Linux Kernel Markers

The marker activation functions sits in kernel/marker.c.  A hash table is used
to keep track of the registered probes and armed markers, so the markers
within a newly loaded module that should be active can be activated at module
load time.

marker_query has been removed. marker_get_first, marker_get_next and
marker_release should be used as iterators on the markers.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Mike Mason <mmlnx@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 7734595bd329..3202c9950073 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1673,6 +1673,8 @@ static struct module *load_module(void __user *umod,
         unsigned int unusedcrcindex;
         unsigned int unusedgplindex;
         unsigned int unusedgplcrcindex;
+        unsigned int markersindex;
+        unsigned int markersstringsindex;
         struct module *mod;
         long err = 0;
         void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
@@ -1939,6 +1941,9 @@ static struct module *load_module(void __user *umod,
                 add_taint_module(mod, TAINT_FORCED_MODULE);
         }
 #endif
+        markersindex = find_sec(hdr, sechdrs, secstrings, "__markers");
+        markersstringsindex = find_sec(hdr, sechdrs, secstrings,
+                                        "__markers_strings");
 
         /* Now do relocations. */
         for (i = 1; i < hdr->e_shnum; i++) {
@@ -1961,6 +1966,11 @@ static struct module *load_module(void __user *umod,
                 if (err < 0)
                         goto cleanup;
         }
+#ifdef CONFIG_MARKERS
+        mod->markers = (void *)sechdrs[markersindex].sh_addr;
+        mod->num_markers =
+                sechdrs[markersindex].sh_size / sizeof(*mod->markers);
+#endif
 
         /* Find duplicate symbols */
         err = verify_export_symbols(mod);
@@ -1979,6 +1989,11 @@ static struct module *load_module(void __user *umod,
 
         add_kallsyms(mod, sechdrs, symindex, strindex, secstrings);
 
+#ifdef CONFIG_MARKERS
+        if (!mod->taints)
+                marker_update_probe_range(mod->markers,
+                        mod->markers + mod->num_markers, NULL, NULL);
+#endif
         err = module_finalize(hdr, sechdrs, mod);
         if (err < 0)
                 goto cleanup;
@@ -2570,3 +2585,18 @@ EXPORT_SYMBOL(module_remove_driver);
 void struct_module(struct module *mod) { return; }
 EXPORT_SYMBOL(struct_module);
 #endif
+
+#ifdef CONFIG_MARKERS
+void module_update_markers(struct module *probe_module, int *refcount)
+{
+        struct module *mod;
+
+        mutex_lock(&module_mutex);
+        list_for_each_entry(mod, &modules, list)
+                if (!mod->taints)
+                        marker_update_probe_range(mod->markers,
+                                mod->markers + mod->num_markers,
+                                probe_module, refcount);
+        mutex_unlock(&module_mutex);
+}
+#endif