tracing/probes: Implement 'stack' fetch method for uprobes

Use separate method to fetch from stack.  Move existing functions to
trace_kprobe.c and make them static.  Also add new stack fetch
implementation for uprobes.

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>

1 files changed, 15 insertions, 0 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index fe3f00c381c0..389f9e4744c8 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -88,6 +88,21 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
                                 struct pt_regs *regs);
 
+/*
+ * Kprobes-specific fetch functions
+ */
+#define DEFINE_FETCH_stack(type)                                        \
+static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
+                                          void *offset, void *dest)     \
+{                                                                       \
+        *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
+                                (unsigned int)((unsigned long)offset)); \
+}
+DEFINE_BASIC_FETCH_FUNCS(stack)
+/* No string on the stack entry */
+#define fetch_stack_string      NULL
+#define fetch_stack_string_size NULL
+
 /* Fetch type information table */
 const struct fetch_type kprobes_fetch_type_table[] = {
         /* Special types */