On Fri 2020-11-13 12:18:12, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rost...@goodmis.org>
>
> 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.
>
> diff --git a/arch/csky/kernel/probes/ftrace.c
> b/arch/csky/kernel/probes/ftrace.c
> index f30b179924ef..ae2b1c7b3b5c 100644
> --- a/arch/csky/kernel/probes/ftrace.c
> +++ b/arch/csky/kernel/probes/ftrace.c
> @@ -11,17 +11,19 @@ int arch_check_ftrace_location(struct kprobe *p)
>
> /* Ftrace callback handler for kprobes -- called under preepmt disabed */
> void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
> - struct ftrace_ops *ops, struct pt_regs *regs)
> + struct ftrace_ops *ops, struct ftrace_regs *fregs)
> {
> int bit;
> bool lr_saver = false;
> struct kprobe *p;
> struct kprobe_ctlblk *kcb;
> + struct pt_regs *regs;
>
> bit = ftrace_test_recursion_trylock(ip, parent_ip);
> if (bit < 0)
> return;
>
> + regs = ftrace_get_regs(fregs);
Should we check for NULL here?
Same in all callers?
> preempt_disable_notrace();
> p = get_kprobe((kprobe_opcode_t *)ip);
> if (!p) {
Otherwise, the patch is pretty strightforard and looks good to me.
Best Regards,
Petr
