Only BL1 specifies '.' in the address field of the stacks section.

Commit 4f59d8359f97 ("Make BL1 RO and RW base addresses configurable")
added '.' on purpose but the commit message does not help to understand
why.

This commit gets rid of it in order to factor out the stacks section
into include/common/bl_common.ld.h

I compared the build result for PLAT=qemu.

'aarch64-linux-gnu-nm -n build/qemu/release/bl1/bl1.elf' will change
as follows:

@@ -336,8 +336,8 @@
 000000000e04e0e0 d max_log_level
 000000000e04e0e4 D console_state
 000000000e04e0e5 D __DATA_RAM_END__
-000000000e04e0e5 B __STACKS_START__
 000000000e04e100 b platform_normal_stacks
+000000000e04e100 B __STACKS_START__
 000000000e04f100 b bl1_cpu_context
 000000000e04f100 B __BSS_START__
 000000000e04f100 B __STACKS_END__

After this change, __STACKS_START__ will match to platform_normal_stacks,
and I think it makes more sense.

'aarch64-linux-gnu-objdump -h build/qemu/release/bl1/bl1.elf' will change
as follows:

@@ -9,11 +9,11 @@
                   CONTENTS, ALLOC, LOAD, READONLY, DATA
   2 .data         000000e5  000000000e04e000  0000000000004a60  0001e000  2**4
                   CONTENTS, ALLOC, LOAD, DATA
-  3 stacks        0000101b  000000000e04e0e5  000000000e04e0e5  0001e0e5  2**6
+  3 stacks        00001000  000000000e04e100  0000000000004b45  0001e100  2**6
                   ALLOC
-  4 .bss          000007e0  000000000e04f100  000000000e04f100  0001e0e5  2**5
+  4 .bss          000007e0  000000000e04f100  0000000000004b50  0001f100  2**5
                   ALLOC
-  5 xlat_table    00006000  000000000e050000  000000000e050000  0001e0e5  2**12
+  5 xlat_table    00006000  000000000e050000  0000000000004b45  00020000  2**12
                   ALLOC
   6 coherent_ram  00000000  000000000e056000  000000000e056000  0001f000  2**12
                   CONTENTS

Sandrine pointed me to a useful document [1] to understand why LMAs of
stacks, .bss, and xlat_table section have changed.

Before this patch, they fell into this scenario:
 "If the section has a specific VMA address, then this is used as the
  LMA address as well."

With this commit, the following applies:
 "Otherwise if a memory region can be found that is compatible with the
  current section, and this region contains at least one section, then
  the LMA is set so the difference between the VMA and LMA is the same
  as the difference between the VMA and LMA of the last section in the
  located region."

Anyway, those three sections are not loaded, so the LMA changes will not
be a problem. The size of bl1.bin is still the same.

QEMU still boots successfully with this change.

A good thing is, this fixes the error for the latest LLD. If I use the
mainline LLVM, I see the following error. The alignment check will probably
be included in the LLVM 11 release, so it is better to fix it now.

$ PLAT=qemu CC=clang CROSS_COMPILE=aarch64-linux-gnu-
  [ snip ]
ld.lld: error: address (0xe04e0e5) of section stacks is not a multiple of alignment (64)
make: *** [Makefile:1050: build/qemu/release/bl1/bl1.elf] Error 1

[1]: https://sourceware.org/binutils/docs/ld/Output-Section-LMA.html#Output-Section-LMA

Change-Id: I3d2f3cc2858be8b3ce2eab3812a76d1e0b5f3a32
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>