ARM: fix CONFIG_SPL_MAX_SIZE semantics

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@aribaud.net>
Reported-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>

README

@@ -2831,8 +2831,18 @@ FIT uImage format:
 		CONFIG_SPL_LDSCRIPT
 		LDSCRIPT for linking the SPL binary.
 
+		CONFIG_SPL_MAX_FOOTPRINT
+		Maximum size in memory allocated to the SPL, BSS included.
+		When defined, the linker checks that the actual memory
+		used by SPL from _start to __bss_end does not exceed it.
+		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_MAX_BSS_SIZE
+		must not be both defined at the same time.
+
 		CONFIG_SPL_MAX_SIZE
-		Maximum binary size (text, data and rodata) of the SPL binary.
+		Maximum size of the SPL image (text, data, rodata, and
+		linker lists sections), BSS excluded.
+		When defined, the linker checks that the actual size does
+		not exceed it.
 
 		CONFIG_SPL_TEXT_BASE
 		TEXT_BASE for linking the SPL binary.
@@ -2845,7 +2855,11 @@ 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 in memory allocated to the SPL BSS.
+		When defined, the linker checks that the actual memory used
+		by SPL from __bss_start to __bss_end does not exceed it.
+		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_MAX_BSS_SIZE
+		must not be both defined at the same time.
 
 		CONFIG_SPL_STACK
 		Adress of the start of the stack SPL will use

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

arch/arm/cpu/u-boot.lds

@@ -107,7 +107,3 @@ 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

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