linux-kernel - [PATCH 2/2] ARM: mm: hide __start_rodata_section

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Date:	Tue, 16 Feb 2016 17:03:27 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Russell King <linux@....linux.org.uk>
Cc:	linux-arm-kernel@...ts.infradead.org,
	Arnd Bergmann <arnd@...db.de>,
	Kees Cook <keescook@...omium.org>,
	Laura Abbott <labbott@...oraproject.org>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	Chris Brandt <chris.brandt@...esas.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] ARM: mm: hide __start_rodata_section_aligned for non-debug builds

The __start_rodata_section_aligned is only referenced by the
DEBUG_RODATA code, which is only used when the MMU is enabled,
but the definition fails on !MMU builds:

arch/arm/kernel/vmlinux.lds:702: undefined symbol `SECTION_SHIFT' referenced in expression

This hides the symbol whenever DEBUG_RODATA is disabled.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
Fixes: 64ac2e74f0b2 ("ARM: 8502/1: mm: mark section-aligned portion of rodata NX")
---
 arch/arm/kernel/vmlinux.lds.S | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 2d7085ae1c2f..bb12933aee22 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -322,12 +322,14 @@ SECTIONS
 	STABS_DEBUG
 }
 
+#ifdef CONFIG_DEBUG_RODATA
 /*
  * Without CONFIG_DEBUG_ALIGN_RODATA, __start_rodata_section_aligned will
  * be the first section-aligned location after __start_rodata. Otherwise,
  * it will be equal to __start_rodata.
  */
 __start_rodata_section_aligned = ALIGN(__start_rodata, 1 << SECTION_SHIFT);
+#endif
 
 /*
  * These must never be empty
-- 
2.7.0