[RFC PATCH 2/6] arm: clean up v7 and v8 linker scripts for bss_start/end

[Ilias Apalodimas]

commit 3ebd1cbc49f0 ("arm: make __bss_start and __bss_end__ compiler-generated")
and
commit f84a7b8f54db ("ARM: Fix __bss_start and __bss_end in linker scripts")
were moving the bss_start/end on c generated variables that were
injected in their own sections. The reason was that we needed relative
relocations for position independent code.

However, the linker documentation pages states that symbols that are
defined within a section definition will create a relocatable
type with the value being a fixed offset from the base of a section.

So let's start cleaning this up starting with the bss_start and bss_end
variables. Convert them into symbols within the .bss section definition.

[0] https://ftp.gnu.org/old-gnu/Manuals/ld-2.9.1/html_mono/ld.html#SEC13

Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---
 arch/arm/cpu/armv8/u-boot-spl.lds         | 14 +++-----------
 arch/arm/cpu/armv8/u-boot.lds             | 15 +++------------
 arch/arm/cpu/u-boot.lds                   | 22 ++++------------------
 arch/arm/lib/sections.c                   |  2 --
 arch/arm/mach-rockchip/u-boot-tpl-v8.lds  | 14 +++-----------
 arch/arm/mach-zynq/u-boot.lds             | 21 +++------------------
 board/qualcomm/dragonboard820c/u-boot.lds | 15 +++------------
 7 files changed, 19 insertions(+), 84 deletions(-)

diff --git a/arch/arm/cpu/armv8/u-boot-spl.lds b/arch/arm/cpu/armv8/u-boot-spl.lds
index 7cb9d731246d..16fddb46e9cb 100644
--- a/arch/arm/cpu/armv8/u-boot-spl.lds
+++ b/arch/arm/cpu/armv8/u-boot-spl.lds
@@ -63,18 +63,10 @@ SECTIONS

 	_image_binary_end = .;

-	.bss_start (NOLOAD) : {
-		. = ALIGN(8);
-		KEEP(*(.__bss_start));
-	} >.sdram
-
-	.bss (NOLOAD) : {
+	.bss : {
+		__bss_start = .;
 		*(.bss*)
-		 . = ALIGN(8);
-	} >.sdram
-
-	.bss_end (NOLOAD) : {
-		KEEP(*(.__bss_end));
+		__bss_end = .;
 	} >.sdram

 	/DISCARD/ : { *(.rela*) }
diff --git a/arch/arm/cpu/armv8/u-boot.lds b/arch/arm/cpu/armv8/u-boot.lds
index fb6a30c922f7..c4ee10ebc3ff 100644
--- a/arch/arm/cpu/armv8/u-boot.lds
+++ b/arch/arm/cpu/armv8/u-boot.lds
@@ -149,19 +149,10 @@ SECTIONS

 	_end = .;

-	. = ALIGN(8);
-
-	.bss_start : {
-		KEEP(*(.__bss_start));
-	}
-
-	.bss : {
+	.bss ALIGN(8): {
+		__bss_start = .;
 		*(.bss*)
-		 . = ALIGN(8);
-	}
-
-	.bss_end : {
-		KEEP(*(.__bss_end));
+		__bss_end = .;
 	}

 	/DISCARD/ : { *(.dynsym) }
diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds
index 7724c9332c3b..90d329b1ebe0 100644
--- a/arch/arm/cpu/u-boot.lds
+++ b/arch/arm/cpu/u-boot.lds
@@ -206,27 +206,13 @@ 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_base (OVERLAY) : {
+	.bss ALIGN(4): {
+		__bss_start = .;
 		*(.bss*)
-		 . = ALIGN(4);
-		 __bss_limit = .;
-	}
-
-	.bss_end __bss_limit (OVERLAY) : {
-		KEEP(*(.__bss_end));
+		__bss_end = .;
 	}

-	.dynsym _image_binary_end : { *(.dynsym) }
+	.dynsym  : { *(.dynsym) }
 	.dynbss : { *(.dynbss) }
 	.dynstr : { *(.dynstr*) }
 	.dynamic : { *(.dynamic*) }
diff --git a/arch/arm/lib/sections.c b/arch/arm/lib/sections.c
index 857879711c6a..8e8bd5797e16 100644
--- a/arch/arm/lib/sections.c
+++ b/arch/arm/lib/sections.c
@@ -19,8 +19,6 @@
  * aliasing warnings.
  */

-char __bss_start[0] __section(".__bss_start");
-char __bss_end[0] __section(".__bss_end");
 char __image_copy_start[0] __section(".__image_copy_start");
 char __image_copy_end[0] __section(".__image_copy_end");
 char __rel_dyn_start[0] __section(".__rel_dyn_start");
diff --git a/arch/arm/mach-rockchip/u-boot-tpl-v8.lds b/arch/arm/mach-rockchip/u-boot-tpl-v8.lds
index 74618eba591b..b7887194026e 100644
--- a/arch/arm/mach-rockchip/u-boot-tpl-v8.lds
+++ b/arch/arm/mach-rockchip/u-boot-tpl-v8.lds
@@ -56,18 +56,10 @@ SECTIONS

 	_image_binary_end = .;

-	.bss_start (NOLOAD) : {
-		. = ALIGN(8);
-		KEEP(*(.__bss_start));
-	}
-
-	.bss (NOLOAD) : {
+	.bss ALIGN(8) : {
+		__bss_start = .;
 		*(.bss*)
-		 . = ALIGN(8);
-	}
-
-	.bss_end (NOLOAD) : {
-		KEEP(*(.__bss_end));
+		__bss_end = .;
 	}

 	/DISCARD/ : { *(.dynsym) }
diff --git a/arch/arm/mach-zynq/u-boot.lds b/arch/arm/mach-zynq/u-boot.lds
index 3b7c9d515f8b..8d3259821719 100644
--- a/arch/arm/mach-zynq/u-boot.lds
+++ b/arch/arm/mach-zynq/u-boot.lds
@@ -102,26 +102,11 @@ SECTIONS

 	_image_binary_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_base (OVERLAY) : {
+	.bss ALIGN(4): {
+		__bss_start = .;
 		*(.bss*)
-		 . = ALIGN(8);
-		 __bss_limit = .;
-	}
-
-	.bss_end __bss_limit (OVERLAY) : {
-		KEEP(*(.__bss_end));
+		__bss_end = .;
 	}
-
 	/*
 	 * Zynq needs to discard these sections because the user
 	 * is expected to pass this image on to tools for boot.bin
diff --git a/board/qualcomm/dragonboard820c/u-boot.lds b/board/qualcomm/dragonboard820c/u-boot.lds
index 5251b59fbe76..d3cc5278b610 100644
--- a/board/qualcomm/dragonboard820c/u-boot.lds
+++ b/board/qualcomm/dragonboard820c/u-boot.lds
@@ -87,19 +87,10 @@ SECTIONS

 	_end = .;

-	. = ALIGN(8);
-
-	.bss_start : {
-		KEEP(*(.__bss_start));
-	}
-
-	.bss : {
+	.bss ALIGN(8): {
+		__bss_start = .;
 		*(.bss*)
-		 . = ALIGN(8);
-	}
-
-	.bss_end : {
-		KEEP(*(.__bss_end));
+		__bss_end = .;
 	}

 	/DISCARD/ : { *(.dynsym) }
--
2.37.2