ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs

In preparation to have arguments of a function passed to callbacks attached to functions as default, change the default callback prototype to receive a struct ftrace_regs as the forth parameter instead of a pt_regs. For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they will now need to get the pt_regs via a ftrace_get_regs() helper call. If this is called by a callback that their ftrace_ops did not have a FL_SAVE_REGS flag set, it that helper function will return NULL. This will allow the ftrace_regs to hold enough just to get the parameters and stack pointer, but without the worry that callbacks may have a pt_regs that is not completely filled.

Steven Rostedt (VMware) committed 6 years ago

Commit d19ad071 parent 58954b318 files · +71 −45Browse files

Showing the changes to kernel/livepatch/patch.c (1 of 18 files). Show all

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kernel/livepatch/patch.c+2−1

@@ -40,8 +40,9 @@ struct klp_ops klp_find_ops(void old_func) · 39 unmodified lines
40	40	static void notrace klp_ftrace_handler(unsigned long ip,
41	41	unsigned long parent_ip,
42	42	struct ftrace_ops *fops,
43		− struct pt_regs *regs)
	43	+ struct ftrace_regs *fregs)
44	44	{
	45	+ struct pt_regs *regs = ftrace_get_regs(fregs);
45	46	struct klp_ops *ops;
46	47	struct klp_func *func;
47	48	int patch_state;