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-rw-r--r--arch/x86/include/asm/asm.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 676ee5807d86..c1eadbaf1115 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -132,4 +132,15 @@
/* 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 */