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From:   Kees Cook <keescook@chromium.org>
To:     Borislav Petkov <bp@alien8.de>
Cc:     Kees Cook <keescook@chromium.org>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Will Deacon <will@kernel.org>, linux-arch@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org,
        linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org,
        linux-c6x-dev@linux-c6x.org,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Michal Simek <monstr@monstr.eu>, linux-parisc@vger.kernel.org,
        linux-xtensa@linux-xtensa.org, x86@kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 14/29] vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
Date:   Thu, 10 Oct 2019 17:05:54 -0700
Message-Id: <20191011000609.29728-15-keescook@chromium.org>
In-Reply-To: <20191011000609.29728-1-keescook@chromium.org>
References: <20191011000609.29728-1-keescook@chromium.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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