[PATCH v2 14/29] vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA

Kees Cook
2019-10-11T00:05:54Z

Many architectures have an EXCEPTION_TABLE that only needs to
be readable. As such, it should live in RO_DATA. Create a macro to
identify this case for the architectures that can move EXCEPTION_TABLE
into RO_DATA.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Deacon <will@kernel.org>
---
include/asm-generic/vmlinux.lds.h | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 356078e50a5c..9867d8e41eed 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -69,6 +69,17 @@
#define NOTES_HEADERS_RESTORE
#endif

+/*
+ * Some architectures have non-executable read-only exception tables.
+ * They can be added to the RO_DATA segment by specifying their desired
+ * alignment.
+ */
+#ifdef RO_EXCEPTION_TABLE_ALIGN
+#define RO_EXCEPTION_TABLE EXCEPTION_TABLE(RO_EXCEPTION_TABLE_ALIGN)
+#else
+#define RO_EXCEPTION_TABLE
+#endif
+
/* Align . to a 8 byte boundary equals to maximum function alignment. */
#define ALIGN_FUNCTION() . = ALIGN(8)

@@ -513,6 +524,7 @@
__stop___modver = .; \
} \
\
+ RO_EXCEPTION_TABLE \
NOTES \
\
. = ALIGN((align)); \
--
2.17.1