[PATCH] depmod: add support for symbol namespaces

[Matthias Maennich <maennich@google.com>]

Linux v5.4 introduces symbol namespaces [1], [2].
They appear in the ksymtab as entries with the scheme

   __ksymtab_NAMESPACE.symbol_name

In order to support these at depmod time, strip out namespaces when
loading the System.map.

[1] https://lore.kernel.org/lkml/20190906103235.197072-1-maennich@google.com/
[2] https://lore.kernel.org/lkml/20191003075826.7478-1-yamada.masahiro@socionext.com/

Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
Cc: Martijn Coenen <maco@android.com>
Cc: linux-modules@vger.kernel.org
Signed-off-by: Matthias Maennich <maennich@google.com>
---
 tools/depmod.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/depmod.c b/tools/depmod.c
index 391afe9fe0a0..723f4c7be88c 100644
--- a/tools/depmod.c
+++ b/tools/depmod.c
@@ -2576,7 +2576,7 @@ static int depmod_load_system_map(struct depmod *depmod, const char *filename)
 
 	/* eg. c0294200 R __ksymtab_devfs_alloc_devnum */
 	while (fgets(line, sizeof(line), fp) != NULL) {
-		char *p, *end;
+		char *p, *end, *delim;
 
 		linenum++;
 
@@ -2601,7 +2601,13 @@ static int depmod_load_system_map(struct depmod *depmod, const char *filename)
 		if (end != NULL)
 			*end = '\0';
 
-		depmod_symbol_add(depmod, p + ksymstr_len, true, 0, NULL);
+		/* Support for namespaced symbols: __ksymtab_NAMESPACE.symbol */
+		delim = strrchr(p + ksymstr_len, '.');
+		if (delim != NULL)
+			depmod_symbol_add(depmod, delim + 1, true, 0, NULL);
+		else
+			depmod_symbol_add(depmod, p + ksymstr_len, true, 0, NULL);
+
 		continue;
 
 	invalid_syntax:
-- 
2.23.0.581.g78d2f28ef7-goog