tracing/probes: Have process_fetch_insn() take a void * instead of pt_regs

In preparation to allow event probes to use the process_fetch_insn()
callback in trace_probe_tmpl.h, change the data passed to it from a
pointer to pt_regs, as the event probe will not be using regs, and make it
a void pointer instead.

Update the process_fetch_insn() callers for kprobe and uprobe events to
have the regs defined in the function and just typecast the void pointer
parameter.

Link: https://lkml.kernel.org/r/20210819041842.291622924@goodmis.orgAcked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_kprobe.c

@@ -1325,9 +1325,10 @@ probe_mem_read(void *dest, void *src, size_t size)
 
 /* Note that we don't verify it, since the code does not come from user space */
 static int
-process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
+process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
 		   void *base)
 {
+	struct pt_regs *regs = rec;
 	unsigned long val;
 
 retry:

kernel/trace/trace_probe_tmpl.h

@@ -54,7 +54,7 @@ fetch_apply_bitfield(struct fetch_insn *code, void *buf)
  * If dest is NULL, don't store result and return required dynamic data size.
  */
 static int
-process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs,
+process_fetch_insn(struct fetch_insn *code, void *rec,
 		   void *dest, void *base);
 static nokprobe_inline int fetch_store_strlen(unsigned long addr);
 static nokprobe_inline int
@@ -188,7 +188,7 @@ __get_data_size(struct trace_probe *tp, struct pt_regs *regs)
 
 /* Store the value of each argument */
 static nokprobe_inline void
-store_trace_args(void *data, struct trace_probe *tp, struct pt_regs *regs,
+store_trace_args(void *data, struct trace_probe *tp, void *rec,
 		 int header_size, int maxlen)
 {
 	struct probe_arg *arg;
@@ -203,7 +203,7 @@ store_trace_args(void *data, struct trace_probe *tp, struct pt_regs *regs,
 		/* Point the dynamic data area if needed */
 		if (unlikely(arg->dynamic))
 			*dl = make_data_loc(maxlen, dyndata - base);
-		ret = process_fetch_insn(arg->code, regs, dl, base);
+		ret = process_fetch_insn(arg->code, rec, dl, base);
 		if (unlikely(ret < 0 && arg->dynamic)) {
 			*dl = make_data_loc(0, dyndata - base);
 		} else {

kernel/trace/trace_uprobe.c

@@ -213,9 +213,10 @@ static unsigned long translate_user_vaddr(unsigned long file_offset)
 
 /* Note that we don't verify it, since the code does not come from user space */
 static int
-process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
+process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
 		   void *base)
 {
+	struct pt_regs *regs = rec;
 	unsigned long val;
 
 	/* 1st stage: get value from context */