[U-Boot] [PATCH v3 4/4] ARM: fix CONFIG_SPL_MAX_SIZE semantics

[Albert ARIBAUD]

Remove SPL-related ASSERT() in arch/arm/cpu/u-boot.lds
as this file is never used for SPL builds.

Rewrite the ASSERT() in arch/arm/cpu/u-boot-spl.lds
to separately test image (text,data,rodata...) size,
BSS size, and full footprint each against its own max,
and make Tegra boards check full footprint.

Also, output section mmutable is not used in SPL builds.
Remove it.

Finally, update README regarding the (now homogeneous)
semantics of CONFIG_SPL_[BSS_]MAX_SIZE and add the new
CONFIG_SPL_MAX_FOOTPRINT macro.

Signed-off-by: Albert ARIBAUD <albert.u.boot at aribaud.net>
Reported-by: Benoît Thébaudeau <benoit.thebaudeau at advansee.com>
---
Changes in v3:
- introduced CONFIG_SPL_MAX_FOOTPRINT
- fixed typo in BSS size test

Changes in v2:
- removed mmutable in SPL linker file

 README                         |   26 ++++++++++++++++++++++++--
 arch/arm/cpu/u-boot-spl.lds    |   24 +++++++++++++-----------
 arch/arm/cpu/u-boot.lds        |    4 ----
 include/configs/tegra-common.h |    2 +-
 4 files changed, 38 insertions(+), 18 deletions(-)

diff --git a/README b/README
index 6272853..c470489 100644
--- a/README
+++ b/README
@@ -2775,8 +2775,24 @@ FIT uImage format:
 		CONFIG_SPL_LDSCRIPT
 		LDSCRIPT for linking the SPL binary.
 
+		CONFIG_SPL_MAX_FOOTPRINT
+		Maximum size in memory allocated to the SPL.
+		When defined, linker checks that the actual memory used
+		by SPL size does not exceed it.
+		CONFIG_MAX_FOOTPRINT should always be equal to or greater
+		than CONFIG_SPL_MAX_SIZE, plus CONFIG_SPL_BSS_MAX_SIZE if
+		it exists.
+		Note: image and BSS are disjoint for some targets.
+
 		CONFIG_SPL_MAX_SIZE
-		Maximum binary size (text, data and rodata) of the SPL binary.
+		Maximum size for the image (sum of the text, data, rodata
+		and linker lists sections) of the SPL executable.
+		When defined, linker checks that the actual image size does
+		not exceed it.
+		CONFIG_MAX_FOOTPRINT should always be equal to or greater
+		than CONFIG_SPL_MAX_SIZE, plus CONFIG_SPL_BSS_MAX_SIZE if
+		it exists.
+		Note: image and BSS are disjoint for some targets.
 
 		CONFIG_SPL_TEXT_BASE
 		TEXT_BASE for linking the SPL binary.
@@ -2789,7 +2805,13 @@ FIT uImage format:
 		Link address for the BSS within the SPL binary.
 
 		CONFIG_SPL_BSS_MAX_SIZE
-		Maximum binary size of the BSS section of the SPL binary.
+		Maximum size for the BSS section of the SPL executable.
+		When defined, linker checks that the actual BSS size does
+		not exceed it.
+		CONFIG_MAX_FOOTPRINT should always be equal to or greater
+		than CONFIG_SPL_MAX_SIZE, plus CONFIG_SPL_BSS_MAX_SIZE if
+		it exists.
+		Note: image and BSS are disjoint for some targets.
 
 		CONFIG_SPL_STACK
 		Adress of the start of the stack SPL will use
diff --git a/arch/arm/cpu/u-boot-spl.lds b/arch/arm/cpu/u-boot-spl.lds
index 3c0d99c..1408f03 100644
--- a/arch/arm/cpu/u-boot-spl.lds
+++ b/arch/arm/cpu/u-boot-spl.lds
@@ -65,15 +65,6 @@ SECTIONS
 
 	_end = .;
 
-	/*
-	 * Deprecated: this MMU section is used by pxa at present but
-	 * should not be used by new boards/CPUs.
-	 */
-	. = ALIGN(4096);
-	.mmutable : {
-		*(.mmutable)
-	}
-
 	.bss __rel_dyn_start (OVERLAY) : {
 		__bss_start = .;
 		*(.bss*)
@@ -88,6 +79,17 @@ SECTIONS
 	/DISCARD/ : { *(.gnu*) }
 }
 
-#if defined(CONFIG_SPL_TEXT_BASE) && defined(CONFIG_SPL_MAX_SIZE)
-ASSERT(__bss_end < (CONFIG_SPL_TEXT_BASE + CONFIG_SPL_MAX_SIZE), "SPL image too big");
+#if defined(CONFIG_SPL_MAX_SIZE)
+ASSERT(__image_copy_end - __image_copy_start < (CONFIG_SPL_MAX_SIZE), \
+	"SPL image too big");
+#endif
+
+#if defined(CONFIG_SPL_BSS_MAX_SIZE)
+ASSERT(__bss_end - __bss_start < (CONFIG_SPL_BSS_MAX_SIZE), \
+	"SPL image BSS too big");
+#endif
+
+#if defined(CONFIG_SPL_MAX_FOOTPRINT)
+ASSERT(__bss_end - _start < (CONFIG_SPL_MAX_FOOTPRINT), \
+	"SPL image plus BSS too big");
 #endif
diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds
index 3a1083d..7bbc4f5 100644
--- a/arch/arm/cpu/u-boot.lds
+++ b/arch/arm/cpu/u-boot.lds
@@ -101,7 +101,3 @@ SECTIONS
 	/DISCARD/ : { *(.interp*) }
 	/DISCARD/ : { *(.gnu*) }
 }
-
-#if defined(CONFIG_SPL_TEXT_BASE) && defined(CONFIG_SPL_MAX_SIZE)
-ASSERT(__bss_end < (CONFIG_SPL_TEXT_BASE + CONFIG_SPL_MAX_SIZE), "SPL image too big");
-#endif
diff --git a/include/configs/tegra-common.h b/include/configs/tegra-common.h
index 036ded0..e9241b8 100644
--- a/include/configs/tegra-common.h
+++ b/include/configs/tegra-common.h
@@ -158,7 +158,7 @@
 #define CONFIG_SPL_RAM_DEVICE
 #define CONFIG_SPL_BOARD_INIT
 #define CONFIG_SPL_NAND_SIMPLE
-#define CONFIG_SPL_MAX_SIZE		(CONFIG_SYS_TEXT_BASE - \
+#define CONFIG_SPL_MAX_FOOTPRINT	(CONFIG_SYS_TEXT_BASE - \
 						CONFIG_SPL_TEXT_BASE)
 #define CONFIG_SYS_SPL_MALLOC_SIZE	0x00010000
 
-- 
1.7.10.4