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

Pull x86 fixes from Ingo Molnar:
"Misc fixes:

- a build race fix

- a Xen entry fix

- a TSC_DEADLINE quirk future-proofing fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Fix if_changed build flip/flop bug
x86/entry/64: Remove %ebx handling from error_entry/exit
x86/apic: Future-proof the TSC_DEADLINE quirk for SKX

arch/x86/boot/compressed/Makefile

···
 	done
 endef
 
+# We need to run two commands under "if_changed", so merge them into a
+# single invocation.
+quiet_cmd_check-and-link-vmlinux = LD      $@
+      cmd_check-and-link-vmlinux = $(cmd_check_data_rel); $(cmd_ld)
+
 $(obj)/vmlinux: $(vmlinux-objs-y) FORCE
-	$(call if_changed,check_data_rel)
-	$(call if_changed,ld)
+	$(call if_changed,check-and-link-vmlinux)
 
 OBJCOPYFLAGS_vmlinux.bin :=  -R .comment -S
 $(obj)/vmlinux.bin: vmlinux FORCE

arch/x86/entry/entry_64.S

···
 
 	call	\do_sym
 
-	jmp	error_exit			/* %ebx: no swapgs flag */
+	jmp	error_exit
 	.endif
 END(\sym)
 .endm
···
 
 /*
  * Save all registers in pt_regs, and switch GS if needed.
- * Return: EBX=0: came from user mode; EBX=1: otherwise
  */
 ENTRY(error_entry)
 	UNWIND_HINT_FUNC
···
 	 * for these here too.
 	 */
 .Lerror_kernelspace:
-	incl	%ebx
 	leaq	native_irq_return_iret(%rip), %rcx
 	cmpq	%rcx, RIP+8(%rsp)
 	je	.Lerror_bad_iret
···
 
 	/*
 	 * Pretend that the exception came from user mode: set up pt_regs
-	 * as if we faulted immediately after IRET and clear EBX so that
-	 * error_exit knows that we will be returning to user mode.
+	 * as if we faulted immediately after IRET.
 	 */
 	mov	%rsp, %rdi
 	call	fixup_bad_iret
 	mov	%rax, %rsp
-	decl	%ebx
 	jmp	.Lerror_entry_from_usermode_after_swapgs
 END(error_entry)
 
-
-/*
- * On entry, EBX is a "return to kernel mode" flag:
- *   1: already in kernel mode, don't need SWAPGS
- *   0: user gsbase is loaded, we need SWAPGS and standard preparation for return to usermode
- */
 ENTRY(error_exit)
 	UNWIND_HINT_REGS
 	DISABLE_INTERRUPTS(CLBR_ANY)
 	TRACE_IRQS_OFF
-	testl	%ebx, %ebx
-	jnz	retint_kernel
+	testb	$3, CS(%rsp)
+	jz	retint_kernel
 	jmp	retint_user
 END(error_exit)
 

arch/x86/kernel/apic/apic.c

···
 	case 0x04: return 0x02000014;
 	}
 
+	if (boot_cpu_data.x86_stepping > 4)
+		return 0;
+
 	return ~0U;
 }