bsps/powerpc: Fix small data area section

Fix small data area in case no fixed size is desired.  Rename
bsp_section_set_sdata_sbss_size into bsp_section_small_data_area_size
since this symbol reflects the overall small data area size (including
space for libdl).  Do not use bsp_section_sbss_size before definition in
linker command file.  Add new symbols to <bsp/linker-symbols.h>.

Update #3687.

bsps/powerpc/include/bsp/linker-symbols.h

@@ -77,10 +77,18 @@ LINKER_SYMBOL(bsp_section_bss_begin)
 LINKER_SYMBOL(bsp_section_bss_end)
 LINKER_SYMBOL(bsp_section_bss_size)
 
+LINKER_SYMBOL(bsp_section_sdata_begin)
+LINKER_SYMBOL(bsp_section_sdata_end)
+LINKER_SYMBOL(bsp_section_sdata_size)
+
 LINKER_SYMBOL(bsp_section_sbss_begin)
 LINKER_SYMBOL(bsp_section_sbss_end)
 LINKER_SYMBOL(bsp_section_sbss_size)
 
+LINKER_SYMBOL(bsp_section_sdata_libdl_begin)
+LINKER_SYMBOL(bsp_section_sdata_libdl_end)
+LINKER_SYMBOL(bsp_section_sdata_libdl_size)
+
 LINKER_SYMBOL(bsp_section_rtemsstack_begin)
 LINKER_SYMBOL(bsp_section_rtemsstack_end)
 LINKER_SYMBOL(bsp_section_rtemsstack_size)

bsps/powerpc/psim/start/linkcmds

@@ -37,9 +37,7 @@ PROVIDE (PSIM_INSTRUCTIONS_PER_MICROSECOND = 10000);
 
 PSIM = 0x0c000000;
 
-/*
+/* Allocate the maximum size to the small data area */
- * Allocate the maximum size to the small data sdata/sbss section.
+bsp_section_small_data_area_size = 65536;
- */
-bsp_section_set_sdata_sbss_size = 65536;
 
 INCLUDE linkcmds.base

bsps/powerpc/qoriq/start/linkcmds.qoriq_e500

@@ -35,9 +35,7 @@ bsp_section_robarrier_align = 0x1000000;
 bsp_section_rwbarrier_align = 0x1000000;
 qoriq = 0xffe00000;
 
-/*
+/* Allocate the maximum size to the small data area */
- * Allocate the maximum size to the small data sdata/sbss section.
+bsp_section_small_data_area_size = 65536;
- */
-bsp_section_set_sdata_sbss_size = 65536;
 
 INCLUDE linkcmds.base

bsps/powerpc/qoriq/start/linkcmds.qoriq_e6500_32

@@ -38,9 +38,7 @@ qoriq = 0xffe000000;
 qoriq_bman_portal = 0xff4000000;
 qoriq_qman_portal = 0xff6000000;
 
-/*
+/* Allocate the maximum size to the small data area */
- * Allocate the maximum size to the small data sdata/sbss section.
+bsp_section_small_data_area_size = 65536;
- */
-bsp_section_set_sdata_sbss_size = 65536;
 
 INCLUDE linkcmds.base

bsps/powerpc/shared/start/linkcmds.base

@@ -23,6 +23,15 @@
 ENTRY (_start)
 STARTUP (start.o)
 
+/*
+ * The upper layer linker command file may optionally define the symbol
+ * bsp_section_small_data_area_size.  By default, the small data area is
+ * defined by the .sdata and .sbss input sections.  Define
+ * bsp_section_small_data_area_size, if you want to make space available for
+ * dynamically loaded libraries (libdl).  Small memory targets which do not use
+ * libdl, should not define this symbol.
+ */
+
 /*
  * Global symbols that may be defined externally
  */
@@ -304,13 +313,6 @@ SECTIONS {
 	bsp_section_data_load_begin = LOADADDR (.data);
 	bsp_section_data_load_end = bsp_section_data_load_begin + bsp_section_data_size;
 
-	/*
-	 * Set bsp_section_set_sdata_bss_size to the system's sdata and bss data size, eg:
-	 *
-	 *  bsp_section_set_sdata_sbss_size = 65536;
-	 */
-	bsp_section_sdata_sbss_size = DEFINED(bsp_section_set_sdata_sbss_size) ?
-							bsp_section_set_sdata_sbss_size : 0;
 	.sbss : ALIGN_WITH_INPUT {
 		bsp_section_sbss_begin = .;
 		*(.dynsbss)
@@ -318,10 +320,12 @@ SECTIONS {
 		*(.scommon)
 		bsp_section_sbss_end = .;
 		bsp_section_sdata_libdl_begin = .;
-		. += bsp_section_sdata_sbss_size - (bsp_section_sdata_size + bsp_section_sbss_size);
+		. = DEFINED(bsp_section_small_data_area_size) ?
+			bsp_section_sdata_begin + bsp_section_small_data_area_size : .;
 		bsp_section_sdata_libdl_end = .;
 	} > REGION_DATA AT > REGION_DATA
 	bsp_section_sbss_size = bsp_section_sbss_end - bsp_section_sbss_begin;
+	bsp_section_sdata_libdl_size = bsp_section_sdata_libdl_end - bsp_section_sdata_libdl_begin;
 
 	.bss : ALIGN_WITH_INPUT {
 		bsp_section_bss_begin = .;