x86/bugs, KVM: Support the combination of guest and host IBRS

[mirror_ubuntu-artful-kernel.git] / arch / x86 / include / asm / asm.h

diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 7a9df3beb89b1c6ba39365eb5059d39373bb6070..be70795a4c1ef94ed2da0f0261768250c6ed7bb6 100644 (file)
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -126,4 +126,15 @@
 /* For C file, we already have NOKPROBE_SYMBOL macro */
 #endif
 
+#ifndef __ASSEMBLY__
+/*
+ * This output constraint should be used for any inline asm which has a "call"
+ * instruction.  Otherwise the asm may be inserted before the frame pointer
+ * gets set up by the containing function.  If you forget to do this, objtool
+ * may print a "call without frame pointer save/setup" warning.
+ */
+register unsigned int __asm_call_sp asm("esp");
+#define ASM_CALL_CONSTRAINT "+r" (__asm_call_sp)
+#endif
+
 #endif /* _ASM_X86_ASM_H */