[U-Boot] [PATCH] ARM: Fix __bss_start and __bss_end in linker scripts

Albert ARIBAUD albert.u.boot at aribaud.net
Fri Apr 5 00:13:53 CEST 2013


Commit 3ebd1cbc introduced compiler-generated __bss_start
and __bss_end__ and commit c23561e7 rewrote all __bss_end__
as __bss_end. Their merge caused silent and harmless but
potentially bug-inducing clashes between compiler- and linker-
enerated __bss_end symbols.

Make __bss_end and __bss_start compiler-only, and create
__bss_base and __bss_limit for linker-only use.

Reported-by: Benoît Thébaudeau <benoit.thebaudeau at advansee.com>
Signed-off-by: Albert ARIBAUD <albert.u.boot at aribaud.net>
---
 arch/arm/cpu/ixp/u-boot.lds        |   14 ++++++++++----
 arch/arm/cpu/u-boot.lds            |   14 ++++++++++----
 board/actux1/u-boot.lds            |   14 ++++++++++----
 board/actux2/u-boot.lds            |   14 ++++++++++----
 board/actux3/u-boot.lds            |   14 ++++++++++----
 board/dvlhost/u-boot.lds           |   14 ++++++++++----
 board/freescale/mx31ads/u-boot.lds |   14 ++++++++++----
 7 files changed, 70 insertions(+), 28 deletions(-)

diff --git a/arch/arm/cpu/ixp/u-boot.lds b/arch/arm/cpu/ixp/u-boot.lds
index 8345b55..c999829 100644
--- a/arch/arm/cpu/ixp/u-boot.lds
+++ b/arch/arm/cpu/ixp/u-boot.lds
@@ -67,17 +67,23 @@ SECTIONS
 
 	_end = .;
 
+/*
+ * Compiler-generated __bss_start and __bss_end, see arch/arm/lib/bss.c
+ * __bss_base and __bss_limit are for linker only (overlay ordering)
+ */
+
 	.bss_start __rel_dyn_start (OVERLAY) : {
 		KEEP(*(.__bss_start));
+		HIDDEN(__bss_base = .);
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 HIDDEN(__bss_limit = .);
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }
diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds
index 3a1083d..0543b06 100644
--- a/arch/arm/cpu/u-boot.lds
+++ b/arch/arm/cpu/u-boot.lds
@@ -81,18 +81,24 @@ SECTIONS
 		*(.mmutable)
 	}
 
+/*
+ * Compiler-generated __bss_start and __bss_end, see arch/arm/lib/bss.c
+ * __bss_base and __bss_limit are for linker only (overlay ordering)
+ */
+
 	.bss_start __rel_dyn_start (OVERLAY) : {
 		KEEP(*(.__bss_start));
+		HIDDEN(__bss_base = .);
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 HIDDEN(__bss_limit = .);
 	}
 
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }
diff --git a/board/actux1/u-boot.lds b/board/actux1/u-boot.lds
index c76728a..7e5c4d8 100644
--- a/board/actux1/u-boot.lds
+++ b/board/actux1/u-boot.lds
@@ -74,17 +74,23 @@ SECTIONS
 
 	_end = .;
 
+/*
+ * Compiler-generated __bss_start and __bss_end, see arch/arm/lib/bss.c
+ * __bss_base and __bss_limit are for linker only (overlay ordering)
+ */
+
 	.bss_start __rel_dyn_start (OVERLAY) : {
 		KEEP(*(.__bss_start));
+		HIDDEN(__bss_base = .);
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 HIDDEN(__bss_limit = .);
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }
diff --git a/board/actux2/u-boot.lds b/board/actux2/u-boot.lds
index 984f70e..ce1b7c9 100644
--- a/board/actux2/u-boot.lds
+++ b/board/actux2/u-boot.lds
@@ -74,17 +74,23 @@ SECTIONS
 
 	_end = .;
 
+/*
+ * Compiler-generated __bss_start and __bss_end, see arch/arm/lib/bss.c
+ * __bss_base and __bss_limit are for linker only (overlay ordering)
+ */
+
 	.bss_start __rel_dyn_start (OVERLAY) : {
 		KEEP(*(.__bss_start));
+		HIDDEN(__bss_base = .);
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 HIDDEN(__bss_limit = .);
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }
diff --git a/board/actux3/u-boot.lds b/board/actux3/u-boot.lds
index fc48cf0..3e091dd 100644
--- a/board/actux3/u-boot.lds
+++ b/board/actux3/u-boot.lds
@@ -74,17 +74,23 @@ SECTIONS
 
 	_end = .;
 
+/*
+ * Compiler-generated __bss_start and __bss_end, see arch/arm/lib/bss.c
+ * __bss_base and __bss_limit are for linker only (overlay ordering)
+ */
+
 	.bss_start __rel_dyn_start (OVERLAY) : {
 		KEEP(*(.__bss_start));
+		HIDDEN(__bss_base = .);
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		HIDDEN(__bss_limit = .);
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }
diff --git a/board/dvlhost/u-boot.lds b/board/dvlhost/u-boot.lds
index b13d3e1..fe3c21b 100644
--- a/board/dvlhost/u-boot.lds
+++ b/board/dvlhost/u-boot.lds
@@ -74,17 +74,23 @@ SECTIONS
 
 	_end = .;
 
+/*
+ * Compiler-generated __bss_start and __bss_end, see arch/arm/lib/bss.c
+ * __bss_base and __bss_limit are for linker only (overlay ordering)
+ */
+
 	.bss_start __rel_dyn_start (OVERLAY) : {
 		KEEP(*(.__bss_start));
+		HIDDEN(__bss_base = .);
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 HIDDEN(__bss_limit = .);
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }
diff --git a/board/freescale/mx31ads/u-boot.lds b/board/freescale/mx31ads/u-boot.lds
index 264c4e8..e6885a5 100644
--- a/board/freescale/mx31ads/u-boot.lds
+++ b/board/freescale/mx31ads/u-boot.lds
@@ -80,17 +80,23 @@ SECTIONS
 
 	_end = .;
 
+/*
+ * Compiler-generated __bss_start and __bss_end, see arch/arm/lib/bss.c
+ * __bss_base and __bss_limit are for linker only (overlay ordering)
+ */
+
 	.bss_start __rel_dyn_start (OVERLAY) : {
 		KEEP(*(.__bss_start));
+		HIDDEN(__bss_base = .);
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 HIDDEN(__bss_limit = .);
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.bss*) }
-- 
1.7.10.4



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