Merge tag 'x86_bugs_pbrsb' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

[linux-2.6-microblaze.git] / arch / x86 / include / asm / nospec-branch.h

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index cba9420..e64fd20 100644 (file)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -60,7 +60,9 @@
 774:                                           \
        add     $(BITS_PER_LONG/8) * 2, sp;     \
        dec     reg;                            \
-       jnz     771b;
+       jnz     771b;                           \
+       /* barrier for jnz misprediction */     \
+       lfence;
 
 #ifdef __ASSEMBLY__
 
@@ -130,13 +132,28 @@
 #endif
 .endm
 
+.macro ISSUE_UNBALANCED_RET_GUARD
+       ANNOTATE_INTRA_FUNCTION_CALL
+       call .Lunbalanced_ret_guard_\@
+       int3
+.Lunbalanced_ret_guard_\@:
+       add $(BITS_PER_LONG/8), %_ASM_SP
+       lfence
+.endm
+
  /*
   * A simpler FILL_RETURN_BUFFER macro. Don't make people use the CPP
   * monstrosity above, manually.
   */
-.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
+.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req ftr2
+.ifb \ftr2
        ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr
+.else
+       ALTERNATIVE_2 "jmp .Lskip_rsb_\@", "", \ftr, "jmp .Lunbalanced_\@", \ftr2
+.endif
        __FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)
+.Lunbalanced_\@:
+       ISSUE_UNBALANCED_RET_GUARD
 .Lskip_rsb_\@:
 .endm