[U-Boot] [PATCH] Mips: When using CONFIG_OF_SEPARATE, mips-relocs mess up _end symbol

[Lars Povlsen]

When converting some MIPS-based platforms from CONFIG_OF_EMBED to
CONFIG_OF_SEPARATE and CONFIG_MULTI_DTB_FIT, I had trouble with getting
to the right offset of the DTB blob.

It turns out that the mips-relocs utility chops off unused space in the
".rel" section, but in doing so it bring the "_end" symbol out of sync
with the actual end of the generated binary. When the DT blob is tacked
on, the "_end" symbol will not point to the start of the blob as
desired, but somewhere into the blob - causing the DT parse to fail.

This fix skips the ".rel" section shrinking to keep "_end" pointing to
the right place. Another possible solution would be to update "_end",
but that is beyond my current skills I'm afraid.

Signed-off-by: Lars Povlsen <lars.povlsen at microsemi.com>
---
 tools/Makefile      | 1 +
 tools/mips-relocs.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/tools/Makefile b/tools/Makefile
index 0c3341e..aabb5b8 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -196,6 +196,7 @@ hostprogs-y += fdtgrep
 fdtgrep-objs += $(LIBFDT_OBJS) fdtgrep.o
 
 hostprogs-$(CONFIG_MIPS) += mips-relocs
+HOSTCFLAGS_mips-relocs.o := $(if $(CONFIG_OF_SEPARATE),-DCONFIG_OF_SEPARATE -Wno-unused-but-set-variable -Wno-unused-variable)
 
 # We build some files with extra pedantic flags to try to minimize things
 # that won't build on some weird host compiler -- though there are lots of
diff --git a/tools/mips-relocs.c b/tools/mips-relocs.c
index 442cc8f..9c5bf07 100644
--- a/tools/mips-relocs.c
+++ b/tools/mips-relocs.c
@@ -401,6 +401,8 @@ int main(int argc, char *argv[])
 		return -ENOMEM;
 	}
 
+        // Shrinking the .rel section mess up the _end symbol when CONFIG_OF_SEPARATE used
+#if !defined(CONFIG_OF_SEPARATE)
 	/* Update the .rel section's size */
 	set_shdr_field(i_rel_shdr, sh_size, rel_actual_size);
 
@@ -414,6 +416,7 @@ int main(int argc, char *argv[])
 		set_phdr_field(i, p_filesz, load_sz);
 		break;
 	}
+#endif
 
 	/* Make sure data is written back to the file */
 	err = msync(elf, st.st_size, MS_SYNC);
-- 
2.7.4