Add a new objtool ignore macro, STACK_FRAME_NON_STANDARD, which can be
used to tell objtool to skip validation of a function.
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
MAINTAINERS | 1 +
arch/x86/kernel/vmlinux.lds.S | 5 ++++-
include/linux/objtool.h | 22 ++++++++++++++++++++++
3 files changed, 27 insertions(+), 1 deletion(-)
create mode 100644 include/linux/objtool.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 7c7cebd..43a940e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7782,6 +7782,7 @@ OBJTOOL
M: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
S: Supported
F: tools/objtool/
+F: include/linux/objtool.h
OMAP SUPPORT
M: Tony Lindgren <tony@xxxxxxxxxxx>
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 92dc211..6038fe0 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -343,7 +343,10 @@ SECTIONS
/* Sections to be discarded */
DISCARDS
- /DISCARD/ : { *(.eh_frame) }
+ /DISCARD/ : {
+ *(.eh_frame)
+ *(__objtool_ignore_*)
+ }
}
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
new file mode 100644
index 0000000..cce9d67
--- /dev/null
+++ b/include/linux/objtool.h
@@ -0,0 +1,22 @@
+#ifndef _LINUX_OBJTOOL_H
+#define _LINUX_OBJTOOL_H
+
+#ifdef CONFIG_STACK_VALIDATION
+/*
+ * This C macro tells objtool to ignore the function when doing stack metadata
+ * validation. 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 tools/objtool/Documentation/stack-validation.txt.
+ */
+#define STACK_FRAME_NON_STANDARD(_func) \
+ static void __used __section(__objtool_ignore_func) \
+ *__objtool_ignore_func_##_func = _func
+
+#else /* !CONFIG_STACK_VALIDATION */
+
+#define STACK_FRAME_NON_STANDARD(_func)
+
+#endif /* CONFIG_STACK_VALIDATION */
+
+#endif /* _LINUX_OBJTOOL_H */
--
2.4.3
--
To unsubscribe from this list: send the line "unsubscribe live-patching" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
