[PATCH] symbols: Generate an xen-sym.map file similar to Linux's

[PATCH] symbols: Generate an xen-sym.map file similar to Linux's

[Konrad Rzeszutek Wilk]

You could construct _most_ of the names of the functions
by doing 'nm --defined' but unfortunatly you do not get the
<file> prefix that is added on. For example:

$ cat xen-syms.symbols |grep do_domain_pause
0xffff82d080104920 t domain.c#do_domain_pause
$ nm --defined xen-syms|grep do_domain_pause
ffff82d080104920 t do_domain_pause

This is normally not an issue, but if one is doing livepatching and
wants during build-time verify that the symbols the livepatch payloads
will patch do correspond to the one the hypervisor has built - this helps a lot.

Also note that during runtime one can do:
ffff82d080104920 t domain.c#do_domain_pause

But one may not want to build and verify a livepatch on the same host.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
Cc:Ross Lagerwall <ross.lagerwall@citrix.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Wei Liu <wei.liu2@citrix.com>
---
 .gitignore            |  1 +
 xen/Makefile          |  4 +++-
 xen/arch/arm/Makefile |  3 +++
 xen/arch/x86/Makefile |  4 ++++
 xen/tools/symbols.c   | 11 ++++++++++-
 5 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/.gitignore b/.gitignore
index e019f2e..46c898f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -284,6 +284,7 @@ tools/flask/policy/policy.conf
 tools/flask/policy/xenpolicy-*
 xen/xen
 xen/xen-syms
+xen/xen-syms.map
 xen/xen.*
 unmodified_drivers/linux-2.6/.tmp_versions
 unmodified_drivers/linux-2.6/*.cmd
diff --git a/xen/Makefile b/xen/Makefile
index ee8ce8e..3198d28 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -62,6 +62,7 @@ _install: $(TARGET)$(CONFIG_XEN_INSTALL_SUFFIX)
 	ln -f -s $(T)-$(XEN_FULLVERSION)$(Z) $(D)$(BOOT_DIR)/$(T)$(Z)
 	[ -d "$(D)$(DEBUG_DIR)" ] || $(INSTALL_DIR) $(D)$(DEBUG_DIR)
 	$(INSTALL_DATA) $(TARGET)-syms $(D)$(DEBUG_DIR)/$(T)-syms-$(XEN_FULLVERSION)
+	$(INSTALL_DATA) $(TARGET)-syms.map $(D)$(DEBUG_DIR)/$(T)-syms-$(XEN_FULLVERSION).map
 	$(INSTALL_DATA) $(KCONFIG_CONFIG) $(D)$(BOOT_DIR)/$(T)-$(XEN_FULLVERSION).config
 	if [ -r $(TARGET).efi -a -n '$(EFI_DIR)' ]; then \
 		[ -d $(D)$(EFI_DIR) ] || $(INSTALL_DIR) $(D)$(EFI_DIR); \
@@ -91,6 +92,7 @@ _uninstall:
 	rm -f $(D)$(BOOT_DIR)/$(T)-$(XEN_VERSION)$(Z)
 	rm -f $(D)$(BOOT_DIR)/$(T)$(Z)
 	rm -f $(D)$(DEBUG_DIR)/$(T)-syms-$(XEN_FULLVERSION)
+	rm -f $(D)$(DEBUG_DIR)/$(T)-syms-$(XEN_FULLVERSION).map
 	rm -f $(D)$(EFI_DIR)/$(T)-$(XEN_FULLVERSION).efi
 	rm -f $(D)$(EFI_DIR)/$(T)-$(XEN_VERSION).$(XEN_SUBVERSION).efi
 	rm -f $(D)$(EFI_DIR)/$(T)-$(XEN_VERSION).efi
@@ -112,7 +114,7 @@ _clean: delete-unfresh-files
 	$(MAKE) -f $(BASEDIR)/Rules.mk -C arch/$(TARGET_ARCH) clean
 	$(MAKE) -f $(BASEDIR)/tools/kconfig/Makefile.kconfig ARCH=$(ARCH) SRCARCH=$(SRCARCH) clean
 	find . \( -name "*.o" -o -name ".*.d" \) -exec rm -f {} \;
-	rm -f include/asm $(TARGET) $(TARGET).gz $(TARGET).efi $(TARGET)-syms *~ core
+	rm -f include/asm $(TARGET) $(TARGET).gz $(TARGET).efi $(TARGET)-syms $(TARGET)-syms.map *~ core
 	rm -f include/asm-*/asm-offsets.h
 	rm -f .banner
 
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index b264ed4..cb138d4 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -97,6 +97,9 @@ $(TARGET)-syms: prelink.o xen.lds $(BASEDIR)/common/symbols-dummy.o
 	    $(@D)/.$(@F).0.o -o $(@D)/.$(@F).1
 	$(NM) -pa --format=sysv $(@D)/.$(@F).1 \
 		| $(BASEDIR)/tools/symbols --sysv --sort >$(@D)/.$(@F).1.S
+	$(NM) -pa --format=sysv $(@D)/.$(@F).1 \
+		| $(BASEDIR)/tools/symbols --xensyms --sysv --sort \
+		>$(@D)/$(@F).map
 	$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
 	$(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
 	    $(@D)/.$(@F).1.o -o $@
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index b18f033..10a7022 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -135,6 +135,10 @@ $(TARGET)-syms: prelink.o xen.lds $(BASEDIR)/common/symbols-dummy.o
 	$(NM) -pa --format=sysv $(@D)/.$(@F).1 \
 		| $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort --warn-dup \
 		>$(@D)/.$(@F).1.S
+	$(NM) -pa --format=sysv $(@D)/.$(@F).1 \
+		| $(BASEDIR)/tools/symbols --xensyms --sysv --sort --warn-dup \
+		>$(@D)/$(@F).map
+	$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
 	$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
 	$(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
 	    $(@D)/.$(@F).1.o -o $@
diff --git a/xen/tools/symbols.c b/xen/tools/symbols.c
index 941fbe7..1a55853 100644
--- a/xen/tools/symbols.c
+++ b/xen/tools/symbols.c
@@ -52,6 +52,7 @@ static unsigned int table_size, table_cnt;
 static unsigned long long _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;
 static int all_symbols = 0;
 static int sort_by_name = 0;
+static int skip_asm = 0;
 static char symbol_prefix_char = '\0';
 static enum { fmt_bsd, fmt_sysv } input_format;
 static int compare_name(const void *p1, const void *p2);
@@ -181,7 +182,7 @@ static int read_symbol(FILE *in, struct sym_entry *s)
 		*sym++ = '#';
 	}
 	strcpy(sym, str);
-	if (sort_by_name) {
+	if (sort_by_name || skip_asm) {
 		s->orig_symbol = strdup(SYMBOL_NAME(s));
 		s->type = stype; /* As s->sym[0] ends mangled. */
 	}
@@ -307,6 +308,12 @@ static void write_src(void)
 	unsigned int *markers;
 	char buf[KSYM_NAME_LEN+1];
 
+	if (skip_asm) {
+		for (i = 0; i < table_cnt; i++)
+			printf("%#llx %c %s\n", table[i].addr, table[i].type, table[i].orig_symbol);
+
+		return;
+	}
 	printf("#include <xen/config.h>\n");
 	printf("#include <asm/types.h>\n");
 	printf("#if BITS_PER_LONG == 64 && !defined(SYMBOLS_ORIGIN)\n");
@@ -609,6 +616,8 @@ int main(int argc, char **argv)
 				sort_by_name = 1;
 			else if (strcmp(argv[i], "--warn-dup") == 0)
 				warn_dup = true;
+			else if (strcmp(argv[i], "--xensyms") == 0)
+				skip_asm = true;
 			else
 				usage();
 		}
-- 
2.5.5


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Re: [PATCH] symbols: Generate an xen-sym.map file similar to Linux's

[Jan Beulich]

>>> On 18.07.16 at 20:39, <konrad.wilk@oracle.com> wrote:

First of all, for the title: Is what you do really similar to Linux? Iirc
there System.map is simply output from nm.

> Also note that during runtime one can do:
> ffff82d080104920 t domain.c#do_domain_pause

I can't seem to make sense of this.

> @@ -307,6 +308,12 @@ static void write_src(void)
>  	unsigned int *markers;
>  	char buf[KSYM_NAME_LEN+1];
>  
> +	if (skip_asm) {

Especially with its use here I don't think this is a good name. How
about using something that positively identifies what is being asked
for, like "map_only" or "dump_symbols"?

> +		for (i = 0; i < table_cnt; i++)
> +			printf("%#llx %c %s\n", table[i].addr, table[i].type, table[i].orig_symbol);

Long line.

Jan


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