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

3 files changed, 13 insertions, 16 deletions

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index fa42f895fdde..169c2feda14a 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -106,9 +106,13 @@ define cmd_check_data_rel
         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
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 73a522d53b53..8ae7ffda8f98 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -981,7 +981,7 @@ ENTRY(\sym)
 
         call    \do_sym
 
-        jmp     error_exit                      /* %ebx: no swapgs flag */
+        jmp     error_exit
         .endif
 END(\sym)
 .endm
@@ -1222,7 +1222,6 @@ END(paranoid_exit)
 
 /*
  * 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
@@ -1269,7 +1268,6 @@ ENTRY(error_entry)
          * for these here too.
          */
 .Lerror_kernelspace:
-        incl    %ebx
         leaq    native_irq_return_iret(%rip), %rcx
         cmpq    %rcx, RIP+8(%rsp)
         je      .Lerror_bad_iret
@@ -1303,28 +1301,20 @@ ENTRY(error_entry)
 
         /*
          * 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)
 
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 2aabd4cb0e3f..adbda5847b14 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -573,6 +573,9 @@ static u32 skx_deadline_rev(void)
         case 0x04: return 0x02000014;
         }
 
+        if (boot_cpu_data.x86_stepping > 4)
+                return 0;
+
         return ~0U;
 }