[PATCH v6 4/4] stackvalidate: Add ignore macros

[Josh Poimboeuf]

Add new stackvalidate ignore macros: STACKVALIDATE_IGNORE_INSN and
STACKVALIDATE_IGNORE_FUNC.  These can be used to tell stackvalidate to
skip validation of an instruction or a function, respectively.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 include/linux/stackvalidate.h | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 include/linux/stackvalidate.h

diff --git a/include/linux/stackvalidate.h b/include/linux/stackvalidate.h
new file mode 100644
index 0000000..30d4a60
--- /dev/null
+++ b/include/linux/stackvalidate.h
@@ -0,0 +1,38 @@
+#ifndef _LINUX_STACKVALIDATE_H
+#define _LINUX_STACKVALIDATE_H
+
+#ifndef __ASSEMBLY__
+
+/*
+ * This C macro tells the stack validation script to ignore the function.  It
+ * should only be used in special cases where you're 100% sure it won't affect
+ * the reliability of frame pointers and kernel stack traces.
+ *
+ * For more information, see Documentation/stack-validation.txt.
+ */
+#define STACKVALIDATE_IGNORE_FUNC(_func) \
+	void __attribute__((section("__stackvalidate_ignore_func,\"ae\"#"))) \
+		*__stackvalidate_ignore_func_##_func = _func
+
+#else /* __ASSEMBLY__ */
+
+/*
+ * This asm macro tells the stack validation script to ignore the instruction
+ * immediately after the macro.  It should only be used in special cases where
+ * you're 100% sure it won't affect the reliability of frame pointers and
+ * kernel stack traces.
+ *
+ * For more information, see Documentation/stack-validation.txt.
+ */
+.macro STACKVALIDATE_IGNORE_INSN
+	.if CONFIG_STACK_VALIDATION
+		163:
+		.pushsection __stackvalidate_ignore_insn, "ae"
+		_ASM_ALIGN
+		.long 163b - .
+		.popsection
+	.endif
+.endm
+
+#endif /* __ASSEMBLY__ */
+#endif /* _LINUX_STACKVALIDATE_H */
-- 
2.1.0

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