tracing/probes: Move 'symbol' fetch method to kprobes

Move existing functions to trace_kprobe.c and add NULL entries to the
uprobes fetch type table.  I don't make them static since some generic
routines like update/free_XXX_fetch_param() require pointers to the
functions.

Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

4 files changed, 91 insertions, 59 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 389f9e4744c8..d2a4fd2fd8c1 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -88,6 +88,51 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
                                 struct pt_regs *regs);
 
+/* Memory fetching by symbol */
+struct symbol_cache {
+        char            *symbol;
+        long            offset;
+        unsigned long   addr;
+};
+
+unsigned long update_symbol_cache(struct symbol_cache *sc)
+{
+        sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
+
+        if (sc->addr)
+                sc->addr += sc->offset;
+
+        return sc->addr;
+}
+
+void free_symbol_cache(struct symbol_cache *sc)
+{
+        kfree(sc->symbol);
+        kfree(sc);
+}
+
+struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
+{
+        struct symbol_cache *sc;
+
+        if (!sym || strlen(sym) == 0)
+                return NULL;
+
+        sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
+        if (!sc)
+                return NULL;
+
+        sc->symbol = kstrdup(sym, GFP_KERNEL);
+        if (!sc->symbol) {
+                kfree(sc);
+                return NULL;
+        }
+        sc->offset = offset;
+        update_symbol_cache(sc);
+
+        return sc;
+}
+
 /*
  * Kprobes-specific fetch functions
  */
@@ -103,6 +148,20 @@ DEFINE_BASIC_FETCH_FUNCS(stack)
 #define fetch_stack_string      NULL
 #define fetch_stack_string_size NULL
 
+#define DEFINE_FETCH_symbol(type)                                       \
+__kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,      \
+                                          void *data, void *dest)       \
+{                                                                       \
+        struct symbol_cache *sc = data;                                 \
+        if (sc->addr)                                                   \
+                fetch_memory_##type(regs, (void *)sc->addr, dest);      \
+        else                                                            \
+                *(type *)dest = 0;                                      \
+}
+DEFINE_BASIC_FETCH_FUNCS(symbol)
+DEFINE_FETCH_symbol(string)
+DEFINE_FETCH_symbol(string_size)
+
 /* Fetch type information table */
 const struct fetch_type kprobes_fetch_type_table[] = {
         /* Special types */
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 77aa7d18821e..a31ad478b7f6 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -180,65 +180,6 @@ __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
                 *(u32 *)dest = len;
 }
 
-/* Memory fetching by symbol */
-struct symbol_cache {
-        char            *symbol;
-        long            offset;
-        unsigned long   addr;
-};
-
-static unsigned long update_symbol_cache(struct symbol_cache *sc)
-{
-        sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
-
-        if (sc->addr)
-                sc->addr += sc->offset;
-
-        return sc->addr;
-}
-
-static void free_symbol_cache(struct symbol_cache *sc)
-{
-        kfree(sc->symbol);
-        kfree(sc);
-}
-
-static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
-{
-        struct symbol_cache *sc;
-
-        if (!sym || strlen(sym) == 0)
-                return NULL;
-
-        sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
-        if (!sc)
-                return NULL;
-
-        sc->symbol = kstrdup(sym, GFP_KERNEL);
-        if (!sc->symbol) {
-                kfree(sc);
-                return NULL;
-        }
-        sc->offset = offset;
-        update_symbol_cache(sc);
-
-        return sc;
-}
-
-#define DEFINE_FETCH_symbol(type)                                       \
-__kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,      \
-                                          void *data, void *dest)       \
-{                                                                       \
-        struct symbol_cache *sc = data;                                 \
-        if (sc->addr)                                                   \
-                fetch_memory_##type(regs, (void *)sc->addr, dest);      \
-        else                                                            \
-                *(type *)dest = 0;                                      \
-}
-DEFINE_BASIC_FETCH_FUNCS(symbol)
-DEFINE_FETCH_symbol(string)
-DEFINE_FETCH_symbol(string_size)
-
 /* Dereference memory access function */
 struct deref_fetch_param {
         struct fetch_param      orig;
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 8211dd674ab6..8be84550ceb3 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -239,6 +239,30 @@ ASSIGN_FETCH_FUNC(bitfield, ftype),			\
 extern __weak const struct fetch_type kprobes_fetch_type_table[];
 extern __weak const struct fetch_type uprobes_fetch_type_table[];
 
+#ifdef CONFIG_KPROBE_EVENT
+struct symbol_cache;
+unsigned long update_symbol_cache(struct symbol_cache *sc);
+void free_symbol_cache(struct symbol_cache *sc);
+struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
+#else
+struct symbol_cache {
+};
+static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
+{
+        return 0;
+}
+
+static inline void __used free_symbol_cache(struct symbol_cache *sc)
+{
+}
+
+static inline struct symbol_cache * __used
+alloc_symbol_cache(const char *sym, long offset)
+{
+        return NULL;
+}
+#endif /* CONFIG_KPROBE_EVENT */
+
 struct probe_arg {
         struct fetch_param      fetch;
         struct fetch_param      fetch_size;
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 5395d37e5e72..24ef6a33d93f 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -115,6 +115,14 @@ DEFINE_BASIC_FETCH_FUNCS(stack)
 #define fetch_stack_string_size NULL
 
 
+/* uprobes do not support symbol fetch methods */
+#define fetch_symbol_u8                 NULL
+#define fetch_symbol_u16                NULL
+#define fetch_symbol_u32                NULL
+#define fetch_symbol_u64                NULL
+#define fetch_symbol_string             NULL
+#define fetch_symbol_string_size        NULL
+
 /* Fetch type information table */
 const struct fetch_type uprobes_fetch_type_table[] = {
         /* Special types */