arm64: relocate-rela: Add support for ld.lld

Cap end of relocations by the binary size.

Linkers like to insert some auxiliary sections between .rela.dyn and
.bss_start. These sections don't make their way to the final binary, but
reloc_rela still tries to relocate them, resulting in attempted read
past the end of file.

When linking U-Boot with ld.lld, the STATIC_RELA feature (enabled by
default on arm64) breaks the build. After this patch, U-Boot can be
linked successfully with and without CONFIG_STATIC_RELA.

Originally-from: Elena Petrova <lenaptr@google.com>
Signed-off-by: Alistair Delva <adelva@google.com>
Cc: David Brazdil <dbrazdil@google.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Tom Rini <trini@konsulko.com>

diff --git a/tools/relocate-rela.c b/tools/relocate-rela.c
index 6a52401..f0bc548 100644 (file)
--- a/tools/relocate-rela.c
+++ b/tools/relocate-rela.c
@@ -63,7 +63,7 @@ int main(int argc, char **argv)
 {
        FILE *f;
        int i, num;
-       uint64_t rela_start, rela_end, text_base;
+       uint64_t rela_start, rela_end, text_base, file_size;
 
        if (argc != 5) {
                fprintf(stderr, "Statically apply ELF rela relocations\n");
@@ -87,8 +87,7 @@ int main(int argc, char **argv)
                return 3;
        }
 
-       if (rela_start > rela_end || rela_start < text_base ||
-           (rela_end - rela_start) % sizeof(Elf64_Rela)) {
+       if (rela_start > rela_end || rela_start < text_base) {
                fprintf(stderr, "%s: bad rela bounds\n", argv[0]);
                return 3;
        }
@@ -96,6 +95,21 @@ int main(int argc, char **argv)
        rela_start -= text_base;
        rela_end -= text_base;
 
+       fseek(f, 0, SEEK_END);
+       file_size = ftell(f);
+       rewind(f);
+
+       if (rela_end > file_size) {
+               // Most likely compiler inserted some section that didn't get
+               // objcopy-ed into the final binary
+               rela_end = file_size;
+       }
+
+       if ((rela_end - rela_start) % sizeof(Elf64_Rela)) {
+               fprintf(stderr, "%s: rela size isn't a multiple of Elf64_Rela\n", argv[0]);
+               return 3;
+       }
+
        num = (rela_end - rela_start) / sizeof(Elf64_Rela);
 
        for (i = 0; i < num; i++) {