Thread (30 messages) 30 messages, 1 author, 2019-10-29
STALE2398d REVIEWED: 11 (11M)

[PATCH v3 14/29] vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA

From: Kees Cook <hidden>
Date: 2019-10-29 21:18:12
Also in: linux-alpha, linux-arch, linux-s390, linuxppc-dev
Subsystem: generic include/asm header files, the rest · Maintainers: Arnd Bergmann, Linus Torvalds

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 <redacted>
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


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