cbfstool: prepare for exposing rmodule logic

The core logic of the rmodule parser is ideal for
processing romstage ELF files for XIP. To that
end start the work of exposing the logic from
rmodule so cbfstool can take advantage of it.

The properties that both need require:
- Single program segment
- Relocation information
- Filter relocation processing

BUG=chrome-os-partner:44827
BRANCH=None
TEST=Built rambi.

Change-Id: I176d0ae0ae1933cdf6adac67d393ba676198861a
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11595
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

1 files changed, 37 insertions, 32 deletions

diff --git a/util/cbfstool/rmodule.c b/util/cbfstool/rmodule.c
index 1f41d1718b..03828f77c9 100644
--- a/util/cbfstool/rmodule.c
+++ b/util/cbfstool/rmodule.c
@@ -50,14 +50,11 @@ struct rmod_context {
 	Elf64_Xword nrelocs;
 	Elf64_Addr *emitted_relocs;
 
-	/* The following fields are addresses within the linked program. */
-	Elf64_Addr link_addr;
-	Elf64_Addr entry;
+	/* The following fields are addresses within the linked program.  */
 	Elf64_Addr parameters_begin;
 	Elf64_Addr parameters_end;
 	Elf64_Addr bss_begin;
 	Elf64_Addr bss_end;
-	Elf64_Xword size;
 };
 
 /*
@@ -371,7 +368,7 @@ populate_sym(struct rmod_context *ctx, const char *sym_name, Elf64_Addr *addr,
 	return -1;
 }
 
-static int populate_program_info(struct rmod_context *ctx)
+static int populate_rmodule_info(struct rmod_context *ctx)
 {
 	int i;
 	const char *strtab;
@@ -423,15 +420,6 @@ static int populate_program_info(struct rmod_context *ctx)
 	if (populate_sym(ctx, "_ebss", &ctx->bss_end, nsyms, strtab, 0))
 		return -1;
 
-	/* Honor the entry point within the ELF header. */
-	ctx->entry = ehdr->e_entry;
-
-	/* Link address is the virtual address of the program segment. */
-	ctx->link_addr = ctx->phdr->p_vaddr;
-
-	/* The program size is the memsz of the program segment. */
-	ctx->size = ctx->phdr->p_memsz;
-
 	return 0;
 }
 
@@ -516,7 +504,6 @@ write_elf(const struct rmod_context *ctx, const struct buffer *in,
 
 	/* Create ELF writer with modified entry point. */
 	memcpy(&ehdr, &ctx->pelf.ehdr, sizeof(ehdr));
-	ehdr.e_entry = ctx->entry;
 	ew = elf_writer_init(&ehdr);
 
 	if (ew == NULL) {
@@ -544,11 +531,11 @@ write_elf(const struct rmod_context *ctx, const struct buffer *in,
 		loc += ctx->nrelocs * sizeof(Elf32_Addr);
 	ctx->xdr->put32(&rmod_header, loc);
 	/* module_link_start_address */
-	ctx->xdr->put32(&rmod_header, ctx->link_addr);
+	ctx->xdr->put32(&rmod_header, ctx->phdr->p_vaddr);
 	/* module_program_size */
-	ctx->xdr->put32(&rmod_header, ctx->size);
+	ctx->xdr->put32(&rmod_header, ctx->phdr->p_memsz);
 	/* module_entry_point */
-	ctx->xdr->put32(&rmod_header, ctx->entry);
+	ctx->xdr->put32(&rmod_header, ctx->pelf.ehdr.e_entry);
 	/* parameters_begin */
 	ctx->xdr->put32(&rmod_header, ctx->parameters_begin);
 	/* parameters_end */
@@ -631,16 +618,15 @@ out:
 	return ret;
 }
 
-int rmodule_create(const struct buffer *elfin, struct buffer *elfout)
+static int rmodule_init(struct rmod_context *ctx, const struct buffer *elfin)
 {
-	struct rmod_context ctx;
 	struct parsed_elf *pelf;
 	int i;
 	int ret;
 
 	ret = -1;
-	memset(&ctx, 0, sizeof(ctx));
-	pelf = &ctx.pelf;
+	memset(ctx, 0, sizeof(*ctx));
+	pelf = &ctx->pelf;
 
 	if (parse_elf(elfin, pelf, ELF_PARSE_ALL)) {
 		ERROR("Couldn't parse ELF!\n");
@@ -656,32 +642,52 @@ int rmodule_create(const struct buffer *elfin, struct buffer *elfout)
 	/* Determine if architecture is supported. */
 	for (i = 0; i < ARRAY_SIZE(reloc_ops); i++) {
 		if (reloc_ops[i].arch == pelf->ehdr.e_machine) {
-			ctx.ops = &reloc_ops[i];
+			ctx->ops = &reloc_ops[i];
 			break;
 		}
 	}
 
-	if (ctx.ops == NULL) {
+	if (ctx->ops == NULL) {
 		ERROR("ELF is unsupported arch: %u.\n", pelf->ehdr.e_machine);
 		goto out;
 	}
 
 	/* Set the endian ops. */
-	if (ctx.pelf.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
-		ctx.xdr = &xdr_be;
+	if (ctx->pelf.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
+		ctx->xdr = &xdr_be;
 	else
-		ctx.xdr = &xdr_le;
+		ctx->xdr = &xdr_le;
 
-	if (find_program_segment(&ctx))
+	if (find_program_segment(ctx))
 		goto out;
 
-	if (filter_relocation_sections(&ctx))
+	if (filter_relocation_sections(ctx))
+		goto out;
+
+	ret = 0;
+
+out:
+	return ret;
+}
+
+static void rmodule_cleanup(struct rmod_context *ctx)
+{
+	free(ctx->emitted_relocs);
+	parsed_elf_destroy(&ctx->pelf);
+}
+
+int rmodule_create(const struct buffer *elfin, struct buffer *elfout)
+{
+	struct rmod_context ctx;
+	int ret = -1;
+
+	if (rmodule_init(&ctx, elfin))
 		goto out;
 
 	if (collect_relocations(&ctx))
 		goto out;
 
-	if (populate_program_info(&ctx))
+	if (populate_rmodule_info(&ctx))
 		goto out;
 
 	if (write_elf(&ctx, elfin, elfout))
@@ -690,7 +696,6 @@ int rmodule_create(const struct buffer *elfin, struct buffer *elfout)
 	ret = 0;
 
 out:
-	free(ctx.emitted_relocs);
-	parsed_elf_destroy(pelf);
+	rmodule_cleanup(&ctx);
 	return ret;
 }