From 6b58e74d04e651cb3adf6986a009e68abcb07901 Mon Sep 17 00:00:00 2001
From: Sascha Hauer <s.hauer@pengutronix.de>
Date: Mon, 1 Oct 2007 10:20:57 +0200
Subject: Resolve the symbols using an extra section and only resolve
 explicitly exported symbols. Using kallsyms for this purpose doesn't do it
 because kallsyms do not resolve variables. Also the symbol table gets quite
 big using kallsyms.

---
 common/module.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 61 insertions(+), 4 deletions(-)

(limited to 'common')

diff --git a/common/module.c b/common/module.c
index 65f0ad0da5..0985567850 100644
--- a/common/module.c
+++ b/common/module.c
@@ -16,6 +16,7 @@
  *   along with this program; if not, write to the Free Software
  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
+#define DEBUG
 
 #include <common.h>
 #include <errno.h>
@@ -27,15 +28,54 @@
 #include <fs.h>
 #include <kallsyms.h>
 
+static unsigned int find_sec(Elf_Ehdr *hdr,
+			     Elf_Shdr *sechdrs,
+			     const char *secstrings,
+			     const char *name, int nlen)
+{
+	unsigned int i;
+
+	for (i = 1; i < hdr->e_shnum; i++)
+		/* Alloc bit cleared means "ignore it." */
+		if ((sechdrs[i].sh_flags & SHF_ALLOC)) {
+			if (nlen && !strncmp(secstrings+sechdrs[i].sh_name, name, nlen))
+				return i;
+			if (!nlen && !strcmp(secstrings+sechdrs[i].sh_name, name))
+				return i;
+		}
+	return 0;
+}
+
+/* Provided by the linker */
+extern const struct kernel_symbol __u_boot_symtab_start[];
+extern const struct kernel_symbol __u_boot_symtab_end[];
+
+/* lookup symbol in given range of kernel_symbols */
+static const struct kernel_symbol *lookup_symbol(const char *name,
+	const struct kernel_symbol *start,
+	const struct kernel_symbol *stop)
+{
+	const struct kernel_symbol *ks = start;
+	for (; ks < stop; ks++) {
+		printf("name: %s\n", ks->name);
+		if (strcmp(ks->name, name) == 0)
+			return ks;
+	}
+	return NULL;
+}
+
 static unsigned long resolve_symbol(Elf32_Shdr *sechdrs, 
 				    const char *name)
 {
-	unsigned long ret;
+	const struct kernel_symbol *ks;
 
 	debug("%s: %s\n", __FUNCTION__, name);
-	ret = kallsyms_lookup_name(name);
+	ks = lookup_symbol(name, __u_boot_symtab_start,
+		__u_boot_symtab_end);
 
-	return ret;
+	if (ks)
+		return ks->value;
+	return 0;
 }
 
 /* Change all symbols so that sh_value encodes the pointer directly. */
@@ -157,6 +197,7 @@ struct module * load_module(void *mod_image, unsigned long len)
 	char *secstrings;
 	void *ptr = NULL;
 	int err;
+	int cmdindex;
 
 	if (len < sizeof(*ehdr))
 		return NULL;
@@ -243,6 +284,22 @@ struct module * load_module(void *mod_image, unsigned long len)
 	numsyms = sechdrs[symindex].sh_size / sizeof(Elf32_Sym);
 	sym = (void *)sechdrs[symindex].sh_addr;
 
+	/*
+	 * FIXME: in .o files we have the command structs in the
+	 * .u_boot_cmd_<name> section to be able to let the linker
+	 * sort the commands alphabetically. When using the .o files
+	 * as modules this is bad because we have the commands in different
+	 * sections. So we probably need a linking stage for modules to 
+	 * put the different sections back into a single one.
+	 *
+	 * For now we only find the _first_ command in a module.
+	 */
+	cmdindex = find_sec(ehdr, sechdrs, secstrings,
+		MODULE_SYMBOL_PREFIX ".u_boot_cmd_", 12);
+	if (cmdindex) {
+		register_command((void *)sechdrs[cmdindex].sh_addr);
+	}
+
 	for (i = 0; i < numsyms; i++) {
 		if (!strcmp(strtab + sym[i].st_name, MODULE_SYMBOL_PREFIX "init_module")) {
 			printf("found init_module() at 0x%08x\n", sym[i].st_value);
@@ -274,7 +331,7 @@ static int do_insmod (cmd_tbl_t *cmdtp, int argc, char *argv[])
 
 	buf = read_file(argv[1], &len);
 	if (!buf) {
-		printf("error\n");
+		perror("insmod");
 		return 1;
 	}
 
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