[U-Boot] [RFC/PATCH] Add support for Linux-like kallsysms

[Mike Frysinger]

The kernel stores address<->symbol names in it so things can be decoded at
runtime.  Do it in U-Boot, and we get nice symbol decoding when crashing.

Signed-off-by: Mike Frysinger <vapier at gentoo.org>
---
 Makefile                          |   17 +++++++++++---
 common/Makefile                   |    1 +
 common/kallsyms.c                 |   44 +++++++++++++++++++++++++++++++++++++
 common/system_map.c               |    8 ++++++
 include/common.h                  |    3 ++
 create mode 100644 common/kallsyms.c
 create mode 100644 common/system_map.c

diff --git a/Makefile b/Makefile
index 3cd18aa..ea6c8a5 100644
--- a/Makefile
+++ b/Makefile
@@ -340,12 +340,19 @@ $(obj)u-boot.sha1:	$(obj)u-boot.bin
 $(obj)u-boot.dis:	$(obj)u-boot
 		$(OBJDUMP) -d $< > $@
 
-$(obj)u-boot:		depend $(SUBDIRS) $(OBJS) $(LIBBOARD) $(LIBS) $(LDSCRIPT)
+GEN_UBOOT = \
 		UNDEF_SYM=`$(OBJDUMP) -x $(LIBBOARD) $(LIBS) | \
 		sed  -n -e 's/.*\($(SYM_PREFIX)__u_boot_cmd_.*\)/-u\1/p'|sort|uniq`;\
 		cd $(LNDIR) && $(LD) $(LDFLAGS) $$UNDEF_SYM $(__OBJS) \
 			--start-group $(__LIBS) --end-group $(PLATFORM_LIBS) \
 			-Map u-boot.map -o u-boot
+$(obj)u-boot:		depend $(SUBDIRS) $(OBJS) $(LIBBOARD) $(LIBS) $(LDSCRIPT)
+		$(GEN_UBOOT)
+ifeq ($(CONFIG_KALLSYMS),y)
+		smap=`$(call SYSTEM_MAP,u-boot) | awk '$$2 ~ /[tTwW]/ {printf $$1 $$3 "\\0"}'` ; \
+		$(CC) $(CFLAGS) -DSYSTEM_MAP="\"$${smap}\"" -c common/system_map.c -o $(obj)common/system_map.o
+		$(GEN_UBOOT) $(obj)common/system_map.o
+endif
 
 $(OBJS):	depend $(obj)include/autoconf.mk
 		$(MAKE) -C cpu/$(CPU) $(if $(REMOTE_BUILD),$@,$(notdir $@))
@@ -444,10 +451,12 @@ cscope:
 						> cscope.files
 		cscope -b -q -k
 
-$(obj)System.map:	$(obj)u-boot
-		@$(NM) $< | \
+SYSTEM_MAP = \
+		$(NM) $1 | \
 		grep -v '\(compiled\)\|\(\.o$$\)\|\( [aUw] \)\|\(\.\.ng$$\)\|\(LASH[RL]DI\)' | \
-		sort > $(obj)System.map
+		LC_ALL=C sort
+$(obj)System.map:	$(obj)u-boot
+		@$(call SYSTEM_MAP,$<) > $(obj)System.map
 
 #
 # Auto-generate the autoconf.mk file (which is included by all makefiles)
diff --git a/common/Makefile b/common/Makefile
index 23171ca..762adbd 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -147,6 +147,7 @@ COBJS-$(CONFIG_CMD_DOC) += docecc.o
 COBJS-$(CONFIG_CONSOLE_MUX) += iomux.o
 COBJS-y += flash.o
 COBJS-$(CONFIG_CMD_KGDB) += kgdb.o
+COBJS-$(CONFIG_KALLSYMS) += kallsyms.o
 COBJS-$(CONFIG_LCD) += lcd.o
 COBJS-$(CONFIG_LYNXKDI) += lynxkdi.o
 COBJS-$(CONFIG_UPDATE_TFTP) += update.o
diff --git a/common/kallsyms.c b/common/kallsyms.c
new file mode 100644
index 0000000..ce42a93
--- /dev/null
+++ b/common/kallsyms.c
@@ -0,0 +1,44 @@
+/*
+ * Helper functions for working with the builtin symbol table
+ *
+ * Copyright (c) 2008-2009 Analog Devices Inc.
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <common.h>
+
+/* We need the weak marking as this symbol is provided specially */
+extern const char system_map[] __attribute__((weak));
+
+/* Given an address, return a pointer to the symbol name and store
+ * the base address in caddr.  So if the symbol map had an entry:
+ *		03fb9b7c_spi_cs_deactivate
+ * Then the following call:
+ *		unsigned long base;
+ *		const char *sym = symbol_lookup(0x03fb9b80, &base);
+ * Would end up setting the variables like so:
+ *		base = 0x03fb9b7c;
+ *		sym = "_spi_cs_deactivate";
+ */
+const char *symbol_lookup(unsigned long addr, unsigned long *caddr)
+{
+	const char *sym, *csym;
+	char *esym;
+	unsigned long sym_addr;
+
+	sym = system_map;
+	csym = NULL;
+	*caddr = 0;
+
+	while (*sym) {
+		sym_addr = simple_strtoul(sym, &esym, 16);
+		sym = esym;
+		if (sym_addr > addr)
+			break;
+		*caddr = sym_addr;
+		csym = sym;
+		sym += strlen(sym) + 1;
+	}
+
+	return csym;
+}
diff --git a/common/system_map.c b/common/system_map.c
new file mode 100644
index 0000000..8307293
--- /dev/null
+++ b/common/system_map.c
@@ -0,0 +1,8 @@
+/*
+ * The builtin symbol table for use with kallsyms
+ *
+ * Copyright (c) 2008-2009 Analog Devices Inc.
+ * Licensed under the GPL-2 or later.
+ */
+
+const char const system_map[] = SYSTEM_MAP;
diff --git a/include/common.h b/include/common.h
index 952ddff..be9afe2 100644
--- a/include/common.h
+++ b/include/common.h
@@ -300,6 +300,9 @@ int	misc_init_r   (void);
 /* common/exports.c */
 void	jumptable_init(void);
 
+/* common/kallsysm.c */
+const char *symbol_lookup(unsigned long addr, unsigned long *caddr);
+
 /* api/api.c */
 void	api_init (void);
 
-- 
1.6.3