ARM: Fix __bss_start and __bss_end in linker scripts

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-
generated __bss_end symbols.

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

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Reported-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>

arch/arm/cpu/ixp/u-boot.lds

@@ -69,17 +69,23 @@ 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));
+		__bss_base = .;
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 __bss_limit = .;
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }

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));
+		__bss_base = .;
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 __bss_limit = .;
 	}
 
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }

board/actux1/u-boot.lds

@@ -77,17 +77,23 @@ 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));
+		__bss_base = .;
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 __bss_limit = .;
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }

board/actux2/u-boot.lds

@@ -77,17 +77,23 @@ 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));
+		__bss_base = .;
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 __bss_limit = .;
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }

board/actux3/u-boot.lds

@@ -77,17 +77,23 @@ 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));
+		__bss_base = .;
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		__bss_limit = .;
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }

board/dvlhost/u-boot.lds

@@ -77,17 +77,23 @@ 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));
+		__bss_base = .;
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 __bss_limit = .;
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.dynstr*) }

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));
+		__bss_base = .;
 	}
 
-	.bss __bss_start (OVERLAY) : {
+	.bss __bss_base (OVERLAY) : {
 		*(.bss*)
 		 . = ALIGN(4);
-		 __bss_end = .;
+		 __bss_limit = .;
 	}
-	.bss_end __bss_end (OVERLAY) : {
-		KEEP(*(__bss_end));
+	.bss_end __bss_limit (OVERLAY) : {
+		KEEP(*(.__bss_end));
 	}
 
 	/DISCARD/ : { *(.bss*) }