[Xen-devel] [PATCH v3 8/9] symbols: Generate an xen-sym.map

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

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 in Xen . 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.

Note that during runtime one can do:
[root@localhost xen]# cat /proc/xen/xensyms |grep do_domain_pause
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@xxxxxxxxxx>
---
Cc: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>

v1: First submission
v2: Do not use intermediary object file but the final one
    Fix comment to have the example from /proc/xen/xensyms. Using '#'
    at start of line is a BAD IDEA.
---
 .gitignore            |  1 +
 xen/Makefile          |  4 +++-
 xen/arch/arm/Makefile |  3 +++
 xen/arch/x86/Makefile |  4 ++++
 xen/tools/symbols.c   | 12 +++++++++++-
 5 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/.gitignore b/.gitignore
index d193820..44cc7bf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -287,6 +287,7 @@ 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 76b60bc..4427771 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 23aaf52..0a96713 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -102,6 +102,9 @@ $(TARGET)-syms: prelink.o xen.lds 
$(BASEDIR)/common/symbols-dummy.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 $@
+       $(NM) -pa --format=sysv $(@D)/$(@F) \
+               | $(BASEDIR)/tools/symbols --xensyms --sysv --sort \
+               >$(@D)/$(@F).map
        rm -f $(@D)/.$(@F).[0-9]*
 
 asm-offsets.s: $(TARGET_SUBARCH)/asm-offsets.c
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index b18f033..d87ecd8 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -136,8 +136,12 @@ $(TARGET)-syms: prelink.o xen.lds 
$(BASEDIR)/common/symbols-dummy.o
                | $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort 
--warn-dup \
                >$(@D)/.$(@F).1.S
        $(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 $@
+       $(NM) -pa --format=sysv $(@D)/$(@F) \
+               | $(BASEDIR)/tools/symbols --xensyms --sysv --sort --warn-dup \
+               >$(@D)/$(@F).map
        rm -f $(@D)/.$(@F).[0-9]*
 
 note.o: $(TARGET)-syms
diff --git a/xen/tools/symbols.c b/xen/tools/symbols.c
index 941fbe7..8c5842d 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 map_only = 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 || map_only) {
                s->orig_symbol = strdup(SYMBOL_NAME(s));
                s->type = stype; /* As s->sym[0] ends mangled. */
        }
@@ -307,6 +308,13 @@ static void write_src(void)
        unsigned int *markers;
        char buf[KSYM_NAME_LEN+1];
 
+       if (map_only) {
+               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 +617,8 @@ 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)
+                               map_only = true;
                        else
                                usage();
                }
-- 
2.4.11


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