linker_script: move bss section to bl_common.ld.h
Move the bss section to the common header. This adds BAKERY_LOCK_NORMAL
and PMF_TIMESTAMP, which previously existed only in BL31. This is not
a big deal because unused data should not be compiled in the first
place. I believe this should be controlled by BL*_SOURCES in Makefiles,
not by linker scripts.
I investigated BL1, BL2, BL2U, BL31 for plat=fvp, and BL2-AT-EL3,
BL31, BL31 for plat=uniphier. I did not see any more unexpected
code addition.
The bss section has bigger alignment. I added BSS_ALIGN for this.
Currently, SORT_BY_ALIGNMENT() is missing in sp_min.ld.S, and with this
change, the BSS symbols in SP_MIN will be sorted by the alignment.
This is not a big deal (or, even better in terms of the image size).
Change-Id: I680ee61f84067a559bac0757f9d03e73119beb33
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/include/common/bl_common.ld.h b/include/common/bl_common.ld.h
index 5c5fe5b..3fc8e97 100644
--- a/include/common/bl_common.ld.h
+++ b/include/common/bl_common.ld.h
@@ -11,8 +11,10 @@
#ifdef __aarch64__
#define STRUCT_ALIGN 8
+#define BSS_ALIGN 16
#else
#define STRUCT_ALIGN 4
+#define BSS_ALIGN 8
#endif
#define CPU_OPS \
@@ -127,6 +129,22 @@
. = . + (__PERCPU_TIMESTAMP_SIZE__ * (PLATFORM_CORE_COUNT - 1)); \
__PMF_TIMESTAMP_END__ = .;
+
+/*
+ * The .bss section gets initialised to 0 at runtime.
+ * Its base address has bigger alignment for better performance of the
+ * zero-initialization code.
+ */
+#define BSS_SECTION \
+ .bss (NOLOAD) : ALIGN(BSS_ALIGN) { \
+ __BSS_START__ = .; \
+ *(SORT_BY_ALIGNMENT(.bss*)) \
+ *(COMMON) \
+ BAKERY_LOCK_NORMAL \
+ PMF_TIMESTAMP \
+ __BSS_END__ = .; \
+ }
+
/*
* The xlat_table section is for full, aligned page tables (4K).
* Removing them from .bss avoids forcing 4K alignment on