microblaze: Add support for run time relocation

Microblaze is using NEEDS_MANUAL_RELOC from the beginnging. This is causing
issues with function pointer arrays which need to be updated manually after
relocation. Building code with -fPIC and linking with -pic will remove this
limitation and there is no longer need to run manual update.

By default still old option is enabled but by disabling NEEDS_MANUAL_RELOC
code will be compiled for full relocation.

The patch does couple of things which are connected to each other.
- Define STATIC_RELA dependency to call relocate-rela to fill sections.
- REMAKE_ELF was already enabled but u-boot file can't be used because
  sections are empty. relocate-rela will fill them and output file is
  u-boot.elf which should be used.
- Add support for full relocation (u-boot.elf)
- Add support for early relocation when u-boot.bin is loaded to different
  address then CONFIG_SYS_TEXT_BASE
- Add rela.dyn and dynsym sections

Disabling NEEDS_MANUAL_RELOC U-Boot size increased by 10% of it's original
size (550kB to 608kB).

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/a845670b34925859b2e321875f7588a29f6655f9.1655299267.git.michal.simek@amd.com

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/microblaze/config.mk b/arch/microblaze/config.mk
index 3e84a832fc..d35b4f6db7 100644
--- a/arch/microblaze/config.mk
+++ b/arch/microblaze/config.mk
@@ -17,6 +17,11 @@ ifeq ($(CONFIG_SPL_BUILD),)
 PLATFORM_CPPFLAGS += -fPIC
 endif
 
+ifeq ($(CONFIG_STATIC_RELA),y)
+PLATFORM_CPPFLAGS += -fPIC
+LDFLAGS_u-boot += -pic
+endif
+
 ifeq ($(CONFIG_SYS_LITTLE_ENDIAN),y)
 PLATFORM_ELFFLAGS += -B microblaze $(OBJCOPYFLAGS) -O elf32-microblazeel
 else