 +749,7 @@@ do_spurious_interrupt_bug(struct pt_reg
  dotraplinkage void
  do_device_not_available(struct pt_regs *regs, long error_code)
  {
-       enum ctx_state prev_state;
- 
-       prev_state = exception_enter();
 -      rcu_lockdep_assert(rcu_is_watching(), "entry code didn't wake RCU");
++      RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
        BUG_ON(use_eager_fpu());
  
  #ifdef CONFIG_MATH_EMULATION
@@@ -802,9 -774,8 +774,8 @@@ NOKPROBE_SYMBOL(do_device_not_available
  dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
  {
        siginfo_t info;
-       enum ctx_state prev_state;
  
-       prev_state = exception_enter();
 -      rcu_lockdep_assert(rcu_is_watching(), "entry code didn't wake RCU");
++      RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
        local_irq_enable();
  
        info.si_signo = SIGILL;

diff --cc arch/x86/kernel/tsc.c
Simple merge

diff --cc arch/x86/kvm/lapic.c
Simple merge

diff --cc arch/x86/kvm/svm.c
Simple merge

diff --cc arch/x86/kvm/vmx.c
Simple merge

diff --cc arch/x86/kvm/x86.c
Simple merge

diff --cc include/linux/spinlock.h
Simple merge

diff --cc kernel/notifier.c
index ae9fc7c,980e433..fd2c9ac
--- 1/kernel/notifier.c
--- 2/kernel/notifier.c
+++ b/kernel/notifier.c
@@@ -544,6 -544,8 +544,8 @@@ int notrace notify_die(enum die_val val
                .signr  = sig,
  
        };
 -      rcu_lockdep_assert(rcu_is_watching(),
++      RCU_LOCKDEP_WARN(!rcu_is_watching(),
+                          "notify_die called but RCU thinks we're quiescent");
        return atomic_notifier_call_chain(&die_chain, val, &args);
  }
  NOKPROBE_SYMBOL(notify_die);