Merge branches 'x86-build-for-linus', 'x86-cleanups-for-linus' and 'x86-debug-for...

Pull x86 build/cleanup/debug updates from Ingo Molnar:
 "Robustify the build process with a quirk to avoid GCC reordering
  related bugs.

  Two code cleanups.

  Simplify entry_64.S CFI annotations, by Jan Beulich"

* 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, build: Change code16gcc.h from a C header to an assembly header

* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Simplify __HAVE_ARCH_CMPXCHG tests
  x86/tsc: Get rid of custom DIV_ROUND() macro

* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/debug: Drop several unnecessary CFI annotations

diff --cc arch/x86/Makefile
Simple merge

diff --cc arch/x86/kernel/entry_64.S
index c844f0816ab8b383615fe9908010be92a7380d16,1e96c3628bf24fc4fe0086ac6f9dc70b2c1c590d,b25ca969edd27eca18210b013508d640775c6613,f72c03a1ac5498af28219ba82280ec5de329605b..2fac1343a90b605fe41ebcde6ca965bd25021489
--- 1/arch/x86/kernel/entry_64.S
--- 2/arch/x86/kernel/entry_64.S
--- 3/arch/x86/kernel/entry_64.S
--- 4/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@@@@ -830,46 -1040,13 -830,49 -829,49 +829,46 @@@@@ restore_args
        RESTORE_ARGS 1,8,1
    
    irq_return:
 -      _ASM_EXTABLE(irq_return, bad_iret)
  ++    INTERRUPT_RETURN
 -  #ifdef CONFIG_PARAVIRT
  ++
  --    jnz irq_return_ldt
  ++ENTRY(native_iret)
 +      /*
 +       * Are we returning to a stack segment from the LDT?  Note: in
 +       * 64-bit mode SS:RSP on the exception stack is always valid.
 +       */
 +  #ifdef CONFIG_X86_ESPFIX64
 +      testb $4,(SS-RIP)(%rsp)
  --irq_return_iret:
  --    INTERRUPT_RETURN
  --    _ASM_EXTABLE(irq_return_iret, bad_iret)
  --
  --#ifdef CONFIG_PARAVIRT
  --ENTRY(native_iret)
 +++    jnz native_irq_return_ldt
 +  #endif
 +  
 +++native_irq_return_iret:
        iretq
 ---    _ASM_EXTABLE(native_iret, bad_iret)
  --#endif
 +++    _ASM_EXTABLE(native_irq_return_iret, bad_iret)
 +  
 +  #ifdef CONFIG_X86_ESPFIX64
  --irq_return_ldt:
 +++native_irq_return_ldt:
 +      pushq_cfi %rax
 +      pushq_cfi %rdi
 +      SWAPGS
 +      movq PER_CPU_VAR(espfix_waddr),%rdi
 +      movq %rax,(0*8)(%rdi)   /* RAX */
 +      movq (2*8)(%rsp),%rax   /* RIP */
 +      movq %rax,(1*8)(%rdi)
 +      movq (3*8)(%rsp),%rax   /* CS */
 +      movq %rax,(2*8)(%rdi)
 +      movq (4*8)(%rsp),%rax   /* RFLAGS */
 +      movq %rax,(3*8)(%rdi)
 +      movq (6*8)(%rsp),%rax   /* SS */
 +      movq %rax,(5*8)(%rdi)
 +      movq (5*8)(%rsp),%rax   /* RSP */
 +      movq %rax,(4*8)(%rdi)
 +      andl $0xffff0000,%eax
 +      popq_cfi %rdi
 +      orq PER_CPU_VAR(espfix_stack),%rax
 +      SWAPGS
 +      movq %rax,%rsp
 +      popq_cfi %rax
  --    jmp irq_return_iret
 +++    jmp native_irq_return_iret
    #endif
    
        .section .fixup,"ax"
@@@@@ -933,39 -1110,13 -936,44 -935,44 +932,39 @@@@@ ENTRY(retint_kernel
        call preempt_schedule_irq
        jmp exit_intr
    #endif
 -  
        CFI_ENDPROC
    END(common_interrupt)
 -  /*
 -   * End of kprobes section
 -   */
 -         .popsection
 +  
 +      /*
 +       * If IRET takes a fault on the espfix stack, then we
 +       * end up promoting it to a doublefault.  In that case,
 +       * modify the stack to make it look like we just entered
 +       * the #GP handler from user space, similar to bad_iret.
 +       */
 +  #ifdef CONFIG_X86_ESPFIX64
 +      ALIGN
 +  __do_double_fault:
 +      XCPT_FRAME 1 RDI+8
 +      movq RSP(%rdi),%rax             /* Trap on the espfix stack? */
 +      sarq $PGDIR_SHIFT,%rax
 +      cmpl $ESPFIX_PGD_ENTRY,%eax
 +      jne do_double_fault             /* No, just deliver the fault */
 +      cmpl $__KERNEL_CS,CS(%rdi)
 +      jne do_double_fault
 +      movq RIP(%rdi),%rax
  --    cmpq $irq_return_iret,%rax
  --#ifdef CONFIG_PARAVIRT
  --    je 1f
  --    cmpq $native_iret,%rax
  --#endif
 +++    cmpq $native_irq_return_iret,%rax
 +      jne do_double_fault             /* This shouldn't happen... */
  --1:
 +      movq PER_CPU_VAR(kernel_stack),%rax
 +      subq $(6*8-KERNEL_STACK_OFFSET),%rax    /* Reset to original stack */
 +      movq %rax,RSP(%rdi)
 +      movq $0,(%rax)                  /* Missing (lost) #GP error code */
 +      movq $general_protection,RIP(%rdi)
 +      retq
 +      CFI_ENDPROC
 +  END(__do_double_fault)
 +  #else
 +  # define __do_double_fault do_double_fault
 +  #endif
    
    /*
     * APIC interrupts.
@@@@@ -1419,8 -1600,8 -1427,8 -1426,9 +1418,9 @@@@@ error_sti
     * compat mode. Check for these here too.
     */
    error_kernelspace:
+++     CFI_REL_OFFSET rcx, RCX+8
        incl %ebx
 -      leaq irq_return(%rip),%rcx
  --    leaq irq_return_iret(%rip),%rcx
 +++    leaq native_irq_return_iret(%rip),%rcx
        cmpq %rcx,RIP+8(%rsp)
        je error_swapgs
        movl %ecx,%eax  /* zero extend */

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